tag:theconversation.com,2011:/global/topics/water-security-3542/articlesWater security – The Conversation2024-01-30T13:36:20Ztag:theconversation.com,2011:article/2222492024-01-30T13:36:20Z2024-01-30T13:36:20ZWhat is an atmospheric river? With flooding and mudslides in California, a hydrologist explains the good and bad of these storms and how they’re changing<figure><img src="https://images.theconversation.com/files/572509/original/file-20240131-15-zr0n4c.jpg?ixlib=rb-1.1.0&rect=164%2C18%2C2084%2C1425&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A satellite image shows a powerful atmospheric river hitting the U.S. West Coast on Jan. 31, 2024.</span> <span class="attribution"><a class="source" href="https://cdn.star.nesdis.noaa.gov/GOES18/ABI/CONUS/GEOCOLOR/20240311721_GOES18-ABI-CONUS-GEOCOLOR-2500x1500.jpg">NOAA GOES</a></span></figcaption></figure><p><em>Millions of Californians were <a href="https://www.nbcnews.com/news/weather/live-blog/potentially-life-threatening-storm-system-begins-pounding-california-l-rcna137204">under flood alerts</a> as a <a href="https://cw3e.ucsd.edu/cw3e-ar-update-2-february-2024-outlook/">powerful atmospheric river</a> brought heavy rain to the West Coast in early February 2024. Los Angeles saw <a href="https://images.theconversation.com/files/573527/original/file-20240205-19-ss87hh.png">one of its wettest days on record</a> with over 4 inches of rain on Feb. 4. Other communities were hit by more than 12 inches of rain and reported <a href="https://ktla.com/news/local-news/live-updates-worst-of-storm-moves-into-southern-california/">widespread flooding</a>. <a href="https://www.youtube.com/watch?v=qCEX7nwXwaI">Debris and mudslides</a> shut down <a href="https://twitter.com/CaltransDist7/status/1754525910676697306">sections of highways</a> and <a href="https://laist.com/news/climate-environment/major-storm-heading-into-socal-sunday">roads into Malibu</a>.</em> </p>
<p><em>It was the <a href="https://cw3e.ucsd.edu/cw3e-ar-update-29-january-2024-outlook/">latest in a series</a> of atmospheric rivers to bring extreme rainfall to the West Coast. While these storms are dreaded for the damage they can cause, they are also essential to the region’s water supply, particularly in California, as <a href="https://scholar.google.com/citations?user=aTFYE98AAAAJ&hl=en">Qian Cao</a>, a hydrologist at the University of California, San Diego, explains.</em></p>
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<h2>What are atmospheric rivers?</h2>
<p>An atmospheric river is a narrow corridor or filament of concentrated water vapor transported in the atmosphere. It’s like a river in the sky that can be <a href="https://pubs.usgs.gov/publication/70036359">1,000 miles long</a>. On average, atmospheric rivers have about <a href="https://www.jpl.nasa.gov/news/ranking-atmospheric-rivers-new-study-finds-world-of-potential">twice the regular flow of the Amazon River</a>.</p>
<p>When atmospheric rivers run up against mountains or run into local atmospheric dynamics and are forced to ascend, the moisture they carry cools and condenses, so they can produce intense rainfall or snowfall.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/w3rtYM0HtIM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A satellite view of atmospheric rivers.</span></figcaption>
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<p>Atmospheric rivers occur all over the world, most commonly in the mid-latitudes. They form when large-scale weather patterns align to create narrow channels, or filaments, of intense moisture transport. These start over warm water, typically tropical oceans, and are guided toward the coast by low-level jet streams ahead of cold fronts of extratropical cyclones.</p>
<p>Along the U.S. West Coast, the Pacific Ocean serves as the reservoir of moisture for the storm, and the mountain ranges act as barriers, which is why the western sides of the coastal ranges and Sierra Nevada see so much rain and snow.</p>
<h2>Why are back-to-back atmospheric rivers a high flood risk?</h2>
<p>Consecutive atmospheric rivers, known as AR families, <a href="https://doi.org/10.1175/JHM-D-18-0217.1">can cause significant flooding</a>.</p>
<p>The first heavy downpours saturate the ground. As <a href="https://doi.org/10.1126/sciadv.abq0995">consecutive storms arrive</a>, their precipitation falls on soil that can’t absorb more water. That contributes to more runoff. Rivers and streams fill up. In the meantime, there may be snowmelt due to warm temperatures, further adding to the runoff and flood risk.</p>
<p>California experienced a <a href="https://theconversation.com/epic-snow-from-all-those-atmospheric-rivers-in-the-west-is-starting-to-melt-and-the-flood-danger-is-rising-203874">historic run</a> of nine consecutive atmospheric rivers in the span of three weeks in December 2022 and January 2023. The storms <a href="https://theconversation.com/is-the-western-drought-finally-ending-that-depends-on-where-you-look-201156">helped bring most reservoirs back</a> to historical averages in 2023 after several drought years, but they also produced damaging <a href="https://www.cbsnews.com/news/california-flooding-landslides-as-atmospheric-river-power-outage">floods and debris flows</a>.</p>
<figure class="align-center ">
<img alt="An animation shows filaments of water heading toward the coast." src="https://images.theconversation.com/files/572019/original/file-20240129-21-24vhfq.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572019/original/file-20240129-21-24vhfq.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=282&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572019/original/file-20240129-21-24vhfq.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=282&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572019/original/file-20240129-21-24vhfq.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=282&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572019/original/file-20240129-21-24vhfq.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=354&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572019/original/file-20240129-21-24vhfq.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=354&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572019/original/file-20240129-21-24vhfq.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=354&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Atmospheric rivers forming over the tropical Pacific Ocean head for the U.S. West Coast.</span>
<span class="attribution"><a class="source" href="https://www.nps.gov/articles/images/AR-animation.gif">NOAA</a></span>
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<p>The cause of AR families is an active area of research. Compared with single atmospheric river events, AR families tend to be associated with lower atmospheric pressure heights across the North Pacific, higher pressure heights over the subtropics, a stronger and more zonally elongated jet stream and warmer tropical air temperatures. </p>
<p>Large-scale weather patterns and climate phenomena such as the <a href="https://www.climate.gov/news-features/blogs/enso/what-mjo-and-why-do-we-care">Madden-Julian Oscillation</a>, or MJO, <a href="https://doi.org/10.1175/BAMS-D-22-0208.1">also play an important role</a> in the generation of AR families. An active MJO shift occurred during the early 2023 events, tilting the odds toward increased atmospheric river activity over California.</p>
<figure class="align-center ">
<img alt="A truck drives through muddy streets that fill a large section of town. People stand on one small patch of pavement not flooded." src="https://images.theconversation.com/files/572098/original/file-20240130-21-dc67s7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572098/original/file-20240130-21-dc67s7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=336&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572098/original/file-20240130-21-dc67s7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=336&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572098/original/file-20240130-21-dc67s7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=336&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572098/original/file-20240130-21-dc67s7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572098/original/file-20240130-21-dc67s7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572098/original/file-20240130-21-dc67s7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=423&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">An aerial view shows a flooded neighborhood in the community of Pajaro in central California on March 11, 2023, after a series of atmospheric rivers.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/an-aerial-view-shows-a-flooded-neighborhood-in-the-news-photo/1248039581">Josh Edelson/AFP via Getty Images</a></span>
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</figure>
<p>A recent study by scientists at Stanford and the University of Florida found that storms within AR families <a href="https://www.science.org/doi/10.1126/sciadv.adi7905">cause three to four times more economic damage</a> when the storms arrive back to back than they would have caused by themselves.</p>
<h2>How important are atmospheric rivers to the West Coast’s water supply?</h2>
<p>I’m a research hydrologist, so I focus on hydrological impacts of atmospheric rivers. Although they can lead to flood hazards, atmospheric rivers are also essential to the Western water supply. Atmospheric rivers have been responsible for ending <a href="https://doi.org/10.1175/JHM-D-13-02.1">more than a third</a> of the region’s major droughts, including the severe California drought of 2012-16.</p>
<p>Atmospheric rivers provide an average of <a href="https://doi.org/10.1111/j.1752-1688.2011.00546.x">30% to 50% of the West Coast’s annual precipitation</a>. </p>
<p>They also contribute to the snowpack, which provides a significant portion of California’s year-round water supply. </p>
<p>In an average year, one to two extreme atmospheric rivers with snow will be the dominant contributors to the snowpack in the Sierra Nevada. Together, atmospheric rivers will <a href="https://doi.org/10.1029/2010GL044696">contribute about 30% to 40%</a> of an average season’s total snow accumulation there.</p>
<figure class="align-center ">
<img alt="A dam spillway with a full reservoir behind it." src="https://images.theconversation.com/files/572102/original/file-20240130-15-f4mjgk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572102/original/file-20240130-15-f4mjgk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=382&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572102/original/file-20240130-15-f4mjgk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=382&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572102/original/file-20240130-15-f4mjgk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=382&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572102/original/file-20240130-15-f4mjgk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=481&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572102/original/file-20240130-15-f4mjgk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=481&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572102/original/file-20240130-15-f4mjgk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=481&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">After several winter storms brought record snowfall to California’s Sierra Nevada in early 2023, Lake Oroville, California’s second-largest reservoir, was at 100% capacity. The previous year, much of the state had faced water restrictions.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/in-an-aerial-view-water-is-released-on-the-main-spillway-at-news-photo/1498829327">Justin Sullivan/Getty Images</a></span>
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<p>That’s why my colleagues at the <a href="https://cw3e.ucsd.edu/">Center for Western Weather and Water Extremes</a> at the Scripps Institution of Oceanography, part of the University of California, San Diego, work on <a href="https://doi.org/10.1175/BAMS-D-22-0208.1">improving atmospheric river forecasts and predictions</a>. Water managers need to be able to regulate reservoirs and figure out how much water they can save for the dry season while still leaving room in the reservoirs to manage flood risk from future storms.</p>
<h2>How is global warming affecting atmospheric rivers?</h2>
<p>Warmer air can <a href="https://theconversation.com/climate-change-is-intensifying-the-water-cycle-bringing-more-powerful-storms-and-flooding-heres-what-the-science-shows-187951">hold more moisture</a>. As global temperatures rise in the future, we can expect more intense atmospheric rivers, leading to an <a href="https://doi.org/10.1038/s41598-019-46169-w">increase in heavy and extreme precipitation events</a>. </p>
<p>My research also shows that more atmospheric rivers are <a href="https://doi.org/10.1175/JHM-D-19-0242.1">likely to occur concurrently during already wet conditions</a>. So, the chance of extreme flooding also increases. Another study, by scientists from the University of Washington, suggests that there will be a <a href="https://doi.org/10.1175/JHM-D-16-0200.1">seasonal shift</a> to more atmospheric rivers earlier in the rainy season.</p>
<p>There will likely also be more <a href="https://doi.org/10.1038/s41598-019-46169-w">year-to-year variability</a> in the total annual precipitation, particularly in California, as a study by my colleagues at the Center for Western Weather and Water Extremes projects.</p>
<p><em>This article was update Feb. 5, 2024, with flooding and mudslides in California.</em></p><img src="https://counter.theconversation.com/content/222249/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Qian Cao does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>These giant rivers in the sky are both destructive and essential for the Western U.S. water supply.Qian Cao, Hydrologist, Center for Western Weather and Water Extremes, University of California, San DiegoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2173522023-12-21T19:26:32Z2023-12-21T19:26:32ZIndia’s new manual for water supply will replicate past failures<iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/indias-new-manual-for-water-supply-will-replicate-past-failures" width="100%" height="400"></iframe>
<p>Water utilities in India supply residents with water for an average of <a href="https://doi.org/10.1016/j.cesys.2021.100062">only four hours per day</a>. Within cities, some neighbourhoods receive water almost all the time, while some receive <a href="https://doi.org/10.1016/j.scitotenv.2023.164393">less than half an hour per week</a>. </p>
<p>Intermittent supply of water <a href="https://doi.org/10.1002/2016WR019702">inconveniences everyone</a> and often disproportionately <a href="https://doi.org/10.1111/j.1548-1360.2011.01111.x">burdens the poorest and most vulnerable</a>. Yet intermittent water supply has been the norm <a href="https://books.google.com/books?id=e8AIAAAAQAAJ&pg=230">in India since at least 1873</a>. </p>
<p>Our research at the University of Toronto studies <a href="https://www.geography.utoronto.ca/people/directories/all-faculty/nidhi-subramanyam">the social</a> <a href="https://civmin.utoronto.ca/home/about-us/directory/professors/david-meyer/">and technical</a> causes and effects of intermittent supply in India.</p>
<h2>Perpetuating past problems</h2>
<p>Over the last few years, the Indian government <a href="https://pib.gov.in/Pressreleaseshare.aspx?PRID=1811880">has launched several</a> <a href="https://jaljeevanmission.gov.in/">initiatives to improve water supply systems</a> and reduce intermittent supply. <a href="https://doi.org/10.1021/acs.est.5b03973">Continuous water supply</a> keeps contaminants out of the pipes and lets users drink from the tap at any time.</p>
<p>In support of these new initiatives, India’s Central Public Health and Environmental Engineering Organisation <a href="https://pib.gov.in/PressReleasePage.aspx?PRID=1933379">issued a new draft of the Manual on Water Supply and Treatment</a>, its first update since 1999. </p>
<p>This manual was prepared in collaboration with the <a href="https://www.giz.de/en/html/about_giz.html">German Development Agency (GIZ</a>), and workshopped over the summer at a national conference organized by the national Ministry of Housing and Urban Affairs. The conference was attended by water supply engineers, experts, and consultants from cities across India. </p>
<p>As in the <a href="https://www.mdws.gov.in/sites/default/files/Manual_on_Water_Supply_and_Treatment_CPHEEO_MoUD_1999.pdf">previous version</a>, the 2023 manual boldly aims to establish continuous piped water supply — a goal that still has not been achieved, nearly 25 years later. This piped water is intended primarily for indoor residential use. </p>
<p>We believe that this new continuous supply target is also unlikely to be reached due to two fatal flaws that are baked into the plan from the start. While continuous supply requires both a realistic projection of water demand and a realistic plan to ensure supply exceeds demand, the government of India’s new initiatives are unrealistic on both fronts. </p>
<h2>Underestimated demand</h2>
<p>First, the manual dramatically underestimates demand, the volume of water people will try to withdraw; true demand is more than double the projections <a href="https://doi.org/10.1029/2018WR024124">in some locations</a>. For a system to operate continuously, the water withdrawn from the system must remain well below the maximum amount that can be conveyed from its source — if not, <a href="https://doi.org/10.1029/2018WR024124">the system will become intermittent</a>. </p>
<p>The new manual estimates the amount of water demand based on the projected number of users multiplied by the estimated amount that each person will withdraw in a day. However, these estimates are based upon 1999 figures for the minimum requirements for drinking, cooking, and bathing: <a href="https://www.mdws.gov.in/sites/default/files/Manual_on_Water_Supply_and_Treatment_CPHEEO_MoUD_1999.pdf">135 litres per person in most cities (150 in the country’s biggest cities</a>). </p>
<p>These estimates are reasonable projections of the minimum amount of water urbanites <em>need</em> but they grossly underestimate how much water urbanites <em>want</em>. Most users attempt to <a href="https://doi.org/10.1029/2018WR024124">withdraw the water they want</a>, rather than what they need. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/india-why-collecting-water-turns-millions-of-women-into-second-class-citizens-104698">India: why collecting water turns millions of women into second-class citizens</a>
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<p>The manual could and should be informed by data about user withdrawals from the last 24 years. The manual’s prescriptions for <a href="https://doi.org/10.2166/aqua.2022.149">calculating water demand should also consider the water wants of low-income populations in informal settlements and seasonal, interstate migrant workers</a>.</p>
<p>Second, the manual’s authors assume that water tariffs will be set high enough to limit users to withdrawing only the water they need. But demand-limiting tariffs have never been realized in India. </p>
<p>Sustaining high tariffs is particularly challenging as Indian politicians like Delhi’s Chief Minister Arvind Kejriwal may use <a href="https://timesofindia.indiatimes.com/city/delhi/24x7-water-supply-for-all-of-delhi-soon/articleshow/103878291.cms">free-water services</a> or lower tariffs as tools to earn voters’ approval.</p>
<p>Consider, for example, water tariffs in Bengaluru, which are higher than many cities. A family of four consuming the guideline-anticipated 150 litres per person per day will be billed Rupees <a href="https://bwssb.karnataka.gov.in/new-page/Prorata%20and%20Water%20Tariff/en">8.6 per day</a> (CAD$0.14/day); if they consume 30 per cent more than expected, their water tariffs increase by only Rupees 2.7 per day (less than $0.05/day). </p>
<p>Bengaluru’s elite will not limit their consumption for Rs 3 (five cents) — which is less than the price of a cup of tea! </p>
<p>If the manual’s anticipated high tariffs strategy for limiting demand fails, then users will withdraw more water than expected. When these higher-than-expected withdrawals exceed the system capacity, the system will become intermittent again. </p>
<p>Tragically, the drawbacks of intermittent supply will be magnified in these systems since the manual recommends they be designed as if continuous operation was guaranteed. </p>
<h2>Supply and demand</h2>
<p>Water system engineers in India are faced with two irreconcilable options: design water systems that meet only users’ minimum needs and accept intermittent operations, or design systems to sustain continuous supply by providing as much water as users want. </p>
<p>The long history of intermittent supply in India suggests that water systems designed using need-based demands are fragile and almost always revert to intermittent operations. </p>
<p>If India’s future systems are built according to the new manual — focused on providing users’ minimum needs — these new systems will never operate continuously. When these systems inevitably become intermittent, they will operate less fairly, less efficiently and less safely than if they had been designed to operate intermittently from the outset.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-indias-civil-society-can-shape-the-countrys-water-policy-144860">How India's civil society can shape the country's water policy</a>
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<p>The new manual’s aim for continuous supply replicates the failures of its predecessor and perpetuates decades of self-defeating water supply projects. </p>
<p>It’s a missed opportunity to design water systems that will operate well under both continuous and intermittent modes which are resilient to problematic demand projections, ineffective demand management, and water supply scarcity.</p><img src="https://counter.theconversation.com/content/217352/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Meyer receives funding from the Natural Sciences and Engineering Research Council of Canada and has previously received in-kind support from several public and private water utilities in India.</span></em></p><p class="fine-print"><em><span>Nidhi Subramanyam has previously received funding from the Social Sciences and Humanities Research Council of Canada and the International Development Research Centre in Ottawa. She has also been involved in projects supporting a private water utility in India.</span></em></p>Achieving continuous supply requires both a realistic assessment of the situation and a realistic plan to meet the goal. The Government of India’s new initiatives have neither.David Meyer, Assistant Professor in Civil and Global Engineering, University of TorontoNidhi Subramanyam, Assistant Professor of Geography and Planning, University of TorontoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2157532023-12-15T13:18:59Z2023-12-15T13:18:59ZHow to provide reliable water in a warming world – these cities are testing small-scale treatment systems and wastewater recycling<figure><img src="https://images.theconversation.com/files/564629/original/file-20231209-21-270hhg.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5615%2C3715&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Water treatment doesn't have to be one large, citywide system.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/kitchen-sink-with-running-water-royalty-free-image/168583229">Deepblue4you/E+ via Getty Images</a></span></figcaption></figure><p>A lot can go wrong in a large urban water system. Pumps malfunction. Valves break. Pipes leak. Even when the system is functioning properly, water can sit in pipes for long periods of time. Water shortages are also a <a href="https://e360.yale.edu/features/on-site-distributed-premise-graywater-blackwater-recycling">growing problem in a warming world</a>, as communities across the Southwestern U.S. and in many developing nations are discovering. </p>
<p>That’s why cities have started experimenting with small-scale alternatives – including wastewater recycling and localized water treatment strategies known as decentralized or distributed systems.</p>
<p>I <a href="https://www.ccee.iastate.edu/liugroup-human-env-research/">study large- and small-scale water systems</a>, focusing on innovative system designs that allow local use of water sources that might otherwise go to waste. As technology improves, cities are discovering something that <a href="https://www.epa.gov/small-and-rural-wastewater-systems/about-small-wastewater-systems">rural communities have long known</a>: Small-scale water treatment, <a href="https://doi.org/10.1021/acs.est.1c04708">properly engineered</a>, can be cheaper and easier to maintain than a centralized system, and it can improve water security and <a href="https://doi.org/10.1088/1748-9326/7/2/024007">even the environment</a>.</p>
<h2>Cleaning water – nature’s lessons</h2>
<p>Almost all water has value and can be cleaned and put to use. </p>
<p>Nature does a <a href="https://www.youtube.com/watch?v=ZwQeTJEeedk">great job of cleaning water naturally</a> as it flows through the ground. The soil physically filters water, and chemical and biological processes help strip away contaminants over time. </p>
<p>Those processes <a href="https://smartwatermagazine.com/news/rice-university/making-wastewater-drinkable-again">can be mimicked</a> by water treatment plants and filters that are becoming increasingly effective. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/KsVfshmK0Ak?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">An illustrated tour of how water treatment systems generally work.</span></figcaption>
</figure>
<p>Traditionally, cities have relied on <a href="https://infrastructurereportcard.org/cat-item/drinking-water-infrastructure/">centralized water systems</a> that treat freshwater from a river or aquifer at a central facility, then distribute it through a large network of pipes. But that infrastructure becomes increasingly vulnerable to disruptions as it ages. And climate change, water scarcity and population growth increase stress on the system.</p>
<p>So, some <a href="https://doi.org/10.3390/ijerph17239060">cities are experimenting</a> with what are known as distributed systems. These are small-scale water treatment, reclamation and recycling plants that are designed to collect, treat and reuse water in close proximity to both the source and the user. <a href="https://doi.org/10.3390/ijerph17239060">Some are separate operations</a>. Others are connected to the larger system in a hybrid model. </p>
<p>For example, a decentralized system might treat wastewater in an urban area and recycle it for reuse within that area by the same users, as <a href="https://www.epwater.org/about_us/newsroom/news_from_the_pipeline/new_facility_funds_help_lead_way_in_reuse">El Paso, Texas</a>, is doing. Or it could <a href="https://doi.org/10.1016/j.jenvman.2020.111639">collect storm runoff and wastewater</a> from homes and <a href="https://smartwatermagazine.com/news/orange-county-water-district/people-are-willing-get-over-yuck-factor-have-a-safe-and-reliable">redirect it specifically for irrigation or to recharge groundwater</a>, as <a href="https://www.austintexas.gov/faq/rainwater-harvesting">Austin, Texas</a>, and <a href="https://www.sfexaminer.com/archives/after-the-storm-how-san-francisco-utilizes-rainwater/article_2870a292-6576-5fb9-8eb3-caf14d853a79.html">San Francisco</a> do. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/vTNWYeTtnLM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Water recycling in Windhoek, Namibia, where freshwater is scarce.</span></figcaption>
</figure>
<p><a href="https://www.umontpellier.fr/en/articles/ces-pays-qui-recyclent-les-eaux-usees-en-eau-potable">Windhoek, Namibia</a>, a city of about 430,000 people surrounded by an arid landscape, has been treating wastewater to achieve a drinking standard and returning it to homes since 1968 for all kinds of uses, including cooking and drinking. Storm water runoff, industrial water, wastewater and even agricultural runoff <a href="https://efcnetwork.org/one-water-approach-for-improvement-in-water-resource-management/">can be treated and recycled with modern technology</a> to become drinkable. California’s State Water Resources Control Board <a href="https://calmatters.org/environment/2023/12/california-rules-turn-sewage-into-drinking-water/">approved regulations</a> in December 2023 to eventually allow water systems there to convert wastewater to drinking water, following a similar move in Colorado. </p>
<p>All of these approaches, whether connected to the main system or as separate closed systems, can reduce the community’s overall demand for freshwater from rivers or aquifers.</p>
<h2>Technology is making more water more reusable</h2>
<p>Small-scale treatment can range from advanced filters inside individual homes to treatment at tanks serving clusters of homes or commercial, industrial and agricultural facilities. </p>
<p>Often, the treated water goes to <a href="https://doi.org/10.1088/1748-9326/aabef0">non-potable uses like toilet flushing</a> or to replenish groundwater. But <a href="https://doi.org/10.1016/j.wroa.2021.100094">advances in technology</a> are making these decentralized water systems more feasible and expanding their uses.</p>
<figure class="align-center ">
<img alt="A man stands on a walkway overlooking wastewater in a small treatment facility." src="https://images.theconversation.com/files/564627/original/file-20231209-25-52ol2p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564627/original/file-20231209-25-52ol2p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=392&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564627/original/file-20231209-25-52ol2p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=392&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564627/original/file-20231209-25-52ol2p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=392&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564627/original/file-20231209-25-52ol2p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564627/original/file-20231209-25-52ol2p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564627/original/file-20231209-25-52ol2p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Murcia, Spain, an arid agriculture region, built dozens of water treatment plants to process and disinfect wastewater from the sewage system for reuse on farm fields. The plants use sand filters and ultraviolet rays. Almost all of the region’s wastewater is reused.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/responsible-for-exploitation-at-edar-water-treatment-news-photo/1258840091">Jose Jordan/STR/AFP via Getty Images</a></span>
</figcaption>
</figure>
<p><a href="https://doi.org/10.1038/s41565-018-0203-2">Membrane-based and electrochemical processes</a> have shown great potential for recovering fresh water, nutrients – which can be used for fertilizer – and energy from wastewater. These processes include reverse osmosis, which pushes water through a semipermeable membrane to remove impurities, and electrodialysis, which uses an electric field.</p>
<p>Microbial fuel cells go a step further and use the microbes present in wastewater to both produce electricity and facilitate the treatment of wastewater simultaneously. Another energy recovery method involves capturing biogas, primarily methane, from decomposing organic matter in wastewater in the absence of oxygen.</p>
<p>Unlike conventional treatment technologies, which work on a large scale, these emerging treatment processes use modular designs that can be easily scaled up or down. </p>
<p>They can also be used to create hybrid systems by supplementing large centralized systems with treated water, particularly in arid regions where water supplies are scarce.</p>
<h2>How a hybrid system might help Houston</h2>
<p>To test how a hybrid system might help avoid water shortages due to disruptions to the system, my colleagues and I created <a href="https://www.nature.com/articles/s44221-023-00166-6">a model of Houston</a>, a city with 7,000 miles of pipelines and 2.2 million residents. We simulated the impact that different types of water outages can have on that large centralized water supply and how distributed sources could help reduce the impact. </p>
<p>Overall, we found that installing hybrid systems did a better job supplying water and avoiding low flows across the city than the centralized system alone, particularly in areas where low water pressure is common.</p>
<figure class="align-center ">
<img alt="An overhead view of 6 round water treatment tanks at a large water treatment facility next to solar panels." src="https://images.theconversation.com/files/564631/original/file-20231209-19-x7y8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564631/original/file-20231209-19-x7y8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564631/original/file-20231209-19-x7y8b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564631/original/file-20231209-19-x7y8b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564631/original/file-20231209-19-x7y8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=473&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564631/original/file-20231209-19-x7y8b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=473&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564631/original/file-20231209-19-x7y8b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=473&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Large centralized water treatment plants can have thousands of miles of pipes and cause widespread problems when equipment fails. In smaller systems, there are fewer components that can go awry.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/aerial-view-solar-cells-near-a-wastewater-treatment-royalty-free-image/1423253122">Songphol Thesakit/Moment via Getty Images</a></span>
</figcaption>
</figure>
<p>The pressurized flow from reclaimed water could also limit the spread of contamination from sources such as a terrorist attack in the vicinity of the reclaimed water source. </p>
<p>That doesn’t mean new water sources are risk-free, of course. Additional sources connecting to a large water system can also introduce new potential sources of contamination, so the design of the system is important.</p>
<p>Several <a href="https://doi.org/10.1029/2022WR033758">factors determine how effective distributed water can be</a>. Population and building density, local water demand, soil characteristics, climate conditions, infrastructure and the state of existing water infrastructure all play a role. Research indicates that regions with <a href="https://doi.org/10.1021/acs.est.1c04708">high energy demands</a> for water distribution, significant local water requirements and the capacity to reuse wastewater <a href="https://doi.org/10.1029/2022WR033758">stand to gain the most</a>. </p>
<p>Notably, <a href="https://smartwatermagazine.com/news/smart-water-magazine/san-franciscos-decentralised-approach-water-recycling">San Francisco has emerged as a pioneer</a> in <a href="https://e360.yale.edu/features/on-site-distributed-premise-graywater-blackwater-recycling">extreme decentralization</a>, with initiatives extending down to the individual building level. In some buildings, water tanks, filters and treatment in the basement make water <a href="https://www.cbsnews.com/sanfrancisco/news/reuse-system-turns-wastewater-at-san-francisco-high-rise-into-clean-water-soil-energy/">reusable for activities such as flushing toilets</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/564628/original/file-20231209-17-26anzm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The rooftop of a building looks like a park, with walking paths, trees and other plants." src="https://images.theconversation.com/files/564628/original/file-20231209-17-26anzm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564628/original/file-20231209-17-26anzm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564628/original/file-20231209-17-26anzm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564628/original/file-20231209-17-26anzm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564628/original/file-20231209-17-26anzm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564628/original/file-20231209-17-26anzm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564628/original/file-20231209-17-26anzm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Salesforce Transit Center in San Francisco filters wastewater from sinks, showers, toilets and other sources for reuse.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/davidyuweb/29062452107">David Yu/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<h2>What’s standing in the way?</h2>
<p>Despite the benefits, water reuse accounts for less than 1% of total water use in the U.S. today.</p>
<p><a href="https://doi.org/10.3389/fenvs.2021.633841">Public perceptions concerning recycled water</a> are one challenge, including <a href="https://decentralizedwater.waterrf.org/documents/04-DEC-2/04-DEC-2full.pdf">enduring skepticism</a> regarding the safety, reliability and appropriate use of reclaimed water.</p>
<p>Wastewater recycled properly is considered safe to drink and <a href="https://engineering.stanford.edu/magazine/cleanest-drinking-water-recycled">may even contain less toxic risk</a> than the sources of water we already drink. However, water that is not treated to the appropriate level <a href="https://nap.nationalacademies.org/read/13303/chapter/8#103">can pose significant human health risks</a>. A <a href="https://straitsresearch.com/report/decentralized-water-treatment-market">robust business model</a> is also <a href="https://www.wateronline.com/doc/best-practices-for-decentralized-wastewater-treatment-system-upgrades-and-replacements-0001">needed to make decentralized systems</a> cost-effective, coupled with a supportive governance structure.</p>
<p>As <a href="https://www.epa.gov/infrastructure/water-infrastructure-investments">federal funds</a> pour in to revitalize America’s water infrastructure, U.S. communities have a golden opportunity to bolster their large water systems with a decentralized approach. Globally, with climate change fueling extreme storms and making water supplies less reliable in many areas, small-scale decentralized systems could provide water security and increase water access in areas that are underserved today. </p>
<p><em>This article, originally published Dec. 15, 2023, has been updated with California’s new regulation.</em></p><img src="https://counter.theconversation.com/content/215753/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lu Liu does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Water shortages are one of the greatest problems created by a warming world. A decentralized water system is a compelling counterargument to the notion that bigger is better.Lu Liu, Assistant Professor of Civil, Construction and Environmental Engineering, Iowa State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2125852023-09-06T12:26:55Z2023-09-06T12:26:55ZThe US committed to meet the UN’s Sustainable Development Goals, but like other countries, it’s struggling to make progress<figure><img src="https://images.theconversation.com/files/546246/original/file-20230904-15-tjmfsz.jpg?ixlib=rb-1.1.0&rect=229%2C467%2C3173%2C2207&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Many colonias along the Texas-Mexico border still lack basic infrastructure, including running water.</span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/TexasBorderColonias/47c19c2a66e340d49a1d534f3b6df91e/photo">AP Photo/Eric Gay</a></span></figcaption></figure><p>In a Zen parable, a man sees a horse and rider galloping by. The man asks the rider where he’s going, and the rider responds, “I don’t know. Ask the horse!”</p>
<p>It is easy to feel out of control and helpless in the face of the many problems Americans are now experiencing – <a href="https://www.kff.org/health-costs/issue-brief/americans-challenges-with-health-care-costs/">unaffordable health care</a>, <a href="https://www.census.gov/newsroom/stories/poverty-awareness-month.html">poverty</a> and <a href="https://theconversation.com/ipcc-report-climate-solutions-exist-but-humanity-has-to-break-from-the-status-quo-and-embrace-innovation-202134">climate change</a>, to name a few. These problems are made harder by the ways in which people, including elected representatives, often talk past each other.</p>
<p>Most <a href="https://www.pewresearch.org/politics/2023/06/21/inflation-health-costs-partisan-cooperation-among-the-nations-top-problems/">people want</a> a strong economy, social well-being and a healthy environment. These goals are interdependent: A strong economy isn’t possible without a society peaceful enough to support investment and well-functioning markets, or without water and air clean enough to support life and productivity. This understanding – that economic, social and environmental well-being are intertwined – is the premise of sustainable development. </p>
<p>In 2015, the United Nations General Assembly <a href="https://press.un.org/en/2015/ga11688.doc.htm">unanimously adopted</a> 17 <a href="https://www.un.org/sustainabledevelopment/blog/2015/12/sustainable-development-goals-kick-off-with-start-of-new-year">Sustainable Development Goals</a>, known as the SDGs, with 169 measurable targets to be achieved by 2030. Though not legally binding, all nations, including the U.S., agreed to pursue this agenda.</p>
<p>The world is now halfway to that 2030 deadline. Countries have made some progress, such as reducing extreme poverty and child mortality, though the COVID-19 pandemic <a href="https://www.un.org/en/desa/it%E2%80%99s-now-or-never-achieving-sdgs-hinges-effective-crises-response">set back progress</a> on many targets.</p>
<p>On Sept. 18-19, 2023, countries are reviewing global progress toward those goals during a meeting at the United Nations. It’s a good opportunity for Americans to review their own progress because, as we see it, sustainable development is fundamentally American.</p>
<h2>Environment, economy and health intertwined</h2>
<p>Though not widely recognized, sustainable development has been a core American policy since President Richard Nixon signed the <a href="https://www.energy.gov/nepa/downloads/national-environmental-policy-act-1969">National Environmental Policy Act </a> into law in 1970. The law says that Americans should “use all practicable means and measures … to create and maintain conditions under which man [sic] and nature can exist in productive harmony and fulfill the social, economic, and other requirements of present and future generations of Americans.”</p>
<p>While it is tempting in today’s sour political climate to dismiss this as wishful thinking, the U.S. has made some progress reconciling economic development with environmental protection. </p>
<p>Gross domestic product, for example, grew 196% between 1980 and 2022, while total emissions of the six most common non-greenhouse air pollutants, including lead and sulfur dioxide, fell 73%, <a href="https://www.epa.gov/air-trends/air-quality-national-summary">according to the Environmental Protection Agency</a>. </p>
<p>The 2022 Inflation Reduction Act, a major sustainable development law, is designed to further accelerate the use of renewable energy and reduce greenhouse gas emissions through tax credits and other incentives. <a href="https://www.goldmansachs.com/intelligence/pages/the-us-is-poised-for-an-energy-revolution.html">Goldman Sachs</a> estimated the law would spur about US$3 trillion in renewable energy investment. The law has <a href="https://www.reuters.com/business/energy/one-year-biden-still-needs-explain-his-signature-clean-energy-legislation-2023-08-16/">already been credited with creating</a> 170,000 new jobs and leading to more than 270 new or expanded clean energy projects. That impact further demonstrates that environmental goals can align with economic growth.</p>
<p>The 2015 Sustainable Development Goals cover a broader range of environmental, social and economic issues, and there are indicators for assessing progress on each.</p>
<h2>How is America doing?</h2>
<p><a href="https://dashboards.sdgindex.org/rankings">The U.S. ranked 39th</a> out of 166 countries in a 2023 review of national efforts to implement the Sustainable Development Goals. </p>
<p>The <a href="https://www.unsdsn.org/about-us">Sustainable Development Solutions Network</a>, which operates under the auspices of the U.N. Secretary-General, finds that America is lagging behind the targets set <a href="https://sdgs.un.org/goals">for many of the Sustainable Development Goals</a> that are critical to the nation’s defense, competitiveness and health, such as reducing obesity, increasing life expectancy at birth, protecting labor rights, reducing maternal mortality, decreasing inequality and protecting biodiversity.</p>
<p>To understand where the U.S. is falling short, we asked <a href="https://www.eli.org/sites/default/files/files-pdf/GoverningforSustainability-TOC.pdf">26 experts working on various areas of sustainable development</a> to review the nation’s progress and make recommendations for future action. The resulting 2023 book, <a href="https://www.eli.org/eli-press-books/governing-sustainability">Governing for Sustainability</a>, provides some 500 U.S.-specific recommendations for achieving the Sustainable Development Goals.</p>
<figure class="align-center ">
<img alt="A young child, looking bored, sits on a woman's lap as a nurse tests her blood pressure." src="https://images.theconversation.com/files/546248/original/file-20230904-27-721s7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546248/original/file-20230904-27-721s7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546248/original/file-20230904-27-721s7p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546248/original/file-20230904-27-721s7p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546248/original/file-20230904-27-721s7p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546248/original/file-20230904-27-721s7p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546248/original/file-20230904-27-721s7p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Residents waited in long lines for a free annual health clinic in Wise, Va., in 2017. A nonprofit operated the annual pop-up clinic for two decades until the state expanded Medicaid eligibility in 2019, which helped more residents afford local health care.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/ruby-partin-and-her-adoptive-son-timothy-huff-visit-a-free-news-photo/820902146">John Moore/Getty Images</a></span>
</figcaption>
</figure>
<p>Health and access to quality health care loom large in many of the goals. The authors in several chapters explain why the nation cannot eliminate poverty or hunger, or have a vibrant economy, gender equality or education gains, without widely available, affordable health care. Yet, the U.S. has some of the <a href="https://www.pgpf.org/blog/2023/07/why-are-americans-paying-more-for-healthcare">highest health care costs in the world</a>. Several states have <a href="https://abcnews.go.com/Health/wireStory/georgia-medicaid-program-work-requirement-off-slow-start-102389380">rejected efforts to expand eligibility</a> for federal Medicaid health insurance for low-income residents, leaving many people without care.</p>
<p>Similarly, the authors show that human health, ecological health, clean water and economic vitality <a href="https://www.eli.org/eli-press-books/governing-sustainability">all require sound climate policy</a>. A quickly warming world <a href="https://theconversation.com/8-billion-people-four-ways-climate-change-and-population-growth-combine-to-threaten-public-health-with-global-consequences-193077">poses new health risks</a>, decimates ecosystems, strains potable water supplies and reduces global economic productivity.</p>
<p>Clean and abundant water is critical to a functioning economy and a stable, diverse ecosystem, and yet some areas of the United States <a href="https://theconversation.com/supreme-court-rules-the-us-is-not-required-to-ensure-access-to-water-for-the-navajo-nation-202588">still lack clean water</a> or <a href="https://theconversation.com/youth-living-in-settlements-at-us-border-suffer-poverty-and-lack-of-health-care-103416">indoor plumbing</a>. This often occurs in communities of color and low income, and it can impede economic prosperity and development in these areas.</p>
<p>Ready access to nutritious food is also a bedrock need to support many of the Sustainable Development Goals, from poverty alleviation to education, yet far too many American children <a href="https://doi.org/10.1001%2Fjamanetworkopen.2021.5262">rely on school lunches</a> for <a href="https://www.ppic.org/blog/feeding-children-when-schools-are-closed-for-covid-19/">basic sustenance</a>.</p>
<figure class="align-center ">
<img alt="A man squints into the sun as he holds a large hose that pours water into a tank in the back of a pickup truck." src="https://images.theconversation.com/files/546249/original/file-20230904-27-t1qoyk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/546249/original/file-20230904-27-t1qoyk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/546249/original/file-20230904-27-t1qoyk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/546249/original/file-20230904-27-t1qoyk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/546249/original/file-20230904-27-t1qoyk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/546249/original/file-20230904-27-t1qoyk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/546249/original/file-20230904-27-t1qoyk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">A U.S. Army veteran fills a tank in the back of his pickup with water in Laredo, Texas, to provide water for his mother’s home. Rural residents in parts of the Southwest have to truck in clean water.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/carlos-salas-u-s-army-veteran-fills-his-water-tank-that-is-news-photo/916823510">Salwan Georges/The Washington Post via Getty Images</a></span>
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<p>The goals covering <a href="https://sdgs.un.org/goals/goal16">peace, justice, strong institutions</a> and <a href="https://sdgs.un.org/goals/goal17">partnerships</a> are necessary to achieve all of the goals. A society at war with itself and without rule of law cannot support a vibrant, diverse economy and lasting democracy. This has been shown repeatedly as some developing nations <a href="https://carnegieendowment.org/2022/10/20/understanding-and-responding-to-global-democratic-backsliding-pub-88173">backslide from democratic progress</a> and prosperity to civil war and poverty. <a href="https://www.eli.org/eli-press-books/governing-sustainability">Developed nations</a> are subject to the same forces.</p>
<h2>Taking the reins</h2>
<p>Sustainable development is emphatically not about government alone solving the nation’s problems. Businesses, universities and other organizations, as well as individuals, are essential to help the country realize its environmental, health and climate goals, fair practices and living wages. </p>
<p>The right place to “take the reins” is where you are, and with the problems or tasks in front of you – at work and at home. Figure out more sustainable ways to use water and energy, for example. Look at what our book recommends and what others are already doing to meet the Sustainable Development Goals. Seize opportunities such as saving money, and reduce risks by, for example, cutting greenhouse gas emissions. Every individual can contribute to a better future.</p><img src="https://counter.theconversation.com/content/212585/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Halfway to the SDGs’ 2030 deadline, countries have made progress, but most are struggling to meet all 17 goals. The US is no exception.Scott Schang, Director of Environmental Law and Policy Clinic; Professor of Practice, Wake Forest UniversityJohn Dernbach, Professor of Law Emeritus, Widener UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2092932023-07-19T12:22:24Z2023-07-19T12:22:24ZSolving water challenges is complex – learn how law, health, climate and Indigenous rights all intersect in developing solutions<figure><img src="https://images.theconversation.com/files/536663/original/file-20230710-27-7kilk5.jpg?ixlib=rb-1.1.0&rect=6%2C64%2C2038%2C1293&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Americans have come to expect abundant clean water, but there are many stressors on water quality and availability.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/clio1789/7578005278/in/photolist-cxDfXq-R8BLgr-PMPgBA-9cyTMV-QR4skU-6eyUbx-PRjrwu-QX7EYr-yT5M74-PMQ3KS-R5bmiK-iWdCxv-QTHQyn-2iJ2Rvv-21eLgQ-NCejiD-83hhrv-BMx5YX-c1AFu3-Bmjh8e-BMsbiK-EGz72e-2mhVwqZ-7TjMYT-6jgSAw-RTLtfw-cC3YHG-iVP9v-LksTds-MaEoR2-MhQpPr-Bmi8Ar-75tTCe-75tTDi-7SsCVE-cC4SQj-MqUfig-cChXK5-9AFPby-2kCF4ZL-2kCAWZH-MaErPB-QEQnju-5RaYCg-MaEnjV-9NyiQ7-2gjmCZn-2kCF6dN-86XPZU-21a1dr">Jessica/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p><em>In the U.S., most consumers take clean and available fresh water for granted, and water usually becomes front-page news only when there’s a crisis. And the past year has seen its share of water-related crises, whether it’s the <a href="https://theconversation.com/colorado-river-states-bought-time-with-a-3-year-water-conservation-deal-now-they-need-to-think-bigger-206386">effects of a prolonged drought in the U.S. Southwest</a> or floods that covered more <a href="https://theconversation.com/2022s-us-climate-disasters-from-storms-and-floods-to-heat-waves-and-droughts-196713">than one third of Pakistan</a> last year.</em></p>
<p><em>But seeing water problems as only environmental disasters does not capture the deeply interconnected nature of water in our society. To mark the release of the book “<a href="https://www.press.jhu.edu/books/title/33266/conversation-water">The Conversation on Water</a>,” a collection of previously published articles on water, The Conversation hosted a webinar with experts with a range of expertise and different perspectives on water issues and potential solutions.</em></p>
<p><em>The edited text and video clips below convey one or two of the key points each speaker made. The full <a href="https://www.youtube.com/watch?v=NhEyZC0xNOw&t=4s">webinar is available on YouTube</a>.</em></p>
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<figcaption><span class="caption">Indigenous scholar Rosalyn LaPier explains Native Americans’ efforts to gain legal personhood status for natural entities to protect waterways.</span></figcaption>
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<h2>Rosalyn LaPier, Professor of History, University of Illinois</h2>
<p>Native American tribes in the United States think of particular waterways – whether it’s a river, a lake, or an underground aquifer – as a part of the supernatural realm. Tribal communities make an effort to protect certain waterways because <a href="https://theconversation.com/for-native-americans-a-river-is-more-than-a-person-it-is-also-a-sacred-place-85302">it is a sacred place to them</a>, which benefits other people as well. The Taos Pueblo, for example, spent almost an entire century fighting for the Blue Lake in New Mexico because it was a sacred site. They wanted to protect not just the lake but also the watershed of the lake, which they succeeded in doing. </p>
<p>Today, tribes are using different approaches both within the federal legal system and tribal systems. One approach is to set aside water systems that they view as sacred and <a href="https://www.youtube.com/watch?v=d42L4hVJmrA">apply personhood status to them</a>. This has been done in other parts of the world and is beginning to be done in the United States as well, mostly now only within tribal communities. </p>
<p>There are different ways that <a href="https://theconversation.com/native-americans-decadeslong-struggle-for-control-over-sacred-lands-is-making-progress-189620">tribes are thinking more creatively</a>, but it’s connected back to their own religious expression. The reason they’re doing this is not necessarily to protect water from environmental degradation – it often is because of religion and religious practice. We have to distinguish between how we use water in America versus how we revere water in America. Tribes are addressing how to work within the system, because the United States does not protect sacred sites, especially Native American sacred places such as rivers, lakes or other water systems. </p>
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<strong>
Read more:
<a href="https://theconversation.com/for-native-americans-a-river-is-more-than-a-person-it-is-also-a-sacred-place-85302">For Native Americans, a river is more than a 'person,' it is also a sacred place</a>
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<figcaption><span class="caption">Water law expert Burke Griggs explains how policy around agriculture encourages overuse rather than conservation.</span></figcaption>
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<h2>Burke Griggs, Professor of Law, Washburn University</h2>
<p>We’re pumping so much groundwater out of the planet right now that it has changed the way the Earth is rotating. It is a massive problem that is not very visible but is extremely worrisome. Agriculture uses anywhere between <a href="https://www.ers.usda.gov/amber-waves/2006/november/agriculture-dominates-freshwater-use-in-the-us/">80% and 95% of the water</a> that exists in the West. Rivers are just the icing on the cake of groundwater supplies, winter snowpack and reservoir storage. </p>
<p>Farmers are not breaking the law. They have property rights to pump this water. The fundamental problem is, since the 1850s, and especially since the 1950s, we’ve granted more water rights to pump and to divert than the water systems can support. That’s a bureaucratic problem. It’s called overappropriation.</p>
<p>There’s also a problem in farm policy. Ever since the 1970s, when the agricultural secretary famously said, <a href="https://www.agweek.com/opinion/considering-the-lessons-of-earl-butz">“Get big or get out”</a> and win the cold war for agriculture, we’ve seen the size of farms increase and get bigger and bigger. In order to make money and keep property, farmers have to continually borrow to add acreage, either as owners or as tenants. That in turn encourages them to pump more water to meet their bank loans and their other financial commitments.</p>
<p>So if people are not breaking the law, farmers are not stealing water – and if these subsidy systems promote overproduction and overpumping – what can the U.S. do?</p>
<p>The first thing to do is reform the subsidy system. Instead of rewarding overproduction and making a fetish out of grain yields, we should focus on conservation. We should pay farmers to not irrigate in sensitive areas and during years they don’t need to. </p>
<p>The state law system is critical, because most water rights are state rights. Here, I think it makes sense to make water rights more flexible. Farmers will be willing to trade less water use over the long term for more flexible water use year to year. Most water rights have an annual limit, and if you allow more variability there, then I think that gets us a long way.</p>
<p>Water conservation can happen, but you’ve got to understand water reform within the context of property rights. Property is a very creative tool, and markets can be very creative tools. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/farmers-are-depleting-the-ogallala-aquifer-because-the-government-pays-them-to-do-it-145501">Farmers are depleting the Ogallala Aquifer because the government pays them to do it</a>
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<figcaption><span class="caption">Gabriel Filippelli of Indiana University explains how climate change is making it more challenging to build resilient water infrastructure.</span></figcaption>
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<h2>Gabriel Filippelli, Chancellor’s Professor of Earth Sciences and Executive Director of the Indiana University Environmental Resilience Institute</h2>
<p>In 2014, Toledo, Ohio, suffered a <a href="https://theconversation.com/climate-change-threatens-drinking-water-quality-across-the-great-lakes-131883">massive harmful algal bloom</a>, likely triggered by climate change and related runoff in that area. It occurred right over the only water intake line for the Toledo water system. That meant that they had to issue a rare warning – not only “do not drink the water,” but “do not boil the water,” because these harmful algal blooms produce a toxin that gets even worse if they’re boiled. It showed that a lot of our water systems are not particularly resilient because we built them for 1920 and not for today or tomorrow. </p>
<p>I and a lot of scholars are thinking through the challenges in water security in a lot of parts of the U.S. Around the Great Lakes in the Midwest there are these prolonged episodes of <a href="https://theconversation.com/for-a-flooded-midwest-climate-forecasts-offer-little-comfort-114140">flooding</a> and <a href="https://theconversation.com/what-is-a-flash-drought-an-earth-scientist-explains-194141">drought</a>. Flooding causes the redistribution of harmful algal blooms and pathogens like <em>E. coli</em> in waterways, which are very harmful. Of course, drought also causes its own stress on water supplies. </p>
<p>Unfortunately, a lot of water infrastructure is not built based on our understanding of water today. These massive sewer stormwater upgrades in a lot of cities are only built to hold the capacity of rainfall today, while in the Midwest extreme precipitation events are coming in fast and furious. </p>
<p>The US$2 billion <a href="https://www.in.gov/governorhistory/mitchdaniels/2980.htm">upgrade to Indianapolis’ water infrastructure</a> was built for the extreme rainfall events that we had in the year 2000. Here we are in 2023, and we already have about 15% more extreme rainfall events, and we’ll have another 15% more by 2050. </p>
<p>So rather than only relying on gray infrastructure consisting of tubes, tunnels and pipes to protect and secure our water systems and our safety, we have to also think about the role that <a href="https://theconversation.com/a-20-foot-sea-wall-wont-save-miami-how-living-structures-can-help-protect-the-coast-and-keep-the-paradise-vibe-165076">green infrastructure – nature-based solutions</a> – can play in augmenting some of those solutions. </p>
<p>We also should not be building new infrastructure based on the capacity we have today but based on the capacity we will have in the year 2050 and beyond. A lot of these very large infrastructure projects will and should last until then. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/climate-change-threatens-drinking-water-quality-across-the-great-lakes-131883">Climate change threatens drinking water quality across the Great Lakes</a>
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<figcaption><span class="caption">Andrea K. Gerlak, water policy expert at the University of Arizona, talks about the progress cities around the world are making in water availability and equity.</span></figcaption>
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<h2>Andrea Gerlak, Director at the Udall Center for Studies in Public Policy and Professor in the School of Geography, Development, and Environment at the University of Arizona</h2>
<p>I’ve studied cities around the world and in the U.S., and at the end of the day, there is no perfect city that is doing everything right. But there are little examples. Since the pandemic, we’ve seen <a href="https://theconversation.com/water-quality-in-south-africa-reports-show-what-needs-to-be-fixed-and-at-what-cost-207538">South Africa make a large investment</a> at the city scale around water access and sanitation. Singapore has been focusing on <a href="https://www.voanews.com/a/east-asia-pacific_singapore-turns-sewage-clean-drinkable-water-meeting-40-demand/6209374.html">reusing a lot of their water supply</a>. It’s been imperfect, but we’ve seen some pretty good developments made by Australia’s First Nations to achieve <a href="https://pursuit.unimelb.edu.au/articles/returning-water-rights-to-aboriginal-people">their appropriate water allocations</a> through a legal process. </p>
<p>In the U.S., Tucson has won awards for its green infrastructure and, along with Los Angeles, views stormwater as a resource. Los Angeles recently announced that in the coming decade, the majority of their drinking water will come <a href="https://www.latimes.com/california/story/2023-02-21/progress-on-l-a-stormwater-capture-program-is-slowing">from capturing stormwater</a>, treating it and using it for potable water supply. </p>
<p>Other cities have been good at recognizing equity concerns, like <a href="https://water.phila.gov/green-city/">Philadelphia</a> and <a href="https://thechisholmlegacyproject.org/policy/baltimores-water-accountability-and-equity-act/">Baltimore</a>. Municipal ordinances have been changed to make water available to people who cannot afford to pay their water bills and whose homes would have historically been repossessed as a result. </p>
<p>There are shining moments here and there, but there’s not any perfect package or perfect city.</p><img src="https://counter.theconversation.com/content/209293/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrea K. Gerlak has received funding from NOAA, the Inter-American Institute for Global Change Research, Lloyd's Register Foundation, and Morris K. Udall and Stewart L. Udall Foundation.</span></em></p><p class="fine-print"><em><span>Burke Griggs receives funding from the U.S. Department of Agriculture; U.S. Department of Commerce, Commercial Law Development Program; U.S. Department of State, Fulbright Commission. </span></em></p><p class="fine-print"><em><span>Gabriel Filippelli receives funding from the US National Science Foundation, the Environmental Protection Agency, the United States Geological Survey, the Honda Foundation, the Health and Hospital Corporation of Marion County, The American Chemical Society-Petroleum Research Fund, and DLA Piper.</span></em></p><p class="fine-print"><em><span>Rosalyn R. LaPier does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A webinar hosted by The Conversation brings together experts in law, health, policy and Indigenous affairs to explain some of the most pressing problems related to water in the US.Andrea K. Gerlak, Professor, School of Geography, Development and Environment, University of ArizonaBurke Griggs, Associate Professor of Law, Washburn UniversityGabriel Filippelli, Chancellor's Professor of Earth Sciences and Executive Director, Indiana University Environmental Resilience Institute, Indiana UniversityRosalyn R. LaPier, Professor of History, University of Illinois at Urbana-ChampaignLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2083622023-06-23T12:29:14Z2023-06-23T12:29:14Z3M offers $10.3B settlement over PFAS contamination in water systems – now, how do you destroy a ‘forever chemical’?<figure><img src="https://images.theconversation.com/files/533599/original/file-20230623-15-nsjvg7.jpg?ixlib=rb-1.1.0&rect=2494%2C1498%2C2997%2C2264&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">How long do chemicals really need to last? </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/pipetting-sample-into-multi-well-tray-royalty-free-image/482185539?phrase=chemicals&adppopup=true">Andrew Brookes via Getty Images</a></span></figcaption></figure><p>PFAS chemicals seemed like a good idea at first. As <a href="https://www.aps.org/publications/apsnews/202104/history.cfm">Teflon</a>, they made pots easier to clean starting in the 1940s. They made jackets waterproof and carpets stain-resistant. Food wrappers, firefighting foam, even makeup seemed better with perfluoroalkyl and polyfluoroalkyl substances.</p>
<p>Then tests started detecting <a href="https://static.ewg.org/reports/2020/pfas-epa-timeline/1998_3M-Alerts-EPA.pdf">PFAS in people’s blood</a>.</p>
<p>Today, PFAS are pervasive in soil, dust and drinking water around the world. Studies suggest they’re in <a href="https://doi.org/10.1289/ehp.10598">98% of Americans’ bodies</a>, where they’ve been <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7906952/">associated with health problems</a> including thyroid disease, liver damage and kidney and testicular cancer. There are now <a href="https://www.cdc.gov/niosh/topics/pfas/default.html">over 9,000 types</a> of PFAS. They’re often referred to as “forever chemicals” because the same properties that make them so useful also <a href="https://www.michigan.gov/-/media/Project/Websites/PFAS-Response/Reports/Report-2018-12-07-Science-Advisory-Board.pdf?rev=4a075fe29d794a3a942729557c4e6745">ensure they don’t break down in nature</a>.</p>
<p>Facing lawsuits over PFAS contamination, the industrial giant 3M, which has made PFAS for many uses for decades, <a href="https://www.prnewswire.com/news-releases/3m-resolves-claims-by-public-water-suppliers-supports-drinking-water-solutions-for-vast-majority-of-americans-301858581.html">announced a US$10.3 billion settlement</a> with public water suppliers on June 22, 2023, to help pay for testing and treatment. The company admits no liability in the settlement, which requires court approval. Cleanup could cost <a href="https://news.bloomberglaw.com/environment-and-energy/3m-heads-to-trial-in-existential-143-billion-pfas-litigation">many times that amount</a>.</p>
<p>But how do you capture and destroy a forever chemical?</p>
<p>Biochemist <a href="https://scholar.google.com/citations?user=fbJ7DGMAAAAJ&hl=en">A. Daniel Jones</a> and soil scientist <a href="https://scholar.google.com/citations?user=K5qNMk4AAAAJ&hl=en">Hui Li</a> work on PFAS solutions at the Michigan State University and explained the promising techniques being tested today. </p>
<h2>How do PFAS get from everyday products into water, soil and eventually humans?</h2>
<p>There are two main exposure pathways for PFAS to get into humans – drinking water and food consumption.</p>
<p>PFAS can get into soil through land application of biosolids, that is, sludge from wastewater treatment, and can they leach out from landfills. If contaminated biosolids are <a href="https://www.michigan.gov/mdard/environment/rtf/biosolids/gen/frequently-asked-biosolids-questions">applied to farm fields as fertilizer</a>, PFAS can get into water and into crops and vegetables.</p>
<p>For example, livestock can consume PFAS through the crops they eat and water they drink. There have been <a href="https://www.michigan.gov/mdard/about/media/pressreleases/2022/01/28/grostic-cattle-company-of-livingston-county-beef-sold-directly-to-consumers-may-contain-pfos">cases reported in Michigan</a>, <a href="https://www.washingtonpost.com/nation/2022/04/11/pfas-forever-chemicals-maine-farm/">Maine</a> and <a href="https://nmpoliticalreport.com/2021/12/21/dairy-farmers-facing-pfas-contamination-now-eligible-for-payment-for-their-cattle/">New Mexico</a> of elevated levels of PFAS in beef and in dairy cows. How big the potential risk is to humans is still <a href="https://www.ewg.org/news-insights/news/2022/04/ewg-forever-chemicals-may-taint-nearly-20-million-cropland-acres">largely unknown</a>. </p>
<figure class="align-center ">
<img alt="Two cows look over a wooden hay trough with a barn in the background." src="https://images.theconversation.com/files/479759/original/file-20220817-18153-uivgbk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/479759/original/file-20220817-18153-uivgbk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479759/original/file-20220817-18153-uivgbk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479759/original/file-20220817-18153-uivgbk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479759/original/file-20220817-18153-uivgbk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479759/original/file-20220817-18153-uivgbk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479759/original/file-20220817-18153-uivgbk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Cows were found with high levels of PFAS at a farm in Maine.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/cows-with-high-levels-of-pfas-on-a-farm-royalty-free-image/1178310633">Adam Glanzman/Bloomberg via Getty Images</a></span>
</figcaption>
</figure>
<p>Scientists in our research group at Michigan State University are working on materials added to soil that could prevent plants from taking up PFAS, but it would leave PFAS in the soil.</p>
<p>The problem is that these chemicals are everywhere, and there is <a href="https://www.michigan.gov/-/media/Project/Websites/PFAS-Response/Reports/Report-2018-12-07-Science-Advisory-Board.pdf?rev=4a075fe29d794a3a942729557c4e6745">no natural process</a> in water or soil effective at breaking them down. Many consumer products are loaded with PFAS, including makeup, dental floss, guitar strings and ski wax.</p>
<h2>How are remediation projects removing PFAS contamination now?</h2>
<p>Methods exist for filtering them out of water. The chemicals will stick to activated carbon, for example. But these methods are expensive for large-scale projects, and you still have to get rid of the chemicals.</p>
<p>For example, near a former military base near Sacramento, California, there is a huge activated carbon tank that takes in <a href="https://www.afcec.af.mil/News/Article-Display/Article/2530050/new-water-treatment-systems-address-pfospfoa-issues-at-former-mather-afb/">about 1,500 gallons</a> of contaminated groundwater per minute, filters it and then pumps it underground. That remediation project has cost <a href="https://www.afcec.af.mil/News/Article-Display/Article/2530050/new-water-treatment-systems-address-pfospfoa-issues-at-former-mather-afb/">over $3 million</a>, but it prevents PFAS from moving into drinking water the community uses.</p>
<p>The U.S. Environmental Protection Agency has <a href="https://www.epa.gov/newsreleases/biden-harris-administration-proposes-first-ever-national-standard-protect-communities">proposed establishing legally enforceable regulations</a> for maximum levels of six PFAS chemicals in public drinking water systems. Two of these chemicals, PFOA and PFOS, would be recognized as individual hazardous chemicals, with regulatory actions enforced when levels of either exceed 4 parts per trillion, which is substantially lower than previous guidance. </p>
<p>Filtering is just one step. Once PFAS is captured, then you have to dispose of PFAS-loaded activated carbons, and PFAS still moves around. If you bury contaminated materials in a landfill or elsewhere, PFAS will eventually leach out. That’s why finding ways to destroy it is essential.</p>
<h2>What are the most promising methods scientists have found for breaking down PFAS?</h2>
<p>The most common method of destroying PFAS is incineration, but most PFAS are remarkably resistant to being burned. That’s why they’re in firefighting foams.</p>
<p><a href="https://www.niehs.nih.gov/health/topics/agents/pfc/index.cfm">PFAS have multiple</a> fluorine atoms attached to a carbon atom, and the bond between carbon and fluorine is one of the strongest. Normally to burn something, you have to break the bond, but fluorine resists breaking off from carbon. Most PFAS will break down completely at incineration temperatures around <a href="https://www.regulations.gov/document/EPA-HQ-OLEM-2020-0527-0002">1,500 degrees Celsius</a> (2,730 degrees Fahrenheit), but it’s energy intensive and suitable incinerators are scarce.</p>
<p>There are several other experimental techniques that are promising but haven’t been scaled up to treat large amounts of the chemicals.</p>
<figure class="align-center ">
<img alt="Several pallets of bottled water sit while people prepare to put it into the trunks of SUVs picking it up." src="https://images.theconversation.com/files/533598/original/file-20230623-29-zc7t2v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/533598/original/file-20230623-29-zc7t2v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/533598/original/file-20230623-29-zc7t2v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/533598/original/file-20230623-29-zc7t2v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/533598/original/file-20230623-29-zc7t2v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/533598/original/file-20230623-29-zc7t2v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/533598/original/file-20230623-29-zc7t2v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Wayland, Mass., one of the cities that sued 3M, distributed bottled water to residents in May 2021 after elevated levels of PFAS were detected in its public water sources.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/because-of-the-elevated-levels-of-pfas-found-in-its-public-news-photo/1233087323?adppopup=true">Pat Greenhouse/The Boston Globe via Getty Images</a></span>
</figcaption>
</figure>
<p>A group at Battelle has developed <a href="https://doi.org/10.1061/(ASCE)EE.1943-7870.0001957">supercritical water oxidation</a> to destroy PFAS. High temperatures and pressures change the state of water, accelerating chemistry in a way that can destroy hazardous substances. However, scaling up remains a challenge. </p>
<p>Others are <a href="https://doi.org/10.1016/j.jhazmat.2020.124452">working with</a> <a href="https://www.af.mil/News/Article-Display/Article/2009997/air-force-tests-plasma-reactor-to-degrade-destroy-synthetic-chemical-compounds/">plasma reactors,</a> which use water, electricity and argon gas to break down PFAS. They’re fast, but also not easy to scale up. </p>
<h2>What are we likely to see in the future?</h2>
<p>A lot will depend on what we learn about where humans’ PFAS exposure is primarily coming from.</p>
<p>If the exposure is mostly from drinking water, there are more methods with potential. It’s possible it could eventually be destroyed at the household level with electro-chemical methods, but there are also potential risks that remain to be understood, such as converting common substances such as chloride into more toxic byproducts.</p>
<p>The big challenge of remediation is making sure we don’t make the problem worse by releasing other gases or creating harmful chemicals. Humans have a long history of trying to solve problems and making things worse. Refrigerators are a great example. Freon, a chlorofluorocarbon, was the solution to replace toxic and flammable ammonia in refrigerators, but then <a href="https://www.pca.state.mn.us/air/chlorofluorocarbons-cfcs-and-hydrofluorocarbons-hfcs">it caused stratospheric ozone depletion</a>. It was replaced with hydrofluorocarbons, which now <a href="https://www.ccacoalition.org/fr/slcps/hydrofluorocarbons-hfcs">contribute to climate change</a>. </p>
<p>If there’s a lesson to be learned, it’s that we need to think through the full life cycle of products. How long do we really need chemicals to last?</p>
<p><em>This is an updated version of an article originally <a href="https://theconversation.com/how-to-destroy-a-forever-chemical-scientists-are-discovering-ways-to-eliminate-pfas-but-this-growing-global-health-problem-isnt-going-away-soon-188965">published Aug. 18, 2022</a>.</em></p><img src="https://counter.theconversation.com/content/208362/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>A. Daniel Jones receives funding from the National Science Foundation, National Institutes of Health, U.S. Department of Agriculture-National Institute of Food and Agriculture, U.S. Forest Service, and the U.S. Department of Defense Strategic Environmental Research and Development Program (SERDP).</span></em></p><p class="fine-print"><em><span>Hui Li receives funding from the Environmental Protection Agency, U.S. Department of Agriculture, and National Institute of Environmental Health Sciences.</span></em></p>PFAS can be filtered, but getting rid of the chemicals is a monumental challenge. A biochemist and soil scientist explain.A. Daniel Jones, Professor of Biochemistry, Michigan State UniversityHui Li, Professor of Environmental and Soil Chemistry, Michigan State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2034722023-04-19T12:44:18Z2023-04-19T12:44:18ZFire danger in the high mountains is intensifying: That’s bad news for humans, treacherous for the environment<figure><img src="https://images.theconversation.com/files/521666/original/file-20230418-22-zv27xr.jpg?ixlib=rb-1.1.0&rect=0%2C2%2C1731%2C1065&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fires are increasing in high mountain areas that rarely burned in the past.</span> <span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/File:Deerfire_high_res.jpg">John McColgan, Bureau of Land Management, Alaska Fire Service</a></span></figcaption></figure><p>As wildfire risk rises in the West, wildland firefighters and officials are keeping a closer eye on the high mountains – regions once considered too wet to burn.</p>
<p>The growing fire risk in these areas became startling clear in 2020, when Colorado’s <a href="https://www.cpr.org/2021/01/25/colorados-east-troublesome-wildfire-may-signal-a-new-era-of-big-fire-blow-ups/">East Troublesome Fire</a> burned up and over the Continental Divide to become the state’s second-largest fire on record. The following year, California’s <a href="https://www.latimes.com/california/story/2021-09-14/californias-wildfires-burning-at-greater-elevations">Dixie Fire</a> became the first on record to burn across the Sierra Nevada’s crest and start down the other side.</p>
<p>We study wildfire behavior as <a href="https://scholar.google.com/citations?user=ZaW8ZbsAAAAJ&hl=en">climate scientists</a> and <a href="https://scholar.google.com/citations?user=tGGNDyUAAAAJ&hl=en">engineers</a>. In a <a href="https://doi.org/10.1038/s41467-023-37311-4">new study</a>, we show that fire risk has intensified in every region across the West over the past four decades, but the sharpest upward trends are in the high elevations. </p>
<figure class="align-center ">
<img alt="Fire burns in the mountains above a building and ranch fence." src="https://images.theconversation.com/files/521653/original/file-20230418-826-n7xjsd.jpg?ixlib=rb-1.1.0&rect=25%2C17%2C5670%2C3236&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521653/original/file-20230418-826-n7xjsd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=343&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521653/original/file-20230418-826-n7xjsd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=343&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521653/original/file-20230418-826-n7xjsd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=343&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521653/original/file-20230418-826-n7xjsd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=431&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521653/original/file-20230418-826-n7xjsd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=431&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521653/original/file-20230418-826-n7xjsd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=431&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">In 2020, Colorado’s East Troublesome fire jumped the Continental Divide.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/Exchange-ColoradoWildfires-Blow-ups/8e10c8213c3847f3a7ef14e7ff81eddf/photo">AP Photo/David Zalubowski</a></span>
</figcaption>
</figure>
<p>High mountain fires can create a cascade of risks for local ecosystems and for millions of people living farther down the mountains.</p>
<p>Since cooler, wetter high mountain landscapes rarely burn, vegetation and dead wood can build up, so <a href="https://doi.org/10.1073/pnas.2009717118">highland fires tend to be intense and uncontrollable</a>. They can affect everything from water quality and the timing of meltwater that communities and farmers rely on, to erosion that can bring debris and mud flows. Ultimately, they can change the hydrology, ecology and <a href="https://www.britannica.com/science/geomorphology">geomorphology</a> of the highlands, with complex feedback loops that can transform mountain landscapes and endanger human safety.</p>
<h2>Four decades of rising fire risk</h2>
<p>Historically, higher moisture levels and cooler temperatures created a flammability barrier in the highlands. This enabled fire managers to leave fires that move away from human settlements and up mountains to run their course without interference. Fire would hit the flammability barrier and burn out.</p>
<p>However, our findings show that’s no longer reliable as the climate warms.</p>
<p>We <a href="https://doi.org/10.1038/s41467-023-37311-4">analyzed fire danger trends</a> in different elevation bands of the Western U.S. mountains from 1979 to 2020. Fire danger describes conditions that reflect the <a href="https://www.fs.usda.gov/detail/inyo/home/?cid=stelprdb5173311">potential for a fire to ignite and spread</a>.</p>
<p>Over that 42-year period, <a href="https://doi.org/10.1126/sciadv.aaz4571">rising temperatures and drying trends</a> increased the number of critical fire danger days in every region in the U.S. West. But in the highlands, certain environmental processes, such as <a href="https://doi.org/10.1038/nclimate2563">earlier snowmelt</a> that allowed the earth to heat up and become drier, intensified the fire danger faster than anywhere else. It was particularly stark in high-elevation forests from about 8,200 to 9,800 feet (2,500-3,000 meters) in elevation, just above the elevation of Aspen, Colorado.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/521494/original/file-20230418-18-ombvln.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Chart showing changing wildfire risks in the high mountains" src="https://images.theconversation.com/files/521494/original/file-20230418-18-ombvln.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521494/original/file-20230418-18-ombvln.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=391&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521494/original/file-20230418-18-ombvln.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=391&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521494/original/file-20230418-18-ombvln.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=391&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521494/original/file-20230418-18-ombvln.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=491&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521494/original/file-20230418-18-ombvln.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=491&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521494/original/file-20230418-18-ombvln.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=491&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">Mohammad Reza Alizadeh</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>We found that the high-elevation band had gained on average 63 critical fire danger days a year by 2020 compared with 1979. That included 22 days outside the traditional warm season of May to September. In previous research, we found that high-elevation fires had been advancing upslope in the West at <a href="https://doi.org/10.1073/pnas.2009717118">about 25 feet (7.6 meters) per year</a>.</p>
<h2>Cascading risks for humans downstream</h2>
<p>Mountains are <a href="https://doi.org/10.1029/2006WR005653">water towers</a> of the world, providing <a href="https://doi.org/10.1002/2017GL073551">70% of the runoff that cities across the West</a> rely on. They support millions of people who live downstream.</p>
<p>High-elevation fires can have a significant impact on snow accumulation and meltwater, even long after they have burned out. </p>
<p>For example, fires remove vegetation cover and tree canopies, which can <a href="https://doi.org/10.1038/s41467-019-09935-y">shorten the amount of time</a> the snowpack stays frozen before melting. Soot from fires also darkens the snow surface, increasing its ability to absorb the Sun’s energy, which facilitates melting. Similarly, darkened land surface increases the absorption of solar radiation and heightens soil temperature after fires.</p>
<p>The result of these changes can be spring flooding, and less water later in the summer when communities downstream are counting on it.</p>
<p>Fire-driven tree loss also removes anchor points for the snowpack, increasing <a href="https://doi.org/10.1016/j.foreco.2009.01.050">the frequency and severity of avalanches</a>.</p>
<figure class="align-center ">
<img alt="A burned area on a mountain ridge with a large reservoir far below." src="https://images.theconversation.com/files/521655/original/file-20230418-26-rde43z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521655/original/file-20230418-26-rde43z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521655/original/file-20230418-26-rde43z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521655/original/file-20230418-26-rde43z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521655/original/file-20230418-26-rde43z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521655/original/file-20230418-26-rde43z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521655/original/file-20230418-26-rde43z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Wildfire burn scars can have many effects on the water quality and quantity reaching communities below.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/iron-mountain-and-whiskeytown-lake-site-of-the-destructive-news-photo/1334892056">George Rose/Getty Images</a></span>
</figcaption>
</figure>
<p>Frequent fires in high-elevation areas can also have a significant impact on the sediment dynamics of mountain streams. The loss of tree canopy means rainfall hits the ground at a higher velocity, increasing the <a href="https://doi.org/10.1073/pnas.1814627116">potential for erosion</a>. This can trigger mudslides and increase the <a href="https://doi.org/10.1038/s41467-019-09864-w">amount of sediment</a> sent downstream, which in turn can affect water quality and aquatic habitats.</p>
<p><a href="https://doi.org/10.1073/pnas.1814627116">Erosion linked to runoff after fire damage</a> can also deepen streams to the point that excess water from storms can’t spread in high-elevation meadows and recharge the groundwater; instead, they route the water quickly downstream and cause flooding.</p>
<h2>Hazards for climate-stressed species and ecosystems</h2>
<p>The highlands generally have long fire return intervals, burning once every several decades if not centuries. Since they don’t burn often, their ecosystems aren’t as fire-adapted as lower-elevation forests, so they may not recover as efficiently or survive repeated fires. </p>
<p>Studies show that more frequent fires could <a href="https://doi.org/10.1111/ele.12889">change the type of trees that grow</a> in the highlands or even convert them to shrubs or grasses. </p>
<figure class="align-center ">
<img alt="A team of pack mules carries supplies up a high mountain in Glacier National Park. Some of the trees have burned, even at this high elevation." src="https://images.theconversation.com/files/521663/original/file-20230418-682-fl98ua.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521663/original/file-20230418-682-fl98ua.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521663/original/file-20230418-682-fl98ua.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521663/original/file-20230418-682-fl98ua.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521663/original/file-20230418-682-fl98ua.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521663/original/file-20230418-682-fl98ua.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521663/original/file-20230418-682-fl98ua.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">High-elevation tree species like whitebark pines face an increasing risk of blister rust infections and mountain pine beetle infestations that can kill trees, creating more fuel for fires.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/park-service-animal-packers-jill-michalak-and-jacob-ellis-news-photo/1175612536">Chip Somodevilla/Getty Images</a></span>
</figcaption>
</figure>
<p>Wet mountain areas, with their cooler temperatures and higher precipitation, are often peppered with hot spots of biodiversity and provide refuges to various species from the warming climate. If these areas lose their tree canopies, <a href="https://doi.org/10.1073/pnas.1103097108">species with small ranges</a> that depend on cold-water mountain streams can face existential risks as <a href="https://doi.org/10.1890/09-0822.1">more energy from the Sun</a> heats up stream water in the absence of tree shading. </p>
<p>While the risk is rising fastest in the high mountains, most of the West is now at increasing risk of fires. With continuing greenhouse gas emissions fueling global warming, this trend of worsening fire danger is expected to intensify further, straining firefighting resources as crews battle more blazes.</p><img src="https://counter.theconversation.com/content/203472/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mojtaba Sadegh receives funding from the Joint Fire Science Program and the National Science Foundation. </span></em></p><p class="fine-print"><em><span>Mohammad Reza Alizadeh does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Fires here can affect meltwater timing and water quality, worsen erosion that triggers mudslides, and much more, as two scientists explain.Mohammad Reza Alizadeh, Postdoctoral Researcher in Environmental Engineering, Massachusetts Institute of Technology (MIT)Mojtaba Sadegh, Assistant Professor of Civil Engineering, Boise State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2025642023-04-17T10:57:51Z2023-04-17T10:57:51ZBillions still lack access to safe drinking water – this is a global human rights catastrophe<figure><img src="https://images.theconversation.com/files/520881/original/file-20230413-495-hhkl4x.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5760%2C3837&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The village well in Mchinji, Malawi. Just 37% of the population of sub-Saharan Africa will be using safely managed
drinking water by 2030.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/ifpri/43460028305/in/photolist-4nTsv2-mMyaA-Nt72vm-Nt72iY-29dq1hR-5fFctJ-2fkrnXP-owoaZM-JQQuG7-DoEsyy-th3f3u-D7YJJ4-dFcW51-hfuaNA-xbM9WC-e13B66-JmKeFn-av7rcz-9bLKoq-k5URWr-o7XSAc-drc6aj-dnFBdj-k5US9R-k5WJaw-k5WHow-k5UQLR-k5UPjx-k5WGY3-k5UccV-eg1rkN-k5WFtu-2qaGbr">Melissa Cooperman/IFPRI/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span></figcaption></figure><p>Leaders and authorities recently gathered in New York for the first UN water conference in decades. The hope was that there would be some landmark breakthroughs to ensure that everyone had access to safe drinking water and sanitation. </p>
<p>The UN secretary-general, António Guterres, called for member states to “<a href="https://unsdg.un.org/latest/stories/countries-commit-bold-water-action-un-water-conference">bring the water action agenda to life</a>” through developing resilient infrastructure, water pipelines and waste water treatment plans and putting in place early warning systems against natural disasters. </p>
<p>But if such pledges are not supported by guaranteed funds as well as legally binding legislation – and they aren’t – they risk undermining the energy and enthusiasm required to achieve <a href="https://sdgs.un.org/goals/goal6">the UN’s own sustainable development goal</a> of making access to clean water a human right.</p>
<p>Climate change and related droughts, hurricanes, floods and other extreme weather events are making it harder to access water for human consumption. In some parts of the world such as the Horn of Africa, the wells have run dry and there simply isn’t enough rain any more. The region is experiencing its <a href="https://www.theguardian.com/world/2022/aug/20/drought-in-horn-of-africa-places-22m-people-at-risk-of-starvation-says-un">worst drought for 40 years</a>. </p>
<p>In places where floods are a bigger risk than droughts, such as the US state of <a href="https://www.theguardian.com/us-news/2022/sep/01/jackson-mississippi-clean-drinking-water-flooding-problems">Mississippi</a> or parts of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6207902/">Kenya</a>, supplies of fresh water have been contaminated by floodwater filled with agricultural pollutants and industrial chemicals. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/521028/original/file-20230414-14-vf81dc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Flooded river with city in background" src="https://images.theconversation.com/files/521028/original/file-20230414-14-vf81dc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521028/original/file-20230414-14-vf81dc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521028/original/file-20230414-14-vf81dc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521028/original/file-20230414-14-vf81dc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521028/original/file-20230414-14-vf81dc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521028/original/file-20230414-14-vf81dc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521028/original/file-20230414-14-vf81dc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">After weeks of heavy rain caused flooding in Jackson, Mississippi, US in 2022, the city lost its access to clean water.</span>
<span class="attribution"><span class="source">Chad Robertson Media / shutterstock</span></span>
</figcaption>
</figure>
<p>Water insecurity – including everything from a lack of drinking water to the threat of homes being swept away – can have serious implications for people’s wellbeing. Flood victims in Pakistan have experienced <a href="https://guilfordjournals.com/doi/10.1521/psyc.2014.77.3.289">post-traumatic stress disorder</a>, for instance. All this means clean water has become a source of widespread climate injustice, especially in the most vulnerable countries. </p>
<p>Alarmingly there are more people now without access to clean water than there were three decades ago. In 2022 the <a href="https://www.unicef.org/reports/state-worlds-drinking-water">Sate of the World’s Drinking Water</a> report by the WHO, UNICEF and the World Bank, noted that one-quarter of the world’s population is left without access to safe drinking water. People in sub-Saharan Africa haven’t benefited from investment and have the lowest levels of access.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/521029/original/file-20230414-28-ensh6k.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Bar chart" src="https://images.theconversation.com/files/521029/original/file-20230414-28-ensh6k.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/521029/original/file-20230414-28-ensh6k.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=486&fit=crop&dpr=1 600w, https://images.theconversation.com/files/521029/original/file-20230414-28-ensh6k.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=486&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/521029/original/file-20230414-28-ensh6k.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=486&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/521029/original/file-20230414-28-ensh6k.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=611&fit=crop&dpr=1 754w, https://images.theconversation.com/files/521029/original/file-20230414-28-ensh6k.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=611&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/521029/original/file-20230414-28-ensh6k.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=611&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Proportion of population using contamination-free drinking water sources in 2020 (%).</span>
<span class="attribution"><a class="source" href="https://www.unicef.org/media/129381/file/State%20of%20drinking%20water%20report.pdf">State Of The World's Drinking Water report (Unicef, WHO, World Bank)</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>In many poorer countries, access to drinking water is not recognised as a basic human right. Research I published with colleagues on water access in two of those countries, Malawi and Zambia, found that <a href="https://www.sciencedirect.com/science/article/pii/S2212608216300079?via%3Dihub">water was neither privatised nor a state provision</a>. </p>
<p>People in these countries instead relied on development aid and donor funding to sink bore holes or provide water pumps in rural areas, and if there was no aid they had to organise clean water themselves on a small community basis. Many pumps and wells do not work, or they are vandalised, and as a result many find themselves drinking unclean water.</p>
<p>In such countries there is lots of wrangling between politicians, traditional leaders and communities over who actually owns or should govern water points. Many different actors are involved, including public and private organisations, NGOs, faith-based organsations and donors. This all makes the job of providing water even less straightforward, and coordinating these different actors is paramount.</p>
<p>This lack of coordination, combined with an over-reliance on donors and a lack of local input in decision-making leads me to wonder at what point will access to water actually become a national priority in water insecure countries. </p>
<p>Governments need to take a leading role by facilitating long-term investment in the sector and promoting initiatives which incorporate the right to water access. Solutions to water access should be part of a broader socioeconomic development model which promotes awareness around rights and responsibilities. </p>
<p>Ultimately the management of water resources lies with the governments, who retain a sovereign duty to ensure the human right to safe drinking water. The water crisis is a climate justice crisis. What is needed is commitment in terms of real funding, not just pledges, to ensure that these basic human rights are exercised with support from the United Nations. </p>
<p>Some good news did emerge from the conference in New York, including calls for the UN to appoint a <a href="https://press.un.org/en/2023/sgsm21742.doc.htm">special envoy for water</a>, and a Water Action Agenda containing <a href="https://sdg.iisd.org/news/un-conference-generates-700-voluntary-water-action-agenda-commitments/">700 commitments</a>. Member states, development banks, large companies and NGOs have all pledged to direct millions of pounds to the water sector. </p>
<p>But just as a village in Malawi might suffer from a lack of coordination between different actors who want to develop a local well, the same problem risks happening on a global scale. What’s really needed is strong leadership so all sectors work collectively to ensure everyone in the world really does have access to clean water.</p><img src="https://counter.theconversation.com/content/202564/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tahseen Jafry receives funding from various research and development agencies</span></em></p>Climate change and related droughts, hurricanes, floods and other extreme weather events are making it harder.Tahseen Jafry, Director Mary Robinson Centre for Climate Justice, Glasgow Caledonian UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2029022023-04-12T11:17:42Z2023-04-12T11:17:42ZHundreds of rivers and lakes cross international borders – countries need to commit to sharing the water<figure><img src="https://images.theconversation.com/files/518768/original/file-20230331-22-1lbwgo.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C7921%2C3562&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Daube in Serbia, country six of ten.</span> <span class="attribution"><span class="source">Mita Stock Images</span></span></figcaption></figure><p>The Danube River starts in Germany and eventually flows into the Black Sea some 2,850 kilometres and ten countries later. If Germany were to dam or pollute the river, it could potentially affect nine other countries – and four of their capitals. </p>
<p>The Danube may be the world’s most multinational river, but it’s only one of an estimated <a href="https://www.gwp.org/en/we-act/themesprogrammes/Transboundary_Cooperation/">310 rivers and lakes</a> shared between two or more countries, along with 468 underground water sources known as aquifers. I recently went to New York to a major <a href="https://sdgs.un.org/conferences/water2023">UN conference</a> – the first dedicated to water in decades – to try and help strengthen political commitment over these “transboundary” bodies of water.</p>
<p>It’s a crucial issue, as these shared water resources can be both a source of conflict and a driver of cooperation, sustainable development and peace. In wars such as those in Ukraine or Syria, water and infrastructure like bridges or sewers have been repeatedly targeted for their strategic value. </p>
<p>Tensions are also running high in Africa because Ethiopia is constructing a large dam on the Nile, upstream of Egypt. At a recent meeting of the <a href="https://www.arabnews.com/node/2265536/middle-east">Council of Arab Foreign Ministers</a>, Egypt’s Sameh Shoukry warned of the “fatal consequences for Egypt’s national security” of “unilateral Ethiopian practices on … common river basins”. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1414861021299232772"}"></div></p>
<p>Conversely, <a href="https://www.savacommission.org/">jointly managing the Sava River</a> (the Danube’s longest tributary) since 2001 helped build peace and trust between former Yugoslav republics less than a decade after they had been at war. And when the mighty Paraná River – South America’s second largest – almost dried up in 2021, Brazil, Paraguay and Argentina were able to share the limited water supplies peacefully and sustainably. </p>
<p>Such positive examples of cooperation are particularly pertinent given the increasing pressures that <a href="https://theconversation.com/ipcc-report-half-the-world-is-facing-water-scarcity-floods-and-dirty-water-large-investments-are-needed-for-effective-solutions-175578">climate change</a> places on the world’s water resources.</p>
<h2>How to make sure countries share their water</h2>
<p>Effective legal and governance arrangements are key. For example, Canada and the US can point to well over 100 years of cooperation through the 1909 Boundary Water Treaty and the International Joint Commission. Similarly, a peace treaty between Brazil and Paraguay in 1966 led to the creation of a binational commission and eventually to one of the world’s largest hydroelectric dams on the Paraná.</p>
<p>Governance arrangements are also capable of both managing conflict and cooperation simultaneously. Hungary and Slovakia have a long-running dispute over the implementation of a 1970s soviet-era hydropower project on the Danube, the Gabčíkovo-Nagymaros project. </p>
<p>But the countries have still worked together through the <a href="https://www.icpdr.org/main/">international Danube River commission</a> to manage water across the basin. And in Asia, there have been examples of cooperation over the Indus (shared by India and Pakistan) and lower Mekong (Cambodia, Loas, Vietnam and Thailand) rivers even while the countries that share them were at war.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/518781/original/file-20230331-28-bbmx2i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="irrigated fields in dry mountains" src="https://images.theconversation.com/files/518781/original/file-20230331-28-bbmx2i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/518781/original/file-20230331-28-bbmx2i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/518781/original/file-20230331-28-bbmx2i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/518781/original/file-20230331-28-bbmx2i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/518781/original/file-20230331-28-bbmx2i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/518781/original/file-20230331-28-bbmx2i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/518781/original/file-20230331-28-bbmx2i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Indus supplies the water for most of Pakistan’s farms. But it begins in far northern India (pictured: fields in Ladakh, India).</span>
<span class="attribution"><span class="source">Kevin Standage / shutterstock</span></span>
</figcaption>
</figure>
<p>As unifying entities, basin organisations can take on responsibilities well beyond water itself. For example, within the context of threats from Islamist militant group Boko Haram, the Lake Chad Basin Commission is able to not only manage shared waters but also promote regional integration, peace, security and development. </p>
<p>Unfortunately, there are not enough of these governance arrangements in place. The UN bodies responsible for monitoring progress say <a href="https://www.unwater.org/publications/progress-transboundary-water-cooperation-2021-update">only 24 countries</a> have all their transboundary basin areas covered by cooperation agreements. The situation is particularly stark in the case of groundwater, where only eight groundwater-specific legal arrangements are in place.</p>
<h2>Notable commitments – but still not enough</h2>
<p>One of the key themes of the UN water conference was cooperation. This led to some notable commitments. A newly-established <a href="https://unece.org/environmental-policy/events/committing-advance-transboundary-water-cooperation-worldwide#:%7E:text=The%2520Transboundary%2520Water%2520Cooperation%2520Coalition%2520is%2520a%2520multistakeholder%2520partnership%2520making,cooperation%2520at%2520all%2520levels%2520worldwide.">Transboundary Water Cooperation Coalition</a> could coordinate countries, international organisations, academia and NGOs. </p>
<p>Also, several countries, including Iraq, Namibia, Nigeria and Zambia, formally joined or committed to joining at least one of the two UN water conventions. These are the 1992 Convention on the Protection and Use of Transboundary Watercourses and International Lakes and the 1997 Convention for the Law of the Non-navigational Uses of International Watercourses. Based on customary international law, they both set out basic principles by which countries can cooperate over their shared waters. </p>
<p>The 1992 convention, with its institutional framework – which includes three yearly meetings of the parties and various expert working groups – acts as a global forum for the exchange of best practice and the development of useful guidance and other tools to <a href="https://documents-dds-ny.un.org/doc/UNDOC/GEN/N23/029/39/PDF/N2302939.pdf?OpenElement">support transboundary cooperation</a>.</p>
<p>Do these commitments provide the requisite step change? The short answer is no. Global pressures on transboundary waters due to population increase, growing water demands, unsustainable consumption patterns, environmental degradation and biodiversity loss, and climate change, require urgent attention. </p>
<p>It is positive that over 20 countries have promised to join one or both water conventions. But currently only about a third of all countries sharing transboundary waters are party to one or both conventions. </p>
<p>The UN’s 2023 water conference may well go down as an important stepping stone in securing commitment on transboundary water cooperation, but much will depend on what countries deliver in the months and years to come.</p><img src="https://counter.theconversation.com/content/202902/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alistair Rieu-Clarke has worked for the United Nations Economic Commission for Europe and received research funding from the World Wide Fund for Nature, the Norwegian Government, the UK Government and HSBC for activities related to the UN Water Conventions and transboundary water cooperation. </span></em></p>Transboundary water cooperation can reduce conflict and promote sustainable development.Alistair Rieu-Clarke, Professor of Law, Northumbria University, NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2018352023-03-20T11:37:30Z2023-03-20T11:37:30ZWater has long been used as a tactical weapon in warfare – the world now has a chance to end this<p>Experts and leaders will soon come together in their thousands at the first <a href="https://sdgs.un.org/conferences/water2023">UN conference dedicated to water</a> in nearly half a century. </p>
<p>At the conference, which begins on March 22 in New York, delegates will no doubt stress that “water is life”. And it’s true: water nourishes, cleanses and even inspires the poetry and painting so desperately needed by our modern and rushed society. We really cannot live without it.</p>
<p>But as a professor of water security who focuses on its role in conflict, I know that water is death, too. And I don’t just mean the awesome destructive force of floods – hundreds of children in Pakistan and twice as many adults drowned when a “<a href="https://edition.cnn.com/2022/08/29/asia/pakistan-flood-damage-imf-bailout-intl-hnk/index.html">monsoon on steroids</a>” burst the banks of the Indus River last summer – or agonising spells of drought.</p>
<p>I mean the way we use water in war – or more specifically, as a tool towards violent political or military objectives, when water becomes a tactical weapon and a strategic battlefield resource. At the UN conference, delegates have a chance to begin to put a stop to this. But before we change our behaviour, we must first reflect on it.</p>
<h2>Water the weapon</h2>
<p>We have for centuries used rivers to hurt our enemies. Back in the early 1500s, Leonardo da Vinci worked with Niccolò Machiavalli on an ultimately unsuccessful attempt to divert the Arno River away from Florence’s rival city, Pisa. </p>
<p>Four centuries later, Belgian teenage troops and farmers knew exactly how to flood the parts of the Yser river that German troops had advanced along during the first world war. Another century after that, Ukrainian forces cut the sole water supply to Crimea after Russia’s annexation of it, and just a few weeks ago <a href="https://www.npr.org/2023/02/10/1155761686/russia-is-draining-a-massive-ukrainian-reservoir-endangering-a-nuclear-plant">Russian troops used the Dnipro river</a> to stop troop advances.</p>
<p>Rivers are also often used to conceal crimes. Paris police threw dozens of their Algerian victims into the Seine <a href="https://theconversation.com/the-french-algerian-war-60-years-on-what-is-behind-frances-reconciliation-agenda-192270">in 1961</a>, while Syrian forces dumped dozens of people they had executed into the Aleppo river in 2013, and into the Al Assi in 2015. Sudanese authorities tossed <a href="https://edition.cnn.com/2019/06/05/africa/sudan-death-toll-intl/index.html">at least 40</a> of their own people into the Nile in their failed attempt to disrupt protests in 2019 – in a way, emulating the British slaughter of 13,000 Sudanese at the confluence of the Blue and White Niles in Omdurman in 1898.</p>
<p>Snipers know the tactical value of water, too. They sat several floors up in Sarajevo’s abandoned buildings in the 1990s, perched like patient storks over the women and children who would risk their lives to get to the tap stand at the end of an alley. Snipers also hid behind their scopes at a distance from a leaky pipe in a refugee camp in Beirut in the 1970s, “as if hunting thirsty gazelles” in the words of poet <a href="https://publishing.cdlib.org/ucpressebooks/view?docId=ft1z09n7g7&chunk.id=s1.1.11&toc.id=&brand=eschol">Mahmoud Darwish</a>. “Killer water”, he concludes.</p>
<p>And water can be used more strategically – to clear the killing fields. Dozens of public reservoirs were pierced like colanders in <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/disa.12039">southern Lebanon in 2006</a>, presumably to keep those who had fled to Beirut away. Similarly, elders who refused to flee the fighting in villages in 1990s Kosovo were regularly <a href="https://www.amazon.co.uk/Reflections-Understanding-Our-Abuse-Water-ebook/dp/B0BW12YD7W/ref=sr_1_2?keywords=mark+zeitoun&link_code=qs&qid=1677050604&sourceid=Mozilla-search&sr=8-2">dumped into backyard wells</a>, to discourage their adult children from returning.</p>
<p>A different type of cleansing also happens along the West Bank of the Jordan river, where Israeli governments provide water to settlers but employ both bureaucratic and physical ways to <a href="https://theconversation.com/israel-is-hoarding-the-jordan-river-its-time-to-share-the-water-126906">deny it to the locals</a>. Here, water policy has mixed with political and military goals to the point where they are virtually indistinguishable.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/515850/original/file-20230316-26-js4ch1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Aerial view of river through dry land" src="https://images.theconversation.com/files/515850/original/file-20230316-26-js4ch1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/515850/original/file-20230316-26-js4ch1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/515850/original/file-20230316-26-js4ch1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/515850/original/file-20230316-26-js4ch1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/515850/original/file-20230316-26-js4ch1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/515850/original/file-20230316-26-js4ch1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/515850/original/file-20230316-26-js4ch1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Much of the Jordan river has been diverted to irrigate fields.</span>
<span class="attribution"><span class="source">Maurizio De Mattei / Shutterstock</span></span>
</figcaption>
</figure>
<p>However, water isn’t always an effective tool of military and political violence. For instance, the enormous British “dambusters” campaign in the second world war, in which dams were targeted with “bouncing bombs”, is <a href="https://www.maxhastings.com/2019/09/04/exploding-the-dambusters-myth/">disingenuously remembered</a>. In fact, it only managed to properly take out two dams in the end, and killed mostly Russian women civilian prisoners of war who had been forced to work in German factories along the Ruhr river. More recently, <a href="https://en.wikipedia.org/wiki/Islamic_State">Islamic State</a> discovered that <a href="https://www.bbc.co.uk/news/world-middle-east-28772478">control of a dam</a> in Iraq and Syria does not automatically give you control of the people who live downstream. </p>
<h2>The battle for water – and ourselves</h2>
<p>Though humanity uses water to nurture, it also uses water to destroy and to contaminate, or to ethnically cleanse territory even as water is made the foundation of global public health. For all its wonderful properties, water is a critical mirror of society. It exposes the extent to which we are led by ideologies and greed, and juxtaposes some of the world’s most inspiring and depraved behaviour.</p>
<p>But now people are fighting back. Lawyers are developing principles on the <a href="https://legal.un.org/ilc/guide/8_7.shtml">protection of the environment</a> and <a href="https://www.genevawaterhub.org/resource/geneva-list-principles-protection-water-infrastructure">water infrastructure</a> during armed conflict. If we muster the will and courage, these initiatives can feed into relevant <a href="http://unscr.com/en/resolutions/2573">security council resolutions</a>, maybe even a UN Convention. Eventually, the tactical use of water could be as unacceptable as using human shields or targeting schools.</p>
<p>The battle to stop the abuse of water will not be won or lost at the UN conference in New York. But if fought well, it will reflect kindly on us all.</p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
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<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
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<p class="fine-print"><em><span>Mark Zeitoun is Professor of Water Security at the School of International Development, University of East Anglia. He is author of Reflections: Understanding our Use and Abuse of Water (OUP 2023).</span></em></p>The first UN conference dedicated to water in nearly half a century is being held in New York.Mark Zeitoun, Professor of Water Security, University of East AngliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1961442022-12-20T19:09:26Z2022-12-20T19:09:26ZFor Australia to lead the way on green hydrogen, first we must find enough water<p>Australia is <a href="https://www.sciencedirect.com/science/article/abs/pii/S2214629622002559">well-positioned</a> to be a global leader in green hydrogen production. Green hydrogen is produced using a renewable power source such as solar or wind. As a substitute for fossil fuels, it will help to meet <a href="https://theconversation.com/labors-renewable-target-is-much-more-ambitious-than-it-seems-we-need-the-best-bang-for-buck-policy-responses-186302">growing renewable energy needs</a>.</p>
<p>However, high-quality water is needed to produce hydrogen. Supplies of high-quality water must also be secured into the future to support our agriculture, industries, cities, towns and communities. Climate change and population growth will increase pressure on these supplies.</p>
<p>Community discussion is needed to identify where the water to produce hydrogen will come from. We need to ensure this developing industry does not disadvantage other water users, as we discuss in our new <a href="https://www.deakin.edu.au/__data/assets/pdf_file/0009/2539584/Water-energy-nexus-whitepaper.pdf">white paper</a>. </p>
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Read more:
<a href="https://theconversation.com/what-will-power-the-future-elon-musks-battery-packs-or-twiggy-forrests-green-hydrogen-truth-is-well-need-both-191333">What will power the future: Elon Musk's battery packs or Twiggy Forrest's green hydrogen? Truth is, we'll need both</a>
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<h2>Green hydrogen industry looks set to boom</h2>
<p>Green hydrogen is likely to partially replace petrol and diesel for large vehicles such as trucks and heavy machinery as Australia moves to a carbon-neutral economy. It has the advantage of being a fuel suitable for sectors such as <a href="https://theconversation.com/when-it-comes-to-climate-change-australias-mining-giants-are-an-accessory-to-the-crime-124077">mining</a> and <a href="https://theconversation.com/tracking-the-transition-the-forgotten-emissions-undoing-the-work-of-australias-renewable-energy-boom-162506">transport</a> that are struggling to reduce emissions.</p>
<p>The green hydrogen market is expected to grow rapidly. Hydrogen energy outputs in Australia are estimated to exceed <a href="https://www.dcceew.gov.au/sites/default/files/documents/state-of-hydrogen-2021.pdf">100MW by 2025</a>. More than <a href="https://www.pwc.com.au/integrated-infrastructure-building-australia/getting-h2-right-australias-competitive-hydrogen-export-industry/producing-at-globally-competitive-prices.html">90 projects representing A$250 billion</a> in investment are planned. </p>
<p>Most demand for hydrogen this decade is <a href="https://igcc.org.au/wp-content/uploads/2022/08/Investor-Group-on-Climate-Change-Hydrogen-Report.pdf">likely to be domestic</a> – for chemical production, industrial processes and other uses. In the longer term, major export demand is <a href="https://igcc.org.au/wp-content/uploads/2022/08/Investor-Group-on-Climate-Change-Hydrogen-Report.pdf">expected from the Asia-Pacific</a>.</p>
<p>By 2040, Australia’s green hydrogen production cost is <a href="https://www.pwc.com.au/integrated-infrastructure-building-australia/getting-h2-right-australias-competitive-hydrogen-export-industry/producing-at-globally-competitive-prices.html">predicted to be the equal-lowest</a> in the world. Electrolysis, which splits water molecules into hydrogen and oxygen, will be the <a href="https://www.irena.org/publications/2022/Jan/Geopolitics-of-the-Energy-Transformation-Hydrogen">main method of producing</a> this green hydrogen.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/501761/original/file-20221219-13-9h4zfh.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/501761/original/file-20221219-13-9h4zfh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/501761/original/file-20221219-13-9h4zfh.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=295&fit=crop&dpr=1 600w, https://images.theconversation.com/files/501761/original/file-20221219-13-9h4zfh.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=295&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/501761/original/file-20221219-13-9h4zfh.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=295&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/501761/original/file-20221219-13-9h4zfh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=370&fit=crop&dpr=1 754w, https://images.theconversation.com/files/501761/original/file-20221219-13-9h4zfh.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=370&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/501761/original/file-20221219-13-9h4zfh.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=370&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">To produce green hydrogen, electricity from a renewable source is used to split water molecules – H₂O – into hydrogen and oxygen.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/breakthrough-in-gas-separation-and-storage-could-fast-track-shift-to-green-hydrogen-and-significantly-cut-global-energy-use-186644">Breakthrough in gas separation and storage could fast-track shift to green hydrogen and significantly cut global energy use</a>
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</em>
</p>
<hr>
<h2>How much water are we talking about?</h2>
<p>The amount of water needed to generate green hydrogen varies. The exact <a href="https://apo.org.au/node/314538">amount of water required</a> depends on the technology used to produce hydrogen, the water quality and any need for cooling or water purification.</p>
<p>On average, a litre of water can produce enough hydrogen to deliver about <a href="https://www.researchgate.net/profile/Wendy-Timms/publication/336498351_More_Joules_per_Drop_-_How_Much_Water_Does_Unconventional_Gas_Use_Compared_to_Other_Energy_Sources_and_What_Are_the_Legal_Implications/links/5da3b326299bf116fea49860/More-Joules-per-Drop-How-Much-Water-Does-Unconventional-Gas-Use-Compared-to-Other-Energy-Sources-and-What-Are-the-Legal-Implications.pdf">10 megajoules of energy</a>. That’s enough to push a 50-tonne truck 15 metres.</p>
<p>The previous Australian government <a href="https://www.minister.industry.gov.au/ministers/taylor/media-releases/strong-potential-future-australia-germany-hydrogen-exports">predicted</a> the hydrogen industry could be worth A$50 billion a year by 2050. At that scale, it would need about <a href="https://theconversation.com/green-hydrogen-is-coming-and-these-australian-regions-are-well-placed-to-build-our-new-export-industry-174466">225 billion litres</a> (gigalitres) of water. While that’s roughly as much as <a href="https://www.abs.gov.au/statistics/environment/environmental-management/water-account-australia/latest-release">residents of a city like Perth use</a> in a year, it’s only about <a href="https://www.abs.gov.au/statistics/industry/agriculture/water-use-australian-farms/latest-release">3% of the water used for agriculture</a> in Australia in 2020-21. </p>
<p>There are many possible sources of water. Surface water, groundwater and recycled water are all available inland. Coastal areas have unlimited seawater, which can be <a href="https://www.rechargenews.com/energy-transition/vast-majority-of-green-hydrogen-projects-may-require-water-desalination-potentially-driving-up-costs/2-1-1070183">desalinated for hydrogen production</a>.</p>
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<p>But there are trade-offs whenever we allocate a water resource. In many areas, the available fresh water is fully allocated to towns, cities, agriculture, industry and the environment. The pressure on water supplies will increase as populations grow and much of Australia becomes hotter and drier under climate change.</p>
<p>Further, most water would have to be treated to be suitable for hydrogen production. Treatment can be expensive and uses additional energy, as does desalination and pumping water long distances.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/new-zealand-is-touting-a-green-hydrogen-economy-but-it-will-face-big-environmental-and-cultural-hurdles-187521">New Zealand is touting a green hydrogen economy, but it will face big environmental and cultural hurdles</a>
</strong>
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<hr>
<h2>Failure to plan for water use could be costly</h2>
<p>Current issues in the gas industry provide a cautionary tale. High gas prices in eastern Australia can be deemed the result of failure to consider impacts on domestic customers of developing a gas export industry. </p>
<p>Western Australia, in contrast, reserved enough gas for domestic users. As a result, its prices are <a href="https://www.energyquest.com.au/western-australia-low-energy-price-paradise/">among the lowest in the OECD</a>.</p>
<p>A similar failure may arise if corporations buy high-quality water for hydrogen generation, diminishing supplies for agricultural, domestic or environmental use. North Africa exports substantial amounts of <a href="https://corporateeurope.org/en/2022/05/hydrogen-north-africa-neocolonial-resource-grab">green hydrogen to Europe</a>, but this is <a href="https://timep.org/commentary/analysis/who-will-benefit-from-tunisias-green-hydrogen-strategy/">controversial</a> because of <a href="https://www.brookings.edu/blog/africa-in-focus/2022/05/10/the-promise-of-african-clean-hydrogen-exports-potentials-and-pitfalls/">regional water shortages</a>. </p>
<p>In Australia, competition for water will intensify due to climate change and ongoing demands from agriculture – <a href="https://www.abs.gov.au/statistics/environment/environmental-management/water-account-australia/latest-release#media-releases">72%</a> of national water consumption in 2020-21 – industry, mining, households and the environment. Using potable water to produce hydrogen may be at odds with community expectations. </p>
<p>Care must be taken to ensure industry expansion does not <a href="https://www.ecnt.org.au/repowerfaq_waterhydrogen">adversely affect other users</a>. This will be particularly difficult in Australia because rainfall is <a href="https://www.ga.gov.au/scientific-topics/national-location-information/dimensions/climatic-extremes">highly variable by world standards</a> – not news to those who have lived through recent years of drought then flooding rains.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/albanese-just-laid-out-a-radical-new-vision-for-australia-in-the-region-clean-energy-exporter-and-green-manufacturer-186815">Albanese just laid out a radical new vision for Australia in the region: clean energy exporter and green manufacturer</a>
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<hr>
<h2>So what are the likely solutions?</h2>
<p>The <a href="https://ecos.csiro.au/hydrogen-industry-australia/">key challenge</a> is to produce hydrogen in large quantities in a way that is cost-effective and sustainable. </p>
<p>This can be achieved by planning effectively for industry growth. Our <a href="https://www.deakin.edu.au/__data/assets/pdf_file/0009/2539584/Water-energy-nexus-whitepaper.pdf">white paper</a> identifies public policy and industry-related issues posed by this growth.</p>
<p>We must identify regions likely to support hydrogen production and storage, find nearby sources of water and calculate volumes needed. Then, we must develop plans to support existing water users while providing a viable solution for the green hydrogen industry.</p>
<p>Alternative sources such as recycled water or treated groundwater are likely part of that solution. Harvesting water from industrial and urban wastewater <a href="https://ecat.ga.gov.au/geonetwork/srv/eng/catalog.search#/metadata/130930">could be a game changer</a>. It would require moderate treatment but have fewer effects on other water users.</p>
<p>We will learn a lot from pilot programs such as the <a href="https://arena.gov.au/projects/new-energies-service-station-geelong-demonstration-project/">New Energies Service Station</a> in Geelong, which will create hydrogen from 100% recycled water.</p>
<p>In planning to overcome the challenges, we’ll need to develop relevant data, information and analysis to get the settings right.</p>
<p>It is possible to create a vibrant, sustainable and profitable green hydrogen industry to support decarbonisation of Australian and global economies, but it won’t happen by accident. Careful planning is essential, and communities must be involved in deciding where water will come from and how it can be accessed.</p><img src="https://counter.theconversation.com/content/196144/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rebecca Lester receives funding from the Australian Research Council, and the Australian and Victorian Governments. </span></em></p><p class="fine-print"><em><span>I was Deputy Director-General then Director-General, Water Victoria (1989-92); then Secretary, Department of Energy and Minerals, Victoria (1992-1995). Later I was Deputy Secretary then General Manager, Office of Water, Victoria. During that time I was a Victorian representative on the Murray Darling Basin Commission and then on the Basin Officials Committee (2004-2011). I was Director and MD of a consulting company owned by a law firm (now called Norton Rose Gledhill) from 1995-2003. During that time I was involved with various water and energy projects including the corporatisation of the Snowy Mountains Scheme. I am a shareholder in Xpansiv, a large renewable energy and water exchange, and was formerly a board member. I am a board member and shareholder in Flinders Peak Water, an organisation dedicated to using recycled water for food/agriculture. Through Deakin University I am connected to various water-related projects, including MDB and Drought Resilience programs, funded out of government grants.</span></em></p><p class="fine-print"><em><span>Wendy Timms receives funding from the Australian Research Council, CO2CRC, Fluid Potential and the Victorian government. </span></em></p><p class="fine-print"><em><span>Don Gunasekera does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Australia’s emerging green hydrogen industry requires a secure supply of high-quality water. Competing demands for this scarce resource mean careful planning is needed to meet all water users’ needs.Rebecca Lester, Professor, Aquatic Ecology and Director, Centre for Regional and Rural Futures, Deakin UniversityDavid Downie, Strategic Adviser, Regional Development, Deakin UniversityDon Gunasekera, Research Fellow, Centre for Supply Chain and Logistics, Deakin UniversityWendy Timms, Professor of Environmental Engineering, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1870422022-11-02T17:27:05Z2022-11-02T17:27:05ZRipple effect: As global freshwater basins dry up, the threat to ecosystems and communities grows<figure><img src="https://images.theconversation.com/files/492515/original/file-20221031-15-781iqe.jpg?ixlib=rb-1.1.0&rect=14%2C85%2C1942%2C1217&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Hundreds of freshwater basins across the world, including the dried-up Santa Olalla permanent freshwater lagoon, in Spain's Doñana National Park, are the most likely to experience social and ecological impacts due to freshwater use.</span> <span class="attribution"><span class="source">(Donana Biological Station/CSIC)</span></span></figcaption></figure><p>When people use freshwater beyond a physically sustainable rate, <a href="https://doi.org/10.1038/nature09440">it sets off a cascade of impacts on ecosystems, people and the planet</a>. These impacts include groundwater <a href="https://calmatters.org/environment/2021/08/california-groundwater-dry/">wells running dry</a>, fish populations becoming stranded <a href="https://hakaimagazine.com/features/what-to-do-with-fish-when-the-river-runs-dry/">before they are able to spawn</a> and <a href="https://www.euronews.com/2022/05/27/spain-s-donana-national-park-under-threat-as-groundwater-pumping-continues">protected wetland ecosystems turning into dry landscapes</a>. </p>
<p>Developments in computer models and satellites have fostered a new understanding of how freshwater is being redistributed around the planet and have made clear the central role that people play in this change. This human impact is so significant that organizations like the United States Geological Survey are <a href="https://www.usgs.gov/special-topics/water-science-school/science/water-cycle-diagrams">redrawing their water cycle diagram</a> to include the impacts of human actions. </p>
<p>Equally important to understanding how people affect freshwater availability, is understanding how people and ecosystems will respond to amplified freshwater challenges including drought, water stress and groundwater depletion. While these challenges impact localized sites, their impacts are scattered across the world. To address this <a href="https://public.wmo.int/en/media/press-release/wake-looming-water-crisis-report-warns">global water crisis</a>, global action is urgently needed. </p>
<p><a href="https://doi.org/10.1038/s41467-022-28029-w">In our recent study</a>, we identified the basins of the world that are most likely to be impacted by two central and interrelated aspects of water scarcity: <a href="https://doi.org/10.1038/srep38495">freshwater stress</a>, which occurs when the consumption of water surpasses renewable water supply, and <a href="https://doi.org/10.1038/s41586-018-0123-1">freshwater storage loss</a>, which is the depletion of freshwater in reservoirs or in groundwater bodies due to persistent overuse. </p>
<h2>Global basins impacted by water scarcity</h2>
<p>We identified <a href="https://www.nature.com/articles/s41467-022-28029-w/figures/3">168 basins</a> across the world that are the most likely to experience social and ecological impacts due to insufficient freshwater availability. These hotspot basins are found on every continent — a clear indication of the widespread, global nature of these challenges.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/492717/original/file-20221101-16-rfgko6.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map of hotspot basins" src="https://images.theconversation.com/files/492717/original/file-20221101-16-rfgko6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492717/original/file-20221101-16-rfgko6.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=339&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492717/original/file-20221101-16-rfgko6.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=339&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492717/original/file-20221101-16-rfgko6.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=339&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492717/original/file-20221101-16-rfgko6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=426&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492717/original/file-20221101-16-rfgko6.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=426&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492717/original/file-20221101-16-rfgko6.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=426&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Hotspot basins (in orange and red), which are the most likely basins to experience severe social and ecological impacts due to limited freshwater availability.</span>
<span class="attribution"><span class="source">(Xander Huggins)</span></span>
</figcaption>
</figure>
<p>To identify these hotspot basins, we assessed patterns in <a href="https://www.nature.com/articles/s41467-022-28029-w/figures/1">freshwater stress and freshwater storage trends</a> and compared these to patterns in <a href="https://www.nature.com/articles/s41467-022-28029-w/figures/2">societal ability to adapt to environmental hazards</a> and freshwater-based ecological sensitivity indicators. </p>
<p>The hotspot basins are most vulnerable largely because they are likely to experience social and ecological impacts at the same time. <a href="https://www.millenniumassessment.org/documents/document.312.aspx.pdf">People and societies depend on freshwater ecosystems</a> for drinking water, irrigation water, water filtration, erosion control, as cultural sites and for recreation. This means that ecological impacts of freshwater stress and storage loss double as social impacts through degraded ecosystem services. </p>
<h2>Managing vulnerable basins</h2>
<p>Hotspot basins are vulnerable as they are likely to face impacts such as low streamflow that harms aquatic biodiversity, reduced food security as agriculture is heavily reliant on freshwater supply, <a href="https://doi.org/10.1088/1748-9326/aa8ac0">wells running dry</a> and higher potential for <a href="https://www.worldwater.org/conflict/map/">social unrest</a>. </p>
<figure class="align-center ">
<img alt="A field irrigation sprinkler system waters rows of lettuce crops on farmland." src="https://images.theconversation.com/files/488148/original/file-20221004-11-fu8x9h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/488148/original/file-20221004-11-fu8x9h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/488148/original/file-20221004-11-fu8x9h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/488148/original/file-20221004-11-fu8x9h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/488148/original/file-20221004-11-fu8x9h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/488148/original/file-20221004-11-fu8x9h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/488148/original/file-20221004-11-fu8x9h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Declining freshwater supply can affect food security as the agriculture sector heavily relies on it.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Reducing vulnerability in intertwined societal and environmental systems requires improved policy and management integration across sectors. <a href="https://www.unep.org/explore-topics/disasters-conflicts/where-we-work/sudan/what-integrated-water-resources-management">Integrated Water Resources Management</a> considers and balances social, ecological and hydrological sustainability goals by co-ordinating management across water, land and other related resources. Its <a href="https://www.sdg6monitoring.org/indicator-651/">inclusion in the United Nations Sustainable Development Goal framework</a> highlights its importance.</p>
<p>Our research found that countries including Afghanistan, Algeria, Argentina, Egypt, India, Iraq, Kazakhstan, Mexico, Somalia, Ukraine, Uzbekistan and Yemen have hotspot basins yet low implementation levels of much-needed integrated management practices. </p>
<h2>Prioritizing hotspot basins</h2>
<p>The location of hotspot basins across the world emphasizes the need for global and urgent action. Prioritizing regions based on their potential to experience social and ecological impacts can improve the effectiveness of global freshwater sustainability initiatives.</p>
<p>Our study calculated how vulnerable all the basins in the world were to the social and ecological impacts of freshwater stress and storage loss. We identified the most vulnerable basins as hotspots for global prioritization. However, while we focus on the identified hotspot basins, this does not mean that impacts cannot occur in basins with lower vulnerabilities. </p>
<figure class="align-right ">
<img alt="A dry section of a river." src="https://images.theconversation.com/files/487948/original/file-20221004-26-t92w96.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/487948/original/file-20221004-26-t92w96.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/487948/original/file-20221004-26-t92w96.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/487948/original/file-20221004-26-t92w96.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/487948/original/file-20221004-26-t92w96.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/487948/original/file-20221004-26-t92w96.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/487948/original/file-20221004-26-t92w96.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A dry section of the Cowichan River on Vancouver Island, B.C.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Kevin Rothbauer</span></span>
</figcaption>
</figure>
<p>For instance, only a number of Canadian basins — all located in the prairies — are identified with moderate vulnerability in our global study. Yet, <a href="https://watershedsentinel.ca/articles/groundwater-pumping-drains-rivers-in-bc-and-globally/">dry streams on Vancouver Island</a>, <a href="https://doi.org/10.1080/07011784.2014.885677">falling groundwater levels in the Lower Mainland</a>, <a href="https://www.cbc.ca/news/canada/manitoba/drought-agriculture-disaster-rm-of-armstrong-manitoba-1.6100138">crop yields affected by drought throughout the prairies</a> and potential for <a href="https://www.cbc.ca/news/canada/nova-scotia/n-s-panel-discussing-climate-change-impacts-on-well-water-groundwater-1.6210051">salt-water intrusion along the East Coast</a> are all instances of freshwater security challenges being faced in Canada. </p>
<p>With <a href="https://thenarwhal.ca/saskatchewan-irrigation-project-explained/">massive expansion planned for irrigated agriculture in Saskatchewan</a> and increasing <a href="https://watershedwatch.ca/wp-content/uploads/2019/09/2019-09-24-Tapped-Out-RGB.pdf">water scarcity across British Columbia</a>, Canada’s current (and enviable) position of being able to act proactively on water security challenges is rapidly shrinking.</p>
<h2>Global action starts locally</h2>
<p>While our study took a global focus, the approach of mapping vulnerability to guide priority setting can be applied at other geographical scales. For instance, this analysis could be refined and applied to Canada or specific provinces or cities using globally unavailable data that may be available for these jurisdictions.</p>
<p>These insights could help boost urgency to act on the emerging national water crisis, aid the <a href="https://gwf.usask.ca/documents/meetings/water-security-for-canada/WaterSecurityForCanada_April-25-2019-2pg1.pdf">modernization of the Canada Water Act</a> or help identify communities that would benefit most from <a href="https://poliswaterproject.org/files/2019/10/POLIS-WSP2019-6e1-web.pdf">water sustainability plans</a> in British Columbia.</p>
<p>While global studies, such as ours, are helpful at systematically highlighting regions for prioritization, they do not — and should not — provide explicit solutions. Rather, in such intricate social and ecological environments, actions to reduce impacts need to be attuned to place-based social norms, cultural values, hydrological conditions and local knowledge systems. </p>
<p>Our hotspot basins can help guide such community-driven local action to help conserve freshwater resources that are most under threat and mitigate the ripple effects of these threats on people and ecosystems.</p><img src="https://counter.theconversation.com/content/187042/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Xander Huggins receives funding from the Natural Sciences and Engineering Research Council of Canada through a doctoral Canada Graduate Scholarship.</span></em></p>While we know how global changes in freshwater pose risks to humans and ecosystems, we know less about how people and ecosystems will respond to these global freshwater challenges.Xander Huggins, PhD Candidate in the Department of Civil Engineering (University of Victoria) and the Global Institute for Water Security (University of Saskatchewan), University of VictoriaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1892222022-09-19T19:12:19Z2022-09-19T19:12:19Z1,000-year-old stalagmites from a cave in India show the monsoon isn’t so reliable – their rings reveal a history of long, deadly droughts<figure><img src="https://images.theconversation.com/files/482572/original/file-20220902-17-s9as81.JPG?ixlib=rb-1.1.0&rect=510%2C11%2C3338%2C2215&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Stalagmites grow from the cave floor up as water drips down.</span> <span class="attribution"><span class="source">Gayatri Kathayat</span></span></figcaption></figure><p>In a remote cave in northeast India, rainwater has slowly dripped from the ceiling in the same spots for over 1,000 years. With each drop, minerals in the water accumulate on the floor below, slowly growing into calcium carbonate towers known as <a href="https://earthobservatory.nasa.gov/features/Paleoclimatology_Speleothems">stalagmites</a>.</p>
<p>These stalagmites are more than geological wonders – like tree rings, their layers record the region’s rainfall history. They also carry a warning about the potential for catastrophic multiyear droughts in the future. </p>
<p>By analyzing the geochemistry of these stalagmites in a <a href="https://www.pnas.org/">new study</a> published Sept. 19, 2022, in the Proceedings of the National Academy of Sciences, we were able to create the most precise chronology yet of the summer Indian monsoon over the past millennium. It documents how the Indian subcontinent frequently experienced long, severe droughts unlike any observed in the last 150 years of reliable <a href="https://mol.tropmet.res.in/monsoon-interannual-timeseries/">monsoon rainfall</a> measurements. </p>
<p>The drought periods we detected are in striking synchrony with <a href="https://famineanddearth.exeter.ac.uk/index.html">historical accounts of droughts, famines</a>, <a href="https://www.indianculture.gov.in/rarebooks/history-and-economics-indian-famines">mass mortality events</a> and <a href="https://doi.org/10.1016/j.eeh.2007.11.002">geopolitical changes in the region</a>.</p>
<p>They show how the decline of the Mughal Empire and India’s textile industries in the 1780s and 1790s coincided with the most severe 30-year period of drought over the millennium. The depth and duration of the drought would have caused widespread crop failures and the level of famine <a href="http://sro.sussex.ac.uk/id/eprint/83046/3/final1780srevised1.pdf">discussed in written documents</a> at the time. </p>
<p>Another long drought encompasses the 1630-1632 Deccan famine, one of the most devastating droughts in India’s history. Millions of people died as crops failed. Around the same time, the elaborate Mughal capital of <a href="https://www.jstor.org/stable/41372237">Fatehpur Sikri was abandoned</a> and the <a href="https://doi.org/10.1126/sciadv.1701296">Guge Kingdom collapsed</a> in western Tibet.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/482563/original/file-20220902-13436-lqzj39.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482563/original/file-20220902-13436-lqzj39.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=518&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482563/original/file-20220902-13436-lqzj39.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=518&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482563/original/file-20220902-13436-lqzj39.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=518&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482563/original/file-20220902-13436-lqzj39.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=651&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482563/original/file-20220902-13436-lqzj39.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=651&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482563/original/file-20220902-13436-lqzj39.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=651&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Buland Darwaza (Door of Victory) at Fatehpur Sikri, India.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Fatehput_Sikiri_Buland_Darwaza_gate_2010.jpg">Marcin Białek via Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>Our findings have important implications today for water planning in a warming world, particularly for India, which, with its vast monsoon-reliant agriculture industry, is on pace to <a href="https://www.un.org/development/desa/pd/sites/www.un.org.development.desa.pd/files/wpp2022_summary_of_results.pdf">soon be the most populous</a> country on the planet.</p>
<h2>Why the monsoon’s history matters</h2>
<p>Scientists began systematically measuring India’s monsoon rainfall with instruments around the 1870s. Since then, India has experienced about 27 regionally widespread droughts. Among them, only one – 1985 to 1987 – was a three-year consecutive drought or worse.</p>
<p><iframe id="7DqHs" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/7DqHs/2/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>The apparent stability of the Indian monsoon in that data might lead one to surmise that neither protracted droughts lasting multiple years nor frequent droughts are intrinsic aspects of its variability. This seemingly reassuring view currently informs the region’s present-day water resource infrastructure.</p>
<p>However, the stalagmite evidence of prolonged, severe droughts over the past 1,000 years paints a different picture.</p>
<p>It indicates that the short instrumental period does not capture the full range of Indian monsoon variability. It also raises questions about the region’s current water resources, sustainability and mitigation policies that discount the possibility of protracted droughts in the future.</p>
<figure class="align-center ">
<img alt="Line chart through time showing drought years and rainy years, with several periods of extreme drought." src="https://images.theconversation.com/files/482443/original/file-20220902-24-7ko4kb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482443/original/file-20220902-24-7ko4kb.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=388&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482443/original/file-20220902-24-7ko4kb.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=388&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482443/original/file-20220902-24-7ko4kb.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=388&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482443/original/file-20220902-24-7ko4kb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=488&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482443/original/file-20220902-24-7ko4kb.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=488&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482443/original/file-20220902-24-7ko4kb.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=488&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Timeline of major societal and geopolitical changes in India and the oxygen isotope record from Mawmluh cave.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1073/pnas.2207487119">Gayatri Kathayat</a></span>
</figcaption>
</figure>
<h2>How do stalagmites capture a region’s monsoon history?</h2>
<p>To reconstruct past variations in rainfall, we analyzed stalagmites from Mawmluh cave, near the town of Cherrapunji in the state of Meghalaya – <a href="https://blog.thomascook.in/cherrapunji-the-wettest-place-on-earth">one of the wettest locations in the world</a>.</p>
<p>Stalagmites are conelike structures that grow slowly from the ground up, typically at a rate of about one millimeter every 10 years. Trapped within their growth layers are minute amounts of uranium and other elements that were acquired as rainwater infiltrated the rocks and soil above the cave. Over time, uranium trapped in stalagmites decays into thorium at a predictable pace, so we can figure out the age of each stalagmite growth layer by <a href="https://doi.org/10.1016/B978-0-12-814124-3.00128-X">measuring the ratio of uranium to thorium</a>.</p>
<p>The oxygen in rainwater molecules comes in two primary types of isotopes – heavy and light. As stalagmites grow, they lock into their structure the oxygen isotope ratios of the percolating rainwater that seeps into the cave. Subtle variations in this ratio can arise from a range of climatic conditions at the time the rainwater originally fell.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/482573/original/file-20220902-26-qic1wi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo from inside a cave, with red ribbons tied around two different stalagmites." src="https://images.theconversation.com/files/482573/original/file-20220902-26-qic1wi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482573/original/file-20220902-26-qic1wi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482573/original/file-20220902-26-qic1wi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482573/original/file-20220902-26-qic1wi.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482573/original/file-20220902-26-qic1wi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482573/original/file-20220902-26-qic1wi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482573/original/file-20220902-26-qic1wi.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Stalagmite formation are marked inside Mawmluh Cave, where the new study was based.</span>
<span class="attribution"><span class="source">Gayatri Kathayat</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/482575/original/file-20220902-20-4ueeds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The interior of a stalagmite when sliced vertically shows its growth rings." src="https://images.theconversation.com/files/482575/original/file-20220902-20-4ueeds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482575/original/file-20220902-20-4ueeds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=294&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482575/original/file-20220902-20-4ueeds.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=294&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482575/original/file-20220902-20-4ueeds.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=294&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482575/original/file-20220902-20-4ueeds.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=369&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482575/original/file-20220902-20-4ueeds.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=369&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482575/original/file-20220902-20-4ueeds.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=369&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A cross-section of a stalagmite shows differences in its ring formation as climate conditions changed.</span>
<span class="attribution"><span class="source">Gayatri Kathayat</span></span>
</figcaption>
</figure>
<p>Our <a href="https://doi.org/10.1038/s43247-021-00165-z">previous research in this area showed</a> that variations in oxygen isotope ratios in rainwater, and consequently, in stalagmites, track changes in the relative abundance of different moisture sources that contribute to summer monsoon rainfall.</p>
<p>During years when monsoon circulation is weak, rainfall here is primarily derived from the moisture that evaporated from the nearby Arabian Sea. During strong monsoon years, however, atmospheric circulation brings copious amounts of moisture to this area all the way from the southern Indian Ocean.</p>
<p>The two moisture sources have quite different oxygen isotope signatures, and this ratio is faithfully preserved in the stalagmites. We can use this clue to learn about the overall strength of the monsoon intensity at the time the stalagmite formed. We pieced together the <a href="https://doi.org/10.1073/pnas.2207487119">monsoon rainfall history</a> by extracting minute amounts of calcium carbonate from its growth rings and then measuring the oxygen isotope ratios. To anchor our climate record to precise calendar years, we measured the uranium and thorium ratio.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/482574/original/file-20220902-20-5e2ea0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A group of stalagmite cones rise from the cave floor in a dramatic image" src="https://images.theconversation.com/files/482574/original/file-20220902-20-5e2ea0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482574/original/file-20220902-20-5e2ea0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482574/original/file-20220902-20-5e2ea0.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482574/original/file-20220902-20-5e2ea0.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482574/original/file-20220902-20-5e2ea0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482574/original/file-20220902-20-5e2ea0.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482574/original/file-20220902-20-5e2ea0.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Stalagmites grow from the ground, and stalactites grow from above. These are in Mawmluh Cave, where the authors conducted their research.</span>
<span class="attribution"><span class="source">Gayatri Kathayat</span></span>
</figcaption>
</figure>
<h2>Next steps</h2>
<p>The paleoclimate records can usually tell what, where and when something happened. But often, they alone cannot answer why or how something happened. </p>
<p>Our new study shows that protracted droughts frequently occurred during the past millennia, but we do not have a good understanding of why the monsoon failed in those years. Similar studies using Himalayan ice cores, tree rings and other caves have also detected protracted droughts but face the same challenge. </p>
<p>In the next phase of our study, we are teaming up with climate modelers to conduct coordinated proxy-modeling studies that we hope will offer more insight into the climate dynamics that triggered and sustained such extended periods of drought during the past millennium.</p><img src="https://counter.theconversation.com/content/189222/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gayatri Kathayat receives funding from the National Natural Science Foundation of China </span></em></p><p class="fine-print"><em><span>Ashish Sinha receives funding from the US National Science Foundation and the Chinese Academy of Sciences President's International Fellowship Initiative.</span></em></p>As water dripped in a remote cave, it left behind evidence of every monsoon season for a millennium. Scientists say it holds a warning for a country about to become the most populous on Earth.Gayatri Kathayat, Associate Professor of Global Environmental Change, Xi'an Jiaotong UniversityAshish Sinha, Professor of Earth and Climate Sciences, California State University, Dominguez HillsLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1908982022-09-19T11:45:55Z2022-09-19T11:45:55ZTyphoon Merbok, fueled by unusually warm Pacific Ocean, pounded Alaska’s vulnerable coastal communities at a critical time<figure><img src="https://images.theconversation.com/files/485177/original/file-20220918-52219-igrjib.jpg?ixlib=rb-1.1.0&rect=28%2C7%2C1649%2C1058&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A satellite image shows how vast the remnants of Typhoon Merbok were as the storm hit the Alaska coast.</span> <span class="attribution"><a class="source" href="https://twitter.com/NWSFairbanks/status/1571054643383533569">National Weather Service</a></span></figcaption></figure><p><em>The powerful remnants of Typhoon Merbok pounded Alaska’s western coast on Sept. 17, 2022, pushing homes off their foundations and tearing apart protective berms as water flooded communities.</em> </p>
<p><em>Storms aren’t unusual here, but Merbok built up over unusually warm water. Its <a href="https://twitter.com/NWSOPC/status/1570883906794311682">waves reached 50 feet</a> over the Bering Sea, and its storm surge sent water levels into communities at <a href="https://twitter.com/AlaskaWx/status/1571266836771270659">near record highs</a> along with near hurricane-force winds.</em></p>
<p><em>Merbok also hit during the fall subsistence harvest season, when the region’s Indigenous communities are stocking up food for the winter. Rick Thoman, a <a href="https://news.uaf.edu/expertsguide/rick-thoman/">climate scientist at the University of Alaska Fairbanks</a>, explained why the storm was unusual and the impact it’s having on coastal Alaskans.</em></p>
<h2>What stands out the most about this storm?</h2>
<p>It <a href="https://www.weather.gov/media/arh/RN-05-0003.pdf">isn’t unusual</a> for typhoons to affect some portion of Alaska, typically in the fall, but Merbok was different. </p>
<p>It <a href="https://twitter.com/Climatologist49/status/1571218582293610496/photo/1">formed in a part of the Pacific</a>, far east of Japan, where historically few typhoons form. The water there is typically too cold to support a typhoon, but right now, we have extremely warm water in the north-central Pacific. Merbok traveled right over waters that are the warmest on record going back about 100 years.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/485179/original/file-20220918-51705-mljo8r.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map shows warm waters off Japan and Russia's Kamchatka region." src="https://images.theconversation.com/files/485179/original/file-20220918-51705-mljo8r.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/485179/original/file-20220918-51705-mljo8r.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=396&fit=crop&dpr=1 600w, https://images.theconversation.com/files/485179/original/file-20220918-51705-mljo8r.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=396&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/485179/original/file-20220918-51705-mljo8r.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=396&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/485179/original/file-20220918-51705-mljo8r.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=498&fit=crop&dpr=1 754w, https://images.theconversation.com/files/485179/original/file-20220918-51705-mljo8r.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=498&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/485179/original/file-20220918-51705-mljo8r.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=498&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sea surface temperatures show unusually warm water over the eastern Pacific Ocean, where Typhoon Merbok passed through.</span>
<span class="attribution"><a class="source" href="https://uaf-accap.org/">Alaska Center for Climate Assessment</a></span>
</figcaption>
</figure>
<p>The Western Bering Sea, closer to Russia, has been running above normal sea surface temperature since last winter. The Eastern Bering Sea – the Alaska part – has been normal to slightly cooler than normal since spring. That temperature difference in the Bering Sea helped to feed the storm and was probably part of the reason the storm intensified to the level it did. </p>
<p>When Merbok moved in to the Bering Sea, it wound up being by far the strongest storm this early in the autumn. We’ve had stronger storms, but they typically occur in October and November.</p>
<h2>Did climate change have a bearing on the storm?</h2>
<p>There’s a strong likelihood that Merbok was able to form where it did because of the <a href="https://www.ncei.noaa.gov/cag/global/time-series/globe/ocean/12/12/1880-2022">warming ocean</a>.</p>
<p>With warm ocean water, there’s <a href="https://climate.nasa.gov/ask-nasa-climate/3143/steamy-relationships-how-atmospheric-water-vapor-amplifies-earths-greenhouse-effect/">more evaporation going in the atmosphere</a>. Because all the atmospheric ingredients came together, Merbok was able to bring that very warm moist air along with it. Had the ocean been a <a href="https://www.ncei.noaa.gov/cag/global/time-series/globe/ocean/12/12/1880-2022">temperature more typical of 1960</a>, there wouldn’t have been as much moisture in the storm.</p>
<figure class="align-center ">
<img alt="Bar chart showing temperatures rising" src="https://images.theconversation.com/files/485199/original/file-20220919-62263-2t01r9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/485199/original/file-20220919-62263-2t01r9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=360&fit=crop&dpr=1 600w, https://images.theconversation.com/files/485199/original/file-20220919-62263-2t01r9.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=360&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/485199/original/file-20220919-62263-2t01r9.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=360&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/485199/original/file-20220919-62263-2t01r9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=453&fit=crop&dpr=1 754w, https://images.theconversation.com/files/485199/original/file-20220919-62263-2t01r9.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=453&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/485199/original/file-20220919-62263-2t01r9.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=453&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Global ocean temperatures have been rising. The bars show how annual temperatures departed from the 20th century average.</span>
<span class="attribution"><a class="source" href="https://www.ncei.noaa.gov/cag/global/time-series/globe/ocean/12/12/1880-2022">NOAA</a></span>
</figcaption>
</figure>
<h2>How extreme was the flooding compared to past storms?</h2>
<p>The most outstanding feature as far as impact is the tremendous area that was damaged. All coastal regions north of Bristol Bay to just beyond the Bering Strait – hundreds of miles of coastline – had some impact. </p>
<p>At Nome – one of the very few places in western Alaska where we have long-term ocean level information – the ocean was <a href="https://twitter.com/AlaskaWx/status/1571266836771270659">10.5 feet</a> (3.2 meters) above the low-tide line on Sept. 17, 2022. That’s the highest there in nearly half a century, since the historic storm of <a href="https://doi.org/10.1080/00431672.1975.9931740">November 1974</a>.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1571514507041595392"}"></div></p>
<p>In <a href="https://www.nytimes.com/2022/09/17/us/alaska-storm.html">Golovin</a> and <a href="https://www.ktoo.org/2022/09/17/powerful-storm-slams-western-alaska/">Newtok</a>, multiple houses floated off their foundations and are no longer habitable.</p>
<p><a href="https://savingplaces.org/stories/fighting-the-rising-tide-in-shaktoolik-alaska#.Yyd7pHbML8A">Shaktoolik</a> lost its protective berm, which is very bad news. Prior to building the berm, the community’s freshwater supply was easily inundated with saltwater. The community is now at greater risk of flooding, and even a moderate storm could inundate their fresh water supply. They can rebuild it, but how fast is a matter of time and money and resources. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1571310275739156480"}"></div></p>
<p>Another important impact is to hunting and fishing camps along the coasts. Because of the <a href="https://www.nps.gov/gis/storymaps/cascade/v1/index.html?appid=42e0af0fd1ab485596a0475d186a0919">region’s subsistence economy</a>, those camps are crucial, and they are expensive to rebuild. </p>
<p>There are no roads into these coastal communities, and <a href="https://www.ktoo.org/2022/02/21/construction-supply-chain-woes-in-rural-alaska/">getting lumber for rebuilding</a> homes and these camps is difficult. And we’re moving into typically the stormiest time of year, which makes recovery harder and planes often can’t land.</p>
<p>Lots of places also lost power and cell phone communication. The power in these remote areas is generated in the community – if that goes out there is no alternative. People lose power to their freezers, which they’re stocking up for the winter. Towns might have one grocery store, and if that can’t open or loses power, there is no other option. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1571235158342373383"}"></div></p>
<p>Winter is coming, and the time when it’s feasible to make repairs is running short. This is also the middle of hunting season, which in western Alaska is not recreation – it’s how you feed your family. These are almost all predominantly or almost exclusively Indigenous communities. Repairs are going to take time away for subsistence hunters, so all of these things are coming together at once. </p>
<h2>Does the lack of sea ice as a buffer make a difference for erosion?</h2>
<p>Historically, with storms later in the season, even a small bit of sea ice can offer protection to dampen the waves. But there’s <a href="http://nsidc.org/arcticseaicenews/2022/09/the-arctics-bald-spot/">no ice in the Bering Sea</a> at all this time of year. The full wave action pounds right to the beach. </p>
<p>As sea ice <a href="https://climate.nasa.gov/vital-signs/arctic-sea-ice/">declines with warming global temperatures</a>, communities will see more damage from storms later in the year, too.</p>
<h2>Are there lessons from this storm for Alaska?</h2>
<p>As bad as this storm was, and it was very bad, others will be coming. This is a stormy part of the world, and state and federal governments need to do a better job of communicating risks and helping communities and tribes ahead of time. </p>
<p>That might mean evacuating vulnerable people. Because if you wait until it’s certain that there’s a problem, it’s too late. Almost all of these communities are isolated. </p>
<p>I would say this is a classic case of large-scale weather models showing a general idea of the risk far in advance, but it takes longer to respond for isolated communities like those in rural Alaska. By Sept. 12, <a href="https://twitter.com/Climatologist49/status/1571218582293610496">Merbok’s storm track was clear</a>, but if communities aren’t briefed until a day or two days before the storm, there isn’t enough time for them to fully prepare.</p><img src="https://counter.theconversation.com/content/190898/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rick Thoman does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Most of the flooded communities are Indigenous and rely on subsistence hunting that residents would normally be doing right now. Recovering from the damage will make that harder.Rick Thoman, Alaska Climate Specialist, University of Alaska FairbanksLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1889652022-08-18T18:00:46Z2022-08-18T18:00:46ZHow to destroy a ‘forever chemical’ – scientists are discovering ways to eliminate PFAS, but this growing global health problem isn’t going away soon<figure><img src="https://images.theconversation.com/files/479758/original/file-20220817-11729-4rn4zo.jpg?ixlib=rb-1.1.0&rect=854%2C251%2C5853%2C3852&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">How long do we really need chemicals to last?</span> <span class="attribution"><a class="source" href="http://gettyimages.com/detail/photo/close-up-of-glasses-royalty-free-image/1338710777">Sura Nualpradid/EyeEm via Getty Images</a></span></figcaption></figure><p>PFAS chemicals seemed like a good idea at first. As <a href="https://www.aps.org/publications/apsnews/202104/history.cfm">Teflon</a>, they made pots easier to clean starting in the 1940s. They made jackets waterproof and carpets stain-resistant. Food wrappers, firefighting foam, even makeup seemed better with perfluoroalkyl and polyfluoroalkyl substances.</p>
<p>Then tests started detecting <a href="https://static.ewg.org/reports/2020/pfas-epa-timeline/1998_3M-Alerts-EPA.pdf">PFAS in people’s blood</a>.</p>
<p>Today, PFAS are pervasive in soil, dust and drinking water around the world. Studies suggest they’re in <a href="https://doi.org/10.1289/ehp.10598">98% of Americans’ bodies</a>, where they’ve been <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7906952/">associated with health problems</a> including thyroid disease, liver damage and kidney and testicular cancer. There are now <a href="https://www.cdc.gov/niosh/topics/pfas/default.html">over 9,000 types</a> of PFAS. They’re often referred to as “forever chemicals” because the same properties that make them so useful also <a href="https://www.michigan.gov/-/media/Project/Websites/PFAS-Response/Reports/Report-2018-12-07-Science-Advisory-Board.pdf?rev=4a075fe29d794a3a942729557c4e6745">ensure they don’t break down in nature.</a></p>
<p>Scientists are working on methods to capture these synthetic chemicals and destroy them, but it isn’t simple. </p>
<p>The <a href="https://doi.org/10.1126/science.abm8868">latest breakthrough</a>, published Aug. 18, 2022, in the journal Science, shows how one class of PFAS can be broken down into mostly harmless components using sodium hydroxide, or lye, an inexpensive compound used in soap. It isn’t an immediate solution to this vast problem, but it offers new insight.</p>
<p>Biochemist <a href="https://scholar.google.com/citations?user=fbJ7DGMAAAAJ&hl=en">A. Daniel Jones</a> and soil scientist <a href="https://scholar.google.com/citations?user=K5qNMk4AAAAJ&hl=en">Hui Li</a> work on PFAS solutions at the Michigan State University and explained the promising PFAS destruction techniques being tested today. </p>
<h2>How do PFAS get from everyday products into water, soil and eventually humans?</h2>
<p>There are two main exposure pathways for PFAS to get into humans – drinking water and food consumption.</p>
<p>PFAS can get into soil through land application of biosolids, that is, sludge from wastewater treatment, and can they leach out from landfills. If contaminated biosolids are <a href="https://www.michigan.gov/mdard/environment/rtf/biosolids/gen/frequently-asked-biosolids-questions">applied to farm fields as fertilizer</a>, PFAS can get into water and into crops and vegetables.</p>
<p>For example, livestock can consume PFAS through the crops they eat and water they drink. There have been <a href="https://www.michigan.gov/mdard/about/media/pressreleases/2022/01/28/grostic-cattle-company-of-livingston-county-beef-sold-directly-to-consumers-may-contain-pfos">cases reported in Michigan</a>, <a href="https://www.washingtonpost.com/nation/2022/04/11/pfas-forever-chemicals-maine-farm/">Maine</a> and <a href="https://nmpoliticalreport.com/2021/12/21/dairy-farmers-facing-pfas-contamination-now-eligible-for-payment-for-their-cattle/">New Mexico</a> of elevated levels of PFAS in beef and in dairy cows. How big the potential risk is to humans is still <a href="https://www.ewg.org/news-insights/news/2022/04/ewg-forever-chemicals-may-taint-nearly-20-million-cropland-acres">largely unknown</a>. </p>
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<img alt="Two cows look over a wooden hay trough with a barn in the background." src="https://images.theconversation.com/files/479759/original/file-20220817-18153-uivgbk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/479759/original/file-20220817-18153-uivgbk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479759/original/file-20220817-18153-uivgbk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479759/original/file-20220817-18153-uivgbk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479759/original/file-20220817-18153-uivgbk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479759/original/file-20220817-18153-uivgbk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479759/original/file-20220817-18153-uivgbk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Cows were found with high levels of PFAS at a farm in Maine.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/cows-with-high-levels-of-pfas-on-a-farm-royalty-free-image/1178310633">Adam Glanzman/Bloomberg via Getty Images</a></span>
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<p>Scientists in our group at Michigan State University are working on materials added to soil that could prevent plants from taking up PFAS, but it would leave PFAS in the soil.</p>
<p>The problem is that these chemicals are everywhere, and there is <a href="https://www.michigan.gov/-/media/Project/Websites/PFAS-Response/Reports/Report-2018-12-07-Science-Advisory-Board.pdf?rev=4a075fe29d794a3a942729557c4e6745">no natural process</a> in water or soil that breaks them down. Many consumer products are loaded with PFAS, including makeup, dental floss, guitar strings and ski wax.</p>
<h2>How are remediation projects removing PFAS contamination now?</h2>
<p>Methods exist for filtering them out of water. The chemicals will stick to activated carbon, for example. But these methods are expensive for large-scale projects, and you still have to get rid of the chemicals.</p>
<p>For example, near a former military base near Sacramento, California, there is a huge activated carbon tank that takes in <a href="https://www.afcec.af.mil/News/Article-Display/Article/2530050/new-water-treatment-systems-address-pfospfoa-issues-at-former-mather-afb/">about 1,500 gallons</a> of contaminated groundwater per minute, filters it and then pumps it underground. That remediation project has cost <a href="https://www.afcec.af.mil/News/Article-Display/Article/2530050/new-water-treatment-systems-address-pfospfoa-issues-at-former-mather-afb/">over $3 million</a>, but it prevents PFAS from moving into drinking water the community uses.</p>
<p>Filtering is just one step. Once PFAS is captured, then you have to dispose of PFAS-loaded activated carbons, and PFAS still moves around. If you bury contaminated materials in a landfill or elsewhere, PFAS will eventually leach out. That’s why finding ways to destroy it are essential.</p>
<h2>What are the most promising methods scientists have found for breaking down PFAS?</h2>
<p>The most common method of destroying PFAS is incineration, but most PFAS are remarkably resistant to being burned. That’s why they’re in firefighting foams.</p>
<p><a href="https://www.niehs.nih.gov/health/topics/agents/pfc/index.cfm">PFAS have multiple</a> fluorine atoms attached to a carbon atom, and the bond between carbon and fluorine is one of the strongest. Normally to burn something, you have to break the bond, but fluorine resists breaking off from carbon. Most PFAS will break down completely at incineration temperatures around <a href="https://www.regulations.gov/document/EPA-HQ-OLEM-2020-0527-0002">1,500 degrees Celsius</a> (2,730 degrees Fahrenheit), but it’s energy intensive and suitable incinerators are scarce.</p>
<p>There are several other experimental techniques that are promising but haven’t been scaled up to treat large amounts of the chemicals.</p>
<p>A group at Battelle has developed <a href="https://doi.org/10.1061/(ASCE)EE.1943-7870.0001957">supercritical water oxidation</a> to destroy PFAS. High temperatures and pressures change the state of water, accelerating chemistry in a way that can destroy hazardous substances. However, scaling up remains a challenge. </p>
<p>Others are <a href="https://doi.org/10.1016/j.jhazmat.2020.124452">working with</a> <a href="https://www.af.mil/News/Article-Display/Article/2009997/air-force-tests-plasma-reactor-to-degrade-destroy-synthetic-chemical-compounds/">plasma reactors,</a> which use water, electricity and argon gas to break down PFAS. They’re fast, but also not easy to scale up. </p>
<p>The method described in the <a href="https://doi.org/10.1126/science.abm8868">new paper</a>, led by scientists at Northwestern, is promising for what they’ve learned about how to break up PFAS. It won’t scale up to industrial treatment, and it uses <a href="https://www.acs.org/content/acs/en/molecule-of-the-week/archive/d/dimethyl-sulfoxide.html">dimethyl sulfoxide</a>, or DMSO, but these findings will guide future discoveries about what might work.</p>
<h2>What are we likely to see in the future?</h2>
<p>A lot will depend on what we learn about where humans’ PFAS exposure is primarily coming from.</p>
<p>If the exposure is mostly from drinking water, there are more methods with potential. It’s possible it could eventually be destroyed at the household level with electro-chemical methods, but there are also potential risks that remain to be understood, such as converting common substances such as chloride into more toxic byproducts.</p>
<p>The big challenge of remediation is making sure we don’t make the problem worse by releasing other gases or creating harmful chemicals. Humans have a long history of trying to solve problems and making things worse. Refrigerators are a great example. Freon, a chlorofluorocarbon, was the solution to replace toxic and flammable ammonia in refrigerators, but then <a href="https://www.pca.state.mn.us/air/chlorofluorocarbons-cfcs-and-hydrofluorocarbons-hfcs">it caused stratospheric ozone depletion</a>. It was replaced with hydrofluorocarbons, which now <a href="https://www.ccacoalition.org/fr/slcps/hydrofluorocarbons-hfcs">contribute to climate change</a>. </p>
<p>If there’s a lesson to be learned, it’s that we need to think through the full life cycle of products. How long do we really need chemicals to last?</p>
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Read more:
<a href="https://theconversation.com/what-are-pfas-the-forever-chemicals-showing-up-in-drinking-water-an-environmental-health-scientist-explains-185015">What are PFAS, the 'forever chemicals' showing up in drinking water? An environmental health scientist explains</a>
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<img src="https://counter.theconversation.com/content/188965/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>A. Daniel Jones receives funding from the National Science Foundation, National Institutes of Health, U.S. Department of Agriculture-National Institute of Food and Agriculture, U.S. Forest Service, and the U.S. Department of Defense Strategic Environmental Research and Development Program (SERDP).</span></em></p><p class="fine-print"><em><span>Hui Li receives funding from the Environmental Protection Agency, U.S. Department of Agriculture, and National Institute of Environmental Health Sciences.</span></em></p>PFAS can be filtered, but getting rid of the chemicals is a monumental challenge. A new breakthrough offers some hope.A. Daniel Jones, Professor of Biochemistry, Michigan State UniversityHui Li, Professor of Environmental and Soil Chemistry, Michigan State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1826402022-05-19T12:49:57Z2022-05-19T12:49:57ZGrim 2022 drought outlook for Western US offers warnings for the future as climate change brings a hotter, thirstier atmosphere<figure><img src="https://images.theconversation.com/files/464126/original/file-20220518-16-7pljn3.jpg?ixlib=rb-1.1.0&rect=0%2C16%2C5576%2C3572&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Farmers in some regions are being encouraged to preserve and establish grasslands that can survive drought and protect the soil.</span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/AquiferDepletionDustBowl/8a21df0f3f4f46c3a513ada5b49c63b7/photo">AP Photo/Mark Rogers</a></span></figcaption></figure><p>Much of the western U.S. has been in the grip of an <a href="https://www.climate.gov/news-features/event-tracker/noaa-led-drought-task-force-concludes-current-southwest-drought-preview">unrelenting drought</a> since early 2020. The dryness has coincided with record-breaking <a href="https://www.theguardian.com/world/2022/may/01/us-new-mexico-drought-wildfire-southwest">wildfires</a>, intense and long-lasting <a href="https://www.worldweatherattribution.org/western-north-american-extreme-heat-virtually-impossible-without-human-caused-climate-change/">heat waves</a>, <a href="https://phys.org/news/2022-04-drought-western-scrambling.html">low stream flows</a> and <a href="https://www.nytimes.com/2022/05/03/climate/lake-powell-mead-water-drought.html">dwindling water supplies in reservoirs</a> that millions of people across the region rely on. </p>
<p>Heading into summer, <a href="https://images.theconversation.com/files/464284/original/file-20220519-11-igtk3o.png">the</a> <a href="https://www.cpc.ncep.noaa.gov/products/expert_assessment/sdo_summary.php">outlook</a> is pretty grim.</p>
<p>One driver of the Western drought has been <a href="https://www.pe.com/2021/09/24/la-nina-is-about-to-take-the-southwest-drought-from-bad-to-worse/">persistent La Niña conditions</a> in the tropical Pacific since the <a href="https://psl.noaa.gov/enso/mei/">summer of 2020</a>. During La Niña, cooler tropical Pacific waters help nudge the jet stream northward. That tends to bring <a href="https://www.climate.gov/news-features/understanding-climate/el-ni%C3%B1o-and-la-ni%C3%B1a-frequently-asked-questions">fewer storms to the southern tier of the U.S.</a> and produce pronounced drought impacts in the Southwest.</p>
<p>The <a href="https://www.nationalgeographic.com/environment/article/the-drought-in-the-western-us-could-last-until-2030">other</a> and perhaps more important part of the story is the <a href="https://thenevadaindependent.com/article/warming-is-making-the-west-thirstier-researchers-say-and-its-stressing-water-supplies-%EF%BF%BC">hotter and thirstier atmosphere, caused by a rapidly warming climate</a>.</p>
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<p>As a <a href="https://cires.colorado.edu/researcher/imtiaz-rangwala">climate scientist</a>, I’ve watched how climate change is making drought conditions increasingly worse – particularly in the western and central U.S. The last two years have been more than 2 degrees Fahrenheit (1.1 Celsius) warmer than normal in these regions. Large swaths of the Southwest have been even hotter, with temperatures more than 3 F (1.7 C) higher. <a href="https://www.scientificamerican.com/article/western-megadrought-is-the-worst-in-1-200-years/">Studies suggest the Southwest’s ongoing 20-year drought</a> is the most severe in at least 1,200 years, based on how dry the soils are.</p>
<h2>A hotter atmosphere sucks more moisture from the soil</h2>
<p>A thristier atmosphere tends to extract more water out of the land. It exacerbates <a href="https://www.drought.gov/data-maps-tools/evaporative-stress-index-esi">evaporative stress</a> on the land, particularly when a region is experiencing below-normal precipitation. High evaporative stress can rapidly deplete soil moisture and lead to hotter temperatures, as the <a href="https://coolcalifornia.arb.ca.gov/how-cool-vegetation-works">evaporative cooling effect</a> is diminished. All this creates hydroclimatic stress for plants, causing restricted growth, drying and even death.</p>
<p>As a consequence of a warming climate, the U.S. Southwest has seen an 8% increase in this evaporative demand since the 1980s. This trend is generally <a href="https://cpo.noaa.gov/News/ArtMID/7875/ArticleID/2523/NIDIS-Funded-Project-Finds-That-Evaporative-Demand-Increase-Across-Lower-48-Means-Less-Water-Supplies-Drier-Vegetation-and-Higher-Fire-Risk">happening across other parts of the country</a>.</p>
<p>The <a href="https://www.climate.gov/news-features/feed/evaporative-demand-increase-across-lower-48-means-less-water-supplies-drier">thistier atmosphere</a> is turning what would otherwise be near-normal or moderately dry conditions into droughts that are more severe or extreme. As the climate heats up further, the increasing atmospheric thirst will continue to intensify drought stress, with consequences for water availability, long-lasting and intense heat stress, and large-scale ecosystem transformation.</p>
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<p>Climate models project ominous prospects of <a href="https://doi.org/10.1073/pnas.2006323117">a more arid climate and more severe droughts</a> in the Southwest and southern Great Plains in the coming decades.</p>
<p>In addition to direct impacts of increasing temperatures on future droughts, these regions are also expected to see <a href="https://doi.org/10.1038/s41561-017-0001-8">fewer storms</a> and <a href="https://doi.org/10.1175/JHM-D-21-0017.1">more days without precipitation</a>. Climate models consistently project a <a href="https://doi.org/10.1038/s41561-017-0001-8">poleward shift in the midlatitude storm tracks</a> during this century as the planet heats up, which is expected to result in fewer storms in the southern tier of the country.</p>
<h2>Expect flash droughts even in wetter areas</h2>
<p>The changing nature of droughts is a concern <a href="https://nca2018.globalchange.gov/">even in parts of the U.S. that are expected to have a net increase</a> in annual precipitation during the 21st century. In a hotter future, because of the high evaporative demand on the land, prolonged periods with weeks to months of below normal precipitation in these areas can lead to significant drought, even if the overall trend is for more precipitation.</p>
<p>Large parts of the northern Plains, for example, have seen precipitation <a href="https://toolkit.climate.gov/regions/northern-great-plains">increase by 10% or more</a> in the last three decades. However, the region is not immune to severe drought conditions in a hotter climate.</p>
<p>At the tail end of what was the <a href="https://www.drought.gov/sites/default/files/2020-07/NorthernPlains_2017DroughtEvolution.pdf">wettest decade</a> on record in the region, the northern Plains experienced <a href="https://www.drought.gov/news/flash-drought-new-reports-examine-2017-northern-plains-drought">an intense flash drought in the summer of 2017</a> that resulted in agricultural losses in excess of $2.6 billion and <a href="https://www.theguardian.com/environment/2017/sep/07/flash-drought-north-dakota-montana-wildfires">wildfires</a> across millions of acres. <a href="https://doi.org/10.1016/B978-0-12-815998-9.00025-7">Record evaporative demand</a> contributed to the severity of the flash drought, in addition to a severe short-term precipitation deficit. A flash drought is a drought that <a href="https://doi.org/10.1175/BAMS-D-17-0149.1">intensifies rapidly over a period of a few weeks</a> and often catches forecasters by surprise. The likelihood of flash droughts that can <a href="https://www.nature.com/articles/s41467-021-26692-z/07/flash-drought-north-dakota-montana-wildfires">cause severe impacts to agriculture and ecosystems and promote large wildfires</a> is expected to <a href="https://doi.org/10.1038/s41467-022-28752-4">increase</a> with a warmer and thirstier atmosphere.</p>
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<img alt="The wheat field is less than knee high to the farmer, who is wearing jeans, a long sleeve shirt and a cap and looking down at the wheat." src="https://images.theconversation.com/files/464128/original/file-20220518-21-jf2l58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/464128/original/file-20220518-21-jf2l58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=421&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464128/original/file-20220518-21-jf2l58.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=421&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464128/original/file-20220518-21-jf2l58.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=421&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464128/original/file-20220518-21-jf2l58.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=529&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464128/original/file-20220518-21-jf2l58.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=529&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464128/original/file-20220518-21-jf2l58.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=529&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">During the 2017 flash drought, a North Dakota farmer stands in a wheat field that should have been twice as high at that point.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/PlainsDrought/6fbb416f8e92416cbf1ea37fef567c9c/photo">AP Photo/Blake Nicholson</a></span>
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<p>Flash droughts are also emerging as a growing concern in the Northeast. In 2020, much of New England experienced an <a href="https://pubs.usgs.gov/of/2020/1148/ofr20201148.pdf">extreme hydrologic drought</a>, with low stream flows and groundwater levels and widespread crop losses between May and September. Aided by very warm and dry atmospheric conditions, the drought developed very rapidly over that period from what had been above-normal wet conditions.</p>
<p>As humanity enters a hotter future, prolonged periods of weeks to months of below-normal precipitation are going to be of a greater concern almost everywhere. </p>
<h2>Heading into unfamiliar territory</h2>
<p>Other forms of droughts are also emerging.</p>
<p>Atmospheric heating is causing <a href="https://www.nationalgeographic.com/environment/article/snow-droughts-coming-to-winters-western-us-california-water">snow droughts</a> as more precipitation falls as rain rather than snow and snow melts earlier. Shorter snow seasons and longer growing seasons because of warmer temperatures are <a href="https://doi.org/10.1111/cobi.13727">changing the timing of ecological responses</a>.</p>
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<img alt="Viewed from an airplane, a long lake snakes through a canyon with a wide white rim around its edge." src="https://images.theconversation.com/files/464127/original/file-20220518-3314-cxkllj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/464127/original/file-20220518-3314-cxkllj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464127/original/file-20220518-3314-cxkllj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464127/original/file-20220518-3314-cxkllj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464127/original/file-20220518-3314-cxkllj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464127/original/file-20220518-3314-cxkllj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464127/original/file-20220518-3314-cxkllj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The ‘bathtub ring’ on Lake Powell, one of the nation’s largest reservoirs, attests to its falling water level over two decades of drought in Arizona. The Colorado River reservoir is crucial for water supplies and hydropower.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/the-tall-bleached-bathtub-ring-is-visible-on-the-rocky-news-photo/1325430487">Justin Sullivan/Getty Images</a></span>
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<p>Land is <a href="https://doi.org/10.1111/gcb.13224">greening up earlier</a> and causing an earlier loss of water from the land surface through <a href="https://www.usgs.gov/special-topics/water-science-school/science/evapotranspiration-and-water-cycle">evapotranspiration</a> – the loss of water from plants and soil. This could result in drier soils in the latter half of the growing season. As a result, parts of the central and western U.S. could see <a href="https://doi.org/10.1175/JCLI-D-17-0213.1">both increased greening and drying in the future</a> that are seasonally separated across the growing season.</p>
<p>With a rapidly changing climate, we are entering <a href="https://doi.org/10.1016/j.oneear.2020.08.019">unfamiliar territory</a>. The world will need new ways <a href="https://doi.org/10.1016/j.oneear.2020.08.019">to better anticipate future droughts</a> that could transform <a href="https://doi.org/10.1126/science.abj6777">natural</a> and <a href="https://theconversation.com/transformational-change-is-coming-to-how-people-live-on-earth-un-climate-adaptation-report-warns-which-path-will-humanity-choose-177604">human</a> systems.</p>
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Read more:
<a href="https://theconversation.com/hydropowers-future-is-clouded-by-droughts-floods-and-climate-change-its-also-essential-to-the-us-electric-grid-182314">Hydropower's future is clouded by droughts, floods and climate change – it's also essential to the US electric grid</a>
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<p class="fine-print"><em><span>Imtiaz Rangwala receives funding from USGS, USDA, NOAA, US Forest Service. He is affiliated with the University of Colorado Boulder, North Central Climate Adaptation Science Center and Western Water Assessment. </span></em></p>La Niña is only part of the problem. The long-term driver of increasing drought – even in areas getting more rainfall overall – is the rapidly warming climate.Imtiaz Rangwala, Research Scientist in Climate, Cooperative Institute for Research in Environmental Sciences, University of Colorado BoulderLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1820122022-05-02T12:37:13Z2022-05-02T12:37:13ZSatellites over the Amazon capture the choking of the ‘house of God’ by the Belo Monte Dam – they can help find solutions, too<figure><img src="https://images.theconversation.com/files/459872/original/file-20220426-12-ce5rr7.jpg?ixlib=rb-1.1.0&rect=110%2C8%2C1886%2C1113&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">NASA's Landsat satellites have been monitoring changes on Earth's landscape for 50 years.</span> <span class="attribution"><a class="source" href="https://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=10812">NASA illustration</a></span></figcaption></figure><p>The Xingu River is revered as the “<a href="https://sites.coloradocollege.edu/indigenoustraditions/sacred-lands/xingu-tribes-and-the-belo-monte-dam/">house of God</a>” by the Indigenous people living along its Volte Grande, or Big Bend, in the Brazilian Amazon. The river is essential to their culture and religion, and a crucial source of fish, transportation and water for trees and plants.</p>
<p>Five years ago, the Big Bend was a broad river valley interwoven with river channels teaming with fish, turtles and other wildlife. Today, as much as 80% of the water flow is gone.</p>
<p>That’s because in late 2015, the massive Belo Monte Dam project began redirecting water from the Xingu River upstream from the Big Bend, channeling it through a canal to a giant new reservoir. The reservoir now powers one of the largest hydropower dams in the world, designed with enough capacity to power around 20 million households, though it has been <a href="https://theconversation.com/this-amazon-dam-is-supposed-to-provide-clean-energy-but-its-destroying-livelihoods-and-unique-species-166773">producing far less</a>.</p>
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<span class="caption">Indigenous communities living in the Big Bend region of the Xingu River and its Bacaja tributary rely on the river for food and to transport crops.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/after-harvesting-a-weeks-worth-of-manioc-from-one-of-the-news-photo/470902995?adppopup=true">Taylor Weidman/LightRocket via Getty Images</a></span>
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<p>Most of the river’s flow now bypasses the Big Bend, and the Indigenous peoples who live there are watching <a href="https://e360.yale.edu/features/an-amazon-defender-stands-up-for-her-land-and-her-people">their livelihoods</a> and <a href="https://www.loe.org/shows/segments.html?programID=21-P13-00013&segmentID=2">way of life become endangered</a>. Some of the most devastating effects are during the rainy season, when wildlife and trees rely heavily on having high water. The consortium of utilities and mining companies that runs the dam has pushed back on government orders to allow more water to reach the Big Bend, claiming it would <a href="https://www.reuters.com/article/brazil-dam-idCNL1N2IR2M8">cut their generation and profits</a>. The group has argued in the past that there was <a href="https://news.mongabay.com/2021/03/amazons-belo-monte-dam-cuts-xingu-river-flow-85-a-crime-indigenous-say/">no scientific proof</a> that the change in water flow harmed fish or turtles.</p>
<p>There is proof of the Belo Monte Dam project’s impact on the Big Bend, though – from above. Satellite data shows how dramatically the dam has altered the hydrology of the river there.</p>
<p><iframe id="3O4sz" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/3O4sz/7/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
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</figure><figure><figcaption>The front satellite image shows the Big Bend of the Xingu River on May 26, 2000, before the Belo Monte Dam project began. Move the slider to the left to see the same region on July 20, 2017.</figcaption></figure>
<p>The same satellite data can also point to potential solutions and ways that operators of the Belo Monte Dam could revise the dam’s operations to keep both its renewable power and the Xingu River flowing at the most important times of the year.</p>
<p>As <a href="https://scholar.google.com/citations?user=fUbQsaoAAAAJ&hl=en">scientists who work with remote sensing</a>, we believe satellite observations can empower populations around the world who face threats to their resources. The fact that satellite observations of surface water of the Xingu River can be clearly tied to the construction and operation of the Belo Monte Dam offers hope that this kind of knowledge can no longer be hidden.</p>
<h2>50 years of Earth observation</h2>
<p>Satellites have been monitoring changes in Earth’s landscapes for 50 years, ever since the U.S. launched the <a href="https://www.usgs.gov/landsat-missions/landsat-1">first Landsat satellite</a> on July 23, 1972. By piecing together data from the Landsat program and other satellites, scientists can reconstruct historical patterns of change in the landscape and predict current and future trends. They can monitor forest cover, drought, wildfire damage and desert expansion, <a href="https://doi.org/10.1016/j.envsoft.2021.105043">as well as river flows</a> and reservoir operations around the world.</p>
<p>An example of how that data can be used to help threatened communities is the global <a href="http://www.satellitedams.net">Reservoir Assessment Tool</a>, which was <a href="https://doi.org/10.1016/j.envsoft.2021.105043">created by</a> colleagues and one of us at the University of Washington. It monitors how much water is in about 1,600 reservoirs around the world.</p>
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<a href="https://images.theconversation.com/files/459869/original/file-20220426-14-ssn5d4.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Screenshot of the tool showing a map of Brazil and an example dam's chart of water outflow." src="https://images.theconversation.com/files/459869/original/file-20220426-14-ssn5d4.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/459869/original/file-20220426-14-ssn5d4.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=361&fit=crop&dpr=1 600w, https://images.theconversation.com/files/459869/original/file-20220426-14-ssn5d4.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=361&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/459869/original/file-20220426-14-ssn5d4.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=361&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/459869/original/file-20220426-14-ssn5d4.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=454&fit=crop&dpr=1 754w, https://images.theconversation.com/files/459869/original/file-20220426-14-ssn5d4.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=454&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/459869/original/file-20220426-14-ssn5d4.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=454&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The Reservoir Assessment Tool allows communities to track river flow changes caused by nearby dams and locate proposed dams. It currently tracks dams built before 2000.</span>
<span class="attribution"><a class="source" href="http://www.satellitedams.net">University of Washington</a></span>
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<p>Dam operators already collect thorough on-site data about water flow, but their datasets are rarely shared with the public. Remote sensing doesn’t face the same restrictions. Making that data public can help hold operators to account for and protect local communities and their rivers.</p>
<h2>How satellites could pressure Belo Monte to share</h2>
<p>Satellite monitoring can provide unprecedented insight into the operations of dams like the Belo Monte and their impact on downstream populations.</p>
<p>Existing satellite data can be used to monitor recent historical behavior of a dam’s operations, track the state of the river and patterns of inflow and outflow at the dam, and even forecast the likely state of the reservoir. Much of that data is easily accessible and free. For example, a tool created for the regional governing body of the Mekong River Commission is empowering communities along the river in Southeast Asia by giving them access to <a href="https://depts.washington.edu/saswe/mekong/">satellite data about water flow at each dam</a> – data that cannot be hidden or modified by those in power.</p>
<p>While estimates based on remote sensing have higher uncertainty than on-site measurements, unfettered access to such information can provide local populations with evidence to argue, in court if necessary, for more water releases.</p>
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<figcaption><span class="caption">Members of Indigenous groups living in the Big Bend region talk about changes they’ve seen since the dam was built.</span></figcaption>
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<p>Long-term observations of dams and hydroclimate records show it is possible to <a href="https://doi.org/10.1016/j.jhydrol.2020.125708">revise the standard operating procedures of dams</a> so they allow more water to flow downstream when needed. A compromise with the Belo Monte Dam could ensure that enough water flows to the Xingu’s Big Bend region while also providing hydropower benefits.</p>
<p>By making the impact of the Belo Monte Dam and others like it public to the world, agencies and the general public can put pressure on the dam’s operators and its investors to release more water. Public pressure will become increasingly important, as water disputes in the Amazon are expected to worsen as the planet warms <a href="https://www.cfr.org/in-brief/deforestation-brazils-amazon-has-reached-record-high-whats-being-done">and deforestation continues</a>. Climate change <a href="https://doi.org/10.1038/s41893-020-0492-y">will affect river flow patterns</a> in the Amazon and likely increase droughts, leaving less water during some periods.</p>
<h2>A tool for social justice</h2>
<p>The Amazonian native population has declined, and dams and nearby mining operations, <a href="https://e360.yale.edu/features/an-amazon-defender-stands-up-for-her-land-and-her-people">like those threatening the Xingu’s Big Bend region</a>, play a role. The current Brazilian government under president Jair Bolsonaro has generally sided with <a href="https://www.iwgia.org/en/brazil.html">wealthy landowners and industry over Indigenous peoples</a>, making access to independent data crucial for protecting these communities.</p>
<p>Monitoring dams is a powerful way satellites can make a difference. Nearly two-thirds of Brazil’s electricity comes from <a href="https://www.abradee.org.br/setor-eletrico/visao-geral-do-setor/">more than 200 large and 400-plus small</a> hydropower plants, and <a href="https://news.mongabay.com/2020/10/brazils-amazon-dam-plans-ominous-warnings-of-future-destruction-commentary/">more large dams are expected</a> to be built in the Amazon this decade. Many are in areas with Indigenous populations.</p>
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<a href="https://images.theconversation.com/files/459955/original/file-20220427-20-c2tqce.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Wide aerial view of Amazon rainforest and the dam under construction." src="https://images.theconversation.com/files/459955/original/file-20220427-20-c2tqce.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/459955/original/file-20220427-20-c2tqce.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/459955/original/file-20220427-20-c2tqce.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/459955/original/file-20220427-20-c2tqce.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/459955/original/file-20220427-20-c2tqce.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/459955/original/file-20220427-20-c2tqce.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/459955/original/file-20220427-20-c2tqce.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The Belo Monte Dam’s construction, shown here in 2012, flooded land and changed the river.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/construction-continues-at-the-belo-monte-dam-complex-in-the-news-photo/146390482?adppopup=true">Mario Tama/Getty Images</a></span>
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<p>Remote sensing may not directly solve the problem of social injustice, but it offers the tools needed to recognize the problems and explore solutions. Being able to monitor changes in near-real time and compare them with historical operations can help maintain the checks and balances required for equitable growth.</p>
<p><em>Raaghul Senthilkumar, a former Master’s student at the University of Washington, contributed to this article.</em></p>
<p><em>This article was updated to highlight the 50th anniversary of the Landsat program, on July 23, 2022.</em></p><img src="https://counter.theconversation.com/content/182012/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Faisal Hossain receives funding from NASA. </span></em></p><p class="fine-print"><em><span>Hörður Bragi Helgason, Pritam Das, and Shahzaib Khan do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>When Indigenous peoples lose their river flow to dams, satellite programs like Landsat – which is celebrating its 50th anniversary – can help them fight for their resources.Pritam Das, Graduate Research Assistant, University of WashingtonFaisal Hossain, Professor of Hydrology, University of WashingtonHörður Bragi Helgason, Graduate Research Assistant, University of WashingtonShahzaib Khan, Graduate Research Assistant in Computational Hydrology, University of WashingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1795772022-04-06T14:55:48Z2022-04-06T14:55:48ZWorrying insights from UN’s first-ever assessment of water security in Africa<figure><img src="https://images.theconversation.com/files/453540/original/file-20220322-15111-o05byu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Franck Metois/ GettyImages</span> </figcaption></figure><p>When it comes to water security – a reliable, good supply of safe water – just 29 African countries have made some progress over the past three to five years. Twenty-five have made none.</p>
<p>This data comes out of the <a href="https://inweh.unu.edu/publications/">UN’s first-ever assessment of water security</a> in Africa. Published by the <a href="https://inweh.unu.edu/">UN University’s Canada-based Institute for Water, Environment and Health</a>, the assessment used 10 indicators to quantify water security in Africa’s 54 countries. Such an assessment had been done before in the Asia-Pacific region, but never for Africa.</p>
<p>The UN’s concept of water security encompasses various needs and conditions. These include: water for drinking, economic activity, ecosystems, governance, financing, and political stability. Water security, therefore, is not just about how much natural water a country has but also how well the resource is managed.</p>
<p>The assessment is limited by very poor data on some issues – such as access to drinking water or sanitation. It nevertheless offers some preliminary, but obvious, conclusions. </p>
<p>Overall levels of water security in Africa are low. Not a single country, let alone a sub-region, is at the highest “model” stage of water security. The top five countries – Egypt, Botswana, Mauritius, Gabon, and Tunisia — are at best at a “modest” (just above average) stage of water security. </p>
<p>Without water security, people are exposed to environmental and health risks, increased susceptibility to water-related disasters and lack water for economic and social use. </p>
<p>The assessment team hopes that as this quantitative tool develops, it will help generate targeted policy recommendations and inform decision-making and public-private investments toward achieving water security in Africa.</p>
<h2>Key findings</h2>
<p>The assessment introduced five stages of water security: Emerging (a score of 0 – 45), slight (45 – 60), modest (60 – 75), effective (75 — 90), and model (90 – 100).</p>
<p>Except for Egypt, all countries scored below 70. Only 13 of 54 countries were found to have a “modest” level of water security. Somalia, Chad and Niger appear to be the three least water-secure countries in Africa. </p>
<p>Over a third of the 54 countries had “emerging” level water security, representing a large gap to be closed to reach an acceptable level. These countries are home to half a billion people. </p>
<p>The situation doesn’t appear to be improving very quickly. Between 2015 and 2020, the continent as a whole progressed only by 1.1% based on the indicators. </p>
<h2>Examining the indicators</h2>
<p>Here is an overview of how countries fared on each indicator.</p>
<p><strong>Access to drinking water</strong></p>
<p>Access to “at least basic” drinking water services ranged from 37% of the population in the Central African Republic to 99% in Egypt. Regionally it ranged from 62% in central Africa to 92% in north Africa. Africa’s average basic drinking water service is 71%. This leaves behind about 29% of the total population, or more than 353 million people. </p>
<p>“At least basic” means access to improved water sources – such as piped water, protected hand-dug wells and springs. These either need to be “safely managed” (accessible on premises, available when needed, and free from contamination) or can be collected in a trip of 30 minutes or less.</p>
<p><strong>Access to sanitation</strong></p>
<p>Access to sanitation – meaning access to, and use of, sanitation facilities and services – was broadly similar at the regional level. There’s an average of 60% access to limited sanitation. This means at least 40% of the total population (483 million people) are left behind. </p>
<p>A few countries – Seychelles and most countries in north Africa – have reached, or nearly reached, 100%. The most challenged countries are Chad and Ethiopia. </p>
<p><strong>Access to hygiene facilities</strong></p>
<p>This indicator refers to access to practices like hand washing. The greatest access was found in north Africa (67%), the least access was in west Africa. Liberia was the lowest in the region with less than 10% access. </p>
<p>Chad and the Central African Republic suffer from the highest number of deaths from diarrhoea, an indicator of ineffective hygiene practices.</p>
<p><strong>Per capita water availability</strong></p>
<p>The amount of water available per person was highest in central Africa, with the Republic of Congo considered Africa’s most water-rich country. At the other end of the spectrum, half of the countries in north Africa appeared to be absolutely water scarce. </p>
<p>Water availability has recently declined in west, central and southern Africa. This was most notable in Cote d'Ivoire, Cameroon, Somalia, Mozambique and Malawi.</p>
<p><strong>Water use efficiency</strong></p>
<p>This indicator assesses the economic and social value. The score is a sum of efficiencies – a measure of how well a country uses the water it has in its economy.</p>
<p>On this basis, water use efficiency appears to be lowest in north Africa (with Somalia lowest at the national level) and highest in central Africa (with Angola highest at a national level). </p>
<p><strong>Water storage infrastructure</strong></p>
<p>Water storage in large dams, measured in volume (m3) per capita, is deemed best in the southern Africa, worst in east Africa. </p>
<p>South Africa, with over 25% of all large dams in Africa, is outscored by Ghana, Zimbabwe, and Zambia, likely due to just one mega reservoir in those countries. </p>
<p>Half of all countries score very low, reflecting the continent’s low level of water storage development. Only Ethiopia and Namibia have increased their storage over recent years. </p>
<p><strong>Wastewater treatment</strong></p>
<p>Scores are highest in north African countries, lowest in east and west Africa, where 12 countries in each region treat less than 5% of wastewater. No country treats more than 75%. Only Tunisia, Egypt and Lesotho treat over 50% of wastewater.</p>
<p><strong>Water governance</strong></p>
<p>Governance takes into account the various users and uses of water with the aim of promoting positive social, economic, and environmental impacts. This includes the transboundary level. </p>
<p>Water governance appears to be most advanced in north and southern Africa and least advanced in central Africa.</p>
<p>Nationally, Ghana reported reaching 86% of integrated water resource management implementation in just two years – a significant improvement. </p>
<p>Liberia, Guinea-Bissau, and Comoros are the lowest-performing countries.</p>
<p><strong>Disaster risk</strong></p>
<p>Disaster risk is a measure of the potential loss of life, injury, or destroyed or damaged assets, which could occur to an ecosystem, or a community in a specific period of time. </p>
<p>North Africa appears to be the least risky sub-region (it has less exposure or high ability to adapt), with Egypt the least risky country. West Africa was the riskiest.</p>
<p>Some 49 of 54 African countries have seen increased disaster risk scores over five recent years.</p>
<p><strong>Water dependency on neighbouring nations and water resources variability</strong></p>
<p>Egypt stands out as Africa’s most water-dependent country. It relies on the Nile river which flows through 10 countries – Tanzania, Uganda, Rwanda, Burundi, Democratic Republic of Congo, Kenya, Ethiopia, Eritrea, South Sudan, and Sudan – before reaching Egypt. And the southern Africa sub-region has a wide disparity in the available water per year.</p>
<h2>Preparing for the future</h2>
<p>Our paper calls for a pioneering effort to create global standards for water security measurement data and assessment.</p>
<p>Some critical components of water security simply cannot be assessed without good data. For example, it’s not possible to estimate the percentage of the African population that will have access to safely managed drinking water services or safely managed sanitation by 2030, a key UN Sustainable Development Goal.</p>
<p>Our water security assessment tool is a work in progress, guided by a goal of an influential and nationally-owned tool used by all African countries and that it helps generate targeted policy recommendations and inform decision-making and public-private investments in Africa.</p><img src="https://counter.theconversation.com/content/179577/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>500 million people live in 19 African countries deemed “water insecure”.Grace Oluwasanya, Research Lead for Water, Climate and Gender, Institute for Water, Environment and Health (UNU-INWEH), United Nations UniversityDuminda Perera, Senior Researcher: Hydrology and Water Resources, Institute for Water, Environment and Health (UNU-INWEH), United Nations UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1777082022-03-01T13:41:40Z2022-03-01T13:41:40ZUS climate risks are rising – a scientist looks at the dangers her children will have to adapt to, from wildfires to water scarcity<figure><img src="https://images.theconversation.com/files/449054/original/file-20220228-21-d3yxso.jpg?ixlib=rb-1.1.0&rect=0%2C28%2C6333%2C4187&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A burned 'Caution: Children at play' sign remained after a wildfire devastated the town of Berry Creek, Calif., in 2020.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/berry-creek-california-sept-17-2020-a-melted-sign-warning-news-photo/1228658291">Carolyn Cole/Los Angeles Times via Getty Images</a></span></figcaption></figure><p>When I was a young researcher studying how forested ecosystems recover from wildfire, I brought my 6-month-old daughter with me to Yellowstone National Park. These forests are <a href="https://theconversation.com/heres-how-forests-rebounded-from-yellowstones-epic-1988-fires-and-why-that-could-be-harder-in-the-future-101495">incredibly resilient</a> to wildfire because they’ve been adapting to it for 10,000 years. Their story of resilience was a hopeful narrative as I began my research career and brought my children into this complex world.</p>
<p>Fast forward to today: My daughter is now in college, and we are facing a much different fire regime in a hotter, drier world. In the western U.S., the <a href="https://doi.org/10.1073/pnas.1607171113">area burned by wildfires has doubled</a> since the mid-1980s compared to natural levels. Wildfires are now more common, from the tundra to the tropics. And the U.S. is seeing fires year-round.</p>
<p>A <a href="https://www.ipcc.ch/report/sixth-assessment-report-working-group-ii/">2022 report</a> from the United Nations’ Intergovernmental Panel on Climate Change shows that the extent and magnitude of many climate change impacts like wildfires are now larger than previously expected. Some animals and plants are <a href="https://www.ipcc.ch/report/sixth-assessment-report-working-group-ii/">reaching limits in their ability to adapt</a>. Droughts are <a href="https://doi.org/10.1038/s41558-021-01000-1">affecting crop productivity</a> and <a href="https://apnews.com/article/business-environment-and-nature-california-e1ba2e38caafb44bf893a2f05a18edb7">power generation</a>. Excess heat and flooding are helping <a href="https://doi.org/10.1371/journal.pone.0160651">diseases to spread</a> in agriculture, wildlife and people. People who work outdoors or live along the coast are especially vulnerable. The <a href="https://www.ipcc.ch/report/sixth-assessment-report-working-group-ii/">social and economic impacts</a> are also growing, with consequences for critical infrastructure, transportation networks, health and food security.</p>
<p>I also have a 9-year-old son. According to the IPCC report, his future will include about <a href="https://doi.org/10.1126/science.abi7339">four times as many extreme events</a> compared to the experience of someone in their 60s today – and that’s if nations reduce fossil fuel use enough to hold global warming to 1.5 degrees Celsius (2.7 Fahrenheit) over pre-industrial times. It’s even more dangerous if they don’t.</p>
<figure class="align-center ">
<img alt="Three adults and two young children wade through flood water carrying suitcases." src="https://images.theconversation.com/files/449099/original/file-20220301-3997-1lofsj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/449099/original/file-20220301-3997-1lofsj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/449099/original/file-20220301-3997-1lofsj6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/449099/original/file-20220301-3997-1lofsj6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/449099/original/file-20220301-3997-1lofsj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/449099/original/file-20220301-3997-1lofsj6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/449099/original/file-20220301-3997-1lofsj6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Rising sea levels are increasing the risks of coastal flooding in Louisiana and other states.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/HurricaneIdaPhotoGallery/b0a16982c0a74dceaefd3c22e6525cb2/photo">AP Photo/Steve Helber</a></span>
</figcaption>
</figure>
<h2>Adapting to a changing world</h2>
<p>The report warns that humanity has a brief but rapidly closing window of opportunity to secure a livable and sustainable future. The risks posed by climate change will be felt differently in different regions, but the most vulnerable people will face the greatest risks.</p>
<p>Ensuring that their voices are included in planning and decision-making is a key recommendation. For example, Indigenous peoples <a href="https://www.ipcc.ch/report/sixth-assessment-report-working-group-ii/">are on the frontlines of climate-driven catastrophes</a> and also can be partners in their solutions. In Alaska, <a href="https://polaris.ghs.alaska.edu/home">where I currently conduct research</a>, sewer systems could be washed out in the next storm, and thawing permafrost is crippling critical underground food storage areas, as well as roads. I’ve seen homes set on coastal cliffs there that are eroding into the sea.</p>
<figure class="align-center ">
<img alt="Two children play on an eroding hill with a house now at the edge of an eroded cliff that stands about one-story high." src="https://images.theconversation.com/files/449075/original/file-20220301-17-677dso.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/449075/original/file-20220301-17-677dso.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=382&fit=crop&dpr=1 600w, https://images.theconversation.com/files/449075/original/file-20220301-17-677dso.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=382&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/449075/original/file-20220301-17-677dso.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=382&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/449075/original/file-20220301-17-677dso.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=481&fit=crop&dpr=1 754w, https://images.theconversation.com/files/449075/original/file-20220301-17-677dso.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=481&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/449075/original/file-20220301-17-677dso.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=481&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">In parts of Alaska, thawing permafrost is eroding hillsides and causing ground to sink, putting homes, roads and pipelines at risk.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/jeremy-hawley-stands-near-his-uncles-home-which-is-news-photo/1175057354?adppopup=true">Joe Raedle/Getty Images</a></span>
</figcaption>
</figure>
<h2>Water and food security</h2>
<p>In North America, the report describes how the ideal climates for many crops and fisheries are shifting northward, leading to reduced productivity of key crops and livestock. The thermal <a href="https://doi.org/10.1002/tafs.10059">habitat for salmon and trout may decline 5% to 31%</a>, lobster and crab distributions will shift, and shellfish harvests will decline due to ocean acidification. </p>
<p>The impacts vary by region, but research shows climate change has generally <a href="https://doi.org/10.1038/s41558-021-01000-1">slowed the growth</a> in <a href="https://phys.org/news/2021-04-climate-global-agricultural-productivity-1960s.html">agricultural productivity</a> in North America since 1961, <a href="https://www.ipcc.ch/report/sixth-assessment-report-working-group-ii/">particularly in drought-prone areas</a>. Rising global temperatures are <a href="https://doi.org/10.1126/science.aay9187">reducing the snowpack</a> that farms and cities rely on for water, and increased <a href="https://theconversation.com/ancient-groundwater-why-the-water-youre-drinking-may-be-thousands-of-years-old-167982">groundwater pumping</a> in response is harming access to fresh water in some areas, particularly in the western U.S.</p>
<p>Adapting might mean <a href="https://www.yahoo.com/video/blistering-drought-california-farmers-rip-015523736.html">planting different crops</a> or <a href="https://www.calwater.com/conservation/drought/prohibited-uses-water/">conserving water</a>. On the Colorado River, falling water levels have triggered <a href="https://theconversation.com/as-colorado-river-basin-states-confront-water-shortages-its-time-to-focus-on-reducing-demand-165646">water use limits</a> agreed to by seven states.</p>
<figure class="align-center ">
<img alt="A family looks over the edge of a viewing area at the Colorado River, now far below." src="https://images.theconversation.com/files/449106/original/file-20220301-25-1d71l89.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/449106/original/file-20220301-25-1d71l89.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/449106/original/file-20220301-25-1d71l89.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/449106/original/file-20220301-25-1d71l89.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/449106/original/file-20220301-25-1d71l89.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/449106/original/file-20220301-25-1d71l89.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/449106/original/file-20220301-25-1d71l89.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Lake Mead’s ‘bathtub ring’ shows how far the giant reservoir on the Colorado River had dropped by mid-2021.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/the-white-bathtub-ring-around-lake-mead-shows-the-record-news-photo/1233759073?adppopup=true">David McNew/Getty Images</a></span>
</figcaption>
</figure>
<h2>Coastal and urban economies</h2>
<p>Along U.S. coasts and in urban areas, damage from storms and <a href="https://theconversation.com/new-flood-maps-show-us-damage-rising-26-in-next-30-years-due-to-climate-change-alone-and-the-inequity-is-stark-175958">sea level rise</a>, and disruption of trade and transportation networks, are likely to cause <a href="https://www.ipcc.ch/report/sixth-assessment-report-working-group-ii/">substantial social and economic upheaval</a>, the report says. <a href="https://theconversation.com/safe-havens-for-coral-reefs-will-be-almost-non-existent-at-1-5-c-of-global-warming-new-study-176084">Up to 99% of coral reefs</a>, which provide natural protection from storms, will be lost by the end of the century in the Gulf of Mexico and along the coasts of Florida and the Yucatan Peninsula if temperatures rise just a half-degree Celsius more. </p>
<p>There are adaptation techniques <a href="https://theconversation.com/a-20-foot-sea-wall-wont-save-miami-how-living-structures-can-help-protect-the-coast-and-keep-the-paradise-vibe-165076">other than building sea walls</a>. <a href="https://www.nrdc.org/stories/green-infrastructure-how-manage-water-sustainable-way">Green infrastructure</a>, typically vegetation in flood-prone areas, can help manage some floodwater. Some communities are also thinking about <a href="https://theconversation.com/managed-retreat-done-right-can-reinvent-cities-so-theyre-better-for-everyone-and-avoid-harm-from-flooding-heat-and-fires-163052">managed migration</a> to help move residents out of harm’s way.</p>
<p>Another big risk is <a href="https://doi.org/10.3390/ijerph15112438">heat-related deaths and illnesses</a>, particularly among outdoor workers and poor urban residents. How much it increases in the future will depend on <a href="https://theconversation.com/a-major-federal-response-to-occupational-extreme-heat-is-here-at-last-168629">how people and countries respond</a>.</p>
<h2>Worsening wildfires</h2>
<p>Last year, <a href="https://scholar.google.com/citations?hl=en&user=5srGGBIAAAAJ&view_op=list_works&sortby=pubdate">I was back</a> in Yellowstone with my 9-year-old son, and I revisited the places I had been as a young researcher. Rather than a scene of resilience, wildfires had returned in just 18 years, burning landscapes that under natural conditions weren’t supposed to burn again for 150 years. </p>
<p>What my colleagues and I saw matched what our research was showing: the <a href="https://doi.org/10.1073/pnas.1110199108">potential for the Yellowstone landscape to be transformed</a> by fire. It also showed how these changes are less than a lifetime away.</p>
<figure class="align-center ">
<img alt="Small pine trees sprout up in a landscape recovering from fire, with burned tree trunks on the ground and standing nearby." src="https://images.theconversation.com/files/448765/original/file-20220227-31836-s9lb52.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/448765/original/file-20220227-31836-s9lb52.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/448765/original/file-20220227-31836-s9lb52.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/448765/original/file-20220227-31836-s9lb52.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/448765/original/file-20220227-31836-s9lb52.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/448765/original/file-20220227-31836-s9lb52.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/448765/original/file-20220227-31836-s9lb52.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Large fires are occurring more frequently than in the past. The author, who is also part of the Science Moms group of climate scientists, took this photo of regrowth at the site of a fire in Yellowstone.</span>
<span class="attribution"><a class="source" href="https://sciencemoms.com/">Erica A.H. Smithwick</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>As temperatures rise, wildfire frequency is <a href="https://www.ipcc.ch/report/sixth-assessment-report-working-group-ii/">projected to increase about 30%</a> globally by the end of the century if greenhouse gas emissions continue at a high rate. Fires will <a href="https://atmosphere.copernicus.eu/copernicus-summer-wildfires-saw-devastation-and-record-emissions-around-northern-hemisphere">release more carbon dioxide</a> into the atmosphere, where it further exacerbates climate change, and they will <a href="https://theconversation.com/whats-in-wildfire-smoke-a-toxicologist-explains-the-health-risks-and-which-masks-can-help-164597">worsen air quality</a> for billions of people.</p>
<p>Strategies exist to help avoid the worst harm. Restoring fire-adapted ecosystems and using forest thinning and prescribed burns, where appropriate, can help prevent megafires. <a href="https://www.firescience.gov/projects/16-1-02-5/project/16-1-02-5_final_report.pdf">Communities can take steps</a> to <a href="https://theconversation.com/how-to-build-wildfire-resistant-communities-in-a-warming-world-174582">reduce the fire risk</a> by building firebreaks and following construction codes.</p>
<figure>
<iframe src="https://player.vimeo.com/video/374158256" width="500" height="281" frameborder="0" webkitallowfullscreen="" mozallowfullscreen="" allowfullscreen=""></iframe>
<figcaption><span class="caption">Wildfires are also a risk in the East. Video by Penn State.</span></figcaption>
</figure>
<h2>A window of opportunity</h2>
<p>The IPCC report concludes that it is unequivocal that climate change has already disrupted human and natural systems and that it threatens human well-being. It also reminds us that we can change it for the better.</p>
<p>Many reports have described pathways to <a href="https://www.ipcc.ch/sr15/">reduce greenhouse gas emissions</a> and reach a “net zero” emissions economy to avoid the worst harm and help communities adapt.</p>
<p>We also need to <a href="https://sciencemoms.com/">talk about climate change</a> with each other. If people don’t talk about it, they don’t act. <a href="https://climatecommunication.yale.edu/visualizations-data/ycom-us/">A Yale survey</a> shows that 72% of Americans think global warming is happening, but only 35% are talking about it. <a href="https://yaleclimateconnections.org/2020/08/how-to-talk-with-kids-about-climate-change/">Talking about climate change</a> with friends, our communities and our children in appropriate ways is critical to sparking action.</p><img src="https://counter.theconversation.com/content/177708/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Erica A.H. Smithwick receives funding from The National Science Foundation and the Joint Fire Sciences Program. </span></em></p>The author’s 9-year-old son will likely face about four times as many extreme events in his lifetime as older adults today. An international report explains the impacts already being felt.Erica A.H. Smithwick, Distinguished Professor of Geography, Penn StateLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1755782022-02-28T18:59:14Z2022-02-28T18:59:14ZIPCC report: Half the world is facing water scarcity, floods and dirty water — large investments are needed for effective solutions<figure><img src="https://images.theconversation.com/files/448701/original/file-20220226-74611-3pbs1w.jpg?ixlib=rb-1.1.0&rect=52%2C22%2C4940%2C3046&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The old village of Aceredo, submerged 30 years ago when a hydropower dam flooded the valley, emerged during a drought in northwestern Spain, in February 2022. </span> <span class="attribution"><span class="source">(AP Photo/Emilio Morenatti)</span></span></figcaption></figure><p>More than <a href="https://doi.org/10.1126/sciadv.1500323">half the world’s population faces water scarcity for at least one month every year</a>. Meanwhile, some people have to deal with too much water, while others have access to only poor water quality. That’s billions of people <a href="https://doi.org/10.5194/nhess-20-695-2020">living with drought in Africa and India</a>, facing <a href="https://doi.org/10.1016/j.landusepol.2020.104868">flood risks in Bangladesh</a> or lacking clean water due to <a href="https://doi.org/10.1002/2017WR020448">excessive fertilizer use</a> in the United States, Brazil, <a href="https://doi.org/10.1021/acs.est.5b03191">China</a> and India. </p>
<p>Climate change exacerbates global water insecurity because it contributes to more frequent and severe droughts, floods and extreme rainfall, accelerated glacier melt, rapid declines in groundwater and the deterioration of water quality. These water-related risks of climate change have negative repercussions for agriculture, energy production, water infrastructure and economic productivity, as well as human health, development and well-being around the world. </p>
<p>Water is central to the discussions about how societies, economies and governments adapt to climate change, and the vast majority of adaptation strategies already in place are water related. Yet researchers know little about how effective they are. </p>
<p>As a researcher in the field of climate change and sustainable food systems, I was part of a team that reviewed more than 1,800 case studies for the “Water” chapter of <em><a href="https://www.ipcc.ch/report/ar6/wg2/">Climate Change 2022: Impacts, Adaptation and Vulnerability</a></em>, the second part of the Intergovernmental Panel of Climate Change’s Sixth Assessment Report (AR6). This newly released report is the most comprehensive review of climate impacts and how much we can adapt to them <a href="https://www.ipcc.ch/assessment-report/ar5/">since 2014</a>. </p>
<h2>Water at the centre of climate change strategies</h2>
<p>The United Nations defines <a href="https://www.unwater.org/publications/water-security-infographic/">water security</a> as having sustainable access to enough water of adequate quality to support people’s well-being, livelihoods and health, without jeopardizing ecosystems. Water insecurity covers a spectrum of issues — too much, too little, too dirty. </p>
<figure class="align-center ">
<img alt="Women wade through waist-deep water in a wetlands." src="https://images.theconversation.com/files/448698/original/file-20220226-42662-ytnv1o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/448698/original/file-20220226-42662-ytnv1o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=411&fit=crop&dpr=1 600w, https://images.theconversation.com/files/448698/original/file-20220226-42662-ytnv1o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=411&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/448698/original/file-20220226-42662-ytnv1o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=411&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/448698/original/file-20220226-42662-ytnv1o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=516&fit=crop&dpr=1 754w, https://images.theconversation.com/files/448698/original/file-20220226-42662-ytnv1o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=516&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/448698/original/file-20220226-42662-ytnv1o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=516&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Women harvest a salt-resistant rice variety in a Pokkali farming system at a wetlands on the Arabian Sea coast in Kochi, India, in October 2021. The same field is used for prawn farming outside of the rainy season.</span>
<span class="attribution"><span class="source">(AP Photo/R S Iyer)</span></span>
</figcaption>
</figure>
<p>Unsurprisingly, a large majority of countries have listed water as the priority for adaptation in their climate change plans. In our review of more than 1,800 climate change adaptation strategies, we found that over 80 per cent were water-related. Some were in response to water hazards (droughts, floods, groundwater depletion, glacier depletion). In others, the response itself was water-related (irrigation, rainwater harvesting and wetlands conservation). </p>
<p>Yet when we looked at the outcomes of these water-based adaptation strategies, we found that only 359 had been analyzed for effectiveness, meaning that we do not know if most of these strategies actually reduce the impacts of climate change and improve health, well-being and livelihood. </p>
<p>Adaptation strategies that are enacted without adequate investigation of their effectiveness not only waste scarce resources, but can also distract us from taking more relevant actions that carry larger benefits for the affected population.</p>
<h2>Are the strategies working?</h2>
<p>Of those 359 strategies, most targeted the agriculture sector. <a href="https://doi.org/10.1073/pnas.1109936109">Agriculture accounts for 80 to 90 per cent of total water consumed globally</a> and <a href="https://data.worldbank.org/indicator/SL.AGR.EMPL.ZS">provides water for to 70 per cent</a> of people in developing countries with their livelihoods. </p>
<p>Many of these water-focused approaches included changing the timing and arrangement of crops, choosing better crop varieties and farming techniques, expanding access to irrigation and adopting water conservation practices. </p>
<p>Non-agricultural water-based adaptations to climate change included <a href="https://doi.org/10.1177%2F1070496519852992">adopting better fishery techniques in Ghana</a>, <a href="https://doi.org/10.1108/IJCCSM-02-2017-0026">planting salt-resistant trees in Bangladesh</a>, <a href="https://doi.org/10.3390/w11010093">setting up desalination plants for urban water use in Spain</a>, building <a href="https://doi.org/10.1016/j.uclim.2014.07.009">flood-resilient housing in Guyana</a>, among others. </p>
<figure class="align-center ">
<img alt="A beach packed with boats, with fishers and people sorting and buying fish." src="https://images.theconversation.com/files/448699/original/file-20220226-15239-1bl9e59.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/448699/original/file-20220226-15239-1bl9e59.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/448699/original/file-20220226-15239-1bl9e59.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/448699/original/file-20220226-15239-1bl9e59.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/448699/original/file-20220226-15239-1bl9e59.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/448699/original/file-20220226-15239-1bl9e59.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/448699/original/file-20220226-15239-1bl9e59.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Fishers sort their catch from nets in James Town, Accra, Ghana, in July 2015.</span>
<span class="attribution"><span class="source">(AP Photo/Sunday Alamba)</span></span>
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</figure>
<p>We also found that local, traditional and Indigenous knowledge play an important role in shaping many adaptation responses. For instance, some <a href="https://doi.org/10.1016/j.apgeog.2016.10.003">farmers in Sri Lanka successfully adapted to the 2014 drought by practising <em>bethma</em></a>, a traditional technique where the community temporarily reallocated agricultural land among farmers so that each would have similar access to the limited water supply.</p>
<p>Combining local, traditional and Indigenous knowledge with a technical understanding of climate change can lead to the development and implementation of more acceptable and successful climate change adaptation strategies. This not only ensures <a href="https://www.idrc.ca/en/perspectives/adaptation-climate-change-must-be-inclusive-equitable-and-representative">equitable and inclusive adaptation actions</a>, but also increases the proposed solutions’ effectiveness at minimizing climate change impacts.</p>
<figure class="align-center ">
<img alt="Water gushing out of a wide pipe into a reservoir." src="https://images.theconversation.com/files/448703/original/file-20220226-32564-1o5obu2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/448703/original/file-20220226-32564-1o5obu2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/448703/original/file-20220226-32564-1o5obu2.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/448703/original/file-20220226-32564-1o5obu2.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/448703/original/file-20220226-32564-1o5obu2.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/448703/original/file-20220226-32564-1o5obu2.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/448703/original/file-20220226-32564-1o5obu2.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A tubewell pumps groundwater to irrigate rice fields in Punjab, India. Exploitation of groundwater for irrigation has made this region a major hotspot of groundwater depletion in the world.</span>
<span class="attribution"><span class="source">(Diljot Jatana)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Largest number of the adaptation responses, especially those in the agriculture sector, were implemented and led by individual households and civil society bodies. Schemes by governments at various levels of administration — from local to multi-national — comprised the second largest chunk of adaptation strategies.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-ancient-water-management-techniques-may-help-prairie-farmers-experiencing-drought-168920">How ancient water management techniques may help Prairie farmers experiencing drought</a>
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<hr>
<p>So far, the role of the private sector has been negligible. Private financing is a minor source of adaptation financing that has mostly focused on developed and emerging economies. Local needs, especially those of the economically disadvantaged communities, have not been adequately addressed by private financing until now. </p>
<p>At the recent climate change conference in Glasgow, Scotland, <a href="https://www.reuters.com/business/cop/wrapup-politicians-exit-cop26-130tn-worth-financiers-take-stage-2021-11-03/">global financial firms agreed to fund projects that address climate change mitigation</a>. The translation of these promises into action remains to be seen, but adaptation projects in low- and middle-income countries could benefit a lot from this.</p>
<h2>Limited utility and unintended consequences</h2>
<p>But we also found that the strategies that work now, might not work in the future. The success of irrigation, soil and water conservation or other agricultural adaptations is contingent on how much warming occurs. </p>
<p>The benefits of these practices are mostly incremental — the have short-term rewards — and may not always lead to transformative outcomes, such as enabling a community to shifts its livelihood to one with reduced exposure to climate hazards.</p>
<p>We found that some responses have co-benefits: they not only help adapt to ongoing climate change, but also help mitigate (or reduce) future climate change. For example, reusing wastewater for irrigation can have adaptive and mitigative co-benefits. If implemented properly, such projects can not only provide a reliable water source throughout the year, but also <a href="https://doi.org/10.1186/s12302-019-0283-0">reduce the pressure on water treatment infrastructure</a>.</p>
<figure class="align-center ">
<img alt="Farmers carry earthen pots to water their fields." src="https://images.theconversation.com/files/448700/original/file-20220226-32551-19f8ldi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/448700/original/file-20220226-32551-19f8ldi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=373&fit=crop&dpr=1 600w, https://images.theconversation.com/files/448700/original/file-20220226-32551-19f8ldi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=373&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/448700/original/file-20220226-32551-19f8ldi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=373&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/448700/original/file-20220226-32551-19f8ldi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=468&fit=crop&dpr=1 754w, https://images.theconversation.com/files/448700/original/file-20220226-32551-19f8ldi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=468&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/448700/original/file-20220226-32551-19f8ldi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=468&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A farmer waters his fields in a dried river bed on the Ganges, in Allahabad, India, in April 2016, when decades of groundwater abuse, flawed water policies and poor monsoons turned large parts of central India into an arid dust bowl.</span>
<span class="attribution"><span class="source">(AP Photo/Rajesh Kumar Singh)</span></span>
</figcaption>
</figure>
<p>Some adaptation strategies, however, can have <a href="https://doi.org/10.1016/j.oneear.2020.09.014">long-term negative impacts, called maladaptations</a>. An often-quoted example is that of <a href="https://doi.org/10.1016/j.jhydrol.2021.126103">groundwater overuse for irrigation in India</a>, which currently supports intensive agriculture but is depleting the limited groundwater reserves at a rapid pace.</p>
<p>Adaptation strategies can work, but we need to have a better understanding of their costs and benefits. If the world continues down a high-emissions pathway, these adaptation strategies will start becoming less effective in response to increasingly complex and severe water security issues. </p>
<p>Water is central to everyone’s health, well-being and livelihood. We must focus on adapting to climate change and mitigating its effects immediately and simultaneously if we are to lessen the hardships of the world’s 10 billion people by 2050. The longer we delay aggressive actions, the higher will be the adaptation costs and smaller will be the opportunity window to undo past actions.</p><img src="https://counter.theconversation.com/content/175578/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Balsher Singh Sidhu does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Water is central to adapting to climate change, but very few of the strategies put in place to respond to water hazards or ensure its availability have been evaluated.Balsher Singh Sidhu, Postdoctoral Research Fellow in Resources, Environment and Sustainability, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1774332022-02-22T13:49:51Z2022-02-22T13:49:51ZFirst solar canal project is a win for water, energy, air and climate in California<figure><img src="https://images.theconversation.com/files/447144/original/file-20220217-23-1r1gg0q.png?ixlib=rb-1.1.0&rect=315%2C147%2C1526%2C922&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An artist's rendering of a solar canal.</span> <span class="attribution"><span class="source">Robin Raj, Citizen Group & Solar Aquagrid</span></span></figcaption></figure><p>Mounting evidence suggests <a href="https://www.nature.com/articles/s41558-022-01290-z">the western United States is now in its worst megadrought</a> in at least 1,200 years. Groundwater supplies are <a href="https://doi.org/10.1088/1748-9326/aa8ac0">being overpumped</a> in many places, and the dryness, wildfires and shrinking water supplies are making <a href="https://doi.org/10.1073/pnas.2006323117">climate change</a> personal for millions of people.</p>
<p>As <a href="https://scholar.google.com/citations?user=S2cxf2IAAAAJ&hl=en">an engineer</a>, I have been working with colleagues on a way to both protect water supplies and boost renewable energy to protect the climate.</p>
<p>We call it the solar-canal solution, and it’s about to be tested in California.</p>
<p>About <a href="https://gis.data.ca.gov/datasets/b788fb2628844f54b92e46dac5bb7229_0?geometry=-131.081%2C33.559%2C-105.548%2C39.723">4,000 miles of canals</a> transport water to some 35 million Californians and 5.7 million acres of farmland across the state. As we <a href="https://doi.org/10.1038/s41893-021-00693-8">explained in a 2021 study</a>, covering these canals with solar panels would reduce evaporation of precious water – one of California’s most critical resources – and help meet the state’s renewable energy goals, while also saving money.</p>
<p>The <a href="https://www.tid.org/about-tid/current-projects/project-nexus/">first prototypes in the U.S.</a> for both wide-span and narrow-span canals are now in development in California’s Central Valley. Researchers at the University of California, Merced, are involved in the project, and we will be trying to determine how this can become a large-scale solution. </p>
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<h2>Conserving water and land</h2>
<p>California is <a href="https://www.ppic.org/publication/droughts-in-california/">prone to drought</a>, and water is a constant concern. Now, the changing climate is bringing hotter, drier weather. </p>
<p>Severe droughts over the past 10 to 30 years <a href="https://doi.org/10.1029/2019EF001339">dried up wells</a>, caused officials to implement <a href="https://www.capradio.org/articles/2022/02/16/no-end-in-sight-california-drought-on-course-to-break-another-record/">water restrictions</a> and fueled <a href="https://www.washingtonpost.com/weather/2021/04/10/drought-wildfires-california-west/">massive wildfires</a>.</p>
<p>At the same time, California has ambitious conservation goals. The state has a mandate to <a href="https://water.ca.gov/Programs/Groundwater-Management/SGMA-Groundwater-Management">reduce groundwater pumping</a> while maintaining reliable supplies to farms, cities, wildlife and <a href="https://theconversation.com/can-we-expand-solar-power-dramatically-without-damaging-protected-lands-49429">ecosystems</a>. As part of a broad climate change initiative, in October 2020 Gov. Gavin Newsom directed the California Natural Resources Agency to spearhead efforts <a href="https://resources.ca.gov/Initiatives/Expanding-Nature-Based-Solutions">to conserve 30% of land and coastal waters by 2030</a>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/californias-water-supplies-are-in-trouble-as-climate-change-worsens-natural-dry-spells-especially-in-the-sierra-nevada-173142">California's water supplies are in trouble as climate change worsens natural dry spells, especially in the Sierra Nevada</a>
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<hr>
<p>Most of California’s rain and snow falls north of Sacramento during the winter, while 80% of its water use <a href="https://water.ca.gov/Water-Basics/The-California-Water-System">occurs in Southern California</a>, mostly in summer. That’s why canals snake across the state – it’s the largest such system in the world. We estimate that about 1%-2% of the water they carry is lost to evaporation under the hot California sun.</p>
<p>In a 2021 study, we showed that covering all 4,000 miles of California’s canals with solar panels would <a href="https://doi.org/10.1038/s41893-021-00693-8">save more than 65 billion gallons of water annually</a> by reducing evaporation. That’s enough to irrigate 50,000 acres of farmland or meet the residential water needs of more than 2 million people. By concentrating solar installations on land that is already being used, instead of building them on undeveloped land, this approach would help California meet its sustainable management goals for both <a href="https://water.ca.gov/Programs/California-Water-Plan">water</a> and <a href="https://calepa.ca.gov/2021/01/08/press-release-governors-task-force-outlines-actions-to-reduce-wildfire-risk-improve-health-of-forests-and-wildlands-1-8-21/">land</a> resources. </p>
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<h2>Climate-friendly power</h2>
<p>Shading California’s canals with solar panels would generate substantial amounts of electricity. Our estimates show that it could provide some 13 gigawatts of renewable energy capacity, which is about half of the new sources the state needs to add to meet its <a href="https://www.energy.ca.gov/news/2021-03/california-releases-report-charting-path-100-percent-clean-electricity">clean electricity goals</a>: 60% from carbon-free sources by 2030 and 100% renewable by 2045.</p>
<p>Installing solar panels over the canals makes both systems more efficient. The solar panels would reduce evaporation from the canals, especially during hot California summers. And because water heats up more slowly than land, the canal water flowing beneath the panels could cool them by 10 F, <a href="https://ieeexplore.ieee.org/document/8634893">boosting production of electricity by up to 3%</a>. </p>
<p>These canopies could also <a href="https://doi.org/10.1016/j.enpol.2003.10.004">generate electricity locally</a> in many parts of California, lowering both <a href="http://insideenergy.org/2015/11/06/lost-in-transmission-how-much-electricity-disappears-between-a-power-plant-and-your-plug/">transmission losses</a> and costs for consumers. Combining solar power with battery storage can help build microgrids in rural areas and underserved communities, making the power system more efficient and resilient. This would mitigate the risk of power losses due to extreme weather, human error and wildfires. </p>
<p>We estimate that the cost to span canals with solar panels will be higher than building ground-mounted systems. But when we added in some of the co-benefits, such as avoided land costs, water savings, aquatic weed mitigation and enhanced PV efficiency, we found that solar canals were a better investment and provided electricity that cost less over the life of the solar installations. And this is before factoring in the human health benefits of improved air quality and reduced greenhouse gas emissions.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/397187/original/file-20210426-23-1xorm5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Solar panels shade canals and canals cool the panels." src="https://images.theconversation.com/files/397187/original/file-20210426-23-1xorm5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397187/original/file-20210426-23-1xorm5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=222&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397187/original/file-20210426-23-1xorm5d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=222&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397187/original/file-20210426-23-1xorm5d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=222&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397187/original/file-20210426-23-1xorm5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=279&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397187/original/file-20210426-23-1xorm5d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=279&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397187/original/file-20210426-23-1xorm5d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=279&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Solar panels installed over canals increase the efficiency of both systems.</span>
<span class="attribution"><span class="source">Brandi McKuin</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Benefits to the land</h2>
<p>To be clear, solar canals are about much more than just generating renewable energy and saving water. Building these long, thin solar arrays could prevent more than 80,000 acres of farmland or natural habitat from being converted for solar farms. </p>
<p>California grows food for an ever-increasing global population and <a href="https://www.cdfa.ca.gov/statistics/">produces more than 50% of the fruits, nuts and vegetables</a> that U.S. consumers eat. However, up to 50% of new renewable energy capacity to meet decarbonization goals could be <a href="https://www.scienceforconservation.org/products/power-of-place">sited in agricultural areas</a>, including large swaths of prime farmland. </p>
<p>Solar canal installations will also protect wildlife, ecosystems and culturally important land. Large-scale solar developments can result in <a href="https://doi.org/10.1016/j.scitotenv.2019.134602">habitat loss, degradation and fragmentation</a>, which can harm threatened species such as the <a href="https://news.bloomberglaw.com/environment-and-energy/massive-desert-solar-project-experiment-in-tortoise-survival">Mojave Desert tortoise</a>. </p>
<p>They also can <a href="https://doi.org/10.1038/s41893-020-0574-x">harm desert-scrub plant communities</a>, including plants that are culturally important to Indigenous tribes. As an example, construction of the <a href="https://www.power-technology.com/projects/genesis-solar-energy-center-riverside-county-california/">Genesis Solar Energy Center</a> in the Sonoran and Mojave deserts in 2012-2014 <a href="https://www.azcentral.com/in-depth/news/local/arizona-environment/2021/01/18/tribes-want-biden-balance-renewable-energy-and-cultural-issues/4102836001/">destroyed trails and burial sites and damaged important cultural artifacts</a>, spurring protracted legal conflict. </p>
<h2>Clearing the air – and the weeds</h2>
<p>By generating clean electricity, solar canals can improve air quality. </p>
<p>Another benefit is curbing aquatic weeds that choke canals. In <a href="https://www.bbc.com/future/article/20200803-the-solar-canals-revolutionising-indias-renewable-energy">India</a>, where developers have been building solar canals since 2014, shade from the panels limits growth of weeds that block drains and restrict water flow. </p>
<p>Fighting these weeds is expensive, and herbicides threaten human health and the environment. For large, 100-foot-wide canals in California, we estimate that shading canals would save about US$40,000 per mile. Statewide, savings could reach $69 million per year.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/397902/original/file-20210429-23-1q3uacf.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Solar panels would form a glass roof over canals." src="https://images.theconversation.com/files/397902/original/file-20210429-23-1q3uacf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397902/original/file-20210429-23-1q3uacf.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=367&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397902/original/file-20210429-23-1q3uacf.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=367&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397902/original/file-20210429-23-1q3uacf.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=367&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397902/original/file-20210429-23-1q3uacf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=461&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397902/original/file-20210429-23-1q3uacf.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=461&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397902/original/file-20210429-23-1q3uacf.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=461&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Artist rendering of a solar canal system for California.</span>
<span class="attribution"><span class="source">Solar Aquagrid LLC</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Bringing solar canals to California</h2>
<p>California’s aging power infrastructure has contributed to catastrophic wildfires and multiday outages. Building smart solar developments on canals and other disturbed land can make power and water infrastructure more resilient while saving water, reducing costs and helping to fight climate change. </p>
<p>[<em>Over 150,000 readers rely on The Conversation’s newsletters to understand the world.</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-150ksignup">Sign up today</a>.]</p>
<p>Turlock Irrigation District, in California’s San Joaquin Valley, will build the first solar canal prototype in partnership with project developer Solar Aquagrid, researchers and others and supported by the state Department of Water Resources.</p>
<p>The prototypes in this mile-long demonstration project, along with future pilots, will help operators, developers and regulators refine designs, assess co-benefits and evaluate how these systems perform. With more data, we can map out strategies for extending solar canals statewide, and potentially across the West.</p>
<p><em>This is an update of <a href="https://theconversation.com/installing-solar-panels-over-californias-canals-could-yield-water-land-air-and-climate-payoffs-158754">an article</a> originally published on May 3, 2021.</em></p><img src="https://counter.theconversation.com/content/177433/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Roger Bales is co-investigator on a research grant to evaluate the prototype described in this article and develop scaling strategies.</span></em></p>Covering the state’s canals with solar panels would reduce evaporation of precious water and help meet renewable energy goals – all while saving money.Roger Bales, Distinguished Professor of Engineering, University of California, MercedLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1768972022-02-14T14:53:13Z2022-02-14T14:53:13ZCities must listen to people to find solutions for climate impacts: stories from Cape Town<figure><img src="https://images.theconversation.com/files/445624/original/file-20220210-26283-uckjqw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">shutterstock</span> </figcaption></figure><p>A few years ago the South African city of Cape Town was close to reaching “day zero” – the day the taps would run dry as a result of a serious drought. Households had to restrict their water usage, water tariffs increased, and businesses had to rethink how they used water. But the situation affected people unequally. Households experienced it in different ways. The poor and vulnerable suffered the most.</p>
<p>With the changing climate, problems like these aren’t going anywhere. Water scarcity, higher temperatures and changing rainfall patterns will become more common, so finding ways to adapt is important. And in a city where inequality and financial pressures are deep and complex, adaptive change will take time.</p>
<p>It also takes information. For city planners and decision makers, data is essential – but not just quantitative data. They need to engage with people to understand how they experience issues like water scarcity.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/RR5kRrGhB0I?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Making sense of a water crisis.</span></figcaption>
</figure>
<p>In today’s episode of Pasha, two researchers discuss <a href="https://www.tandfonline.com/doi/full/10.1080/07900627.2020.1841605">their work</a> on inequality in water and describe a <a href="https://doi.org/10.1080/14693062.2020.1863180">project</a> that brought city authorities and community members together. Gina Ziervogel is in the Department of Environmental and Geographical Science and Johan Enqvist is with the African Climate and Development Initiative, both at the University of Cape Town. </p>
<hr>
<p><strong>Photo:</strong>
“Lines of people waiting to collect natural spring water for drinking in Newlands in the drought in Cape Town South Africa.” Photo by Mark Fisher <a href="https://www.shutterstock.com/image-photo/cape-town-south-africa-january-25-1010387179">Shutterstock</a>.</p>
<p><strong>Music:</strong>
“Happy African Village” by John Bartmann, found on <a href="http://freemusicarchive.org/music/John_Bartmann/Public_Domain_Soundtrack_Music_Album_One/happy-african-village">FreeMusicArchive.org</a> licensed under <a href="https://creativecommons.org/publicdomain/zero/1.0/">CC0 1</a>.</p>
<p>“Ambient guitar X1 - Loop mode” by frankum, found on <a href="https://freesound.org/people/frankum/sounds/393520/">Freesound</a> licensed under <a href="http://creativecommons.org/licenses/by/3.0/">Attribution License.</a></p>
<p><strong>Video:</strong>
“Making sense of a water crisis” filmed by <a href="https://www.odendaalesterhuyse.com/uct">Odendaal Esterhuyse</a></p><img src="https://counter.theconversation.com/content/176897/count.gif" alt="The Conversation" width="1" height="1" />
Academic research can have a direct impact on people's lives. It's crucial to come together to deal with problems like climate change. If we don't, the poor and vulnerable will suffer the most.Ozayr Patel, Digital EditorLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1765142022-02-07T16:01:12Z2022-02-07T16:01:12ZMountain glaciers may hold less ice than previously thought – here’s what that means for 2 billion downstream water users and sea level rise<figure><img src="https://images.theconversation.com/files/444660/original/file-20220206-27-1x4umu8.jpg?ixlib=rb-1.1.0&rect=106%2C44%2C3628%2C2323&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Mountain glaciers are under threat from global warming.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/in-this-photo-taken-on-may-17-mountaineers-make-their-way-news-photo/962297762">Phunjo Lama/AFP via Getty Images</a></span></figcaption></figure><p><em>Mountain glaciers are essential water sources for nearly a quarter of the global population. But figuring out just how much ice they hold – and how much water will be available as glaciers shrink in a warming world – has been notoriously difficult.</em></p>
<p><em>In a new study, scientists mapped the speed of over 200,000 glaciers to get closer to an answer. They discovered that widely used estimates of glacier ice volume <a href="https://www.nature.com/articles/s41561-021-00885-z">may be off by about 20%</a> in terms of how much Earth’s glaciers outside the Greenland and Antarctic ice sheets could contribute to sea level rise.</em></p>
<p><em><a href="https://faculty-directory.dartmouth.edu/mathieu-morlighem">Mathieu Morlighem</a>, a leader in ice sheet modeling and a coauthor of the study, explains why <a href="https://www.nature.com/articles/s41561-021-00885-z">the new results</a> hold a warning for regions that rely on glaciers’ seasonal meltwater, but barely register in the big picture of rising seas.</em> </p>
<h2>1) If mountain glaciers hold less ice than previously believed, what does that mean for people who depend on glaciers for water?</h2>
<p>Globally, <a href="https://theconversation.com/the-worlds-mountain-water-towers-are-melting-putting-1-9-billion-people-at-risk-128501">almost 2 billion people</a> rely on mountain glaciers and snowpack as their main source of drinking water. Many also rely on glacier water for hydropower generation or agriculture, particularly in the dry season. But the vast majority of glaciers around the world are losing more mass than they gain during the year as the climate warms, and they <a href="https://doi.org/10.1038/s41586-021-03436-z">are slowly disappearing</a>. That will <a href="https://www.ipcc.ch/srocc/chapter/chapter-2/">profoundly affect these populations</a>.</p>
<p>These communities need to know how long their glaciers will continue to provide water and what to expect as the glaciers disappear so they can prepare.</p>
<p>In most places, we found significantly lower total ice volumes than previous estimates indicated.</p>
<p>In the tropical Andes, from Venezuela to northern Chile, for example, we found that the glaciers have about 23% less ice than previously believed. This means downstream populations have less time to adjust to climate change than they may have planned for. </p>
<figure class="align-center ">
<img alt="A herder moves sheep down a road next to a large water pipe with mountains in the background." src="https://images.theconversation.com/files/444748/original/file-20220207-85126-106wv1o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/444748/original/file-20220207-85126-106wv1o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=353&fit=crop&dpr=1 600w, https://images.theconversation.com/files/444748/original/file-20220207-85126-106wv1o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=353&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/444748/original/file-20220207-85126-106wv1o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=353&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/444748/original/file-20220207-85126-106wv1o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=444&fit=crop&dpr=1 754w, https://images.theconversation.com/files/444748/original/file-20220207-85126-106wv1o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=444&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/444748/original/file-20220207-85126-106wv1o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=444&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A herder walks beside a water pipe near La Paz, Bolivia. A glacier long relied on for water there is nearly gone.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/local-indigenous-sheep-herder-walks-past-a-water-pipe-at-news-photo/523905156">Tim Clayton/Corbis via Getty Images</a></span>
</figcaption>
</figure>
<p>Even in the Alps, where scientists have a lot of direct ice thickness measurements, we found that the glaciers may have 8% less than previously thought.</p>
<p>The big exception is the Himalayas. We calculated that there may be 37% more ice in these remote mountains than previously estimated. This buys some time for communities that rely on these glaciers, but it does not change the fact that these glaciers are melting with global warming.</p>
<p>Policymakers should look at these new estimates to revise their plans. We do not provide new predictions of the future in this study, but we do provide <a href="https://www.nature.com/articles/s41561-021-00885-z">a better description</a> of what the glaciers and their water supplies look like today.</p>
<p><iframe id="0Qk4G" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/0Qk4G/13/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>2) How do these finding affect estimates of future sea level rise?</h2>
<p>First, it’s important to understand that melting glaciers are only one contributor to sea level rise as the climate warms. About one-third of today’s sea level rise is due to <a href="https://sealevel.nasa.gov/understanding-sea-level/global-sea-level/thermal-expansion">thermal expansion</a> of the ocean – as the ocean warms, water expands and takes up more space. The other two-thirds come from <a href="https://www.climate.gov/news-features/understanding-climate/climate-change-global-sea-level">shrinking mountain glaciers and ice sheets</a>. </p>
<p>We found that if all the glaciers, not including the big ice sheets in Greenland and Antarctica, were to melt entirely, <a href="https://www.nature.com/articles/s41561-021-00885-z">sea level would rise by about 10 inches</a> instead of 13 inches. This may sound like a large difference, considering the size of the ocean, but you have to put things in perspective. A complete disintegration of the Antarctic ice sheet would contribute <a href="https://climate.nasa.gov/news/2749/ramp-up-in-antarctic-ice-loss-speeds-sea-level-rise/">190 feet</a> to sea level and the Greenland ice sheet would contribute <a href="https://www.jpl.nasa.gov/news/nasa-greenland-mission-completes-six-years-of-mapping-unknown-terrain">24 feet</a>.</p>
<p>The 3 inches that we are talking about in this study do not call into question current projections of sea level rise.</p>
<h2>3) Why has it been so hard to figure out the ice volume of glaciers, and what did your study do differently?</h2>
<p>You might be surprised by how much is still unknown about some of the basic characteristics of remote mountain glaciers.</p>
<p>Satellites have transformed our understanding of glaciers since the 1970s, and they provide an increasingly clear picture of <a href="https://www.glims.org/RGI/">glacier locations and surface area</a>. But satellites cannot see “through” the ice. In fact, for 99% of the world’s glaciers, there is no direct measurement of ice thickness. Scientists have spent more time mapping the <a href="https://www.antarcticglaciers.org/glaciers-and-climate/estimating-glacier-contribution-to-sea-level-rise/">Greenland and Antarctica ice sheets</a> and the terrain below, and we have much more detailed volume measurements there. NASA, for example, dedicated an entire airborne mission, <a href="https://www.nasa.gov/mission_pages/icebridge/mission/index.html">Operation IceBridge</a>, to collect ice thickness measurements in Greenland and Antarctica.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/444625/original/file-20220206-501-1ts25eb.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/444625/original/file-20220206-501-1ts25eb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/444625/original/file-20220206-501-1ts25eb.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=223&fit=crop&dpr=1 600w, https://images.theconversation.com/files/444625/original/file-20220206-501-1ts25eb.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=223&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/444625/original/file-20220206-501-1ts25eb.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=223&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/444625/original/file-20220206-501-1ts25eb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=280&fit=crop&dpr=1 754w, https://images.theconversation.com/files/444625/original/file-20220206-501-1ts25eb.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=280&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/444625/original/file-20220206-501-1ts25eb.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=280&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The new mapping techniques are more precise, as a comparison of Iceland’s Vatnajökull ice cap shows. The image on the left is the new map.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1038/s41561-021-00885-z">R. Millan et al., 2022</a></span>
</figcaption>
</figure>
<p>Scientists have come up with <a href="https://doi.org/10.1038/s41561-019-0300-3">various techniques</a> to <a href="https://doi.org/10.1002/2014RG000470">determine the volume</a> of glaciers, but the uncertainty for remote mountain glaciers has been pretty high.</p>
<p>We did something different compared to previous studies. We used satellite imagery to map the glaciers’ speed. Glacier ice, when it is thick enough, behaves like thick syrup. We can measure how far the ice is moving using two satellite images and map its speed, which goes from a few feet to about 1 mile per year. Mapping the displacement of more than 200,000 glaciers was no easy task, but that created a data set nobody had seen before.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/444626/original/file-20220206-17-kwn95c.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/444626/original/file-20220206-17-kwn95c.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/444626/original/file-20220206-17-kwn95c.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=527&fit=crop&dpr=1 600w, https://images.theconversation.com/files/444626/original/file-20220206-17-kwn95c.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=527&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/444626/original/file-20220206-17-kwn95c.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=527&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/444626/original/file-20220206-17-kwn95c.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=663&fit=crop&dpr=1 754w, https://images.theconversation.com/files/444626/original/file-20220206-17-kwn95c.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=663&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/444626/original/file-20220206-17-kwn95c.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=663&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Images show the velocity of glacier ice in regions around the world.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1038/s41561-021-00885-z">R. Millan et al., 2022</a></span>
</figcaption>
</figure>
<p>We used this new information of ice speed and simple principles of ice deformation to determine the thickness of the ice at each pixel of these satellite images. In short, the ice speed we observe from space is due to the ice sliding on its bed and also its internal deformation. The internal deformation depends on its surface slope and ice thickness, and the slipperiness of its bed depends on the temperature of the ice at its base, the presence or absence of liquid water, and the nature of the sediments or rocks underneath. Once we could calibrate a relationship between ice speed and sliding, we could calculate ice thickness.</p>
<p>[<em>Over 140,000 readers rely on The Conversation’s newsletters to understand the world.</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-140ksignup">Sign up today</a>.]</p>
<p>To map the flow speed of all of these glaciers, we analyzed 800,000 pairs of images collected by satellites from the European Space Agency and NASA.</p>
<p>Of course, as with any indirect method, they are not perfect estimates and they will be further improved as we collect more data. But we have made a lot of progress in reducing the overall uncertainty.</p><img src="https://counter.theconversation.com/content/176514/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mathieu Morlighem receives funding from NASA, NASA and the Heising-Simons Foundation.</span></em></p>Glaciers in North America, Europe and the Andes, in particular, have significantly less ice than people realized.Mathieu Morlighem, Professor of Earth Sciences, Dartmouth CollegeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1734792021-12-10T13:38:56Z2021-12-10T13:38:56Z‘Zero Day’ for California water? Not yet, but unprecedented water restrictions send a sharp warning<figure><img src="https://images.theconversation.com/files/436480/original/file-20211208-172173-e03zaj.jpg?ixlib=rb-1.1.0&rect=0%2C24%2C5374%2C3547&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">California has been through two straight year of drought, and water supplies are limited.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/portion-of-the-152-mile-friant-kern-canal-an-aqueduct-to-news-photo/1328043632">George Rose/Getty Images</a></span></figcaption></figure><p>California triggered headlines heard around the world when officials <a href="https://water.ca.gov/programs/state-water-project/management/swp-water-contractors">announced how much water</a> suppliers would be getting from the State Water Project. “<a href="https://www.theguardian.com/us-news/2021/dec/02/california-water-districts-zero-water-requested-supplies">California water districts to get 0% of requested supplies</a> in an unprecedented decision,” one headline proclaimed. “<a href="https://www.farmprogress.com/water/no-state-water-california-farms">No state water for California farms</a>,” read another.</p>
<p>The headlines suggested a comparison with the “<a href="https://theconversation.com/day-zero-is-meant-to-cut-cape-towns-water-use-what-is-it-and-is-it-working-92055">Zero Day</a>” announcement in Cape Town, South Africa, during a drought in 2018. That was the projected date when water would no longer be available at household taps without significant conservation. Cape Town <a href="https://www.bbc.com/news/world-africa-59221823">avoided a water shutoff</a>, barely.</p>
<p>While California’s announcement on Dec. 1, 2021, represents uncharted territory and is meant to promote water conservation going into what many people fear will be another dry water year, there is more to the story. </p>
<figure class="align-center ">
<img alt="Map of drought conditions for the contiguous United States as of Dec. 7, 2021" src="https://images.theconversation.com/files/438909/original/file-20211222-25-1dxg3sd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/438909/original/file-20211222-25-1dxg3sd.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/438909/original/file-20211222-25-1dxg3sd.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/438909/original/file-20211222-25-1dxg3sd.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/438909/original/file-20211222-25-1dxg3sd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=494&fit=crop&dpr=1 754w, https://images.theconversation.com/files/438909/original/file-20211222-25-1dxg3sd.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=494&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/438909/original/file-20211222-25-1dxg3sd.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=494&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Most of California was in extreme drought or worse in mid-December 2021.</span>
<span class="attribution"><a class="source" href="https://droughtmonitor.unl.edu/">U.S. Drought Monitor/David Simeral, Western Regional Climate Center</a></span>
</figcaption>
</figure>
<h2>California’s drought solution</h2>
<p>California is a semi-arid state, so a dry year isn’t a surprise. But <a href="https://water.ca.gov/-/media/DWR-Website/Web-Pages/Water-Basics/Drought/Files/Publications-And-Reports/091521-Water-Year-2021-broch_v2.pdf">a recent state report</a> observed that California is now in a dry pattern “interspersed with an occasional wet year.” The state suffered a three-year drought from 2007 to 2009, a five-year drought from 2012 to 2016, and now two dry years in a row; 2020 was the fifth-driest year on record, and 2021 was the second-driest.</p>
<p>Coming into the 2022 water year – which began Oct. 1 – the ground was dry and reservoirs were low. December’s <a href="https://www.washingtonpost.com/weather/2021/12/20/snow-california-storm-west/">rain and several feet of snow in the Sierra Nevada</a> should help put a dent in the drought. However predictions have suggested <a href="https://www.climate.gov/news-features/blogs/enso/what-expect-winter-noaa%E2%80%99s-2021-22-winter-outlook">another drier than normal year may be ahead</a>.</p>
<p>Over a century ago, well before climate change became evident, officials began planning ways to keep California’s growing cities and farms supplied with water. They developed a complex system of reservoirs and canals that funnel water from where it’s plentiful to where it’s needed.</p>
<p>Part of that system is the State Water Project.</p>
<p><a href="https://water.ca.gov/Programs/State-Water-Project/SWP-Facilities/History">First envisioned</a> in 1919, the State Water Project delivers water from the relatively wetter and, at the time, less populated areas of Northern California to more populated and drier areas, mostly in Southern California. <a href="https://water.ca.gov/Programs/State-Water-Project">The State Water Project provides water</a> for 27 million people and 750,000 acres of farmland, with about 70% for residential, municipal and industrial use and 30% for irrigation. There are 29 local water agencies – the <a href="https://water.ca.gov/Programs/State-Water-Project/Management/SWP-Water-Contractors">state water contractors</a> – that helped fund the State Water Project and in return receive water under a contract dating to the 1960s.</p>
<figure class="align-center ">
<img alt="Map of the State Water Project's reservoirs and primary canals" src="https://images.theconversation.com/files/436505/original/file-20211208-19-14q5zsp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/436505/original/file-20211208-19-14q5zsp.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=644&fit=crop&dpr=1 600w, https://images.theconversation.com/files/436505/original/file-20211208-19-14q5zsp.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=644&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/436505/original/file-20211208-19-14q5zsp.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=644&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/436505/original/file-20211208-19-14q5zsp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=809&fit=crop&dpr=1 754w, https://images.theconversation.com/files/436505/original/file-20211208-19-14q5zsp.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=809&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/436505/original/file-20211208-19-14q5zsp.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=809&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The reservoirs (circles reflect comparative size) and primary canals and aqueducts (bold lines) connected with California’s State Water Project.</span>
<span class="attribution"><a class="source" href="https://water.ca.gov/Programs/State-Water-Project">California Department of Water Resources</a></span>
</figcaption>
</figure>
<p>While the State Water Project is important to these local water agencies, it is usually not their only source of water. Nor is all water in California supplied through the State Water Project. Most water agencies have a portfolio of water supplies, which can include pumping groundwater.</p>
<h2>What does 0% mean?</h2>
<p>Originally, the State Water Project planned to deliver 4.2 million acre-feet of water each year. An <a href="https://www.watereducation.org/general-information/whats-acre-foot">acre-foot is about 326,000 gallons</a>, or enough water to cover a football field in water 1 foot deep. An average California household uses around one-half to 1 acre-foot of water per year for both indoor and outdoor use. However, contractors that distribute water from the State Water Project have historically received only part of their allocations; the long-term average is <a href="https://www.cvwd.org/170/Californias-State-Water-Project">60%, with recent years much lower</a>.</p>
<p>Based on water conditions each year, the state Department of Water Resources makes an initial allocation by Dec. 1 to help these state water contractors plan. As the year progresses, the state can adjust the allocation based on additional rain or snow and the amount of water in storage reservoirs. In 2010, for example, the allocation <a href="https://water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/State-Water-Project/Management/SWP-Water-Contractors/Files/1996-2022-Allocation-Progression-120121.pdf">started at 5%</a> and was raised to 50% by June. In 2014, the allocation started at 5%, dropped to 0% and then finished at 5%.</p>
<p>This year is the lowest initial allocation on record. According to the state Department of Water Resources, “<a href="https://water.ca.gov/News/News-Releases/2021/Dec-21/SWP-December-Allocation">unprecedented drought conditions</a>” and “reservoirs at or near historic lows” led to this year’s headline-producing 0% allocation.</p>
<p><iframe id="oG89t" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/oG89t/1/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>That’s <a href="https://water.ca.gov/programs/state-water-project/management/swp-water-contractors">0% of each state water contractor’s allocation</a>; however, <a href="https://water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/State-Water-Project/Management/SWP-Water-Contractors/Files/NTC-21-07_2022-SWP-Initial-Allocation-Minimum-Human-Health-and-Safety_120121.pdf">the department committed to meet</a> “unmet minimum health and safety needs.” In other words, if the contractors cannot find water from other sources, they could request up to 55 gallons per capita per day of water to “meet domestic supply, fire protection and sanitation needs.” That’s <a href="https://pubs.usgs.gov/circ/1441/circ1441.pdf">about two-thirds</a> of what the average American uses.</p>
<p><a href="https://water.ca.gov/News/News-Releases/2021/Dec-21/SWP-December-Allocation">The department is also prioritizing</a> water for salinity control in the Sacramento Bay Delta area, water for endangered species, water to reserve in storage and water for additional supply allocations if the weather conditions improve.</p>
<p>Under the current plan, there will be no water from the State Water Project for roughly 10% of California’s irrigated land. As a result, both municipal and agricultural suppliers will be seeking to conserve water, looking elsewhere for water supplies, or not delivering water. None are easy solutions.</p>
<h2>The problem with pumping groundwater</h2>
<p>To weather previous droughts, many water suppliers relied on groundwater, which led to increased costs for wells, <a href="https://www.science.org/content/article/droughts-exposed-california-s-thirst-groundwater-now-state-hopes-refill-its-aquifers">declines in groundwater levels</a>, <a href="https://ca.water.usgs.gov/land_subsidence/california-subsidence-areas.html">land subsidence</a> and <a href="https://www.usgs.gov/news/state-news-release/increased-pumping-californias-central-valley-during-drought-worsens">degraded water quality</a>. California’s <a href="https://water.ca.gov/programs/groundwater-management/sgma-groundwater-management">Sustainable Groundwater Management Act</a> was enacted in 2014 to help address overpumping of groundwater, but it hasn’t turned these conditions around.</p>
<figure class="align-center ">
<img alt="Chart showing water level dropping and subsidence increasing." src="https://images.theconversation.com/files/436494/original/file-20211208-17-n5bdlm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/436494/original/file-20211208-17-n5bdlm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=197&fit=crop&dpr=1 600w, https://images.theconversation.com/files/436494/original/file-20211208-17-n5bdlm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=197&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/436494/original/file-20211208-17-n5bdlm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=197&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/436494/original/file-20211208-17-n5bdlm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=248&fit=crop&dpr=1 754w, https://images.theconversation.com/files/436494/original/file-20211208-17-n5bdlm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=248&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/436494/original/file-20211208-17-n5bdlm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=248&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Groundwater pumping during droughts in California’s Central Valley lowered underground water levels and contributed to land subsidence. The chart shows levels at one monitoring station.</span>
<span class="attribution"><a class="source" href="https://www.usgs.gov/news/state-news-release/during-recent-droughts-central-valley-groundwater-levels-reached-historical">USGS</a></span>
</figcaption>
</figure>
<p>Those who can afford to dig deeper wells have done so, while others have no water as <a href="https://www.circleofblue.org/2021/world/as-a-hot-dry-summer-begins-in-california-more-water-wells-are-failing/">their wells have gone dry</a>. During the 2012-2016 drought, the <a href="https://www.ppic.org/blog/commentary-how-better-data-can-help-california-avoid-a-drinking-water-crisis/">Public Policy Institute of California</a> found that a majority of affected households that lost water access from their wells were in “small rural communities reliant on shallow wells – many of them communities of color.”</p>
<p>Gov. Gavin Newsom called on residents to voluntarily conserve 15% of their water during summer 2021. <a href="https://www.latimes.com/california/story/2021-09-21/southern-california-spurns-drought-conservation-request">Statewide reductions were only 1.8%</a> in July but <a href="https://subscriber.politicopro.com/article/eenews/2021/12/08/californians-cut-water-use-13-in-october-still-behind-goal-284051">jumped to 13.2% in October</a>. The year’s <a href="https://cdec.water.ca.gov/snowapp/sweq.action">snowpack, which acts as a natural reservoir, was still well below normal</a> even after snowstorms in early and mid-December.</p>
<p>Irrigators who depend on the federal <a href="https://www.usbr.gov/mp/cvp/">Central Valley Project</a> are facing similar drought conditions. Imports from the Colorado River system are also limited, as this basin is also <a href="https://theconversation.com/as-colorado-river-basin-states-confront-water-shortages-its-time-to-focus-on-reducing-demand-165646">facing its first-ever shortage declaration due to drought</a>.</p>
<h2>What’s next?</h2>
<p>As someone who has worked in California and the Western U.S. on complex water issues, I am familiar with both drought and floods and the challenges they create. However, the <a href="https://droughtmonitor.unl.edu/">widespread nature of the latest drought</a> – in California and beyond – makes the challenge even harder. </p>
<p>This “zero allocation” for California’s State Water Contractors is an unprecedented early warning, and likely a sign of what’s ahead.</p>
<figure class="align-center ">
<img alt="An aerial photo of the Sacramento-San Joaquin Delta" src="https://images.theconversation.com/files/436508/original/file-20211208-19-16npgj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/436508/original/file-20211208-19-16npgj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=382&fit=crop&dpr=1 600w, https://images.theconversation.com/files/436508/original/file-20211208-19-16npgj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=382&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/436508/original/file-20211208-19-16npgj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=382&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/436508/original/file-20211208-19-16npgj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=480&fit=crop&dpr=1 754w, https://images.theconversation.com/files/436508/original/file-20211208-19-16npgj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=480&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/436508/original/file-20211208-19-16npgj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=480&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Sacramento-San Joaquin Delta provides fresh water to two-thirds of the state’s population.</span>
<span class="attribution"><a class="source" href="https://water.ca.gov/Programs/State-Water-Project">California Department of Water Resources</a></span>
</figcaption>
</figure>
<p>A recent study warned that the snowpack in Western states like California <a href="https://www.washingtonpost.com/weather/2021/12/03/snow-water-resources-california/">may decline by up to 45% by 2050</a>, with low- and no-snow years becoming increasingly common. <a href="https://www.spur.org/publications/spur-report/2021-10-21/water-growing-bay-area">Thirty-seven cities in California</a> have already issued moratoriums on development because of water supply concerns.</p>
<p>If voluntary conservation does not work, enacting mandatory conservation measures like San Jose’s <a href="https://www.mercurynews.com/2021/11/18/how-san-jose-water-companys-new-drought-rules-and-fees-will-affect-your-water-bill/">tough new drought rules</a> may be needed. The state has been <a href="https://www.waterboards.ca.gov/water_issues/programs/conservation_portal/docs/emergency_reg/notice_droughtrulemaking.pdf">weighing emergency regulations</a> on water use, and everyone is hoping for enough precipitation.</p>
<p>[<em>Over 140,000 readers rely on The Conversation’s newsletters to understand the world.</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-140ksignup">Sign up today</a>.]</p>
<p><em>This article was updated Dec. 22, 2021, with details about the drought after storms in early December.</em></p><img src="https://counter.theconversation.com/content/173479/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lara B. Fowler worked in California as a mediator prior to 2012 on different projects and received funding from the California Department of Water Resources, the State Water Contractors, and the Water Replenishment District of Southern California. </span></em></p>Long before climate change was evident, California began planning a system of canals and reservoirs to carry water from the mountains to drier farms and cities. It’s no longer enough.Lara B. Fowler, Senior Lecturer in Law and Assistant Director for Outreach and Engagement, Penn State Institutes of Energy and the Environment, Penn StateLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1679822021-10-07T12:22:51Z2021-10-07T12:22:51ZAncient groundwater: Why the water you’re drinking may be thousands of years old<figure><img src="https://images.theconversation.com/files/425134/original/file-20211006-19-hm7er4.jpg?ixlib=rb-1.1.0&rect=871%2C578%2C3009%2C2087&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Some of North America’s groundwater is so old, it fell as rain before humans arrived here thousands of years ago.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/senior-woman-holding-glass-of-water-close-up-royalty-free-image/961181838">Maria Fuchs via Getty Images</a></span></figcaption></figure><p>Communities that rely on the Colorado River are facing a water crisis. Lake Mead, the river’s largest reservoir, has fallen to levels not seen since it was created by the construction of the Hoover Dam roughly a century ago. Arizona and Nevada are <a href="https://theconversation.com/as-colorado-river-basin-states-confront-water-shortages-its-time-to-focus-on-reducing-demand-165646">facing their first-ever mandated water cuts</a>, while water is being <a href="https://coloradosun.com/2021/07/19/lake-powell-drought-blue-mesa-reservoir-drained/">released from other reservoirs</a> to keep the Colorado River’s hydropower plants running.</p>
<p>If even the mighty Colorado and its reservoirs are not immune to the heat and drought worsened by climate change, where will the West get its water?</p>
<p>There’s one hidden answer: underground.</p>
<p>As rising temperatures and drought dry up rivers and melt mountain glaciers, people are increasingly dependent on the water under their feet. Groundwater resources currently supply <a href="http://nora.nerc.ac.uk/id/eprint/19395/">drinking water to nearly half the world’s population</a> and <a href="https://doi.org/10.1016/j.jog.2011.05.001">roughly 40% of water used for irrigation globally</a>.</p>
<p>What many people don’t realize is how old – and how vulnerable – much of that water is.</p>
<p>Most water stored underground has been there for decades, and much of it has sat for hundreds, thousands or even millions of years. Older groundwater tends to reside deep underground, where it is <a href="https://theconversation.com/water-underground-source-for-billions-could-take-more-than-a-century-to-respond-fully-to-climate-change-110551">less easily affected by surface conditions</a> such as drought and pollution.</p>
<p>As shallower wells dry out under the pressure of urban development, population growth and climate change, old groundwater is becoming increasingly important.</p>
<h2>Drinking ancient groundwater</h2>
<p>If you bit into a piece of bread that was 1,000 years old, you’d probably notice.</p>
<p>Water that has been underground for a thousand years can taste different, too. It leaches natural chemicals from the surrounding rock, changing its mineral content. Some natural contaminants <a href="https://www.usgs.gov/center-news/lithium-us-groundwater">linked to groundwater age</a> – <a href="https://doi.org/10.1192/bjp.2020.128">like mood-boosting lithium</a> – can have positive effects. Other contaminants, like iron and manganese, can be troublesome. </p>
<p>Older groundwater is also sometimes <a href="https://doi.org/10.1029/2021GL093549">too salty to drink</a> without expensive treatment. This problem can be worse near the coasts: Overpumping creates space that can draw seawater into aquifers and contaminate drinking supplies.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/423398/original/file-20210927-25-wpt4qy.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Illustration of layers of groundwater below the surface" src="https://images.theconversation.com/files/423398/original/file-20210927-25-wpt4qy.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/423398/original/file-20210927-25-wpt4qy.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=386&fit=crop&dpr=1 600w, https://images.theconversation.com/files/423398/original/file-20210927-25-wpt4qy.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=386&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/423398/original/file-20210927-25-wpt4qy.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=386&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/423398/original/file-20210927-25-wpt4qy.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=485&fit=crop&dpr=1 754w, https://images.theconversation.com/files/423398/original/file-20210927-25-wpt4qy.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=485&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/423398/original/file-20210927-25-wpt4qy.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=485&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Flow timescales of groundwater through different layers.</span>
<span class="attribution"><a class="source" href="https://www.wtamu.edu/~cbaird/sq/2013/07/16/how-do-wells-get-their-water-from-underground-rivers">USGS</a></span>
</figcaption>
</figure>
<p>Ancient groundwater can take thousands of years to replenish naturally. And, as California saw during its 2011-2017 drought, natural underground storage spaces compress as they empty, so they <a href="https://doi.org/10.1002/2016WR019861">can’t refill to their previous capacity</a>. This compaction in turn causes the land above to crack, buckle and sink.</p>
<p>Yet people today are <a href="https://www.wpr.org/without-enough-water-go-around-farmers-california-are-exhausting-aquifers">drilling deeper wells in the West</a> as droughts deplete surface water and farms rely more heavily on groundwater.</p>
<h2>What does it mean for water to be ‘old’?</h2>
<p>Let’s imagine a rainstorm over central California 15,000 years ago. As the storm rolls over what’s now San Francisco, most of the rain falls into the Pacific Ocean, where it will eventually evaporate back into the atmosphere. However, some rain also falls into rivers and lakes and over dry land. As that rain seeps through layers of soil, it enters slowly trickling “flowpaths” of underground water.</p>
<p>Some of these paths lead deeper and deeper, where water collects in crevices within the bedrock hundreds of meters underground. The water gathered in these underground reserves is in a sense cut off from the active water cycle – at least on timescales relevant to human life.</p>
<p>In California’s arid Central Valley, <a href="https://linkinghub.elsevier.com/retrieve/pii/S0022169416302773">much of the accessible ancient water</a> has been <a href="https://www.science.org/doi/10.1126/sciadv.abf3503">pumped out</a> of the earth, mostly for agriculture. Where the natural replenishment timescale would be on the order of millennia, agricultural seepage <a href="https://www.science.org/doi/10.1126/sciadv.abf3503">has partially refilled some aquifers with newer</a> – too often polluted – water. In fact, places like Fresno now actively refill aquifers with clean water (such as treated wastewater or stormwater) in a process known as “<a href="https://www.americangeosciences.org/geoscience-currents/managed-aquifer-recharge">managed aquifer recharge</a>.”</p>
<figure class="align-center ">
<img alt="Map showing longest turnover times are in the West and Great Plains" src="https://images.theconversation.com/files/424251/original/file-20211001-23-taw2of.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/424251/original/file-20211001-23-taw2of.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=534&fit=crop&dpr=1 600w, https://images.theconversation.com/files/424251/original/file-20211001-23-taw2of.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=534&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/424251/original/file-20211001-23-taw2of.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=534&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/424251/original/file-20211001-23-taw2of.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=671&fit=crop&dpr=1 754w, https://images.theconversation.com/files/424251/original/file-20211001-23-taw2of.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=671&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/424251/original/file-20211001-23-taw2of.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=671&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Average turnover times for groundwater in the U.S.</span>
<span class="attribution"><span class="source">Alan Seltzer, based on data from Befus et al 2017</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>In 2014, midway through their worst drought in modern memory, California became the last western state <a href="https://water.ca.gov/programs/groundwater-management/sgma-groundwater-management">to pass a law</a> requiring local groundwater sustainability plans. Groundwater may be resilient to heat waves and climate change, but if you use it all, you’re in trouble.</p>
<p>One response to water demand? Drill deeper. Yet that answer <a href="https://theconversation.com/drilling-deeper-wells-is-a-band-aid-solution-to-us-groundwater-woes-121219">isn’t sustainable</a>.</p>
<p>First, it’s expensive: Large agricultural companies and lithium mining firms tend to be the sort of investors who can afford to drill deep enough, while <a href="https://www.nytimes.com/2021/08/14/us/drought-california-water-shortage.html">small rural communities can’t</a>. </p>
<p>Second, once you pump ancient groundwater, aquifers need time to refill. Flowpaths may be disrupted, choking off a natural water supply to springs, wetlands and rivers. Meanwhile, the change in pressure underground can destabilize the earth, <a href="https://ca.water.usgs.gov/land_subsidence/california-subsidence-areas.html">causing land to sink</a> and even <a href="https://doi.org/10.1029/2019GL083491">leading to earthquakes</a>.</p>
<figure class="align-right ">
<img alt="Chart showing how nitrates enter water as more groundwater is pumped out" src="https://images.theconversation.com/files/422559/original/file-20210922-21-blruso.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/422559/original/file-20210922-21-blruso.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=684&fit=crop&dpr=1 600w, https://images.theconversation.com/files/422559/original/file-20210922-21-blruso.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=684&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/422559/original/file-20210922-21-blruso.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=684&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/422559/original/file-20210922-21-blruso.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=860&fit=crop&dpr=1 754w, https://images.theconversation.com/files/422559/original/file-20210922-21-blruso.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=860&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/422559/original/file-20210922-21-blruso.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=860&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Pumping accelerates groundwater flow to a well, delivering dissolved chemicals.</span>
<span class="attribution"><a class="source" href="https://www.usgs.gov/media/images/nitrate-groundwater-pumping">USGS</a></span>
</figcaption>
</figure>
<p>Third is contamination: While deep, mineral-rich ancient groundwater is often cleaner and safer to drink than younger, shallower groundwater, overpumping can change that. As water-strapped regions rely more heavily on deep groundwater, overpumping lowers the water table and draws down polluted modern water that can mix with the older water. This mixing <a href="https://www.usgs.gov/news/increased-pumping-california-s-central-valley-during-drought-worsens-groundwater-quality">causes the water quality to deteriorate</a>, leading to demand for ever-deeper wells.</p>
<h2>Reading climate history in ancient groundwater</h2>
<p>There are other reasons to care about ancient groundwater. Like actual fossils, extremely old “fossil groundwater” can teach us about the past. </p>
<p>Envision our prehistoric rainstorm again: 15,000 years ago, the climate was quite different from today. Chemicals that dissolved in ancient groundwater are detectable today, opening windows into a past world. Certain dissolved chemicals act as clocks, telling scientists the groundwater’s age. For example, we know how fast dissolved carbon-14 and krypton-18 decay, so we can measure them to calculate when the water last interacted with air. </p>
<p>Younger groundwater that disappeared underground after the 1950s has a unique, man-made chemical signature: high levels of tritium from atomic bomb testing.</p>
<figure class="align-center ">
<img alt="Illustration of water flowing among rocks, close up and at a distance." src="https://images.theconversation.com/files/422556/original/file-20210922-26-tcnb2j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/422556/original/file-20210922-26-tcnb2j.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=369&fit=crop&dpr=1 600w, https://images.theconversation.com/files/422556/original/file-20210922-26-tcnb2j.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=369&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/422556/original/file-20210922-26-tcnb2j.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=369&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/422556/original/file-20210922-26-tcnb2j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=464&fit=crop&dpr=1 754w, https://images.theconversation.com/files/422556/original/file-20210922-26-tcnb2j.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=464&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/422556/original/file-20210922-26-tcnb2j.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=464&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The various components and properties of an unconfined aquifer.</span>
<span class="attribution"><a class="source" href="https://pubs.usgs.gov/gip/gw/how_a.html">USGS</a></span>
</figcaption>
</figure>
<p>Other dissolved chemicals behave like tiny thermometers. Noble gases like argon and xenon, for instance, dissolve more in cold water than in warm water, along a precisely known temperature curve. Once groundwater is isolated from air, dissolved noble gases don’t do much. As a result, they preserve information about environmental conditions at the time the water first seeped into the subsurface.</p>
<p>The concentrations of noble gases in fossil groundwater have provided some of our most reliable estimates of <a href="https://doi.org/10.1038/s41586-021-03467-6">temperature on land during the last ice age</a>. Such findings provide insight into modern climates, including how sensitive Earth’s average temperature is to carbon dioxide in the atmosphere. These methods support a <a href="https://doi.org/10.1038/s41586-020-2617-x">recent study</a> that found 3.4 degrees Celsius of warming with each doubling of carbon dioxide.</p>
<h2>Groundwater’s past and future</h2>
<p>People in some regions, like New England, have been drinking ancient groundwater for years with little danger of exhausting usable supplies. Regular rainfall and varied water sources – including surface water in lakes, rivers and snowpack – provide alternatives to groundwater and also refill aquifers with new water. If aquifers can keep up with the demand, the water <a href="https://doi.org/10.1038/s41561-020-0629-7">can be used sustainably</a>. </p>
<p>Out West, though, over a century of unmanaged and exorbitant water use means that some of the places most dependent on groundwater – arid regions vulnerable to drought – have squandered the ancient water resources that once existed underground.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/424254/original/file-20211001-27-1f9d7aq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Cross section of California showing rivers, groundwater and wells, including recharge wells" src="https://images.theconversation.com/files/424254/original/file-20211001-27-1f9d7aq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/424254/original/file-20211001-27-1f9d7aq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=355&fit=crop&dpr=1 600w, https://images.theconversation.com/files/424254/original/file-20211001-27-1f9d7aq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=355&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/424254/original/file-20211001-27-1f9d7aq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=355&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/424254/original/file-20211001-27-1f9d7aq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=446&fit=crop&dpr=1 754w, https://images.theconversation.com/files/424254/original/file-20211001-27-1f9d7aq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=446&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/424254/original/file-20211001-27-1f9d7aq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=446&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">How water use and recharge fit into the hydrological cycle.</span>
<span class="attribution"><a class="source" href="https://www.waterboards.ca.gov/rwqcb2/water_issues/programs/groundwater_protection.html">State of California</a></span>
</figcaption>
</figure>
<p>A famous precedent for this problem is in the Great Plains. There, the ancient water of the Ogallala Aquifer supplies drinking water and irrigation for millions of people and farms from South Dakota to Texas. If people were to pump this aquifer dry, <a href="https://blogs.scientificamerican.com/observations/farmers-deplete-fossil-water-in-worlds-breadbaskets/">it would take thousands of years to refill naturally</a>. It is a vital buffer against drought, yet irrigation and water-intensive farming <a href="https://theconversation.com/farmers-are-depleting-the-ogallala-aquifer-because-the-government-pays-them-to-do-it-145501">are lowering its water levels at unsustainable rates</a>. </p>
<p>As the planet warms, ancient groundwater is becoming increasingly important – whether flowing from your kitchen tap, irrigating food crops, or offering warnings about Earth’s past that can help us prepare for an uncertain future.</p>
<p>[<em>Understand new developments in science, health and technology, each week.</em> <a href="https://theconversation.com/us/newsletters/science-editors-picks-71/?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=science-understand">Subscribe to The Conversation’s science newsletter</a>.]</p><img src="https://counter.theconversation.com/content/167982/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>As surface water diminishes in the Western US, people are drilling deeper wells – and tapping into older groundwater that can take thousands of years to replenish naturally.Marissa Grunes, Environmental Fellow, Harvard UniversityAlan Seltzer, Assistant Scientist in Marine Chemistry and Geochemistry, Woods Hole Oceanographic InstitutionKevin M. Befus, Assistant Professor of Hydrogeology, University of ArkansasLicensed as Creative Commons – attribution, no derivatives.