tag:theconversation.com,2011:/ca/topics/pollution-306/articlesPollution – The Conversation2024-03-18T19:21:57Ztag:theconversation.com,2011:article/2253542024-03-18T19:21:57Z2024-03-18T19:21:57ZStudy links microplastics with human health problems – but there’s still a lot we don’t know<figure><img src="https://images.theconversation.com/files/582403/original/file-20240317-28-ha8xio.jpg?ixlib=rb-1.1.0&rect=62%2C0%2C7008%2C4668&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/microplastics-hand-air-pollution-aquatic-food-2164471827">Naiyana Somchitkaeo/Shutterstock</a></span></figcaption></figure><p>A <a href="https://www.nejm.org/doi/full/10.1056/NEJMoa2309822">recent study</a> published in the prestigious New England Journal of Medicine has linked microplastics with risk to human health.</p>
<p>The study involved patients in Italy who had a condition called carotid artery plaque, where plaque builds up in arteries, potentially blocking blood flow. The researchers analysed plaque specimens from these patients. </p>
<p>They found those with carotid artery plaque who had microplastics and nanoplastics in their plaque had a higher risk of heart attack, stroke, or death (compared with carotid artery plaque patients who didn’t have any micro- or nanoplastics detected in their plaque specimens). </p>
<p>Importantly, the researchers didn’t find the micro- and nanoplastics <em>caused</em> the higher risk, only that it was correlated with it. </p>
<p>So, what are we to make of the new findings? And how does it fit with the broader evidence about microplastics in our <a href="https://www.science.org/doi/10.1126/sciadv.aax1157">environment</a> and <a href="https://www.sciencedirect.com/science/article/pii/S0160412022001258">our bodies</a>?</p>
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<h2>What are microplastics?</h2>
<p>Microplastics are plastic particles less than five millimetres across. Nanoplastics are less than one micron in size (1,000 microns is equal to one millimetre). The precise size classifications <a href="https://doi.org/10.1016/j.envpol.2018.01.024">are still a matter of debate</a>. </p>
<p>Microplastics and nanoplastics are created when everyday products – including clothes, food and beverage packaging, home furnishings, plastic bags, toys and toiletries – degrade. Many personal care products contain microsplastics in the form of microbeads.</p>
<p>Plastic is also used widely in agriculture, and can degrade over time into microplastics and nanoplastics.</p>
<p>These particles are made up of common polymers such as polyethylene, polypropylene, polystyrene and polyvinyl chloride. The constituent chemical of polyvinyl chloride, vinyl chloride, is <a href="https://wwwn.cdc.gov/TSP/ToxFAQs/ToxFAQsDetails.aspx?faqid=281&toxid=51">considered carcinogenic</a> by the <a href="https://19january2017snapshot.epa.gov/sites/production/files/2016-09/documents/vinyl-chloride.pdf">US Environmental Protection Agency</a>.</p>
<p>Of course, the actual risk of harm depends on your level of exposure. As toxicologists are fond of <a href="https://onlinelibrary.wiley.com/doi/10.1111/bcpt.12622">saying</a>, it’s the dose that makes the poison, so we need to be careful to not over-interpret emerging research.</p>
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Read more:
<a href="https://theconversation.com/australians-are-washing-microplastics-down-the-drain-and-its-ending-up-on-our-farms-223079">Australians are washing microplastics down the drain and it's ending up on our farms</a>
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<h2>A closer look at the study</h2>
<p>This new study in the New England Journal of Medicine was a small cohort, initially comprising 304 patients. But only 257 completed the follow-up part of the study 34 months later. </p>
<p>The study had a number of limitations. The first is the findings related only to asymptomatic patients undergoing carotid endarterectomy (a procedure to remove carotid artery plaque). This means the findings might not be applicable to the wider population.</p>
<p>The authors also point out that while exposure to microplastics and nanoplastics has been likely increasing in recent decades, heart disease rates have been <a href="https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.115.015293">falling</a>.</p>
<p>That said, the fact so many people in the study had detectable levels of microplastics in their body is notable. The researchers found detectable levels of polyethylene and polyvinyl chloride (two types of plastic) in excised carotid plaque from 58% and 12% of patients, respectively. </p>
<p>These patients were more likely to be younger men with diabetes or heart disease and a history of smoking. There was no substantive difference in where the patients lived.</p>
<p>Inflammation markers in plaque samples were more elevated in patients with detectable levels of microplastics and nanoplastics versus those without. </p>
<figure class="align-center ">
<img alt="Plastic bottles washed up on a beach." src="https://images.theconversation.com/files/582404/original/file-20240317-18-nz99jb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/582404/original/file-20240317-18-nz99jb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/582404/original/file-20240317-18-nz99jb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/582404/original/file-20240317-18-nz99jb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/582404/original/file-20240317-18-nz99jb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/582404/original/file-20240317-18-nz99jb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/582404/original/file-20240317-18-nz99jb.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">Microplastics are created when everyday products degrade.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/close-waste-beach-1234533793">JS14/Shutterstock</a></span>
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<p>And, then there’s the headline finding: patients with microplastics and nanoplastics in their plaque had a higher risk of having what doctors call “a primary end point event” (non-fatal heart attack, non-fatal stroke, or death from any cause) than those who did not present with microplastics and nanoplastics in their plaque.</p>
<p>The authors of the study note their results “do not prove causality”.</p>
<p>However, it would be remiss not to be cautious. The history of environmental health is replete with examples of what were initially considered suspect chemicals that avoided proper regulation because of what the US National Research Council refers to as the “<a href="https://nap.nationalacademies.org/catalog/12209/science-and-decisions-advancing-risk-assessment">untested-chemical assumption</a>”. This assumption arises where there is an absence of research demonstrating adverse effects, which obviates the requirement for regulatory action. </p>
<p>In general, more research is required to find out whether or not microplastics cause harm to human health. Until this evidence exists, we should adopt the precautionary principle; absence of evidence should not be taken as evidence of absence.</p>
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Read more:
<a href="https://theconversation.com/were-all-ingesting-microplastics-at-home-and-these-might-be-toxic-for-our-health-here-are-some-tips-to-reduce-your-risk-159537">We're all ingesting microplastics at home, and these might be toxic for our health. Here are some tips to reduce your risk</a>
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<h2>Global and local action</h2>
<p>Exposure to microplastics in our home, work and outdoor environments is inevitable. Governments across the globe have started to acknowledge we must intervene. </p>
<p>The <a href="https://www.un.org/en/climatechange/nations-agree-end-plastic-pollution">Global Plastics Treaty</a> will be enacted by 175 nations from 2025. The treaty is designed, among other things, to limit microplastic exposure globally. Burdens are greatest <a href="https://doi.org/10.1016/j.envpol.2022.119957">especially in children</a> and especially those in low-middle income nations. </p>
<p>In Australia, legislation <a href="https://www.epa.vic.gov.au/about-epa/our-programs-and-projects/single-use-plastics-ban">ending single use plastics</a> will help. So too will the increased rollout of <a href="https://recyclingnearyou.com.au/containerdeposit/">container deposit schemes</a> that include plastic bottles.</p>
<p>Microplastics pollution is an area that requires a collaborative approach between researchers, civil societies, industry and government. We believe the formation of a “microplastics national council” would help formulate and co-ordinate strategies to tackle this issue.</p>
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<strong>
Read more:
<a href="https://theconversation.com/the-problem-with-oodies-hooded-blankets-are-cosy-but-they-are-not-great-for-oceans-or-our-health-163087">The problem with Oodies: hooded blankets are cosy but they are not great for oceans or our health</a>
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<p>Little things matter. Small actions by individuals can also translate to significant overall environmental and human health benefits. </p>
<p>Choosing natural materials, fabrics, and utensils not made of plastic and disposing of waste thoughtfully and appropriately – including recycling wherever possible – is helpful.</p><img src="https://counter.theconversation.com/content/225354/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Patrick Taylor is a full-time employee of EPA Victoria, appointed to the statutory role of Chief Environmental Scientist.
He previously received funding via an Australian Government Citizen Science Grant (2017-2020), CSG55984 ‘Citizen insights to the composition and risks of household dust’ (the DustSafe project). Outputs from this project included published work on microplastics with Drs Neda Sharifi Soltani and Scott Wilson who were at Macquarie University at that time.
</span></em></p><p class="fine-print"><em><span>Scott P. Wilson works for the Australian Microplastic Assessment Project run by the not for profit organisation the Total Environment Centre. He has previously received funding from the NSW EPA for research into microplastic source tracking in Deewhy Lagoon and for developing a Microlitter Reduction Framework. </span></em></p>Microplastics are created when everyday products – including clothes, food and beverage packaging, home furnishings, plastic bags, toys and toiletries – degrade.Mark Patrick Taylor, Chief Environmental Scientist, EPA Victoria; Honorary Professor, School of Natural Sciences, Macquarie UniversityScott P. Wilson, Research Director, Australian Microplastic Assessment Project (AUSMAP); Honorary Senior Research Fellow, School of Natural Sciences, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2246762024-03-12T17:51:20Z2024-03-12T17:51:20ZHigh levels of PFAS forever chemicals found flowing into River Mersey – new study<figure><img src="https://images.theconversation.com/files/580908/original/file-20240311-18-qst8cz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Heavy industry and dense urban populations both contribute to high levels of effluent containing toxic forever chemicals that don't biodegrade. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/iconic-image-liverpool-130521821">Shaun Jeffers/Shutterstock</a></span></figcaption></figure><p>Huge volumes of toxic and cancer-causing forever chemicals are flowing into the River Mersey in north-west England. With a busy, industrialised skyline and both <a href="https://www.merseyrivers.org/index.php/about/who-we-are">Manchester and Liverpool</a> nearby, it’s the <a href="https://www.nature.com/articles/s41561-018-0080-1">second-most populated</a> river catchment in the UK after the Thames. </p>
<p><a href="https://theriverstrust.org/key-issues/state-of-our-rivers#:%7E:text=No%20single%20stretch%20of%20river,every%20stretch%20of%20English%20rivers.">None of England’s rivers</a> are in good chemical health. The recent <a href="https://theriverstrust.org/key-issues/state-of-our-rivers">State of Our Rivers 2024</a> report from The Rivers Trust found that one of the most concerning groups of synthetic chemicals, per- and polyfluorinated substances (PFAS), contaminates almost every river in England. </p>
<p>Known as forever chemicals because they can take <a href="https://www.unep.org/topics/chemicals-and-pollution-action/pollution-and-health/persistent-organic-pollutants-pops/and">thousands of years</a> to break down, PFAS <a href="https://enveurope.springeropen.com/articles/10.1186/s12302-023-00721-8">persist</a> in the <a href="https://www.theguardian.com/environment/2022/feb/14/forever-chemicals-pcb-pfas-use-marine-life-to-travel-world-by-sea">environment</a> and accumulate in living things. They <a href="https://chemtrust.org/wp-content/uploads/PFAS_Brief_CHEMTrust_2019.pdf">threaten ecosystems and human health</a>, not just in the Mersey, but in every industrialised river around the world. </p>
<p>My team of hydrologists and I found that levels of two <a href="https://www.iarc.who.int/faq/iarc-monographs-evaluate-the-carcinogenicity-of-perfluorooctanoic-acid-pfoa-and-perfluorooctanesulfonic-acid-pfos/#:%7E:text=PFOA%20is%20carcinogenic%20to%20humans,and%20immunosuppression%20in%20exposed%20humans">cancer-causing PFAS</a> washing off the land and into the Mersey – perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA)– are among the highest in the world. Both PFOS and PFOA, now <a href="https://chm.pops.int/Implementation/IndustrialPOPs/PFAS/Overview/tabid/5221/Default.aspx">banned in most countries</a>, were used to make many consumer and <a href="https://www.theguardian.com/environment/2021/sep/14/forever-chemicals-the-hidden-threat-from-the-pfas-toxins-on-your-shelf">industrial products</a> including furniture, cookware and fire-fighting foams.</p>
<p><a href="https://pubs.acs.org/doi/10.1021/acs.estlett.4c00017#:%7E:text=The%20total%20%E2%88%918PFAS,year">Our study</a> established that around 50% of PFOS, a type of PFAS that’s classed as probably carcinogenic, in the River Mersey was coming from supposedly clean water discharges from 44 different wastewater treatment works. PFAS are found in treated water because they are very difficult to remove using current water treatment technologies. Almost all wastewater treatment work effluents in the UK <a href="https://pubmed.ncbi.nlm.nih.gov/34412376/">contain PFAS</a>.</p>
<p>Our research highlights that we don’t really know where the remaining 50% of that PFOS is coming from. Other potential sources include runoff from <a href="https://pfas-exchange.org/wp-content/uploads/PFAS-Exchange-Firefighting-Foam-6.pdf">airports</a> where big amounts of fire-fighting foams are used,
<a href="https://pubs.acs.org/doi/10.1021/acs.estlett.1c00750">agricultural land</a> and <a href="https://www.theguardian.com/environment/2024/feb/01/seventeen-landfills-in-england-make-toxic-liquid-hazardous-to-drinking-water">landfills</a>. Some PFAS could contaminate groundwater or surface waters used as <a href="https://www.usgs.gov/news/national-news-release/tap-water-study-detects-pfas-forever-chemicals-across-us#:%7E:text=At%20least%2045%25%20of%20the,by%20the%20U.S.%20Geological%20Survey.">drinking water</a>. </p>
<p><a href="https://theconversation.com/pfas-you-cant-smell-see-or-taste-these-chemicals-but-they-are-everywhere-and-theyre-highly-toxic-to-humans-196168">PFAS chemicals</a> are all around us and impossible to avoid. Found in everything from food packaging to cosmetic products, they are also used to manufacture <a href="https://www.acea.auto/news/importance-of-fluoropolymers-for-the-clean-energy-transition-and-the-eus-net-zero-industry/">green energy technologies</a> like electric cars and wind turbines. </p>
<p>Whenever PFAS are used to make <a href="https://greensciencepolicy.org/harmful-chemicals/pfas/">these products</a> they end up draining into rivers, so wildlife and humans living in the river basin are exposed to them. We don’t really know the long-term <a href="https://chemtrust.org/pfas/">implications</a> of the current exposure levels. But these chemicals will persist. If we keep discharging them into the environment, PFAS exposure levels – and potential risk to humans – can increase through drinking water contamination and accumulation in the food chain. </p>
<p>Pinpointing exactly where, how and when these chemicals enter rivers is not straightforward so scientists and governments don’t really have the regulatory measures and tools to hold <a href="https://www.sciencedirect.com/science/article/abs/pii/S0048969721034628">polluters to account</a>. </p>
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<a href="https://images.theconversation.com/files/581351/original/file-20240312-28-tsp3dw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Aerial shot of round water treatment container, gree water, spinning filters with grey infrastructure" src="https://images.theconversation.com/files/581351/original/file-20240312-28-tsp3dw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581351/original/file-20240312-28-tsp3dw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581351/original/file-20240312-28-tsp3dw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581351/original/file-20240312-28-tsp3dw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581351/original/file-20240312-28-tsp3dw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581351/original/file-20240312-28-tsp3dw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581351/original/file-20240312-28-tsp3dw.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>
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<span class="caption">Significant PFAS levels were found in effluent from 44 wastewater treatment plants flowing into the River Mersey.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/water-treatment-solution-industrial-aerial-top-1241037328">Avigator Fortuner/Shutterstock</a></span>
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<h2>Dilute, disperse and detect</h2>
<p>Since the 1850s, <a href="https://www.merseybasin.org.uk/archive/assets/5/original/MERSEY_6_MINUTE_EXPERT.pdf">the Mersey</a> has been a hub of industry, particularly for <a href="https://www.liverpoolmuseums.org.uk/city-built-cotton">cotton manufacturing</a> and <a href="https://www.sciencedirect.com/science/article/abs/pii/S0048969703000949">chemical production</a>. Most cities, including Liverpool and Manchester, have been built close to rivers and seas, partly to dilute pollution and <a href="https://onlinelibrary.wiley.com/doi/10.1002/rvr2.7">transport it away</a>. Out of sight, out of mind. </p>
<p>Today, enormous volumes of toxic waste are discharged into rivers and seas because dilution reduces chemical concentrations to extremely low or undetectable levels. But undetectable does not mean toxic chemicals are not present. </p>
<p>PFAS are ubiquitous. These forever chemicals have been detected almost everywhere we look, including in <a href="https://pubs.acs.org/doi/10.1021/acs.est.2c02592">Antarctica</a>, in <a href="https://www.ewg.org/news-insights/news/2023/02/wildlife-warning-more-330-species-contaminated-forever-chemicals">whales and polar bears</a> and in <a href="https://pubs.acs.org/doi/10.1021/acs.est.2c02765">rainwater</a>. <a href="https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(23)00106-7/fulltext">Most people on Earth</a> probably have detectable concentrations of PFAS in their blood. An estimated [<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4483690/">97% of the US population</a>] have PFAS in their blood, according to one study of 1,682 people.</p>
<h2>A state of flux</h2>
<p>Governments need to <a href="https://echa.europa.eu/hot-topics/perfluoroalkyl-chemicals-pfas">phase out PFAS</a> from society to reduce human exposure and halt their accumulation in the environment and wildlife. The development of safer, healthier, greener alternatives is essential. </p>
<p>Even if the tap gets turned off immediately, the PFAS already in the environment, and in the River Mersey, will persist for thousands of years. To prevent further PFAS entering our rivers, more needs to be known about how they move into and through river systems. As part of our study, we measured this flux. </p>
<p>Instead of measuring a chemical’s concentration, flux is a measure of how much PFAS, for example in kilograms per year, flows off the land and out to sea. By measuring PFAS flux at multiple locations across a river basin like the Mersey, we can distinguish different sources of PFAS to the river, such as runoff from landfills, and establish how much comes from that source. </p>
<p>Governments and environmental regulators need more data like this to develop strategies that will prevent PFAS entering rivers. Our study not only confirmed wastewater treatment works effluents as a source of PFAS to the Mersey, we established exactly how much is coming from that source. This direct accountability is required to effectively target regulations and apply measures that make a difference. </p>
<p>Greater understanding of the flux and movement of PFAS in rivers and seas will help ensure better monitoring and regulation of these toxic forever chemicals – especially in hotspots like the Mersey that should be a top priority for enforcement. </p>
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<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">
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<p class="fine-print"><em><span>Patrick Byrne receives funding from the UKRI Natural Environment Research Council. </span></em></p>Huge amounts of PFAS come from wastewater treatment plants, new study finds.Patrick Byrne, Reader in Hydrology and Environmental Pollution, Liverpool John Moores UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2239212024-03-12T11:46:23Z2024-03-12T11:46:23ZLagos bans single-use plastics – why I think Nigeria should have taxed them instead<p>Waste pollution is a huge problem in Nigeria, with serious impacts on the environment. In response, the Lagos state government has <a href="https://lagosstate.gov.ng/lagos-announces-ban-on-usage-of-styrofoams-single-use-plastics/">banned</a> styrofoam (a type of plastic widely used as food containers) and <a href="https://www.youtube.com/watch?v=OPr_5fdI_BQ">other single-use products</a>. </p>
<p>Following a <a href="https://punchng.com/lagos-begins-enforcement-of-single-use-plastics-ban-after-three-weeks/#:%7E:text=Lagos%20begins%20enforcement%20of%20single%2Duse%20plastics%20ban%20after%20three%20weeks,-25th%20January%202024&text=Kindly%20share%20this%20story%3A,which%20full%20enforcement%20will%20start.">three-week moratorium</a> for producers and sellers to mop up styrofoam containers, enforcement <a href="https://moelagos.gov.ng/lasg-commences-full-enforcement-of-ban-on-styrofoam-monday-env-comm/">began</a> on 4 March 2024. </p>
<p>In 2019, Nigeria was estimated to generate about <a href="https://www.voanews.com/a/africa_nigerian-recyclers-reduce-plastic-waste-exchanging-trash-cash/6175035.html">2.5 million tonnes</a> of plastic waste yearly. Lagos State generated <a href="https://www.wacaprogram.org/sites/waca/files/knowdoc/Nigeria_plastics_PWC_final%20%281%29.pdf#page=4">8,400 tonnes of waste daily, of which 11% was plastic</a>. The estimate is higher today. </p>
<p>The habit of residents discarding used plastic wherever it suits them hurts the environment in many ways. Evidence abounds of the impact in <a href="https://youtu.be/m0eu_Bj82TM?si=8Mn4Putp7fnSz0Jg">Lagos</a> and <a href="https://www.sciencedirect.com/science/article/pii/S277241662400010X">other parts</a> of Nigeria. Yearly, more than 130,000 tonnes of plastic waste <a href="https://www.aljazeera.com/gallery/2024/1/31/lagos-ban-on-styrofoam-and-plastics-brings-applause-and-concern">end up</a> in the country’s waterways. Producers of these plastics are not without blame: they are negligent about taking measures to combat the pollution their products cause. </p>
<p>As an <a href="https://iceesr.org.ng/news/introducing-iceesr-uniuyo-cim-and-giz-sponsored-diaspora-scholar-dr-kehinde-allen-taylor/">expert</a> in environmental and sustainability issues, who has <a href="https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/macau_derivate_00002344/Max_Mustermann.pdf">studied</a> the impact of plastic waste on the ecosystem in Lagos State, I have an informed view on how to deal with the problem. I argue that Lagos State would have achieved its objectives better had it taxed single-use plastics instead of banning them. The ban could undermine the potential success of the plastics value chain from a social, economic and environmental perspective. </p>
<p>A plastic ban is a <a href="https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3173844">costly measure</a> which turns a small environmental problem into a bigger one. The ban could lead to black market sales, smuggling from neighbouring states, high costs for purchasing environmentally friendly alternatives and unnecessary expenses for monitoring, enforcement, evaluation and assessment. </p>
<p>In contrast, a tax on single-use plastic would create incentives to use less of this material. </p>
<h2>Taxes work better than bans</h2>
<p>Rwanda, Kenya and Uganda’s bans of single-use plastic offer lessons. The policy’s success has been limited by <a href="https://kinder.world/articles/problems/plastic-free-is-not-problem-free-rwanda-struggles-despite-ban-17698">black market sales</a>, <a href="https://www.unep.org/news-and-stories/story/how-smuggling-threatens-undermine-kenyas-plastic-bag-ban">smuggling</a> and the <a href="https://rwandatoday.africa/rwanda/news/traders-smuggle-banned-single-use-plastic-bags-to-avoid-costly-packing-envelopes-3728844">high cost of eco-friendly packaging materials</a>. Pollution from single-use plastic bags <a href="https://allianceforscience.org/blog/2023/04/earth-day-east-african-nations-choked-by-single-use-plastic-pollution-because-laws-are-not-enforced">continues</a>.</p>
<p>For example, Rwanda’s plastic bags ban affects traders and consumers who rely on them. Reusable bags offered as an alternative are not affordable, of inferior quality and not durable. This has led to smuggling across the border into Rwanda and an increase in black market sales. </p>
<p>The consequences of being caught are <a href="https://africacheck.org/fact-checks/meta-programme-fact-checks/yes-plastic-bags-illegal-rwanda-punishment-includes-jail">fines and imprisonment</a>. But people are still finding ways to bring these plastic bags into Rwanda. Meanwhile, the resources put into monitoring, enforcement and evaluation cost taxpayers a lot of money.</p>
<h2>Countries where single-use plastic tax has worked</h2>
<p><a href="https://ieep.eu/wp-content/uploads/2022/12/IE-Plastic-Bag-Levy-final-1-1.pdf">Ireland</a>, <a href="https://ceem.ugent.be/publications/tax.pdf">Belgium</a>, <a href="https://www.bdo.de/en-gb/insights/publishments/tax-legal/plastics-tax-in-germany-the-single-use-plastic-fund-act">Spain, the United Kingdom and Germany</a> have successfully introduced a tax on single-use plastic.</p>
<p>In 2002, the Irish government saw a <a href="https://ieep.eu/wp-content/uploads/2022/12/IE-Plastic-Bag-Levy-final-1-1.pdf#page+1">significant decrease</a> in plastic bags after introducing a tax of €0.15 (US$0.16) at points of sale. </p>
<p>In 2007, the tax was increased to €0.22 (US$0.24), aiming to eliminate the use of plastic bags in the country. This approach helped the Irish government to solve part of its plastic waste problem. And the income generated helped to finance environmental projects, clean-up measures, education and awareness-raising measures. The tax also created incentives for alternatives to plastic bags. </p>
<p>In Germany, the city of Tübingen <a href="https://wts.com/wts.com/publications/climate-protection-green-tax-energy/2022/wtsglobal-plastic-taxation-in-europe.pdf#page=7">introduced</a> a packaging tax of €0.20 and €0.50 for disposable containers and cutlery at the municipal level from January 2022. </p>
<p>From January 2023, styrofoam for food packaging was <a href="https://www.thelocal.de/20221230/how-customers-in-germany-can-demand-multi-use-packaging-from-2023">listed</a> among the banned single-use materials in Germany. Food outlets had to provide alternatives. Retailers or consumers who can afford it can still buy styrofoam online, but sustainable alternatives are more affordable. </p>
<p>The German Ministry of the Environment <a href="https://www.thelocal.de/20221230/how-customers-in-germany-can-demand-multi-use-packaging-from-2023">said</a> that a complete ban on single-use packaging was not yet possible under EU law, as there was not yet a completely environmentally friendly alternative. This approach has kept styrofoam producers in business and created opportunities for start-up companies interested in reusable production.</p>
<h2>Plastic tax can check pollution</h2>
<p>In Nigeria, a more effective approach would have been to introduce a plastic tax. It would create incentives by regulating the market costs for single-use plastics. The tax would force producers to switch to sustainable and reusable plastics. Also, consumers would have to decide whether it was worth paying more to use single-use plastics or opt for sustainable and reusable ones. </p>
<p>Income generated from the tax could be used to keep cities clean, raise public awareness, support recycling companies and promote sustainable, reusable and affordable plastics. The plastic tax revenue would be spent on monitoring, enforcement and evaluation.</p>
<p>Plastic tax has the potential to address the harmful effects of styrofoam and other single-use plastics if the <a href="https://assets.publishing.service.gov.uk/media/5a74b84ee5274a3f93b48418/scho0811bucc-e-e.pdf">abatement cost</a> is analysed. <a href="https://assets.publishing.service.gov.uk/media/5a74b84ee5274a3f93b48418/scho0811bucc-e-e.pdf">Abatement costs are measures to reduce or eliminate the release of pollutants into the environment</a>. For plastics, these costs are analysed based on the amount or units of plastic released and eliminated from the environment. Regular consultations, assessments and evaluations are necessary to achieve the targets set.</p>
<p>Plastic tax could serve as a bridge to the <a href="https://www.nesrea.gov.ng/extended-producer-responsibility/">extended producer responsibility policy</a>, which was adopted by the Nigerian Environmental Standards and Regulations Enforcement Agency in 2014 but is not yet fully in place. The policy <a href="https://www.oecd.org/environment/extended-producer-responsibility.htm">requires</a> producers to be responsible for their product until the end of their life cycle, including disposal and recycling.</p>
<p>This way, the true cost of plastic waste is revealed and sustainable alternative products are created within the plastics value chain.</p><img src="https://counter.theconversation.com/content/223921/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kehinde Allen-Taylor 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>Plastic tax would work better than a ban in Lagos, Nigeria.Kehinde Allen-Taylor, Researcher, Technical University BraunschweigLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2247052024-03-06T17:15:02Z2024-03-06T17:15:02ZFive hotspots where floating plastic litter poses the greatest risk to North Atlantic marine life – new study<figure><img src="https://images.theconversation.com/files/579868/original/file-20240305-15007-nfvgpd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">So much ocean plastic originates from sources on land, but once floating in the sea it poses a risk to marine wildlife and habitats. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/plastic-rubbish-pollution-ocean-environment-427946419">Rich Carey/Shutterstock</a></span></figcaption></figure><p>Plastic has been found in every single part of the ocean, from the surface to the seafloor and from the <a href="https://www.nature.com/articles/536263a">tropics to the poles</a>. Land-based sources of plastic account for the <a href="https://www.science.org/doi/10.1126/science.1260352">majority of this pollution</a>, with plastic bags, bottles, wrappers, food containers and cutlery among the most <a href="https://www.sciencedirect.com/science/article/pii/S0959378021001394">common items found</a>. </p>
<p>These items are often buoyant and float on the sea surface. As they travel long distances, they get pushed by the <a href="https://www.frontiersin.org/articles/10.3389/fmars.2021.697430/full">wind, waves and currents</a>. This means they have the potential to cause harm far beyond the country from <a href="https://www.frontiersin.org/articles/10.3389/fmars.2021.762235/full">which they originated</a>. For example, land-based plastic waste from Indonesia has been shown to travel over <a href="https://www.sciencedirect.com/science/article/pii/S0025326X22011791">4,000km to the Seychelles</a>.</p>
<p>As it travels, plastic litter can cause harm to wildlife. Megafauna (large marine animals) can <a href="https://link.springer.com/chapter/10.1007/978-3-319-16510-3_4#:%7E:text=Entangled%20biota%20are%20hindered%20in,1985%3B%20Laist%201997">eat or become entangled in it</a>. Consuming plastic litter can <a href="https://www.iucn.org/resources/issues-brief/marine-plastic-pollution">block or damage</a> the gastrointestinal tract of animals, causing significant health impacts or death. </p>
<p>While ghost fishing gear (lost fishing nets that float freely) is the most common entanglement threat to <a href="https://www.sciencedirect.com/science/article/pii/S0025326X16304386">marine megafauna</a>, they can also become <a href="https://www.sciencedirect.com/science/article/abs/pii/S0025326X17300127">entangled</a> in land-sourced plastics such as plastic bags, frisbees, potato nets, elastic bands and other <a href="https://www.mdpi.com/2673-1924/3/3/26#:%7E:text=The%20current%20study%20summarizes%20data,quadrupled%20compared%20with%20previous%20studies.">circular plastics</a>. This can cause severe trauma to the animal, and in some cases <a href="https://www.sciencedirect.com/science/article/pii/S0025326X23007609?via%3Dihub">entanglement causes death</a>. </p>
<p>If plastic is transported towards the shore, it can get caught or lodged in shallow environments where it can entangle or cover plant or animal habitats, <a href="https://portlandpress.com/emergtoplifesci/article/6/4/371/231922/Plastic-pollution-of-four-understudied-marine">causing damage</a>. Plastic entanglement can cause breakage, and if it covers a habitat it will restrict access to food or light. </p>
<p>At <a href="https://www.pml.ac.uk/">Plymouth Marine Laboratory</a>, our team of marine researchers have developed a risk assessment approach to understand where this plastic litter could cause the most harm in the North Atlantic, and which countries that plastic originated from. Our research highlighted five areas of high risk – the US Atlantic, the US Gulf of Mexico, the UK, French Atlantic and Portuguese Azores.</p>
<h2>Reducing risk</h2>
<p><a href="https://www.sciencedirect.com/science/article/pii/S0048969724014219#bb0890">In our new study</a>, we assessed the risk of land-sourced plastic litter to marine megafauna. That includes seabirds, whales and dolphins, seals and sea lions, manatees and dugongs, sharks and rays, tuna and billfish. We also assessed the risk to shallow water habitats including coral reefs, mangroves, seagrass beds, saltmarsh and kelp seaweed beds.</p>
<p>Using a particle tracking model, we tracked the flow of buoyant plastic litter released from the rivers of 16 countries bordering the North Atlantic between 2000 and 2015 using the most <a href="https://www.science.org/doi/10.1126/sciadv.aaz5803">recent data available</a>. Billions of virtual particles were released at the mouths of the rivers each month, with surface currents and wind used to drive their movement. After 15 years of tracking, our model showed us where plastic was likely to accumulate.</p>
<p>We also assessed the vulnerability of each of the megafauna groups and shallow water habitats to this plastic. For marine megafauna, we developed vulnerability scores by quantifying the amount of scientific evidence of ingestion or entanglement in land-sourced plastic. For habitats, we developed vulnerability scores by quantifying the scientific evidence available for this plastic causing harm by entanglement or smothering. </p>
<figure class="align-center ">
<img alt="Blue sea, green turtle swimming with fishing net attached behind it" src="https://images.theconversation.com/files/579866/original/file-20240305-16-gp5lsb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579866/original/file-20240305-16-gp5lsb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579866/original/file-20240305-16-gp5lsb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579866/original/file-20240305-16-gp5lsb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579866/original/file-20240305-16-gp5lsb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579866/original/file-20240305-16-gp5lsb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579866/original/file-20240305-16-gp5lsb.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">Marine wildlife such as this green sea turtle can become entangled in ghost fishing gear that is left floating in the sea.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/green-sea-turtle-entangled-discarded-fishing-1688232751">Mohamed Abdulraheem/Shutterstock</a></span>
</figcaption>
</figure>
<p>To assess risk, we mapped the vulnerability and distribution of each megafauna group or habitat against the abundance of plastic. Each point within the map was given a risk score from zero to five. The greatest risk occurred in areas where high numbers of vulnerable megafauna or habitats overlapped with high concentrations of plastic.</p>
<h2>Managing the plastic problem</h2>
<p>We found that much of the modelled plastic litter causing risk in the UK originated from UK rivers. In other high-risk zones such as the Azores and the US Gulf of Mexico, plastic primarily originated from other regions. More than 99% of plastic litter in the Azores was estimated to come from the other countries, mainly Caribbean islands and the US. </p>
<p>The potential of this plastic to travel vast distances across the ocean makes management of this pollutant <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/reel.12257">particularly difficult</a>. More than 90% of plastic waste in the Dominican Republic and Haiti are <a href="https://publications.iadb.org/en/publications/english/viewer/Plastic-Waste-Management-and-Leakage-in-Latin-America-and-the-Caribbean.pdf">estimated to be mismanaged</a>. This waste has the potential to cause ecological harm across both sides of the Atlantic. </p>
<p>UN member nations have agreed to forge an international legally binding agreement to tackle plastic pollution, called the <a href="https://www.un.org/en/climatechange/nations-agree-end-plastic-pollution">Global Plastics Treaty</a>, with negotiations expected to be completed by the end of this year. This study highlights the importance of the treaty in ensuring international cooperation to reduce plastic consumption and waste, including the provision of financial support to help lower-income nations such as the Caribbean islands implement measures. Identification of high-risk zones will also help prioritise areas where interventions and monitoring should be targeted.</p>
<p>Even if all plastic intervention measures are implemented, it is likely that substantial amounts of plastic will still <a href="https://www.science.org/doi/10.1126/science.aba9475">enter our oceans</a>. The production, sale and distribution of many of single-use items are likely to be phased out under the <a href="https://wedocs.unep.org/bitstream/handle/20.500.11822/43239/ZERODRAFT.pdf">Global Plastics Treaty</a>, as nations move to restrict avoidable plastic products. </p>
<p>While global measures are hugely important in the fight against plastic, the choices of consumers also play a significant role. Reducing, re-using and recycling plastic are powerful ways to cut your plastic footprint. At both ends of the spectrum, the choices made at international and household level can be good news for marine wildlife.</p>
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<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">
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<p class="fine-print"><em><span>Samantha Garrard receives funding from the Natural Environment Research Council and the Economic and Social Research Council</span></em></p>As it travels around the ocean, plastic litter can harm wildlife and marine habitats in many ways. This study highlights five key hotspots where floating plastic poses the biggest risk.Samantha Garrard, Senior Marine Ecosystem Services Researcher, Plymouth Marine LaboratoryLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2244952024-03-05T21:19:45Z2024-03-05T21:19:45ZThe Anthropocene is not an epoch − but the age of humans is most definitely underway<figure><img src="https://images.theconversation.com/files/580004/original/file-20240305-26-j0m1i7.jpg?ixlib=rb-1.1.0&rect=17%2C180%2C5727%2C3599&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Human influence on the climate started even before the Industrial Revolution.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/factoryscape-in-the-potteries-smoke-from-chimneys-in-the-news-photo/1036135896?adppopup=true">Print Collector/Getty Images</a></span></figcaption></figure><p>When people talk about the “Anthropocene,” they typically picture the <a href="https://global.oup.com/academic/product/the-anthropocene-a-very-short-introduction-9780198792987?cc=us&lang=en&">vast impact human societies are having</a> on the planet, from <a href="https://www.ipbes.net/news/Media-Release-Global-Assessment">rapid declines in biodiversity</a> to <a href="https://www.ipcc.ch/report/sixth-assessment-report-cycle/">increases in Earth’s temperature</a> by burning fossil fuels.</p>
<p>Such massive planetary changes did not begin all at once at any single place or time.</p>
<p>That’s why <a href="https://theconversation.com/did-the-anthropocene-start-in-1950-or-much-earlier-heres-why-debate-over-our-world-changing-impact-matters-209869">it was controversial</a> when, after over a decade of study and debate, an international committee of scientists – <a href="http://quaternary.stratigraphy.org/working-groups/anthropocene/">the Anthropocene Working Group</a> – proposed to mark the Anthropocene as an epoch in the <a href="https://stratigraphy.org/chart#latest-version">geologic time scale</a> starting precisely in 1952. The marker was radioactive fallout from hydrogen bomb tests.</p>
<p>On March 4, 2024, the commission responsible for recognizing time units within our most recent period of geologic time – the <a href="http://quaternary.stratigraphy.org/">Subcommission on Quarternary Stratigraphy</a> – rejected that proposal, with 12 of 18 members voting no. These are the scientists most expert at reconstructing Earth’s history from the evidence in rocks. They determined that adding an Anthropocene Epoch – and terminating the Holocene Epoch – was not supported by the standards used to define epochs.</p>
<p>To be clear, this vote has no bearing on the overwhelming evidence that human societies are indeed transforming this planet.</p>
<p>As <a href="https://ges.umbc.edu/ellis/">an ecologist who studies global change</a>, I served on the <a href="http://quaternary.stratigraphy.org/working-groups/anthropocene/">Anthropocene Working Group</a> from its start in 2009 until 2023. <a href="https://anthroecology.org/why-i-resigned-from-the-anthropocene-working-group/">I resigned</a> because I was convinced that this proposal defined the Anthropocene so narrowly that it would damage broader scientific and public understanding. </p>
<p>By tying the start of the human age to such a recent and devastating event – nuclear fallout – this proposal risked sowing confusion about the deep history of how humans are transforming the Earth, from climate change and biodiversity losses to pollution by plastics and tropical deforestation.</p>
<h2>The original idea of the Anthropocene</h2>
<p>In the years since the term Anthropocene was coined by Nobel Prize-winning <a href="https://acp.copernicus.org/articles/23/15445/2023/">atmospheric chemist Paul Crutzen</a> in 2000, it has increasingly defined our times as an age of human-caused planetary transformation, from climate change to biodiversity loss, plastic pollution, megafires and much more.</p>
<p>Crutzen originally proposed that the Anthropocene began in the <a href="https://doi.org/10.1038/415023a">latter part of the 18th century</a>, as a product of the Industrial age. He also noted that setting a more precise start date would be “<a href="https://www.mpic.de/3865097/the-anthropocene">arbitrary</a>.” </p>
<p>According to geologists, we humans have been living in the Holocene Epoch for about 11,700 years, since the end of the last ice age. </p>
<p>Human societies began influencing Earth’s biodiversity and climate through agriculture <a href="https://cligs.vt.edu/blog/climate-change--a-new-twist-on-a-very-old-story.html">thousands of years ago</a>. These changes began to accelerate about five centuries ago with the <a href="https://theconversation.com/anthropocene-began-with-species-exchange-between-old-and-new-worlds-38674">colonial collision of the old and new worlds</a>. And, as Crutzen noted, Earth’s climate really began to change with the increasing use of <a href="https://www.britannica.com/topic/history-of-Europe/The-Industrial-Revolution">fossil fuels in the Industrial Revolution</a> that began in the late 1700s.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/579988/original/file-20240305-20-6j3yag.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/579988/original/file-20240305-20-6j3yag.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579988/original/file-20240305-20-6j3yag.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=430&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579988/original/file-20240305-20-6j3yag.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=430&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579988/original/file-20240305-20-6j3yag.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=430&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579988/original/file-20240305-20-6j3yag.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=540&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579988/original/file-20240305-20-6j3yag.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=540&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579988/original/file-20240305-20-6j3yag.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=540&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 chart reflecting timing of the ‘Anthropocene Event’ shows how various human activities have affected the planet over mlllennia in the recent geologic time scale. Click the image to enlarge.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1002/jqs.3416">Philip Gibbard, et al., 2022</a></span>
</figcaption>
</figure>
<h2>The Anthropocene as an epoch</h2>
<p>The rationale for proposing to define an Anthropocene Epoch starting around 1950 came from overwhelming evidence that many of the most consequential changes of the human age shifted upward dramatically about that time in a so-called “<a href="https://doi.org/10.1177/2053019614564785">Great Acceleration” identified by climate scientist Will Steffen</a> and others. </p>
<p>Radioisotopes like plutonium from hydrogen bomb tests conducted around this time left clear traces in soils, sediments, trees, corals and other potential geological records across the planet. The plutonium peak in the sediments of Crawford Lake in Ontario, Canada – <a href="https://theconversation.com/did-the-anthropocene-start-in-1950-or-much-earlier-heres-why-debate-over-our-world-changing-impact-matters-209869">chosen as the “golden spike</a>” for determining the start of the Anthropocene Epoch – is well marked in the lake bed’s exceptionally clear sediment record. </p>
<h2>The Anthropocene Epoch is dead; long live the Anthropocene</h2>
<p>So why was the Anthropocene Epoch rejected? And what happens now?</p>
<p>The proposal to add an Anthropocene Epoch to the geological time scale was rejected for a variety of reasons, none of them related to the fact that human societies are changing this planet. In fact, the opposite is true. </p>
<p>If there is one main reason why geologists rejected this proposal, it is because its recent date and shallow depth are too narrow to encompass the deeper evidence of human-caused planetary change. As geologist <a href="https://doi.org/10.1126/science.aaa7297">Bill Ruddiman and others wrote in Science Magazine in 2015</a>, “Does it really make sense to define the start of a human-dominated era millennia after most forests in arable regions had been cut for agriculture?”</p>
<p>Discussions of an Anthropocene Epoch aren’t over yet. But it is very unlikely that there will be an official Anthropocene Epoch declaration anytime soon.</p>
<p>The lack of a formal definition of an Anthropocene Epoch will not be a problem for science. </p>
<p>A scientific definition of the Anthropocene is already widely available in the form of <a href="https://doi.org/10.1002/jqs.3416">the Anthropocene Event</a>, which basically defines Anthropocene <a href="https://doi.org/10.1016/j.earscirev.2023.104340">in simple geological terms</a> as “a complex, transformative, and ongoing event analogous to the Great Oxidation Event and others in the geological record.”</p>
<p>So, despite the “no” vote on the Anthropocene Epoch, the Anthropocene will continue to be as useful as it has been for more than 20 years in stimulating discussions and research into the nature of human transformation of this planet. </p>
<p><em>This article was updated to clarify that a new attempt at an official Anthropocene Epoch declaration is unlikely soon.</em></p><img src="https://counter.theconversation.com/content/224495/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Erle C. Ellis is a former member of the Anthropocene Working Group of the International Commission on Stratigraphy. He is a member of the American Association of Geographers.</span></em></p>Scientists have been debating the start of the Anthropocene Epoch for 15 years. I was part of those discussions, and I agree with the vote rejecting it.Erle C. Ellis, Professor of Geography and Environmental Systems, University of Maryland, Baltimore CountyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2239542024-03-04T13:41:22Z2024-03-04T13:41:22ZRiver pollution is causing harmful outbreaks of sewage fungus in the UK<figure><img src="https://images.theconversation.com/files/577615/original/file-20240223-22-5xtkj2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sewage fungus outbreaks are a sign that our freshwater ecosystems are unhealthy and polluted. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/draining-sewage-pipe-into-river-pollution-2163327235">Dmitriy Prayzel</a></span></figcaption></figure><p>The pollution of the UK’s waterways and coastlines with sewage is throwing its ecosystems out of balance. One well documented example is the spread of microscopic bacteria that can multiply rapidly into <a href="https://theconversation.com/extensive-algal-blooms-in-englands-lakes-heres-why-189481">algal blooms</a>, causing extensive dead zones once oxygen in the water has been used up. </p>
<p>But there’s another pollution problem that has been largely overlooked, until now. Dangerous outbreaks of <a href="https://besjournals.onlinelibrary.wiley.com/action/getFTRLinkout?url=http%3A%2F%2Fscholar.google.com%2Fscholar_lookup%3Fhl%3Den%26volume%3D5%26publication_year%3D1971%26pages%3D281-296%26journal%3DWater%2BResearch%26author%3DE.%2BJ.%2BC.%2BCurtis%26author%3DD.%2BW.%2BHarrington%26title%3DOccurrence%2Bof%2Bsewage%2Bfungus%2Bin%2Brivers%2Bin%2Bthe%2BUnited%2BKingdom&doi=10.1002%2F2688-8319.12277&doiOfLink=10.1016%2F0043-1354%2871%2990173-4&linkType=gs&linkLocation=Reference&linkSource=FULL_TEXT">sewage fungus</a> are becoming a big problem for the UK’s rivers, ponds and lakes. </p>
<p>While working at the University of Oxford with associate professor Michelle Jackson, my aquatic ecology colleagues and I studied how to detect sewage fungus in polluted rivers. We also investigated how changes in a river’s chemical and physical characteristics might be related with the spread of sewage fungus, for example, the high concentration of nitrates <a href="https://onlinelibrary.wiley.com/doi/10.1111/gcb.16934">from fertilisers</a> coming from farmland. </p>
<p>Healthy rivers are crucial for ecosystems, drinking water, biodiversity and our wellbeing. But <a href="https://www.ox.ac.uk/news/2023-09-22-new-study-finds-sewage-release-worse-rivers-agriculture">sewage pollution</a>, and the sewage fungus within it, threaten all of this, endangering aquatic life, human health and our economy. </p>
<p>Frequent <a href="https://www.theguardian.com/environment/2024/jan/30/english-rivers-pollution-sewage-agriculture-uk">sewage fungus outbreaks</a> indicate how badly polluted our environment is. Our rivers are in trouble and governments, water companies and regulators need to act fast to protect them before it is too late. </p>
<p>Sewage fungus isn’t actually a fungus. It’s a mix of microscopic bacteria, viruses and organisms that can form visible masses in water. Despite their fungus-like appearance, these masses of threads are made up of tiny single rod-shaped cells. </p>
<p>These bacteria multiply quickly in <a href="https://books.google.co.uk/books?hl=en&lr=&id=T6biHTO4E3kC&oi=fnd&pg=PA113&dq=Kator,+H.,+%26+Rhodes,+M.+(2003).+Handbook+of+water+and+wastewater+microbiology.&ots=hVSd4St48d&sig=HLDrK3mfL2GNIS4p6TQxk0kHIKI&redir_esc=y#v=onepage&q=Kator%2C%20H.%2C%20%26%20Rhodes%2C%20M.%20(2003).%20Handbook%20of%20water%20and%20wastewater%20microbiology.&f=false">nutrient-rich environments</a>, such as <a href="https://www.sciencedirect.com/science/article/pii/0043135469900840">rivers contaminated</a> with <a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1002/2688-8319.122%20or%20animal%20slurry77">sewage effluent</a>. More than 100 types of sewage fungus have been identified, with two known as <em>Sphaerotilus natans</em> and <em>Beggiatoa alba</em> commonly found in <a href="https://www.sciencedirect.com/science/article/pii/0043135471901734">most English rivers</a>.</p>
<p>Sewage fungus predominantly lives in polluted waters with high levels of nutrients. That’s typically in areas with poor water quality or inadequate sewage treatment.</p>
<p>That includes ponds and reservoirs near urban areas with high levels of sewage run-off or polluted rivers and streams where untreated or treated sewage is <a href="https://www.sciencedirect.com/science/article/pii/0043135469900840">discharged regularly</a>. Sewage fungus also grows naturally in wastewater treatment plants due to the high concentrations of organic material present.</p>
<p>Sewage fungus, although not always visible to the naked eye, is likely to be present in rivers that receive sewage discharge. Most common methods used to detect it rely on visual inspection of the river, so it is hard to identify early or smaller growth, and we don’t have accurate figures on how widespread the problem is. </p>
<p>However, more hi-tech approaches such as machine learning combined with microscopy can detect and quantify sewage fungus filaments, even before they <a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1002/2688-8319.12277">become visible</a>. We have applied one such technique, using a machine called <a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1002/2688-8319.12277">FlowCam</a> which made it possible to quickly identify and count fungus filaments.</p>
<h2>Dangerous for wildlife and humans</h2>
<p>High levels of sewage fungus indicate poor water quality. Sewage fungus can harm freshwater environments by reducing oxygen levels in the water, affecting aquatic life, reducing the numbers of sensitive organisms and disrupting the natural balance of rivers. </p>
<p>Fish and shellfish can become stressed due to low oxygen levels, making them more prone to disease and ultimately leading to <a href="https://www.tandfonline.com/doi/abs/10.1080/15287390500259483?casa_token=nN1JI8PAlZ0AAAAA:rOF_RBf9gCTuS-LXo8FCDhvv18tf-HGcEDEM8IldMR6k1b_hrQ2Rp6I6m9mEry-3nBVhRxkfHWiIQg">their death</a>. </p>
<p>High levels of sewage fungus can also have negative effects on human health. If contaminated water is used for swimming or fishing this can lead to human sickness, because some of the microorganisms can include <a href="https://www.sciencedirect.com/science/article/pii/S2405676623000239">human parasites</a> </p>
<p>Sewage fungus effects can interact with other types of human pollution, including agricultural and <a href="https://www.sciencedirect.com/science/article/pii/S0048969718318333#bb0545">urban runoff</a>. The full impact of these interactions is not yet well understood. </p>
<p>But it is important to consider all sources of pollution, from sewage to agricultural run-off, when estimating the effect sewage fungus might have on ecosystems. By doing so, water companies and environmental groups can work towards more effective management and protection of rivers and freshwater resources.</p>
<h2>What to do about it</h2>
<p>By using more advanced detection methods, regulatory bodies and water companies can monitor rivers more efficiently. More timely action could help limit the source of pollution and prevent future outbreaks of sewage fungus, protecting both freshwater ecosystems and human health.</p>
<p>On a local level, people can report pollution incidents, including sewage fungus outbreak, to the respective authorities: <a href="https://www.gov.uk/report-an-environmental-incident">Environment Agency</a> in England, <a href="https://naturalresources.wales/about-us/contact-us/report-an-incident/?lang=en">Natural Resources Wales</a>, the <a href="https://www.mygov.scot/report-environmental-incident">Scottish Environment Protection Agency</a> or the <a href="https://www.nidirect.gov.uk/information-and-services/environment-and-outdoors/environmental-quality-your-area">Department of Agriculture, Environment and Rural Affairs for Northern Ireland</a>. </p>
<p>Before calling those authorities, it is useful to collect details about the date, time and precise location of the sewage fungus. Passing this information on to the authorities will hopefully encourage more comprehensive monitoring in the future.</p><img src="https://counter.theconversation.com/content/223954/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dania Albini received funding from the University of Oxford, the John Fell Fund (University of Oxford), a UK water company and a NERC Discipline Hopping Grant
</span></em></p>Sewage fungus is actually not a fungus. Our expert explains what it is, where it lives and what can be done to reduce outbreaks in polluted rivers.Dania Albini, Postdoctoral Research Fellow, Aquatic Ecology, University of ExeterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2233072024-03-01T13:36:06Z2024-03-01T13:36:06ZRemembering the 1932 Ford Hunger March: Detroit park honors labor and environmental history<figure><img src="https://images.theconversation.com/files/579009/original/file-20240229-25-snzdp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A Dearborn policeman knocked unconscious was the first casualty of the 1932 Ford Hunger March in Detroit and Dearborn.</span> <span class="attribution"><a class="source" href="https://wayne.contentdm.oclc.org/digital/collection/vmc/id/35955/rec/1">Walter P. Reuther Library, Archives of Labor and Urban Affairs, Wayne State University/Detroit News Burckhardt.</a></span></figcaption></figure><p>The intersection of Fort Street and Oakwood Boulevard in southwest Detroit today functions mostly as a thoroughfare for trucks and commuters. </p>
<p>However, as you sit idling at the stoplight waiting to cross the bridge over the Rouge River, you might glance to the side and see something unexpected in this heavily industrialized area: A sculpture of weathered steel reaches toward the sky alongside a spray of flowers and waves of grasses and people fishing. </p>
<p>This inconspicuous corner, now the home of the <a href="https://www.motorcities.org/fortstreet">Fort Street Bridge Park</a>, has several stories to tell: of a river, a region, a historic conflict and an ongoing struggle. </p>
<p>If you pull over, you’ll enter a place that attempts to pull together threads of history, environment and sustainable redevelopment.</p>
<p>Signs explain why this sculpture and park are here: to honor the memory of <a href="https://www.zinnedproject.org/news/tdih/hunger-march-ford/">protesters who met on this very spot on March 7, 1932</a>, before marching up Miller Road to the massive Ford Rouge River Complex located in the adjacent city of Dearborn. </p>
<p>As a <a href="https://scholar.google.com/citations?user=K9xPsDgAAAAJ&hl=en&oi=ao">sociology professor</a>, I have a strong interest in how the history of labor and industrial pollution have influenced Detroit. </p>
<p>I’m also interested in the potential for <a href="https://doi.org/10.1007/s11252-018-0765-7">environmental restoration</a> or “<a href="https://doi.org/10.1016/j.cities.2019.05.002">green reparations</a>” to <a href="https://doi.org/10.1016/j.cities.2019.05.002">offer a new way forward</a>.</p>
<p>To understand this potential future, we must first recognize and honor the past.</p>
<figure class="align-center ">
<img alt="An iron sculpture commemorates industry and sits as the centerpiece of the Ford Street Bridge Park." src="https://images.theconversation.com/files/577974/original/file-20240226-24-rb9wdh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/577974/original/file-20240226-24-rb9wdh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/577974/original/file-20240226-24-rb9wdh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/577974/original/file-20240226-24-rb9wdh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/577974/original/file-20240226-24-rb9wdh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/577974/original/file-20240226-24-rb9wdh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/577974/original/file-20240226-24-rb9wdh.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">The Fort Street Bridge Park is located along the banks of the Rouge River in southwest Detroit.</span>
<span class="attribution"><span class="source">Paul Draus</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>14 demands</h2>
<p>In their book “<a href="https://www.ueunion.org/labors-untold-story#:%7E:text=Extensively%20researched%2C%20yet%20highly%20readable,conflict%20from%20the%20workers'%20perspective.">Labor’s Untold Story</a>,” published in 1955, journalist Richard Boyer and historian Herbert Morais quote a contemporary account of the Hunger March: </p>
<p><em>It was early, it was cold when the first of the unemployed Ford workers (many of whom had been laid off the day before) arrived at Baby Creek Bridge. They were a small gray group and they stood slapping their sides, warding off the cold, and wondering if they alone would come.</em></p>
<p>Others soon joined them: Black and white, men and women, immigrants and American-born. They united to deliver a list of 14 demands to the auto tycoon <a href="https://corporate.ford.com/articles/history/henry-ford-biography.html">Henry Ford</a>, whose US$5 daily wage for his workers was once considered revolutionary. </p>
<figure class="align-center ">
<img alt="Police with bats follow Hunger March marchers on March 7, 1932." src="https://images.theconversation.com/files/579052/original/file-20240229-30-qh3912.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579052/original/file-20240229-30-qh3912.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=463&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579052/original/file-20240229-30-qh3912.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=463&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579052/original/file-20240229-30-qh3912.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=463&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579052/original/file-20240229-30-qh3912.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=582&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579052/original/file-20240229-30-qh3912.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=582&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579052/original/file-20240229-30-qh3912.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=582&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Hunger March protesters demanded better pay and working conditions at the Ford Rouge plant.</span>
<span class="attribution"><a class="source" href="https://wayne.contentdm.oclc.org/digital/collection/vmc/id/37798/rec/1">Detroit News Staff via Walter P. Reuther Library, Archives of Labor and Urban Affairs, Wayne State University.</a></span>
</figcaption>
</figure>
<p>Among the marchers’ demands: jobs for laid-off workers, a seven-hour workday without a pay reduction, two 15-minute rest periods a day, an end to discrimination against Black workers and the right to organize. </p>
<p>This crowd of several thousand marched up the road on one of the coldest days of winter. They were greeted at the Dearborn border with clouds of tear gas, jets of cold water and a shower of bullets. </p>
<p>It was then that the Ford Hunger March became the Ford Massacre. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/HFEskpjPbfE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Detroit Workers News Special 1932: Ford Massacre via Workers Film & Photo League International.</span></figcaption>
</figure>
<h2>The seeds of a labor movement</h2>
<p>Beth Tompkins Bates, in her book “<a href="https://uncpress.org/book/9781469613857/the-making-of-black-detroit-in-the-age-of-henry-ford/">The Making of Black Detroit in the Age of Henry Ford</a>,” wrote that “The response of the Ford Motor Company on that day shot holes in the myth that Ford cared about his workers, that he was different from other businessmen.” </p>
<figure class="align-left ">
<img alt="Black and white portrait of a young man with wavy hair" src="https://images.theconversation.com/files/578741/original/file-20240228-32-57ksmd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/578741/original/file-20240228-32-57ksmd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=736&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578741/original/file-20240228-32-57ksmd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=736&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578741/original/file-20240228-32-57ksmd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=736&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578741/original/file-20240228-32-57ksmd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=926&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578741/original/file-20240228-32-57ksmd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=926&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578741/original/file-20240228-32-57ksmd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=926&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Portrait of Joe Bussell, killed by Ford Servicemen during the 1932 Ford Hunger March in Detroit. Bussell’s relatives contributed to the Fort Street Bridge Park.</span>
<span class="attribution"><a class="source" href="https://reuther.wayne.edu/node/7269">Walter P. Reuther Library</a></span>
</figcaption>
</figure>
<p>At the end of the day, four marchers lay dead, while many others were injured and hospitalized. A fifth would die months later of his wounds. </p>
<p>More than 30,000 people showed up for the dead marchers’ funerals. The violent reactions of Ford security and Dearborn police during the march were widely condemned. </p>
<p>In an effort to address the stain on its public image, the Ford family first commissioned then expanded a major work by <a href="https://www.nps.gov/places/detroit-industry-murals-detroit-institute-of-arts.htm">Mexican muralist Diego Rivera</a> that was to become the centerpiece of the Detroit Institute of Arts, known as the Detroit Industry Mural. Rivera, <a href="https://doi.org/10.1017/S0018246X0800678X">a known communist</a>, depicted both ruthless efficiency and the racialized inequality of the industrial process. </p>
<p>Ford’s battle against unions was ultimately a failure. Five years after the Hunger March, the so-called “<a href="https://reuther.wayne.edu/ex/exhibits/battle.html">Battle of the Overpass</a>” led to the organization of the Rouge plant by the United Auto Workers. </p>
<p>The Ford Hunger March, long forgotten by many, is now <a href="https://www.workers.org/2022/03/62190/">acknowledged as an important catalyst</a> in the growth of the union movement. </p>
<h2>Struggle for sustainability and justice</h2>
<p>The fight for sustainability and environmental justice is another major theme of the park, which chronicles the history of the Rouge River, including the day in 1969 when the <a href="https://www.greatlakesnow.org/2019/10/rouge-river-fire-anniversary-great-lakes-moment/">oily water infamously caught fire</a>. </p>
<p>The hellish image of burning rivers helped motivate the signing of the <a href="https://www.boem.gov/air-quality-act-1967-or-clean-air-act-caa">Clean Air</a> and <a href="https://www.epa.gov/laws-regulations/summary-clean-water-act">Clean Water acts</a>, as well as <a href="https://www.epa.gov/history">the creation of the Environmental Protection Agency</a>. </p>
<p>The air and water in and around Detroit are <a href="https://www.greatlakesnow.org/2023/05/once-beset-industrial-pollution-rouge-river-slow-path-recovery/">much cleaner today</a> than they were 1969. But this doesn’t change the fact that the area where the park sits bears a disproportionate burden of the pollution generated by the region’s industrial production, which includes cement plants, gypsum and aggregates processors, salt mining and asphalt storage, as well as a steel mill and petroleum refinery.</p>
<p>Another <a href="https://www.marathonpetroleum.com/content/documents/Citizenship/2018/Sustainability_Report_10_21.pdf">donor to the park</a> is Marathon Petroleum Corporation whose Detroit Refinery occupies the adjoining neighborhood. Though Marathon has invested in the development of green spaces on its own property, the refinery has also expanded in recent years, <a href="https://wdi-publishing.com/product/marathon-petroleum-and-southwest-detroit-the-intersection-of-community-and-environment/">further degrading the local environment</a>.</p>
<p>Research shows that workers <a href="https://doi.org/10.1016/j.pmedr.2021.101502">benefit from unionization</a> in myriad ways, not only directly but indirectly. But <a href="https://theconversation.com/2023s-historic-hollywood-and-uaw-strikes-arent-labors-whole-story-the-total-number-of-americans-walking-off-the-job-remained-relatively-low-219903">recent labor victories</a> by the UAW, Hollywood writers and other organizers stand in stark contrast to the <a href="https://theconversation.com/1-in-10-us-workers-belong-to-unions-a-share-thats-stabilized-after-a-steep-decline-221571">long-term erosion of union membership</a>.</p>
<p>Today, the Fort Street Bridge Park in southwest Detroit serves to remind us of the complexities of history and how apparent progress in one area may be followed by a setback somewhere else. It also represents how the spirit of community, unbroken, keeps pushing for something better.</p><img src="https://counter.theconversation.com/content/223307/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Draus is affiliated with Friends of the Rouge and Downriver Delta CDC, two nonprofit organizations involved with the Fort Street Bridge Park. He is also the facilitator of the Fort-Rouge Gateway (FRoG) Partnership, a coalition of representatives from nonprofit, community-based, academic and industry that is focused on the sustainable redevelopment of the industrial Rouge region. </span></em></p>On March 7, workers at the Ford Rouge River plant marched for better working conditions, sparking America’s labor movement. Almost a century later, a quiet park honors their memory.Paul Draus, Professor of Sociology; Director, Master of Science in Criminology and Criminal Justice, University of Michigan-DearbornLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2230482024-02-27T14:07:04Z2024-02-27T14:07:04ZBenefits of using cleaner cooking fuels are blunted in urban areas where outdoor air is polluted: findings from Ghana, Cameroon and Kenya<p>Household air pollution from cooking, heating and lighting with fuels like wood, charcoal and kerosene poses a substantial global health problem. </p>
<p>Globally, <a href="https://www.who.int/news/item/20-01-2022-who-publishes-new-global-data-on-the-use-of-clean-and-polluting-fuels-for-cooking-by-fuel-type">2 billion</a> people cook with polluting fuels and are exposed to high levels of household air pollution. The highest proportion live in sub-Saharan Africa, where <a href="https://www.nihr.ac.uk/news/new-research-could-help-boost-growth-of-clean-cooking-in-sub-saharan-africa/29340#:%7E:text=Approximately%20900%20million%20people%20cook,health%2Ddamaging%20and%20climate%20pollutants">about 900 million</a> people cook with polluting fuels.</p>
<p><a href="https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(20)30197-2/fulltext">Studies</a> have shown that use of cleaner cooking fuels, like electricity, ethanol and liquefied petroleum gas, reduces exposure to fine particulate matter (PM2.5), a damaging pollutant. But <a href="https://ehjournal.biomedcentral.com/articles/10.1186/s12940-021-00756-5">other studies</a> have also shown that the use of cleaner cooking fuels doesn’t necessarily reduce PM2.5 levels in people’s homes.</p>
<p>To understand why, our research looked at three rapidly urbanising communities in Cameroon (Mbalmayo), Ghana (Obuasi) and Kenya (Eldoret). We looked at differences in air pollutant levels across cooking fuel types as well as other environmental factors. We measured levels of PM2.5 as well as carbon monoxide (CO), another damaging air pollutant. </p>
<p>Half of the households that were part of our study were mostly cooking with LPG, which is considered a cleaner cooking fuel. The other half were cooking only with polluting fuels, including wood and charcoal.</p>
<p>Our findings showed that the type of cooking fuel households used did indeed affect levels of pollution inside people’s homes. But we found wide disparities between the three communities. For example, there was hardly any difference in average PM2.5 exposures between LPG and charcoal users in the Ghanaian setting. However, in the Kenyan and Cameroonian communities, women’s average PM2.5 levels were much higher among those cooking with wood, compared with those cooking with LPG. In Eldoret, Kenya, women cooking with charcoal were also exposed to substantially higher levels than those cooking with LPG. </p>
<p>We concluded from our results that this could be explained by the fact that environmental factors were also at play – air pollution levels outside people’s homes. In the Ghanaian area, outdoor air pollution levels were around double the levels in the other two communities. This difference is likely due in part to <a href="https://www.sciencedirect.com/science/article/abs/pii/S1352231099002964?via%3Dihub">increased levels</a> of Saharan dust in Ghana during the <a href="https://www.britannica.com/science/harmattan">harmattan</a> season. </p>
<p>In addition, most women in the Ghanaian setting usually cooked outdoors on a veranda. This increased their exposure to outdoor air pollution. In contrast, women in Kenya and Cameroon typically cooked indoors.</p>
<p>We also found that women, regardless of the cooking fuel they used, had higher exposure to PM2.5 if they lived closer to a busy road (less than a five minute walk away) and travelled outdoors during the day. This suggested that traffic emissions probably made up a substantial proportion of the air pollution that women were breathing in these urban areas. And emissions generated from cooking might have contributed less to overall PM2.5 exposures. </p>
<p>This may explain why there were minimal differences between PM2.5 exposures among women using LPG and charcoal stoves in the Ghanaian community, despite LPG stoves generally emitting lower levels of PM2.5. It follows that, in some areas with rapid urbanisation, outdoor air pollution is probably lowering the ability of clean cooking fuels to reduce PM2.5 exposures. </p>
<h2>What next</h2>
<p>As cities continue to urbanise and the African population increasingly migrates to cities, <a href="https://www.nature.com/articles/s41561-023-01311-2">evidence</a> points to the fact that localised levels of air pollution from industrial sources, traffic, and trash burning are likely to increase. This means that people will become increasingly exposed to air pollutants outdoors and that reductions in PM2.5 exposure that happens when people switch from polluting fuels to LPG may be lower. </p>
<p>Our findings show that clean cooking fuels can reduce indoor air pollution. However, a focus on reducing indoor pollution by switching cooking fuels may only have a limited effect on people’s exposure to damaging air pollutants. Our findings point to the need for developing strategies for reducing both indoor and outdoor air pollution levels. Lower outdoor PM2.5 concentrations can be achieved through stricter regulations on traffic emissions and limiting or eliminating trash burning in favour of less polluting methods for solid waste disposal.</p>
<p>Nevertheless, efforts to encourage a transition towards clean cooking fuels should remain an important policy priority, particularly in communities that are exposed to lower levels of outdoor PM2.5. The transition to clean cooking fuels can potentially have a greater health benefit in these settings. </p>
<p>A more targeted approach and prioritising certain areas in the drive for access to cleaner cooking fuels makes sense. As the <a href="https://cleancooking.org/">Clean Cooking Alliance</a> has pointed out, there are limited resources and funding to tackle the move towards cleaner cooking fuels. Targeting specific areas for clean cooking transitions may therefore be a useful strategy. </p>
<p>In the meantime, the global health community must devote more resources to providing universal access to clean cooking by 2030 <a href="https://www.unep.org/explore-topics/sustainable-development-goals/why-do-sustainable-development-goals-matter/goal-7">(United Nations Sustainable Development Goal 7)</a>].</p><img src="https://counter.theconversation.com/content/223048/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Shupler is also a researcher in the Department of Public Health, Policy and Systems at the University of Liverpool. This research was funded by the National Institute for Health and Care Research (NIHR) (ref: 17/63/155) using UK aid from
the UK Government to support global health research. The views expressed in this article are those of the authors and not necessarily those of the NIHR or the UK government.</span></em></p><p class="fine-print"><em><span>Esong Miranda Baame and Theresa Tawiah 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>Dust and traffic pollution add to the health hazard posed by some cooking fuels.Matthew Shupler, Postdoctoral Research Associate in Environmental Public Health, Harvard UniversityEsong Miranda Baame, PhD Candidate, Université de DschangTheresa Tawiah, Health Economist ,Department of Environmental Health, Kintampo Health Research CenterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2191402024-02-27T12:41:39Z2024-02-27T12:41:39ZCould a couple of Thai otters have helped the UK’s otter population recover? Our study provides a hint<p>Otter populations crashed in Britain around the 1960s from the lethal effects of chemical pollution in rivers and lakes – or so we thought. <a href="https://academic.oup.com/mbe/article/40/11/msad207/7275014">Our research</a> has looked more closely at what happened to otters in Britain over the last 800 years and has revealed a more complex picture. </p>
<p>Since Eurasian otters (<em>Lutra lutra</em>) are at the top of the aquatic food chain in Britain, any contamination consumed by their prey, and by the prey of their prey, <a href="https://pubs.acs.org/doi/10.1021/acs.est.1c05410">accumulates in otters</a>. So otters are particularly susceptible to any toxic chemicals in their environment. </p>
<p>Following the banning of many chemical pollutants, otter populations began to recover, and we now have otters in <a href="https://onlinelibrary.wiley.com/doi/10.1111/eva.13505">every county in Britain</a>. National otter surveys have been conducted in Wales, Scotland and England since 1977 and have helped to track population recovery. </p>
<p>However, we didn’t have a good grasp on what population sizes were like in the decades before this time. We only had anecdotal evidence that otter hunting was becoming less “successful” over time, and that both sightings and signs of otters were rarer. </p>
<h2>Otter population decline</h2>
<p>Our research shows that roughly between 1950 and 1970, an extreme population decline happened in the east of England, and a strong decline in south-west England. They were probably caused by chemical pollution. </p>
<p>In Scotland, otter populations showed a long-term, but smaller decline, which suggests less chemical pollution. There was a smaller population decline in Wales, which started around 1800, possibly linked to otter hunting and changes in how people shaped and used the landscape. </p>
<p>While both deal with DNA, genetics focuses on individual genes and their roles, while genomics examines the entire set of an organism’s DNA. Although there have been genetic studies of otters in Britain, our research was the first time genomics was used to study Eurasian otters anywhere in the world.</p>
<p>Working with scientists from the Smithsonian Conservation Biology Institute and the Wellcome Sanger’s Darwin Tree of Life project, we looked at the entire otter genome. The upgrade from genetics to genomics threw up a few surprises. </p>
<p>First, there was a mitochondrial DNA sequence found in the east of England, which was very different to the sequences in the rest of Britain. Mitochondrial DNA is a sequence of DNA found in a cell’s mitochondria, which is what generates the energy. Mitochondrial DNA is inherited only from the mother, while the rest of the DNA is a mix of both the mother’s and the father’s DNA.</p>
<p>Another <a href="https://www.tandfonline.com/doi/full/10.1080/19768354.2023.2283763">recent study</a> by our research group, in collaboration with colleagues in South Korea, suggested a divergence between these two lineages at least 80,000 years ago. Finding this mitochondrial lineage (that, based on our data, is otherwise restricted to Asia) in the UK was surprising. </p>
<p>Second, we found high levels of genetic diversity in the east of England. Normally, after an extreme population decline such as the one we identified in this area, genetic diversity decreases. Yet we saw much greater diversity here than in the population in Scotland, where there was no clear evidence for such a decline. </p>
<h2>Thai otters</h2>
<p>With a little detective work, we discovered that a pair of Eurasian otters (the same species that we have in the UK), were brought to Britain from Thailand in the 1960s. Populations of Eurasian otters range right across Europe and Asia. Although they are the same species, there are several genetically distinct subspecies, particularly in Asia. </p>
<p>It seems possible that these genetically different otters from Thailand bred with otters in the east of England. At the time of the population decline, when native UK populations were at their smallest, even a few individuals introduced into the population may have made a big difference. And they left unexpected marks on the genome. </p>
<p>We don’t know for sure if this is what happened, and we need to do more work to find out what effect this may have had on otters in the east of England. High genetic diversity is usually good for a population or species. But on the other hand, conservation often strives to maintain genetic differences between populations, rather than mixing distinct populations.</p>
<p>One way to find out more would be to compare the genome of a Eurasian otter from Thailand to the otters we see in the east of England. Unfortunately, it’s not that easy. Since the 1960s, otters in Thailand and across Asia have become increasingly rare. This is due to habitat loss, pollution and the illegal otter trade. So getting samples for genome sequencing is very difficult. It highlights the importance of conserving the species in Asia, despite population recoveries in Europe.</p>
<p>Our work shows the value of using modern genomic tools to look at the genetic diversity of a threatened species. The application of such tools can uncover surprising facts, even in supposedly well-studied species.</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">
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<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
<br><em><a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">Get a weekly roundup in your inbox instead.</a> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 30,000+ readers who’ve subscribed so far.</a></em></p>
<hr><img src="https://counter.theconversation.com/content/219140/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Frank Hailer receives funding from NERC and Dŵr Cymru Welsh Water. </span></em></p><p class="fine-print"><em><span>Elizabeth Chadwick receives funding from the UK Natural Environment Research Council and from the Environment Agency</span></em></p><p class="fine-print"><em><span>Sarah du Plessis receives funding from the UK Natural Environment Research Council and the Global Wales International Mobility Fund.</span></em></p>Research has revealed how British otters may have been able to recover from species loss in the 1950s with the help of otters from Asia.Frank Hailer, Senior Lecturer in Evolutionary Biology, Cardiff UniversityElizabeth Chadwick, Senior Lecturer at the School of Biosciences, Cardiff UniversitySarah du Plessis, PhD Candidate, Cardiff UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2230792024-02-16T04:57:13Z2024-02-16T04:57:13ZAustralians are washing microplastics down the drain and it’s ending up on our farms<figure><img src="https://images.theconversation.com/files/576094/original/file-20240215-30-6i3a89.jpg?ixlib=rb-1.1.0&rect=25%2C34%2C5725%2C3794&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/beautiful-young-woman-doing-laundry-home-1491577367">Pixel-Shot, Shutterstock</a></span></figcaption></figure><p>Australian wastewater treatment plants produce thousands of tonnes of treated sewage sludge every year. This nutrient-rich material is then dried to make “biosolids”, which are used to fertilise agricultural soil. </p>
<p>Unfortunately every kilogram of biosolids also contains thousands of tiny pieces of plastic. These pieces are so small they can only be seen under a microscope, so they’re called <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/microplastics">microplastics</a>.</p>
<p>In <a href="https://www.sciencedirect.com/science/article/pii/S0043135423015117">our new research</a>, we sampled biosolids from three states and calculated the average contribution of microplastics per person: 3g in New South Wales and 4.5g in Queensland. But the average in South Australia was 11.5g – that’s about the same amount of plastic as a plastic bag.</p>
<p>Roughly 80% of this microplastic comes from washing clothes. We need to protect agricultural soil from contamination by making simple changes at home, mandating filters on washing machines and introducing more effective wastewater treatment. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/microplastics-are-common-in-homes-across-29-countries-new-research-shows-whos-most-at-risk-189051">Microplastics are common in homes across 29 countries. New research shows who's most at risk</a>
</strong>
</em>
</p>
<hr>
<h2>Biosolids as fertiliser</h2>
<p>Most domestic wastewater comes from household kitchens, bathrooms and laundries. </p>
<p>Wastewater treatment separates most of the water and leaves sewage sludge behind. This mixture of water and organic material can then be sent to landfill for disposal or dried to form a material called “biosolids”.</p>
<p>In Australia, two-thirds of the <a href="https://www.biosolids.com.au/guidelines/australian-biosolids-statistics/">340,000 tonnes produced annually</a> are used on farms to improve soil quality and stimulate plant growth. This not only boosts agricultural productivity but also allows for more sustainable disposal of treated sewage sludge. The waste becomes a resource, a useful and economically viable fertiliser, rather than ending up in landfill.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/more-than-1-200-tonnes-of-microplastics-are-dumped-into-aussie-farmland-every-year-from-wastewater-sludge-137278">More than 1,200 tonnes of microplastics are dumped into Aussie farmland every year from wastewater sludge</a>
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<h2>Microplastics in Australian biosolids</h2>
<p>Wastewater treatment plants can capture anywhere from <a href="https://doi.org/10.1016/j.jece.2022.107831">60% to more than 90%</a> of the microplastics in sewage before the wastewater is discharged. But plastic is durable and does not degrade during treatment. So the microplastic particles removed from the wastewater are simply transferred to the sludge. </p>
<p>We assessed the abundance, characteristics and size ranges of microplastics in biosolids collected from 13 wastewater treatment plants across three states.</p>
<p>We found every kilogram of biosolid contains between 11,000 and 150,000 microplastic particles. </p>
<p>Most of the microplastics found were invisible to the naked eye, ranging from 20 to 200 micrometres in size. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/575745/original/file-20240214-24-di49kb.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Grid showing four separate microscopy images of microplastics in biosolid samples" src="https://images.theconversation.com/files/575745/original/file-20240214-24-di49kb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/575745/original/file-20240214-24-di49kb.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=454&fit=crop&dpr=1 600w, https://images.theconversation.com/files/575745/original/file-20240214-24-di49kb.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=454&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/575745/original/file-20240214-24-di49kb.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=454&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/575745/original/file-20240214-24-di49kb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=571&fit=crop&dpr=1 754w, https://images.theconversation.com/files/575745/original/file-20240214-24-di49kb.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=571&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/575745/original/file-20240214-24-di49kb.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=571&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Various microplastic particles from biosolid samples can be as seen under the microscope.</span>
<span class="attribution"><span class="source">Shima Ziajahromi</span></span>
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</figure>
<p>The most common type of microplastic was microfibres from fabric. We found more microplastic fibres during cold seasons. We suspect this corresponds to people washing more synthetic fleece clothing and blankets. </p>
<p>Microbeads are tiny balls of microplastic sometimes added to personal care products and detergents. We did not find any microbeads in samples from South Australia and New South Wales. These states were among the first to support a <a href="https://www.dcceew.gov.au/environment/protection/waste/plastics-and-packaging/plastic-microbeads">voluntary industry phase-out of plastic microbeads</a>. </p>
<p>In contrast, we found a small amount of microbeads in samples from Queensland, which only <a href="https://statements.qld.gov.au/statements/98573">banned microbeads in September last year</a>. That was more than a year after samples were collected for this study.</p>
<p>We estimate Australians release between 0.7g and 21g of microplastics per person into wastewater every year. This wide range is based on our results, which varied from state to state: 0.7g to 5.9g in NSW, 1g to 7.2g in Queensland and 1.9g to 21g in SA. We don’t know why it varies so much between states.</p>
<p>This contributes to the amount of microplastics in biosolids. Our biosolid samples contained anywhere from 1kg to 17kg of microplastics per tonne. Remember this is being transported into our farmlands.</p>
<h2>What’s the problem?</h2>
<p>Microplastics are steadily accumulating in agricultural soils, where they will remain for hundreds of years. While natural weathering processes such as sunshine and rain will slowly break down microplastics into smaller and smaller particles, that only makes matters worse. Smaller particles cause more harmful effects to soil organisms.</p>
<p>Eating small pieces of plastic can cause internal abrasions and blockages in the digestive tract. In very small aquatic animals such as zooplankton, microplastics can reduce absorption of nutrients from food, <a href="https://pubs.acs.org/doi/full/10.1021/acs.est.7b03574">decrease reproduction rates, and cause death</a>.</p>
<p>These tiny particles also contain a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7355763/">cocktail of toxic chemicals</a>, either added during manufacturing to improve the product or soaked up from the environment. This makes them <a href="https://www.sciencedirect.com/science/article/pii/S0304389420319026?casa_token=4Ny10i4YQ_UAAAAA:71b3vKN1UUA7TaSKkWQ76Up0TiRR_MoE6enVmKLeynDLo_2alsz_5aWeNS_Eal5LchEt91Gedg">even more dangerous</a>.</p>
<p>Smaller microplastics (less than 100 micrometres in size) are <a href="https://www.sciencedirect.com/science/article/abs/pii/S0304389423005113">even more harmful for soil organisms</a>. </p>
<p>Microplastics in soil can be ingested by soil organisms such as earthworms and cause harmful effects on these vital organisms. Microplastic exposure has also been shown to <a href="https://doi.org/10.1016/j.scitotenv.2021.149338">adversely affect soil health and plant growth</a>.</p>
<p><a href="https://www.biosolids.com.au/wp-content/uploads/Emerging-Contaminants-in-Biosolids-Research-report.pdf">Australian regulations</a> govern the amounts of heavy metals, nutrients, pathogens and some emerging contaminants allowed in biosolids, but there is no guideline for microplastics concentrations. We think that has to change. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/574840/original/file-20240212-18-j43xxo.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Stockpiles of biosolids from sludge lagoons with a tractor in the background" src="https://images.theconversation.com/files/574840/original/file-20240212-18-j43xxo.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/574840/original/file-20240212-18-j43xxo.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/574840/original/file-20240212-18-j43xxo.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/574840/original/file-20240212-18-j43xxo.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/574840/original/file-20240212-18-j43xxo.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/574840/original/file-20240212-18-j43xxo.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/574840/original/file-20240212-18-j43xxo.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">Biosolids from sludge lagoons in South Australia.</span>
<span class="attribution"><span class="source">SA Water</span></span>
</figcaption>
</figure>
<h2>Here’s what we can do</h2>
<p>Our research shows biosolids are a significant source of microplastics in agricultural systems. More research is needed to better understand the risks. </p>
<p>We need to put effective control measures in place to minimise the accumulation of microplastic in productive agricultural soils. </p>
<p>The most effective way to do this is to reduce the level of microplastics in biosolids at the source. </p>
<p>We know most microplastics in biosolids come from washing clothes. While it may not be possible to eliminate the use of synthetic fabrics, there are some measures we can all take to reduce the amount of microplastic washing off our clothes into the wastewater stream. Properly installed <a href="https://doi.org/10.3389/fmars.2021.777865">filters in washing machines</a> have been shown to significantly reduce microplastic levels in wastewater. </p>
<p>Australia’s <a href="https://www.agriculture.gov.au/sites/default/files/documents/national-plastics-plan-2021.pdf">National Plastics Plan</a> recommends the Australian government work with industry to “phase-in” microfibre filters on all washing machines by 2030. But why wait until 2030? </p>
<p>Several jurisdictions, including <a href="https://www.legifrance.gouv.fr/loda/id/JORFTEXT000041553759">France</a>, <a href="https://www.ola.org/en/legislative-business/bills/parliament-42/session-1/bill-279">Ontario</a> and <a href="https://fastdemocracy.com/bill-search/ca/20212022/bills/CAB00022073/">California</a>, have already made microfibre filters on washing machines mandatory. It’s time Australia did the same. </p>
<p>In the meantime, there are simple things everyone can do at home. Wash clothes in cold water, avoid running the machine for light loads if you can wait to do a full load, and wash synthetic fabrics less frequently. These steps will also save energy and money. </p>
<p>It’s far better to stop microplastics entering the wastewater stream than <a href="https://www.sciencedirect.com/science/article/abs/pii/S2213343722007047?via%3Dihub">trying to remove them at the wastewater treatment plant</a>. Prevention is always better than a cure. </p>
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Read more:
<a href="https://theconversation.com/humanitys-signature-study-finds-plastic-pollution-in-the-worlds-lakes-can-be-worse-than-in-oceans-209487">'Humanity's signature': study finds plastic pollution in the world's lakes can be worse than in oceans</a>
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<img src="https://counter.theconversation.com/content/223079/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Shima Ziajahromi receives funding from the Queensland Government through Advance Queensland Industry Research Project. This project was co-sponsored by Urban Utilities, Sydney Water, SA Water, Water Corporation (WA) and Eurofins Environment Testing Australia.</span></em></p><p class="fine-print"><em><span>Frederic Leusch receives funding related to this research topic from the Queensland Government through an Advance Queensland Industry Research Project, Water Research Australia, and various Australian water utilities. This project was co-sponsored by Urban Utilities, Sydney Water, SA Water, Water Corporation (WA) and Eurofins Environment Testing Australia.</span></em></p>We sampled sewage sludge from 13 wastewater treatment plants across three states. We found every resident adds microplastics to farmland, in dried sewage sludge (biosolids) used as fertiliser.Shima Ziajahromi, Advance Queensland Research Fellow, Griffith UniversityFrederic Leusch, Professor of Environmental Science, Griffith UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2230472024-02-15T13:43:44Z2024-02-15T13:43:44ZGhana’s new vehicle tax aims to tackle pollution – expert unpacks how it’ll work and suggests reforms<p><em>Ghana has introduced an <a href="https://gra.gov.gh/implementation-of-new-tax-laws-and-amendments/">annual carbon levy on vehicles and industrial emissions</a>. It’s only the third <a href="https://carbonpricingdashboard.worldbank.org/">African country</a> to introduce an explicit carbon tax, after <a href="https://www.tandfonline.com/doi/pdf/10.1080/0376835X.2023.2171366">South Africa and Mauritius</a>. The tax is intended to address <a href="https://mofep.gov.gh/sites/default/files/budget-statements/2024%20Budget%20Statement_v2.pdf">harm</a> associated with vehicle emissions. But it has prompted a <a href="https://www.ghanaweb.com/GhanaHomePage/NewsArchive/Inconsiderate-vehicle-emissions-tax-won-t-prevent-carbon-emission-Ben-Boakye-1914538">pushback</a> from various citizens, civic and consumer groups.</em></p>
<p><em>The Conversation Africa’s Godfred Akoto Boafo spoke to Theophilus Acheampong, an energy economist who has consulted for Ghana’s finance ministry on environmental fiscal reform, about the impact and implementation of this kind of levy.</em></p>
<h2>Why is the government taxing emissions?</h2>
<p>The proposed vehicle emissions tax under the <a href="https://gra.gov.gh/implementation-of-new-tax-laws-and-amendments/">Emissions Levy Act, 2023</a> is one of several environmental fiscal reform measures being introduced by the government. I am among several consultants who have worked on these proposed reforms since 2010. </p>
<p>Environmental tax reform <a href="https://www.eea.europa.eu/highlights/environmental-tax-reform-increasing-individual">aims</a> to shift the burden of taxation to environmentally damaging activities, such as pollution. </p>
<p>Reforms like this can help raise domestic revenue, protect the environment by meeting country climate targets under the <a href="https://www.ciwf.org.uk/research/environment/paris-climate-agreement-2030-sustainable-development-goals/#:%7E:text=Paris%20Climate%20Agreement%20%26%202030%20Sustainable%20Development%20Goals,-Implementing%20the%20Paris&text=The%20goals%20include%20zero%20hunger,lifestyles%20in%20harmony%20with%20nature">Paris Agreement and the Sustainable Development Goals</a>, and reduce poverty. These benefits have been confirmed in many <a href="https://doi.org/10.3390/su10020501">studies</a> but with mixed results.</p>
<p>Ghana’s government believes the vehicle emissions tax is a more cost-effective and equitable way to make sure the <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/polluter-pays-principle">polluter pays</a>, <a href="https://www.gov.uk/government/publications/environmental-principles-policy-statement/environmental-principles-policy-statement#:%7E:text=Description%3A%20The%20prevention%20principle%20means,%5Bfootnote%206%5D%20is%20avoided.">prevent harm</a> and <a href="https://eur-lex.europa.eu/EN/legal-content/glossary/precautionary-principle.html">protect the public</a>. </p>
<p>Ghana’s energy sector is the <a href="https://unfccc.int/sites/default/files/resource/gh_nir5_15052022_final.pdf">major source</a> (46%) of the country’s greenhouse emissions. Within this, mobile combustion emissions <a href="https://unfccc.int/sites/default/files/resource/gh_nir5_15052022_final.pdf">accounted</a> for 34% of the total energy emissions and 15% of the total national emissions in 2019. Transportation emissions, predominantly from road transport, have <a href="https://unfccc.int/sites/default/files/resource/gh_nir5_15052022_final.pdf">increased</a> by 47% compared to 2016 levels due to growing vehicle ownership and the associated traffic congestion in cities and peri-urban areas.</p>
<p>Lower respiratory <a href="https://www.cdc.gov/globalhealth/countries/ghana/default.htm#death">infections</a>, which are linked to air pollution, are among the top five causes of <a href="https://www.who.int/data/gho/data/themes/mortality-and-global-health-estimates/ghe-leading-causes-of-death">death</a> in the country. Some <a href="https://www.cleanairfund.org/geography/ghana/">28,000</a> Ghanaians died prematurely from air pollution in 2020. Air pollution-related deaths cost Ghana 0.95% of gross domestic product, according to a <a href="https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(22)00090-0/fulltext">2021 Lancet study</a>.</p>
<h2>What has been done so far to reduce air pollution?</h2>
<p>In 2021, the government introduced a sanitation and pollution levy on petrol and diesel under the <a href="https://atugubaassociates.com/file/Energy%20Sector%20Levies%20(Amendment)%20Act.pdf">Energy Sector Levies Act</a> to raise revenue to improve air quality, among other goals. The levy accrued <a href="https://mofep.gov.gh/sites/default/files/reports/economic/Final_%202022-Annual-ESLA-Report.pdf">GHS452 million</a> (US$55 million) in 2022. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/ghana-wants-fewer-polluting-old-cars-on-the-road-but-its-going-about-it-the-wrong-way-198805">Ghana wants fewer polluting old cars on the road. But it’s going about it the wrong way</a>
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<p>In 2018, the government also <a href="https://mofep.gov.gh/sites/default/files/news/Notice-Luxury-Vehicle.pdf">introduced</a> a luxury vehicle tax on vehicles with engine capacities of three litres or more, except for commercial vehicles. However, following a public outcry, the government <a href="https://www.graphic.com.gh/business/business-news/govt-withdraws-vehicle-luxury-tax.html">suspended</a> the tax in July 2019. There were <a href="https://www.graphic.com.gh/news/politics/bring-back-luxury-vehicle-tax-upsa-to-government.html">subsequent calls</a> for it to be reintroduced. </p>
<p>These measures weren’t well designed from a tax policy point of view as they were not tied to actual vehicular emissions. Hence the need for an vehicle emissions tax. </p>
<h2>How should an emissions tax work and how does the new tax work?</h2>
<p>Ghana’s <a href="https://gra.gov.gh/implementation-of-new-tax-laws-and-amendments/">proposed</a> emissions tax is based on internal combustion engine capacities. Charges range from GHS75 (US$6) for motorcycles and tricycles to GHS150 (US$12) for motor vehicles, buses and coaches up to 3 litre engine. A higher threshold of GHS300 (US$24) applies for motor vehicles, buses and coaches above 3 litre engine capacity, and cargo trucks and articulated trucks. </p>
<p>Ideally, the tax should be based on the actual carbon dioxide and other pollutant emissions from a vehicle, measured in grams of carbon dioxide per kilometre. A threshold of tailpipe CO₂ is set. Each car owner would pay an annual tax for the amount of CO₂ their car emits above that threshold.</p>
<p>The <a href="https://caura.com/blog/why-does-an-mot-include-an-exhaust-emissions-test#:%7E:text=An%20exhaust%20emissions%20test%20ensures,a%20visual%20test%20is%20applied">tailpipe emissions test</a> would be done during the annual roadworthiness check by Ghana’s <a href="https://www.dvla.gov.gh/">Driver Vehicle and Licensing Authority</a>. It would also collect the amounts and then remit them to the Treasury. </p>
<p>There is scope in Ghana’s case to tie it to actual tailpipe emissions and also revise the upper end of the tax as it is prohibitive. This would make the tax more equitable and better reflect the “polluter pays” principle. </p>
<h2>What are the objections to the tax and can they be accommodated?</h2>
<p>The main objection is that it amounts to double taxation. Critics point to the existing pollution levy. There is also no clear plan for what the tax will be used for after it is collected. </p>
<p>Several critics, especially in the<a href="https://www.graphic.com.gh/news/general-news/emissions-levy-premature-antibusiness-food-and-beverage-association.html"> manufacturing</a> and <a href="https://citinewsroom.com/2024/02/emissions-levy-well-increase-our-fares-accordingly-gprtu/">transport sector</a>, say there are already too many taxes. A new one adds to the cost of operating a business. This cost will be passed on to consumers in an already struggling economy. </p>
<p>Some have <a href="https://citinewsroom.com/2024/02/withdraw-emissions-levy-itll-worsen-already-acidic-business-environment-fabag-to-govt/">urged </a>the government to develop environmentally friendly power sources like nuclear and solar energy.</p>
<p>But the government is under pressure to <a href="https://theconversation.com/ghana-and-the-imf-have-struck-a-deal-but-hard-choices-lie-ahead-206240">raise domestic revenue</a> as part of its International Monetary Fund conditionalities. It is therefore difficult to predict whether it will accommodate the concerns that have been raised.</p>
<h2>How does Ghana’s tax compare with others in Africa?</h2>
<p>Ghana, Zambia, South Africa and Namibia have various environmental taxes covering energy, transport, air pollution and waste. </p>
<p>For example South Africa <a href="https://www.reuters.com/article/us-safrica-carbontax-idUSKCN1SW0K6/">introduced</a> a carbon emissions tax on vehicles in 2010. This was updated in 2019 and 2022. The tax applies when cars have emissions above 120g CO₂ per km as well as 3litre engine capacity. The former is about the typical emission from a Ford Fiesta 1.0T EcoBoost or KiaPicanto 1.0. The rate is adjusted for inflation every year. The tax rate ranges from R132 (US$7; GHS86) to R176(US$9; GHS115) for every gram of carbon dioxide per kilometre above the threshold. A 2018 <a href="https://www.tandfonline.com/doi/abs/10.1080/10291954.2018.1505265">study</a> indicated that South Africa’s CO₂ emissions tax had failed to influence which new cars consumers were buying. This is understandable given <a href="https://www.statssa.gov.za/?p=15473">low income levels</a> and that <a href="https://www.statssa.gov.za/?p=14063">35% of households</a> used public transport, according to the 2020 National Household Travel Survey.</p>
<p>Ghana’s proposed emissions tax for vehicles up to 3 litre engine capacity is not unreasonable when benchmarked to South Africa’s. </p>
<p>However, the tax for engines above 3 litres is steep. It targets the main means of transport for many citizens. The 2012 Ghana National Transport Household Survey showed that <a href="https://www2.statsghana.gov.gh/docfiles/publications/Second%20National%20Household%20Transport%20Survey%20Report%202012.pdf">90%</a> of commuters used shared public transport (known locally as “tro-tro”); this figure may have declined in recent times. </p>
<h2>Can the tax be implemented and will it meet its objectives?</h2>
<p>Ghana is already implementing several environment tax reforms across different sectors, with varying degrees of success. There is the potential to harmonise these instruments to improve environmental outcomes and behavioural incentives. </p>
<p>The existing sanitation and pollution levy must first be scrapped and replaced with the vehicle emissions tax. This should be based on actual carbon dioxide, nitric oxide and other tailpipe emissions to maximise efficiency. The tax bands should conform to emission standards set by the <a href="https://www.gsa.gov.gh/">Ghana Standards Authority</a> and the vehicle licensing authority. </p>
<p>Having both the sanitation and pollution levy and vehicle emissions tax operating at the same time amounts to double taxation. </p>
<p>Ghana must also agree to earmark and allocate an agreed proportion of the proceeds to address environmental issues. </p>
<h2>What is the tax collection picture in Ghana?</h2>
<p>Ghana tax collection is currently <a href="https://www.oecd.org/tax/tax-policy/revenue-statistics-africa-ghana.pdf">around</a> 14% of GDP. Its aim is to get to 18% by 2028, comparable with its <a href="https://www.oecd.org/tax/tax-policy/brochure-revenue-statistics-africa.pdf">peers</a> such as Senegal, Namibia, Togo and Rwanda. Other revenue generation avenues have been met with stiff resistance. A recent value added tax on electricity has just been <a href="https://www.bbc.com/news/world-africa-68236869?ns_mchannel=social&ns_source=twitter&ns_campaign=bbc_live&ns_linkname=68236869%26Ghana%20suspends%20controversial%20power%20tax%20after%20uproar%262024-02-08T17%3A42%3A01.000Z&ns_fee=0&pinned_post_locator=urn:bbc:cps:curie:asset:af7380e7-a5ab-4afb-9364-57740148921b&pinned_post_asset_id=68236869&pinned_post_type=share">suspended</a>. </p>
<p>In 2024, Ghana plans to improve revenue performance through <a href="https://mofep.gov.gh/sites/default/files/budget-statements/2024%20Budget%20Statement_v2.pdf">extending</a> the electronic VAT system to cover 600 large taxpayers and more than 2,000 small and medium-sized taxpayers, as well as taxing industrial and vehicle emissions, among others.</p><img src="https://counter.theconversation.com/content/223047/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Theophilus Acheampong is affiliated with the IMANI Centre for Policy and Education in Accra, Ghana. He has also consulted for the Government of Ghana on environmental fiscal reform in a private capacity. </span></em></p>Critics have described Ghana’s emissions tax as premature.Theophilus Acheampong, Associate Lecturer, University of AberdeenLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2151272024-02-13T13:20:14Z2024-02-13T13:20:14ZFlowers grown floating on polluted waterways can help clean up nutrient runoff and turn a profit<figure><img src="https://images.theconversation.com/files/573604/original/file-20240205-30-14awa7.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6173%2C4087&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The cut flowers could pay for themselves and even turn a profit.</span> <span class="attribution"><span class="source">Margi Rentis</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Flowers grown on inexpensive floating platforms can help clean polluted waterways, over 12 weeks extracting 52% more phosphorus and 36% more nitrogen than the natural nitrogen cycle removes from untreated water, according to our <a href="https://doi.org/10.1016/j.envadv.2023.100405">new research</a>. In addition to filtering water, the cut flowers can generate income via the <a href="https://www.ers.usda.gov/data-products/chart-gallery/gallery/chart-detail/?chartId=106472">multibillion-dollar floral market</a>. </p>
<p>In our trials of various flowers, giant marigolds stood out as the most successful, producing long, marketable stems and large blooms. Their yield matched typical <a href="https://www.lsuagcenter.com/articles/page1662131594449">flower farm production</a>.</p>
<h2>Why it matters</h2>
<p><a href="https://www.epa.gov/nps/basic-information-about-nonpoint-source-nps-pollution">Water pollution</a> is caused in large part by runoff from farms, urban lawns and even septic tanks. When it rains, excess phosphorus, nitrogen and other chemicals wash into lakes and rivers.</p>
<p>These nutrients feed algae, leading to widespread and harmful algae blooms, which can severely lower oxygen in water, creating “<a href="https://unstats.un.org/sdgs/report/2021/goal-14/">dead zones</a>” where aquatic life cannot survive. Nutrient runoff is a critical issue as urban areas expand, affecting the health of water ecosystems. </p>
<p>Water pollution is an escalating crisis in our area of Miami-Dade and Broward counties in Florida. The <a href="https://storymaps.arcgis.com/stories/b5d43852c8984a4c8db4d077ec04bd35">2020 Biscayne Bay fish kill</a>, the largest mass death of aquatic life on record for the region, serves as a stark reminder of this growing environmental issue.</p>
<h2>How we do our work</h2>
<p>We study <a href="https://case.fiu.edu/earth-environment/agroecology/">sustainable agriculture</a> and <a href="https://crestcache.fiu.edu/">water pollution</a> in South Florida.</p>
<p>Inspired by traditional floating farm practices, including the Aztecs’ <a href="https://www.bbc.com/travel/article/20221009-the-return-of-aztec-floating-farms">chinampas in Mexico</a> and the <a href="https://www.pbs.org/video/the-secret-islands-of-the-everglades-lncj6r/">Miccosukees’ tree island settlements in Florida</a>, we tested the idea of growing cut flowers on floating rafts as a way to remove excess nutrients from waterways. Our hope was not only that the flowers would pay for themselves, but that they could provide jobs here in Miami, the center of the U.S. cut-flower trade.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An outdoor tank contains a large floating perforated mat. Each hole contains a young plant." src="https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.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">Chemical conditions in the test tanks were the same as in nearby polluted waterways.</span>
<span class="attribution"><span class="source">Jazmin Locke-Rodriguez</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>We floated 4-by-6-foot (1.2-by-1.8-meter) mats of inexpensive polyethylene foam called <a href="http://www.beemats.com/">Beemats</a> in 620-gallon (2,300-liter) outdoor test tanks that mirrored water conditions of nearby polluted waterways. Into the mats we transplanted flower seedlings, including zinnias, sunflowers and giant marigolds. The polluted tank water was rich in nutrients, eliminating the need for any fertilizer. As the seedlings matured into plants over 12 weeks, we tracked the tanks’ improving water quality. </p>
<p>Encouraged by the success of the marigolds in our tanks, we moved our trials to the nearby canals of Coral Gables and Little River. We anchored the floating platforms with 50-pound (22.7-kilograms) weights and also tied them to shore for extra stability. No alterations to the landscape were needed, making the process simple and doable.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Closeup photo of base of a marigold plant showing a tangle of visible roots." src="https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.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>
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<span class="caption">Some plants grow roots in places – such as the stem – other than where their original roots began.</span>
<span class="attribution"><span class="source">Jazmin Locke-Rodriguez</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<h2>What still isn’t known</h2>
<p>The success of the giant marigolds might be linked to the extra roots that grow from their stems known as <a href="https://propg.ifas.ufl.edu/05-cuttings/01-terminology/01-cuttingterms-adventitiousroot.html">adventitious roots</a>. These roots likely help keep the plants stable on the floating platforms. Identifying additional plants with roots like these could help broaden plant choices. </p>
<p>Future raft designs may also need modifications to ensure better stability and growth for other cut-flower and crop species. </p>
<h2>What’s next</h2>
<p>Our promising findings show floating cut-flower farms could be a sustainable option for mitigating water pollution. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/Nim52wi_4z4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">How floating cut-flower farms can clean polluted waterways.</span></figcaption>
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<p>One of us (Locke-Rodriguez) is expanding this research and working to scale up floating farms in South Florida as a demonstration of what could take place in the many locations facing similar issues worldwide.</p>
<p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take on interesting academic work.</em></p><img src="https://counter.theconversation.com/content/215127/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jazmin Locke received funding from the USDA-NIFA-NNF and NSF-CREST as a PhD student to help fund this dissertation research at Florida International University.</span></em></p><p class="fine-print"><em><span><a href="mailto:jayachan@fiu.edu">jayachan@fiu.edu</a> receives funding from USDA-NIFA. </span></em></p>Phosphorus and nitrogen contribute to water pollution and cause harmful algal blooms. New research shows how mats of floating flower beds can take advantage of these nutrients while cleaning the water.Jazmin Locke-Rodriguez, Post Doctoral Associate in the Institute of Environment, Florida International UniversityKrishnaswamy Jayachandran, Professor of Agroecology, Florida International UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2231772024-02-12T19:09:29Z2024-02-12T19:09:29ZOne of NZ’s most contentious climate cases is moving forward. And the world is watching<p>In recent weeks, the Supreme Court of New Zealand has delivered a <a href="https://www.courtsofnz.govt.nz/assets/cases/2024/2024-NZSC-5.pdf">landmark decision</a> on a case brought by Māori elder Mike Smith against a group of New Zealand’s largest corporate greenhouse gas (GHG) emitters.</p>
<p>The Supreme Court overturned lower court rulings which had struck out Smith’s ambitious claim seeking to establish civil (tort) liability for those emitters’ contributions to climate change. Smith argued these contributions had a negative impact on his family’s and tribe’s land, water and cultural values.</p>
<p>With the Supreme Court decision, Smith has won the right to present his full case before the High Court. </p>
<p>While only the beginning of what could be a long legal process, the Supreme Court’s decision has attracted local and international attention as one that “<a href="https://www.rnz.co.nz/news/national/508603/mike-smith-s-case-against-major-nz-emitters-garners-international-interest-lawyer-says">may open a new avenue in climate law</a>”.</p>
<h2>The case against the corporate emitters</h2>
<p>In 2019, Smith sued seven New Zealand-based corporate entities in his capacity as an elder of the Ngāpuhi and Ngāti Kahu iwi (tribes) and climate change spokesperson for a national forum of tribal leaders. </p>
<p>The defendants include New Zealand’s largest company <a href="https://www.fonterra.com/nz/en.html">Fonterra</a> (responsible for around 30% of the world’s dairy exports), along with other corporate entities involved in industries either directly emitting GHGs or supplying fossil fuels such as oil, gas or coal. </p>
<p>Smith argued the activities and effects of the corporate defendants amount to three forms of “tort” or civil wrong: public nuisance, negligence, and a new form of civil wrong described as a “proposed climate system damage tort”.</p>
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Read more:
<a href="https://theconversation.com/childrens-climate-change-case-at-the-european-court-of-human-rights-whats-at-stake-151417">Children's climate change case at the European Court of Human Rights: what's at stake?</a>
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<p>The first two causes of action – public nuisance and negligence – have long lineages in the common law. </p>
<p>As touched on in the Supreme Court decision, public nuisance claims were used by claimants affected by various forms of pollution and other harm during the Industrial Revolution in the 19th century. </p>
<p>Many of the leading common law tort cases – especially on public nuisance – were decided well before the emergence of modern scientific understanding and consensus on climate change. </p>
<p>A major issue for the Supreme Court (and now the High Court, where this claim will proceed) was whether longstanding rules and principles of tort liability should be adjusted in light of the contemporary, existential challenges presented by climate change. </p>
<p>This might involve adapting established tort categories of public nuisance and negligence. It might also involve fashioning an entirely new “climate system damage” tort.</p>
<p>A key plank of the corporate emitters’ argument was that the courts “are ill-suited to deal with a systemic problem of this nature with all the complexity entailed”. They argued the courts should leave those inherently political issues to the politicians. </p>
<p>The Supreme Court rejected that argument. Unless parliament has, through statute, clearly displaced civil obligations – and the court found that it had not – a judicial pathway is “open for the common law to operate, develop and evolve”.</p>
<h2>The challenges of establishing causation</h2>
<p>Questions of causation and proximity have been <a href="https://www.ejiltalk.org/a-guide-to-tackling-the-collective-causation-problem-in-international-climate-change-litigation/">stumbling blocks for litigants overseas</a> attempting to bring similar tort claims to Smith’s. </p>
<p>Defendants typically argue it is impossible to show the global emission contributions of a small group of even relatively large entities can be evidentially linked to the climate-related harm experienced by plaintiffs. In this case, the seven corporate emitters are associated with around 30% of total New Zealand emissions. </p>
<p>However, New Zealand contributes less than 0.2% of global emissions. As the High Court judge put it, “the defendants’ contribution to […] global emissions is minute”. To accept Smith’s claim “would be to expose (them) to an undue burden of legal responsibility, way beyond their contribution to damaging global greenhouse gas emissions”.</p>
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<strong>
Read more:
<a href="https://theconversation.com/a-peruvian-farmer-is-trying-to-hold-energy-giant-rwe-responsible-for-climate-change-the-inside-story-of-his-groundbreaking-court-case-218408">A Peruvian farmer is trying to hold energy giant RWE responsible for climate change – the inside story of his groundbreaking court case</a>
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<p>The Supreme Court did not agree that the challenges of causation or proximity necessarily doom Smith’s case to failure. The court suggested that there may be scope for adjusting the causation rules to better reflect the nature of modern environmental issues like climate change. </p>
<p>Smith’s position (in part) is that instead of requiring litigants to prove that damage to their land and resources is directly attributable to the activities of one or more corporate emitters, the legal test should be adjusted to establish civil liability if defendants have materially contributed to the global problem. </p>
<p>But the Court didn’t think these difficult questions could be resolved without a full trial.</p>
<h2>What role for tikanga and where now?</h2>
<p>An important dimension of the case which distinguishes it from similar proceedings overseas is the relevance of a body of indigenous custom, law and practice known as “<a href="https://www.otago.ac.nz/maori/world/tikanga/lore">tikanga Māori</a>”. </p>
<p>Recent Supreme Court <a href="https://www.lawcom.govt.nz/our-work/tikanga-maori/">decisions</a> have accepted and applied tikanga as the “first law of New Zealand” including in relation to environmental protection.</p>
<p>The Court followed that approach in this case, accepting that crucial aspects of Smith’s case rely on tikanga principles. </p>
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<strong>
Read more:
<a href="https://theconversation.com/new-research-shows-ancestral-maori-adapted-quickly-in-the-face-of-rapid-climate-change-194155">New research shows ancestral Māori adapted quickly in the face of rapid climate change</a>
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<p>Smith is not just suing on his own behalf, “but as a kaitiaki (carer) acting on behalf of the whenua (land), wai (freshwater) and moana (sea) – distinct entities in their own right”. The court pronounced that “addressing and assessing matters of tikanga simply cannot be avoided”.</p>
<p>With Smith’s claim having been reinstated, the parties now return to the High Court. Unless there is legislative intervention, the normal pretrial steps of discovery, evidence exchange and preparation will proceed. It promises to be one of New Zealand’s hardest fought and most closely watched private law climate cases.</p><img src="https://counter.theconversation.com/content/223177/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vernon Rive has previously received funding from the New Zealand Law Foundation. </span></em></p>By allowing a case against local greenhouse gas emitters to go ahead, the Supreme Court of New Zealand has opened the door to a new front in climate law – one that takes tikanga Māori into account.Vernon Rive, Associate professor, University of Auckland, Waipapa Taumata RauLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2220912024-02-01T14:50:17Z2024-02-01T14:50:17ZHermit crabs find new homes in plastic waste: shell shortage or clever choice?<figure><img src="https://images.theconversation.com/files/571882/original/file-20240129-15-j4gupx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Scientists have found that hermit crabs are increasingly using plastic and other litter as makeshift shell homes</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/hermit-crab-carrying-plastic-bottle-cap-1962035515">metamorworks/Shutterstock</a></span></figcaption></figure><p>Land hermit crabs have been using bottle tops, parts of old light bulbs and broken glass bottles, instead of shells. </p>
<p>New research by <a href="https://www.sciencedirect.com/science/article/pii/S0048969723075885">Polish researchers</a> studied 386 images of hermit crabs occupying these artificial shells. The photos had been uploaded by users to online platforms, then analysed by scientists using a research approach known as <a href="https://www.sciencedirect.com/science/article/pii/S016953472030077X">iEcology</a>. Of the 386 photos, the vast majority, 326 cases, featured hermit crabs using plastic items as shelters. </p>
<p>At first glance, this is a striking example of how human activities can alter the behaviour of wild animals, and potentially the ways that <a href="https://www.frontiersin.org/articles/10.3389/fevo.2022.893453/full">populations and ecosystems function</a> as a result. But there are lots of factors at play and, while it’s easy to jump to conclusions, it’s important to consider exactly what might be driving this particular change. </p>
<h2>Shell selection</h2>
<p>Hermit crabs are an excellent model organism to study because they behave in many different ways and those differences can be easily measured. Instead of continuously growing their own shell to protect their body, like a normal crab or a lobster would, they use empty shells left behind by dead snails. As they walk around, the shell protects their soft abdomen but whenever they are threatened they retract their whole body into the shell. Their shells act as portable shelters.</p>
<p>Having a good enough shell is critical to an individual’s survival so they acquire and upgrade their shells as they grow. They fight other hermit crabs for shells and assess any new shells that they might find for suitability. Primarily, they look for shells that are large enough to protect them, but <a href="https://royalsocietypublishing.org/doi/10.1098/rsbl.2010.0761">their decision-making</a> also takes into account the type of snail shell, its condition and even its colour – a factor that could impact how conspicuous the crab might be.</p>
<p>Another factor that constrains shell choice is the actual availability of suitable shells. For some as yet unknown reason, a proportion of land hermit crabs are choosing to occupy plastic items rather than natural shells, as highlighted by this <a href="https://www.sciencedirect.com/science/article/pii/S0048969723075885">latest study</a>. </p>
<h2>Housing crisis or ingenious new move?</h2>
<p>Humans have intentionally changed the behaviour of animals for millennia, through the process of <a href="https://www.sciencedirect.com/science/article/abs/pii/S2213305413000052">domestication</a>. Any unintended behavioural changes in natural animal populations are potentially concerning, but how worried should we be about hermit crabs using plastic litter as shelter? </p>
<p>The Polish research raises a number of questions. First, how prevalent is the adoption of plastic litter instead of shells? While 326 crabs using plastic seems like a lot, this is likely to be an underestimation of the raw number given that users are likely to encounter crabs only in accessible parts of the populations. Conversely, it seems probable that users could be biased towards uploading striking or unusual images, so the iEcology approach might produce an exaggerated impression of the proportion of individuals in a population opting for plastic over natural shells. We need structured field surveys to clarify this. </p>
<p>Second, why are some individual crabs using plastic? One possibility is that they are forced to due to a lack of natural shells, but we can’t test this hypothesis without more information on the demographics of local snail populations. Or perhaps the crabs prefer plastic or find it easier to locate, compared with real shells? As the authors point out, plastic might be lighter than the equivalent shells affording the same amount of protection but at lower energy cost of carrying them. Intriguingly, chemicals that leach out of plastic are known to attract marine hermit crabs by <a href="https://www.sciencedirect.com/science/article/abs/pii/S0025326X21005671#:%7E:text=Our%20findings%20show%20that%20the,the%20artificial%20feeding%20stimulant%20betaine">mimicking the odour of food</a>. </p>
<figure class="align-center ">
<img alt="Hermit crab using red plastic bottle cap as a shell, walking across beach surface covered in sand and seaweed." src="https://images.theconversation.com/files/572811/original/file-20240201-23-4epat6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/572811/original/file-20240201-23-4epat6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/572811/original/file-20240201-23-4epat6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/572811/original/file-20240201-23-4epat6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/572811/original/file-20240201-23-4epat6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/572811/original/file-20240201-23-4epat6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/572811/original/file-20240201-23-4epat6.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">As hermit crabs adapt to an increase in plastic pollution, more research is needed to investigate the nuances.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/hermit-crab-plastic-shell-zanzibar-2270754839">Bertrand Godfroid/Shutterstock</a></span>
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<p>This leads to a third question about the possible downsides of using plastic. Compared to real shells plastic waste tends to be brighter and might contrast more with the background making the crabs more vulnerable to predators. Additionally, we know that exposure to microplastics and compounds that leach from plastic can change the behaviour of hermit crabs, making them <a href="https://pubmed.ncbi.nlm.nih.gov/36978596/#:%7E:text=Plastic%2Dexposed%20hermit%20crabs%20were,exposure%20disrupting%20hermit%20crab%20cognition">less fussy</a> about the shells that they choose, less adept at <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8511743/">fighting for shells</a> and even changing their personalities by making them more prone to <a href="https://www.sciencedirect.com/science/article/pii/S2666911020300058">take risks</a>. To answer these questions about the causes and consequences of hermit crabs using plastic waste in this way, we need to investigate their shell selection behaviour through a series of laboratory experiments.</p>
<h2>Pollution changes behaviour</h2>
<p>Plastic pollution is just one of the ways we are changing our environment. It’s by far the most <a href="https://www.sciencedirect.com/science/article/abs/pii/S0025326X14008571">highly reported form</a> of debris that we have introduced to marine environments. But animal behaviour is affected by <a href="https://www.sciencedirect.com/science/article/pii/S0048969723059879?via%3Dihub">other forms of pollution</a> too, including microplastics, pharmaceuticals, light and noise, plus the rising temperatures and ocean acidification caused by climate change. </p>
<p>So while investigating the use of plastic waste by hermit crabs could help us better understand the consequences of certain human impacts on the environment, it doesn’t show how exactly animals will adjust to the Anthropocene, the era during which human activity has been having a significant impact on the planet. Will they cope by using plastic behavioural responses or evolve across generations, or perhaps both? In my view, the iEcology approach cannot answer questions like this. Rather, this study acts as an alarm bell highlighting potential changes that now need to be fully investigated.</p>
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<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">
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<p class="fine-print"><em><span>Mark Briffa works for the University of Plymouth. He receives funding from the UK BBSRC. </span></em></p>Hermit crabs have been using plastic waste such as bottle tops as homes instead of empty snail shells.Mark Briffa, Professor of Animal Behaviour, University of PlymouthLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2212842024-01-22T20:05:54Z2024-01-22T20:05:54ZTiny water-walking bugs provide scientists with insights on how microplastics are pushed underwater<figure><img src="https://images.theconversation.com/files/570372/original/file-20240119-29-p4evyd.jpg?ixlib=rb-1.1.0&rect=242%2C9%2C5985%2C4146&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">You may hardly feel a raindrop, but for some tiny insects, one drop can have an intense impact. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/raindrop-royalty-free-image/682204834?phrase=raindrop+falling&adppopup=true">Mendowong Photography/Moment via Getty Images</a></span></figcaption></figure><p><a href="https://doi.org/10.1016/j.envpol.2016.06.074">Microplastics are tiny plastic particles</a> that can cause <a href="https://doi.org/10.3390/su151410821">big problems</a> when they enter the water supply. One way my <a href="https://www.dickersonlab.com/">fluid dynamics lab</a> explores microplastic movement is by studying how tiny water-walking insects are pushed underwater by raindrops.</p>
<p>Exposure to microplastic pollution can pose health risks, such as <a href="https://doi.org/10.3390/nano11020496">respiratory and digestive problems</a>, increased <a href="https://doi.org/10.5334/aogh.4056">risk of diabetes</a> and <a href="https://doi.org/10.3390/ijerph17041212">disrupted sleep</a>. But <a href="https://mabe.utk.edu/people/andrew-dickerson/">physicists like me</a> can study how they move through water to learn how to clean them up. </p>
<p><a href="https://www.britannica.com/animal/water-strider">Water striders</a> are tiny insects that can <a href="https://doi.org/10.1038/nature01793">walk on water</a>. They’re abundant in humid, rainy areas, and some species go their entire lives without ever touching land. Raindrops can weigh more than 40 times a water strider, and during storms they occasionally strike striders directly. The drops form a tiny crater under the surface of the water that envelops the strider before jettisoning it out as the crater collapses back to the surface. </p>
<p>The water striders have strong exoskeletons that allow them to survive being hit by a raindrop. Because these insects are <a href="https://doi.org/10.1016/j.matpr.2022.04.901">water-repellent</a> and very lightweight, they usually bounce right back. But sometimes the raindrops will form a second, smaller crater right below the surface. The second crater usually forms from a large, fast drop.</p>
<p>If the water strider finds itself inside this second crater, it could get trapped under the water. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/570376/original/file-20240119-18-v7fklk.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Four photos showing a raindrop colliding with the surface of the water, the first showing a dip below the surface in which a small, long-legged insect floats, the second showing the insect meeting the surface, and the third showing another small sip with the insect inside, and the fourth showing the insect submerged under the water." src="https://images.theconversation.com/files/570376/original/file-20240119-18-v7fklk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570376/original/file-20240119-18-v7fklk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=606&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570376/original/file-20240119-18-v7fklk.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=606&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570376/original/file-20240119-18-v7fklk.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=606&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570376/original/file-20240119-18-v7fklk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=761&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570376/original/file-20240119-18-v7fklk.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=761&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570376/original/file-20240119-18-v7fklk.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=761&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Raindrops form two craters, the second of which can submerge striders.</span>
<span class="attribution"><span class="source">Daren A. Watson and Andrew K. Dickerson, from the Proceedings of the National Academy of Sciences</span></span>
</figcaption>
</figure>
<p>In my lab’s <a href="https://doi.org/10.1073/pnas.2315667121">latest study</a>, we captured water striders from local ponds and released falling drops above their tanks. We used high-speed videography and image analysis to see how fast the insects submerged when the raindrops hit them.</p>
<p>My colleagues and I also measured the acceleration of the second, smaller crater. This crater retracts quickly – according <a href="https://doi.org/10.1073/pnas.2315667121">to our measurements</a>, 50 times the acceleration due to gravity. Water striders cannot support themselves inside this second bubble, as the surface they’re on moves upward so quickly, and they might fall underwater and become submerged. If that happens, the water striders make powerful swimming strokes to try to resurface.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/570392/original/file-20240119-25-h4qkfd.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two illustrations show the process of a strider underwater using its legs to kick up to the water's surface." src="https://images.theconversation.com/files/570392/original/file-20240119-25-h4qkfd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570392/original/file-20240119-25-h4qkfd.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=121&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570392/original/file-20240119-25-h4qkfd.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=121&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570392/original/file-20240119-25-h4qkfd.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=121&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570392/original/file-20240119-25-h4qkfd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=153&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570392/original/file-20240119-25-h4qkfd.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=153&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570392/original/file-20240119-25-h4qkfd.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=153&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Striders can often kick back up to the surface if they get submerged, unlike plastic particles.</span>
<span class="attribution"><span class="source">Daren A. Watson and Andrew K. Dickerson, from the Proceedings of the National Academy of Sciences</span></span>
</figcaption>
</figure>
<h2>Why it matters</h2>
<p>Like water striders, microplastics are very light and often water-repellent. They tend to move on top of the water in a similar way, and raindrops can submerge them. When pollutants get submerged, they’re <a href="https://doi.org/10.1007/s10311-020-00983-1">harder to clean up</a>, and <a href="https://journals.openedition.org/factsreports/5257">marine life might consume</a> them.</p>
<p>Our research tells us that the second crater’s quick acceleration toward the water’s surface plays a big part in sinking tiny particles – water striders and microplastics alike.</p>
<p>Studying how small particles and organisms disperse in water could help scientists figure out how to prevent and mediate microplastic pollution. </p>
<h2>What still isn’t known</h2>
<p>Water striders are so water-repellent that they carry a bubble around them <a href="https://doi.org/10.1017/S0022112008002048">called a plastron</a> when pushed underwater.</p>
<p>In the lab, the more times they are struck by drops before repelling away the water, the more likely water striders are to remain submerged <a href="https://doi.org/10.1073/pnas.2315667121">for extended periods</a>.</p>
<p>Raindrop impacts seem to deplete the plastron. We don’t yet know how many repeated impacts striders can tolerate and how chemical pollutants in waterways affect their resistance to submersion. </p>
<h2>What’s next</h2>
<p>Future work will replace the water striders in our experiments with floating particles that mimic microplastics, with a range of size, density and water-repellency. We expect larger particles to make the drops break apart upon contact, while the smaller particles will likely get carried into the air, or <a href="https://doi.org/10.1186/s43591-021-00018-8">aerosolized</a>, by the splash.</p>
<p>And the striders aren’t just good models for microplastic movement. Studying water striders’ legs as they swim could also help researchers design underwater robots.</p><img src="https://counter.theconversation.com/content/221284/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Dickerson receives funding from the National Science Foundation. </span></em></p>Microplastic pollution is a growing problem − one lab is looking at tiny insects as inspiration for how these pollutants might move through water.Andrew Dickerson, Assistant Professor of Mechanical, Aerospace and Biomedical Engineering, University of TennesseeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2183082023-12-01T12:27:24Z2023-12-01T12:27:24ZEmissions inequality is getting worse – here’s how to end the reign of the ultra-polluters<figure><img src="https://images.theconversation.com/files/562478/original/file-20231129-17-c0wtki.jpg?ixlib=rb-1.1.0&rect=11%2C2167%2C6838%2C3161&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/shadow-plane-on-agricultural-field-concept-2270822133">Scharfsinn/Shutterstock</a></span></figcaption></figure><p>Climate change is overwhelmingly a problem of wealthy people. The wealthiest 1% of humanity produce <a href="https://www.iea.org/commentaries/the-world-s-top-1-of-emitters-produce-over-1000-times-more-co2-than-the-bottom-1">over 1,000 times</a> the emissions of the poorest 1%. In fact, these <a href="https://www.oxfam.org/en/press-releases/richest-1-emit-much-planet-heating-pollution-two-thirds-humanity">77 million people are responsible</a> for more climate-changing emissions than the poorest 66% (5 billion people) of humanity. </p>
<p>Since 1990, the personal emissions of the world’s wealthiest have exploded. They are now 77 times larger than the level that would be compatible with a 1.5°C warming limit – a threshold beyond which <a href="https://www.theguardian.com/world/2021/aug/10/ipcc-report-shows-possible-loss-of-entire-countries-within-the-century">whole island nations will possibly disappear</a>.</p>
<p>If we are to keep future climate change to under 2°C then we must find a way to massively reduce economic inequality and redistribute both economic power and wealth.</p>
<p>Oxfam and the Stockholm Environment Institute have recently set out the scale of global carbon inequality. Carbon inequality is a measure of the difference in carbon pollution across society. It measures the degree to which someone is responsible for generating climate change through their consumption and control over social and economic resources.</p>
<p>The <a href="https://www.oxfam.org/en/press-releases/richest-1-emit-much-planet-heating-pollution-two-thirds-humanity">report</a> sets out the vast scale of the disparity between the super-wealthy and the rest, arguing it would take approximately 1,500 years for someone in the bottom 99% to produce as much carbon as a single billionaire does in a year. </p>
<h2>The great carbon divide</h2>
<p>The wealthiest 10% of humanity are responsible for half of all emissions. And the poorest 50% are responsible for just 8% – a decrease of 2% from the previous report in 2019, meaning carbon inequality has worsened over the past four years.</p>
<p>Who are these super-polluters? The richest 1% are billionaires, millionaires and people earning over US$140,000 (£110,000). The <a href="https://theconversation.com/top-1-of-eu-households-have-carbon-footprints-22-times-larger-than-climate-targets-allow-142357">threshold to join</a> the rarefied club of the top 10% is US$41,000 (£32,000), including most of the middle class in wealthier countries.</p>
<figure class="align-center ">
<img alt="Elon Musk looking directly at the camera." src="https://images.theconversation.com/files/562486/original/file-20231129-25-oglsdb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562486/original/file-20231129-25-oglsdb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562486/original/file-20231129-25-oglsdb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562486/original/file-20231129-25-oglsdb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562486/original/file-20231129-25-oglsdb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562486/original/file-20231129-25-oglsdb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562486/original/file-20231129-25-oglsdb.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">South African billionaire, Elon Musk.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/paris-france-june-16-2023-elon-2318800323">Frederic Legrand - COMEO/Shutterstock</a></span>
</figcaption>
</figure>
<p>But these figures can be misleading. They don’t really tell us what the average person in these groups earns (the average person in the top 10% earns US$90,000 per year), nor do they tell us where they live or why their emissions are so high.</p>
<p>Most of the 10% live in a <a href="https://www.iea.org/commentaries/the-world-s-top-1-of-emitters-produce-over-1000-times-more-co2-than-the-bottom-1">small number of countries</a> – Australia, Canada, the EU, US, UK, Japan, Korea, New Zealand and China. One-third of the emissions of the richest 1% come from the US, while 40% from the richest 10% come from the US and the EU. Another 20% come from individuals in China and India. </p>
<p>But as stark are the inequalities within countries. In fact, over the past 30 years, there has been a <a href="https://wid.world/wp-content/uploads/2023/01/CBV2023-ClimateInequalityReport1.pdf">major shift</a> from carbon inequality primarily being a consequence of differences in emissions between countries (62% in 1990) to differences within countries (64% in 2019). </p>
<p>The wealthiest 10% in most countries now produce five times the emissions of the average person, and vastly more than the poorest. As inequality between countries has decreased (although it is still significant), inequality within them has increased.</p>
<h2>What causes this extreme level of pollution?</h2>
<p>Being rich is essentially about having more stuff in general, including bigger houses. For the remaining 10% this also holds true. For example, if SUVs had not become widely adopted largely as a status symbol for the global middle classes, emissions from transport would have <a href="https://www.theguardian.com/environment/2023/nov/24/motor-emissions-could-have-fallen-without-suv-trend-report">fallen by 30%</a> over the past ten years. </p>
<p>For the largest class of SUVs, <a href="https://www.newscientist.com/article/2273696-most-fuel-hungry-suvs-in-the-uk-are-bought-by-people-in-cities/">six of the ten</a> areas of the UK registering the most sales were affluent London boroughs like Kensington and Chelsea. </p>
<p>A similar pattern holds for air travel. The richest people in the UK produce <a href="https://www.carbonbrief.org/richest-people-in-uk-use-more-energy-flying-than-poorest-do-overall/">more carbon emissions from air travel</a> than the poorest do through every aspect of their lives.</p>
<figure class="align-center ">
<img alt="Range Rover parked in front of apartment buildings." src="https://images.theconversation.com/files/562485/original/file-20231129-17-6r026w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562485/original/file-20231129-17-6r026w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562485/original/file-20231129-17-6r026w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562485/original/file-20231129-17-6r026w.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562485/original/file-20231129-17-6r026w.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562485/original/file-20231129-17-6r026w.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562485/original/file-20231129-17-6r026w.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">
<figcaption>
<span class="caption">SUVs have become a status symbol for the global middle classes.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/london-united-kingdom-england-january-4-2102244055">Vadi Fuoco/Shutterstock</a></span>
</figcaption>
</figure>
<p>But the super-rich are responsible for climate change well beyond consumption-based emissions. The super-rich, by and large, run major companies, direct investments and shape national and international laws. They have an oversized and controlling impact on our media and public opinion, including through advertising and ownership of media outlets. And they directly shape policy through lobbying and paid-for influence.</p>
<p>While their money and power make them overwhelmingly responsible for climate change, they are also insulated from the worst impacts. They are less affected by increased food prices and climate disasters, can afford insurance and to move from one place to another, and have greater resources to draw on in times of crisis. </p>
<p>It is the poorest – those least responsible for climate changing emissions – who <a href="https://policy-practice.oxfam.org/resources/climate-equality-a-planet-for-the-99-621551/">suffer the most</a>. They suffer higher losses, live in the most impacted regions, and have little to no access to savings, public support or welfare when crisis strikes. They are also least able to exercise their rights as they are the least powerful and less well represented politically.</p>
<h2>What can we do?</h2>
<p>There are two things we can do to address global carbon inequity. The first is to institute wealth and income taxes to reduce damaging social inequality and the carbon pollution of the super rich. </p>
<p>Oxfam’s report found that a 60% tax on the richest 1% could <a href="https://www.oxfam.org/en/press-releases/richest-1-emit-much-planet-heating-pollution-two-thirds-humanity">cut the equivalent</a> of the total emissions of the UK. We could go <a href="https://theconversation.com/why-billionaire-climate-philanthropists-will-always-be-part-of-the-problem-132383">further still</a> and introduce a progressive land and inheritance tax as well as introduce maximum wages in industries to further reduce inequality.</p>
<p>The second is to curb high-polluting forms of extreme consumption, from SUVs to short-haul air travel, as well as excessive meat and dairy consumption. For this to not be regressive, it would have to be accompanied by massive investment in public services and provisioning, as well as action on insulation and fuel poverty.</p>
<p>Ultimately it is not just the consumption of the super-rich that needs to be massively reduced. Control over major industries and sectors needs to be moved out of private hands into public ownership. An economy run for the benefit of a wealthy minority will never be socially or environmentally just. </p>
<p>In order to close the great carbon divide we must transform private excess into public control and wealth.</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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</figure>
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<p class="fine-print"><em><span>Nicholas Beuret 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>Society’s wealthiest are responsible for generating climate change – but who are these people, and why are their emissions so high?Nicholas Beuret, Lecturer in Management and Ecological Sustainability, University of EssexLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2182312023-11-23T19:04:01Z2023-11-23T19:04:01ZPollution from coal power plants contributes to far more deaths than scientists realized, study shows<figure><img src="https://images.theconversation.com/files/560874/original/file-20231121-4173-worc70.jpg?ixlib=rb-1.1.0&rect=0%2C107%2C5083%2C3435&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Kids jump on a trampoline as steam rises from a coal power plant in Adamsville, Ala., in 2021. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/kids-jump-on-a-trampoline-at-their-grandparents-home-as-news-photo/1232409457?adppopup=true"> Andrew Caballero-Reynolds/AFP via Getty Images</a></span></figcaption></figure><p>Air pollution particles from coal-fired power plants are more harmful to human health than many experts realized, and it’s <a href="https://doi.org/10.1126/science.adf4915">more than twice as likely to contribute to premature deaths</a> as air pollution particles from other sources, new research demonstrates.</p>
<p>In the study, published in the journal Science, colleagues and I mapped how U.S. coal power plant emissions traveled through the atmosphere, then linked each power plant’s emissions with death records of Americans over 65 years old on Medicare.</p>
<p>Our results suggest that air pollutants released from coal power plants were associated with nearly half a million premature deaths of elderly Americans from 1999 to 2020.</p>
<p>It’s a staggering number, but the study also has good news: Annual deaths associated with U.S. coal power plants have fallen sharply since the mid-2000s as <a href="https://theconversation.com/3-reasons-us-coal-power-is-disappearing-and-a-supreme-court-ruling-wont-save-it-187254">federal regulations compelled operators</a> to install emissions scrubbers and many utilities shut down coal plants entirely.</p>
<p>In 1999, 55,000 deaths were attributable to coal air pollution in the U.S., according to our findings. By 2020, that number had fallen to 1,600.</p>
<figure><img src="https://cdn.theconversation.com/static_files/files/2941/lucas-maps-GIF5.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=720&fit=crop&dpr=2"><figcaption> How PM2.5 levels from coal power plants in the U.S. have declined since 1999 as more plants installed pollution-control devices or shut down. Lucas Henneman.</figcaption></figure>
<p>In the U.S., coal is being displaced by natural gas and renewable energy for generating electricity. Globally, however, coal use is <a href="https://www.iea.org/reports/coal-2022">projected to increase</a> in coming years. That makes our results all the more urgent for global decision-makers to understand as they develop future policies.</p>
<h2>Coal air pollution: What makes it so bad?</h2>
<p>A landmark study in the 1990s, known as the <a href="https://www.nejm.org/doi/full/10.1056/NEJM199312093292401">Harvard Six Cities Study</a>, linked tiny airborne particles called PM2.5 to increased risk of early death. Other studies have since linked PM2.5 to <a href="https://doi.org/10.3390/nano12152656">lung and heart disease, cancer</a>, <a href="https://doi.org/10.1001/jamainternmed.2023.3300">dementia</a> and other diseases. </p>
<p>Following that research, the Environmental Protection Agency <a href="https://www.epa.gov/pm-pollution/timeline-particulate-matter-pm-national-ambient-air-quality-standards-naaqs">began regulating PM2.5 concentrations in 1997</a> and has lowered the acceptable limit over time.</p>
<p>PM2.5 – particles small enough to be inhaled deep into our lungs – comes from several different sources, including gasoline combustion in vehicles and smoke from wood fires and power plants. It is <a href="https://www.epa.gov/pm-pollution/particulate-matter-pm-basics#PM">made up of many</a> different chemicals.</p>
<p>Coal is also a mix of many chemicals – <a href="https://doi.org/10.1016/j.atmosenv.2011.04.070">carbon, hydrogen, sulfur, even metals</a>. When coal is burned, <a href="https://www.eia.gov/energyexplained/coal/coal-and-the-environment.php">all of these chemicals</a> are emitted to the atmosphere either as gases or particles. Once there, they are transported by the wind and interact with other chemicals already in the atmosphere.</p>
<p>As a result, anyone downwind of a coal plant may be breathing a complex cocktail of chemicals, each with its own potential effects on human health.</p>
<figure><img src="https://cdn.theconversation.com/static_files/files/2934/lucas-gif1.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=720&fit=crop&dpr=2"><figcaption> Two months of emissions from Plant Bowen, a coal-fired power station near Atlanta, show how wind influences the spread of air pollution. Lucas Henneman.</figcaption></figure>
<h2>Tracking coal PM2.5</h2>
<p>To understand the risks coal emissions pose to human health, we tracked how sulfur dioxide emissions from each of the 480 largest U.S. coal power plants operating at any point since 1999 traveled with the wind and turned into tiny particles – <a href="https://doi.org/10.1126/science.adf4915">coal PM2.5</a>. We used sulfur dioxide because of its known health effects and drastic decreases in emissions over the study period.</p>
<p>We then used a statistical model to link coal PM2.5 exposure to Medicare records of nearly 70 million people from 1999 to 2020. This model allowed us to calculate the number of deaths associated with coal PM2.5.</p>
<p>In our statistical model, we controlled for other pollution sources and accounted for many other known risk factors, like smoking status, local meteorology and income level. We tested multiple statistical approaches that all yielded consistent results. We compared the results of our statistical model with <a href="https://www.science.org/doi/10.1126/sciadv.aba5692">previous results</a> testing the health impacts of PM2.5 from other sources and found that PM2.5 from coal is twice as harmful as PM2.5 from all other sources.</p>
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<img alt="Two people stand outside an older brick home with power plant smokestacks in the background." src="https://images.theconversation.com/files/561153/original/file-20231122-17-wwzsob.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/561153/original/file-20231122-17-wwzsob.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=396&fit=crop&dpr=1 600w, https://images.theconversation.com/files/561153/original/file-20231122-17-wwzsob.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=396&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/561153/original/file-20231122-17-wwzsob.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=396&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/561153/original/file-20231122-17-wwzsob.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=498&fit=crop&dpr=1 754w, https://images.theconversation.com/files/561153/original/file-20231122-17-wwzsob.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=498&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/561153/original/file-20231122-17-wwzsob.jpg?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">
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<span class="caption">Residents living near the Cheswick coal-fired power plant in Springdale, Pa., publicly complained about the amount of sulfur dioxide, nitrogen oxide and coal particles from the plant for years.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/marti-blake-speaks-to-the-postman-in-front-of-the-smoke-news-photo/874051624">Robert Nickelsberg/Getty Images</a></span>
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<p>The number of deaths associated with individual power plants depended on multiple factors – how much the plant emits, which way the wind blows and how many people breathe in the pollution. Unfortunately, U.S. utilities located many of their plants upwind of major population centers on the East Coast. This siting amplified these plants’ impacts.</p>
<p>In an <a href="https://cpieatgt.github.io/cpie/">interactive online tool</a>, users can look up our estimates of annual deaths associated with each U.S. power plant and also see how those numbers have fallen over time at most U.S. coal plants.</p>
<h2>A US success story and the global future of coal</h2>
<p>Engineers have been <a href="https://doi.org/10.1002/ep.670200410">designing effective scrubbers</a> and other pollution-control devices that can reduce pollution from coal-fired power plants for several years. And the <a href="https://www.epa.gov/Cross-State-Air-Pollution/overview-cross-state-air-pollution-rule-csapr">EPA has rules</a> specifically to encourage utilities that used coal to install them, and most facilities that did not install scrubbers have shut down.</p>
<p>The results have been dramatic: Sulfur dioxide emissions <a href="https://doi.org/10.1002/ep.670200410">decreased about 90%</a> in facilities that reported installing scrubbers. Nationwide, sulfur dioxide emissions decreased 95% since 1999. According to our tally, deaths attributable to each facility that installed a scrubber or shut down decreased drastically.</p>
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<p>As advances in fracking techniques reduced the cost of natural gas, and regulations made running coal plants more expensive, <a href="https://www.worldscientific.com/doi/abs/10.1142/S2010007819500088">utilities began replacing coal with natural gas</a> plants and renewable energy. The shift to natural gas – a cleaner-burning fossil fuel than coal but still a greenhouse gas <a href="https://theconversation.com/biden-announces-a-sweeping-methane-plan-heres-why-cutting-the-greenhouse-gas-is-crucial-for-protecting-climate-and-health-168220">contributing to climate change</a> – led to even further air pollution reductions.</p>
<p>Today, coal contributes about 27% of electricity in the U.S., <a href="https://www.eia.gov/totalenergy/data/browser/index.php?tbl=T02.06#/?f=A">down from 56% in 1999</a>.</p>
<p>Globally, however, the outlook for coal is mixed. While the U.S. and other nations are headed toward a future with substantially less coal, the International Energy Agency <a href="https://www.iea.org/reports/coal-2022">expects global coal use to increase</a> through at least 2025.</p>
<p>Our study and others like it make clear that increases in coal use will harm human health and the climate. Making full use of emissions controls and a turn toward renewables are surefire ways to reduce coal’s negative impacts.</p><img src="https://counter.theconversation.com/content/218231/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lucas Henneman receives funding from the Health Effects Institute, the National Institute of Health, and the Environmental Protection Agency.</span></em></p>The longest-running study of its kind reviewed death records in the path of pollution from coal-fired power plants. The numbers are staggering − but also falling fast as US coal plants close.Lucas Henneman, Assistant Professor of Engineering, George Mason UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2151312023-11-19T13:00:27Z2023-11-19T13:00:27Z‘Forever contaminant’ road salts pose an icy dilemma: Do we protect drivers or our fresh water?<p>As winter approaches, many communities in Canada and around the world arm themselves against icy roads and sidewalks with a time-honoured ally: road salt. For decades, applying road salt has been regarded as a simple but vital tool in countering the dangers of slippery road conditions, but the downsides of its use are apparent with implications that <a href="https://doi.org/10.1007/s11270-018-4060-2">extend beyond the cold months</a>. </p>
<p>Scientists have long known that the substance which has safeguarded us through the colder months poses a threat to aquatic life and drinking water quality. But now we are finding that this chemical also <a href="https://doi.org/10.1016/j.scitotenv.2022.157336">disrupts the delicate balance of oxygen and nutrients</a> in our freshwater lakes and ponds. </p>
<p>Road salt, commonly referred to as rock salt, is a mixture primarily composed of sodium chloride (NaCl). It is used to de-ice roads and highways during winter to enhance safety by preventing the formation of ice and reducing slippery conditions. Road salt persists as an environmental contaminant due to its chemical stability and the cyclic nature of its dispersal. </p>
<p>Introduced through activities like road de-icing, salts move from roads to surface water such as streams and lakes, groundwater, remaining indefinitely in the environment without significant degradation. The continual cycling and lack of substantial transformation underscore the long-term impact of sodium chloride as a “forever contaminant.”</p>
<p>With a growing awareness of its ecological repercussions, a critical dilemma emerges. Do we prioritize driver safety or acquatic ecosystem health?</p>
<h2>Negative impacts revisited</h2>
<p>The detrimental effects of road salt on aquatic ecosystems and drinking water supplies <a href="https://doi.org/10.1016/j.scitotenv.2021.150289">have long been recognized</a>. Its heavy application during winter months leads to a buildup of road salt ions in both soil and water bodies, altering their natural chemical composition. </p>
<p>These elevated salt concentrations can harm freshwater organisms and vegetation, change soil structure, and, when <a href="https://doi.org/10.1016/j.scitotenv.2023.166466">seeping into groundwater</a>, compromise the potable water supply of nearby communities.</p>
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Read more:
<a href="https://theconversation.com/winter-road-salting-has-year-round-consequences-173621">Winter road salting has year-round consequences</a>
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<p><a href="https://doi.org/10.1016/j.scitotenv.2022.157336">Recent research</a> has shed light on a less conspicuous yet equally significant consequence of road salt usage: its contribution to oxygen depletion in lakes. The occurrence of <a href="https://doi.org/10.1029/2023JG007558">very low oxygen concentrations, or hypoxia, in a lake is generally attributed to an excessive input of nutrients, especially that of phosphorus</a>. </p>
<p>Nutrient enrichment can trigger algal blooms that, in turn, lower the oxygen level in the lake’s deeper waters. The continued expansion of hypoxic conditions deteriorates the lake’s water quality and may ultimately cause the die-off of most aquatic life. This nutrient-driven process, <a href="https://doi.org/10.5194/bg-14-3585-2017">known as eutrophication</a>, is affecting the ecological health of a growing number of lakes around the world.</p>
<h2>Salt and oxygen in water</h2>
<p><a href="https://doi.org/10.5194/egusphere-egu2020-16637">Phosphorus</a>, the nutrient frequently implicated in lake eutrophication, plays a multifaceted role in this scenario. <a href="https://doi.org/10.1016/j.scitotenv.2022.157336">Salinization</a> increases the density of the water reducing the mixing of the lake waters and. Consequently, this reduces the amount of oxygen that reaches the lake’s depths. </p>
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Read more:
<a href="https://theconversation.com/road-salt-makes-winter-driving-safer-but-what-does-it-do-to-the-environment-87860">Road salt makes winter driving safer, but what does it do to the environment?</a>
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<p>Oxygen depletion, paradoxically, favours the remobilization of phosphorus from the sediments accumulating at the bottom of the lake. That is, the sediments become an increasingly important <em>internal</em> source of phosphorus, escalating the nutrient enrichment of the lake. </p>
<p>In that way, salinization — driven by extensive road salt application — <a href="https://doi.org/10.1016/j.scitotenv.2022.157336">intensifies eutrophication symptoms</a> that are usually associated with phosphorus supplied to lakes from external sources in the surrounding landscape.</p>
<h2>Navigating the saline challenge</h2>
<p>Canada has been <a href="https://doi.org/10.1016/j.scitotenv.2021.151717">proactive in responding</a> to eutrophication. For instance, reduced phosphorus pollution in Lake Erie in the 1980s and 1990s led to significant <a href="https://doi.org/10.1029/2019WR025019">water quality improvements</a>. However, addressing accelerating salinization of lakes requires new thinking and innovative solutions that recognize the complexity of the issue. It’s not just de-icers, such as road salts, that need to be considered. </p>
<p><a href="https://doi.org/10.1098/rstb.2018.0019">Other sources of salt</a>, such as agricultural runoff, discharges from water softeners and other domestic activities and drainage from mine waste and geological salt deposits, are all part of the problem. Salinization is a <a href="https://doi.org/10.1073/pnas.1620211114">threat to water resources globally</a>, not just those of cold regions.</p>
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<figcaption><span class="caption">A brief overview of the process of eutrophication, produced by the National Oceanic and Atmospheric Administration.</span></figcaption>
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<p>Chloride, a key component of road salt, has earned the moniker of a “forever contaminant” <a href="https://doi.org/10.1016/j.scitotenv.2018.10.242">due to its persistence in soil and water systems</a>. When introduced into the environment, chloride ions readily dissolve into water <a href="https://doi.org/10.1016/j.scitotenv.2018.10.242">where they tend to remain</a>. </p>
<p>Over time, chloride not only accumulates in surface water bodies <a href="https://doi.org/10.1016/j.scitotenv.2023.166466">but also in groundwater</a>. In fact, ground (or subsurface) water has been identified as a persistent source of chloride to surface freshwater bodies, especially during the summer months. </p>
<p>While <a href="https://doi.org/10.2166/wqrjc.2011.105">proactive management practices have been introduced</a>, the accumulation of chloride and other problematic <a href="https://doi.org/10.1111/j.1747-6593.2012.00371.x">salt ions</a>, including sodium, in soil and water will require expensive and <a href="https://doi.org/10.2134/jeq2009.0108">time-consuming restoration efforts</a>. </p>
<h2>Paving the path to solutions</h2>
<p>To mitigate the impacts of salinization, evidence-based approaches are urgently required. Solutions and policy recommendations must promote the reduction of salt runoff from road salt applications and other sources, and establish effective and comprehensive monitoring programs. </p>
<p>We have much to learn from how we’ve successfully managed excessive nutrient pollution — these lessons can help inform salt management strategies that work hand in hand with water quality and climate change solutions.</p>
<p>One potential alternative to the application of road salts is to use other de-icers. This requires a cautious stance because, as history teaches us, replacing one troublesome chemical with another often comes with unexpected ecological consequences. </p>
<p>Thorough examination and research are vital to ensure that alternatives don’t inadvertently introduce new threats.</p>
<h2>Protecting people and ecosystems</h2>
<p>The stakes are high when it comes to road salts: compromised drinking water, shrinking aquatic habitats and long-term pollution from legacy salt stores in soil and groundwater requiring costly remediation. It’s imperative that research, investment and public awareness converge to address this challenge holistically. </p>
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Read more:
<a href="https://theconversation.com/to-make-less-harmful-road-salts-were-studying-natural-antifreezes-produced-by-fish-153087">To make less-harmful road salts, we're studying natural antifreezes produced by fish</a>
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<p>The impacts of road salt’s application extend far beyond the icy surfaces it’s intended to protect us from. As winter approaches, policy should work towards protecting our ecosystems and the many services they provide.</p><img src="https://counter.theconversation.com/content/215131/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jovana received support from the Natural Sciences and Engineering Research Council of Canada (NSERC) Strategic Partnerships Grant (STPGP 521515-18), and the Lake Futures project and Managing Urban Eutrophication Risks under Climate Change project within the Global Water Futures (GWF) program funded by the Canada First Research Excellence Fund (CFREF).</span></em></p><p class="fine-print"><em><span>David L Rudolph receives funding from the Natural Sciences and Engineering Research Council of Canada, the Ontario Ministry of the Environment, Conservation and Parks and the Regional Municipality of Waterloo. </span></em></p><p class="fine-print"><em><span>Fereidoun received support from the Natural Sciences and Engineering Research Council of Canada (NSERC) Strategic Partnerships Grant (STPGP 521515-18), and the Lake Futures project and Managing Urban Eutrophication Risks under Climate Change project within the Global Water Futures (GWF) program funded by the Canada First Research Excellence Fund (CFREF).</span></em></p><p class="fine-print"><em><span>Nancy received support from the Natural Sciences and Engineering Research Council of Canada (NSERC) Strategic Partnerships Grant (STPGP 521515-18), and the Lake Futures project and Managing Urban Eutrophication Risks under Climate Change project within the Global Water Futures (GWF) program funded by the Canada First Research Excellence Fund (CFREF).</span></em></p><p class="fine-print"><em><span>Philippe received support from the Natural Sciences and Engineering Research Council of Canada (NSERC) Strategic Partnerships Grant (STPGP 521515-18), and the Lake Futures project and Managing Urban Eutrophication Risks under Climate Change project within the Global Water Futures (GWF) program funded by the Canada First Research Excellence Fund (CFREF).</span></em></p><p class="fine-print"><em><span>Jiangyue Ju 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>Increasing awareness of the dangers ‘forever chemical’ road salts pose to our fresh water systems highlights the urgent importance of finding new approaches to de-icing our roads.Jovana Radosavljevic, Postdoctoral Fellow, Ecohydrology Research Group, University of WaterlooDavid L Rudolph, Professor of Hydrogeology, Department of Earth & Environmental Sciences, University of WaterlooFereidoun Rezanezhad, Research Associate Professor, Department of Earth & Environmental Sciences, University of WaterlooJiangyue Ju, PhD Student in Earth and Environmental Sciences, University of WaterlooNancy Goucher, Knowledge Mobilization Specialist, University of WaterlooPhilippe Van Cappellen, Professor of Biogeochemistry and Canada Excellence Research Chair Laureate in Ecohydrology, University of WaterlooLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2169872023-11-13T23:07:59Z2023-11-13T23:07:59ZConflict pollution, washed-up landmines and military emissions – here’s how war trashes the environment<p>When armed conflict breaks out, we first focus on the people affected. But the suffering from war doesn’t stop when the fighting does. War <a href="https://www.un.org/en/observances/environment-in-war-protection-day">trashes the environment</a>. Artillery strikes, rockets and landmines release pollutants, wipe out forests and can make farmland unusable. </p>
<p>One in six people around the world have been <a href="https://acleddata.com/2023/09/08/acled-conflict-index-2023-mid-year-update">exposed to conflict</a> this year, from civil war in Sudan to Russia’s war in Ukraine to the Israel-Hamas war. </p>
<p>War has returned. Conflicts are at their <a href="https://press.un.org/en/2022/sgsm21216.doc.htm">highest point</a> since the second world war. Deaths are at a <a href="https://reliefweb.int/report/world/conflict-trends-global-overview-1946-2022">28-year high</a>. As we grapple with the immediate plight of people, we must not lose sight of what war leaves behind – the silent casualty of the environment. </p>
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Read more:
<a href="https://theconversation.com/the-environmental-impact-of-russias-invasion-goes-beyond-ukraine-how-do-we-deal-with-problems-without-passports-202505">The environmental impact of Russia’s invasion goes beyond Ukraine – how do we deal with ‘problems without passports’?</a>
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<h2>What damage does war do?</h2>
<p>Armed conflict leaves a long trail of environmental damage, which in turn can worsen our health and that of other species. </p>
<p>Chemical weapons and pollution from weapons stay in the environment as a <a href="https://theconversation.com/war-leaves-a-toxic-legacy-that-lasts-long-after-the-guns-go-quiet-can-we-stop-it-197051">toxic legacy</a>. Explosives release pollutants such as <a href="https://www.sciencedirect.com/science/article/pii/S0265931X02000413?via%3Dihub">depleted uranium</a> into soil, while landscapes can be destroyed by troop movement and the breakdown of infrastructure. </p>
<p>The damage can last far longer than you’d think. The bloody WWI Battle of Verdun in France left the once-fertile farmland contaminated. Over a century later, no one can live in the <a href="https://education.nationalgeographic.org/resource/red-zone/">Red Zone</a> due to the threat from unexploded bombs. </p>
<p>As the Russia-Ukraine war wears on, severe air pollution, deforestation and soil degradation <a href="https://www.sciencedirect.com/science/article/pii/S004896972202962X?via%3Dihub">have mounted</a>. </p>
<p>Conflict also causes habitat loss and decreased biodiversity. Between 1946 and 2010, wildlife <a href="https://www.nature.com/articles/nature25194">noticeably declined</a> in African nations affected by armed conflict. </p>
<p>Landmines are particularly bad, as they are designed to remain in place until stepped on. Long after a war ends, they can still kill people or animals. Landmines also cause degradation and limit access to safe land, which can then become over-exploited. Landmines have been unearthed by flood waters <a href="https://reliefweb.int/report/libya/libya-flood-update-flash-update-no3-16-september-2023-5pm-local-time">in Libya</a>, <a href="https://www.reuters.com/world/europe/mines-uprooted-ukraine-dam-disaster-could-pose-danger-years-come-red-cross-2023-06-08/">Ukraine</a>, <a href="https://www.arabnews.com/node/1857786/middle-east">Lebanon</a> and <a href="https://reliefweb.int/report/bosnia-and-herzegovina/undp-flooding-unearths-landmine-danger">Bosnia Herzegovina</a>. </p>
<p>Many explosive weapons are designed to withstand short periods of intense heat. But when high temperatures linger, unexploded bombs can detonate. As the world heats up, we may see more explosions – not just from remnant bombs, but from munitions dumps. </p>
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Read more:
<a href="https://theconversation.com/the-war-on-tigray-wiped-out-decades-of-environmental-progress-how-to-start-again-201062">The war on Tigray wiped out decades of environmental progress: how to start again</a>
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<p>In the <a href="https://www.nytimes.com/2023/07/29/world/middleeast/iraq-water-crisis-desertification.html">fast-heating</a> Middle East, this is already happening. In Iraq, six arms depots <a href="https://www.scientificamerican.com/article/climate-change-may-be-blowing-up-arms-depots">exploded</a> during intense heatwaves between 2018 and 2019. In Jordan, heatwaves <a href="https://www.abc.net.au/news/2020-09-12/explosions-rock-military-facility-in-jordan-army-blames-heat/12657276">have been blamed</a> for a similar arms dump explosion in 2020. </p>
<p>At war’s end, weapons are often dumped in the ocean. From the first world war until the 1970s, out of date munitions and chemical weapons in the <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/663876/Future_of_the_sea_-_non_plastic_pollution.pdf">United Kingdom</a> were dumped into the sea. It may have seemed like an easy solution, but the bombs haven’t gone away. Over 1 million tonnes of munitions litter the floor of a natural ocean trench between Northern Ireland and Scotland. These sometimes detonate underwater, while chemical weapons have washed up on beaches. </p>
<p>During the second world war, intense fighting took place on the Solomon Islands. Even today, people die or are wounded every year when uncovered bombs <a href="https://pulitzercenter.org/stories/whats-next-solomon-islands-experts-say-uxo-problem-shocking">go off</a>. Fishers have to be wary of underwater bombs. </p>
<p>Environmental exploitation such as illegal logging or diamond mining <a href="https://documents1.worldbank.org/curated/en/099520010272224660/pdf/P1771510b38fda01e0afec01edd810d8cde.pdf">can accelerate during wartime</a>, with profits used to buy weapons to fuel more fighting. At least 40% of civil war and internal conflicts between 1946–2006 were tied to natural resources such as <a href="https://www.indiatimes.com/explainers/news/explained-why-teak-imported-from-myanmar-is-called-conflict-wood-595202.html">teak</a> and gold, according to the <a href="https://wedocs.unep.org/handle/20.500.11822/7867">United Nations</a>. </p>
<p>Sometimes, natural resources can become targets, as in the <a href="https://landsat.visibleearth.nasa.gov/view.php?id=78594">deliberate firing of oil wells</a> in Kuwait or destruction of Ukraine’s <a href="https://theconversation.com/ukraine-war-what-we-know-about-the-nova-kakhovka-dam-and-who-gains-from-its-destruction-207130">Kakhovka Dam</a>. These scorched-earth tactics do untold damage to the environment. </p>
<h2>How do war and climate change interact?</h2>
<p>The long-running war in Sudan’s Darfur region has been dubbed the world’s first <a href="https://www.theguardian.com/world/2019/dec/18/how-water-is-helping-to-end-the-first-climate-change-war#:%7E:text=The%20Darfur%20conflict%20was%20labelled,shown%20that%20climate%20impacts%20such">climate change war</a> due to its origins in drought and ecological crisis. While it’s difficult to clearly draw a link between the changing climate and an armed conflict, climate change is at minimum an indirect driver of armed conflict and can exacerbate existing social, economical and environmental factors. In turn, conflict worsens the damage done by climate change as it limits people’s ability to respond or cope with climate shocks. </p>
<p>Wars and extreme weather can both force people from their homes. At the end of last year, the number of people forced to <a href="https://www.internal-displacement.org/global-report/grid2023">seek refuge elsewhere</a> in their own country was at an all time high. When people are forced to move, the disruption can add <a href="https://www.unep.org/news-and-stories/story/displacement-and-environment-africa-what-relationship#:%7E:text=Displacement%20itself%20can%20have%20environmental,lead%20to%20uncontrolled%20waste%20disposal">extra environmental damage</a> through plastic and other types of waste. </p>
<p>When wars are raging, they take priority for governments. That, in turn, can limit efforts to reduce emissions or adapt to climate change. </p>
<p>That can make disasters worse. Colombia’s deadly <a href="https://odi.org/en/about/features/when-disasters-and-conflict-collide/">2017 landslide</a> killed over 300 people. Why was it so deadly? In part, because many people had fled to the affected town, Mocoa, to avoid war and had built makeshift houses with no protection against disasters. We also know deaths from disasters <a href="https://www.sciencedirect.com/science/article/pii/S2212420923003618?via%3Dihub">increase</a> in nations riven by armed conflict. </p>
<p>The world’s military forces are intense users of fossil fuels, accounting for <a href="https://ceobs.org/wp-content/uploads/2022/11/SGRCEOBS-Estimating_Global_MIlitary_GHG_Emissions_Nov22_rev.pdf">5.5% of global emissions</a>. If we took the world’s military forces as one country, they would be the fourth highest emitter, after China, America and India.</p>
<p>We can no longer ignore the devastating coupling between war and environmental damage, including climate change. Wars make our ability to adapt to climate change worse, and environmental damage from conflict will exacerbate climate change.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/war-leaves-a-toxic-legacy-that-lasts-long-after-the-guns-go-quiet-can-we-stop-it-197051">War leaves a toxic legacy that lasts long after the guns go quiet. Can we stop it?</a>
</strong>
</em>
</p>
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<img src="https://counter.theconversation.com/content/216987/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>Wars are multiplying – and the damage these conflicts do isn’t just immediate. They leave long-term environmental damageStacey Pizzino, PhD Candidate, The University of QueenslandJo Durham, Senior Lecturer in Disaster Risk Management and Health, Queensland University of TechnologyMichael Waller, Senior Lecturer Biostatistics, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2133262023-11-07T13:38:21Z2023-11-07T13:38:21ZEngineered ‘living materials’ could help clean up water pollution one day<figure><img src="https://images.theconversation.com/files/556959/original/file-20231031-27-mncpgs.jpg?ixlib=rb-1.1.0&rect=18%2C0%2C2048%2C1358&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Researchers at the University of California, San Diego have developed a new 'living' material.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/jsoe/53172954946/in/album-72177720311058323/">David Baillot/UC San Diego Jacobs School of Engineering</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>Water pollution is a growing concern globally, with <a href="https://doi.org/10.1016/j.oneear.2022.01.005">research estimating</a> that chemical industries discharge <a href="https://cleanwaterinternational.org/water-pollution-everything-we-need-to-know/amp/">300-400 megatonnes</a> (600-800 billion pounds) of industrial waste into bodies of water each year. </p>
<p>As a <a href="https://www.pokorskilab.com/">team of materials scientists</a>, we’re working on an engineered “living material” that may be able to transform chemical dye pollutants from the <a href="https://www.cnn.com/2023/04/21/middleeast/textile-wastewater-pollutant-cleaner-hnk-scn-spc-intl/index.html">textile industry</a> into harmless substances.</p>
<p><a href="https://www.safewater.org/fact-sheets-1/2017/1/23/industrial-waste">Water pollution</a> is both an environmental and humanitarian issue that can affect ecosystems and human health alike. We’re hopeful that the materials we’re developing could be one tool available to help combat this problem.</p>
<h2>Engineering a living material</h2>
<p>The “<a href="https://www.nature.com/collections/fhcabedjaa">engineered living material</a>” our team has been working on <a href="https://my.clevelandclinic.org/health/articles/24494-bacteria">contains programmed bacteria</a> embedded in a soft hydrogel material. We first published a paper showing the potential effectiveness of this material in <a href="https://doi.org/10.1038/s41467-023-40265-2">Nature Communications</a> in August 2023.</p>
<p><a href="https://www.snexplores.org/article/explainer-what-is-a-hydrogel">The hydrogel</a> that forms the base of the material has similar properties to Jell-O – it’s soft and made mostly of water. Our particular hydrogel is made from a natural and biodegradable <a href="https://dalchem.com.au/how-to/what-is-alginate/">seaweed-based polymer called alginate</a>, an ingredient common <a href="https://kitchen-theory.com/sodium-alginate-spherification/">in some foods</a>.</p>
<p>The alginate hydrogel provides a solid physical support for bacterial cells, similar to how <a href="https://theconversation.com/mapping-the-100-trillion-cells-that-make-up-your-body-103078">tissues support cells</a> in the human body. We intentionally chose this material so that the bacteria we embedded could grow and flourish. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A green polymer, arranged in a square with a 5 by 5 grid of smaller squares, sits on a clear surface." src="https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556960/original/file-20231031-15-o1t0v7.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 grid shape of the material helps the bacteria take in carbon dioxide.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/jsoe/53173442373/in/album-72177720311058323/">David Baillot/UC San Diego Jacobs School of Engineering</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>We picked the seaweed-based alginate as the material base because it’s porous and can retain water. It also allows the <a href="https://www.microscopemaster.com/photosynthetic-bacteria.html">bacterial cells</a> to take in nutrients from the surrounding environment.</p>
<p>After we prepared the hydrogel, we embedded photosynthetic – or sunlight-capturing – bacteria called <a href="https://www.britannica.com/science/blue-green-algae">cyanobacteria</a> into the gel.</p>
<p>The cyanobacteria embedded in the material still needed to take in light and carbon dioxide <a href="https://education.nationalgeographic.org/resource/photosynthesis/">to perform photosynthesis</a>, which keeps them alive. The hydrogel was porous enough to allow that, but to make the configuration as efficient as possible, we <a href="https://www.cellink.com/3d-bioprinting/">3D-printed</a> the gel into custom shapes – grids and honeycombs. These structures have a higher surface-to-volume ratio that allow more light, CO₂ and nutrients to come into the material. </p>
<p>The cells were happy in that geometry. We observed higher cell growth and density over time in the alginate gels in the grid or honeycomb structures when compared with the default disc shape.</p>
<h2>Cleaning up dye</h2>
<p>Like all other bacteria, cyanobacteria has different <a href="https://www.ibiology.org/bioengineering/genetic-circuits/">genetic circuits</a>, which tell the cells what outputs to produce. Our team <a href="https://www.britannica.com/science/genetic-engineering/Process-and-techniques">genetically engineered</a> the bacterial <a href="https://www.newscientist.com/definition/dna/">DNA</a> so that the cells created a specific enzyme <a href="https://en.wikipedia.org/wiki/Laccase">called laccase</a>. </p>
<p>The laccase enzyme produced by the cyanobacteria works by performing a chemical reaction with a pollutant that transforms it into a form that’s no longer functional. By breaking the chemical bonds, it can make a toxic pollutant nontoxic. The enzyme is regenerated at the end of the reaction, and it goes off to complete more reactions. </p>
<p>Once we’d embedded these laccase-creating cyanobacteria into the alginate hydrogel, we put them in a solution made up of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10532910/">industrial dye pollutant</a> to see if they could clean up the dye. In this test, we wanted to see if our material could change the structure of the dye so that it went from being colored to uncolored. But, in other cases, the material could potentially change a chemical structure to go from toxic to nontoxic. </p>
<p>The dye we used, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10532910/">indigo carmine</a>, is a common industrial wastewater pollutant usually found in the water near textile plants – it’s the main pigment in blue jeans. We found that our material took all the color out of the bulk of the dye over about 10 days.</p>
<p>This is good news, but we wanted to make sure that our material wasn’t adding waste to polluted water by leaching bacterial cells. So, we also engineered the bacteria to produce a protein that could damage the cell membrane of the bacteria – a programmable kill switch. </p>
<p>The genetic circuit was programmed to respond to a harmless chemical, called <a href="https://academic.oup.com/pcp/article/54/10/1724/1908151">theophylline</a>, commonly found in caffeine, tea and chocolate. By adding theophylline, we could destroy bacterial cells at will. </p>
<p>The field of engineered living materials is still developing, but this just means there are plenty of opportunities to develop new materials with both living and nonliving components.</p><img src="https://counter.theconversation.com/content/213326/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jonathan K. Pokorski receives funding from the National Science Foundation and Department of Energy.</span></em></p><p class="fine-print"><em><span>Debika Datta 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>‘Living materials’ made with genetically engineered bacteria and Jell-O-like gel could make pollutants in water bodies nontoxic.Jonathan K. Pokorski, Professor of Nanoengineering, University of California, San DiegoDebika Datta, Postdoctoral Scholar in Nanoengineering, University of California, San DiegoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2145982023-10-30T16:16:45Z2023-10-30T16:16:45ZNiger delta is rich in resources, but environmental destruction is pushing people into poverty<p>Nigeria’s Niger Delta region is rich in natural resources. Its <a href="https://www.researchgate.net/publication/284727294_Review_of_Ecological_Effects_of_Oil_Exploration_in_the_Niger-Delta_Nigeria">vast oil and gas deposits</a> are the mainstay of the country’s economy. </p>
<p>The region, in the southernmost part of the country, features coastal barrier islands, mangroves, freshwater swamp forests and lowland rain forests. The coast offers various ways of making a living, like fishing, tourism, producing salt, and farming coconut and bananas. </p>
<p>Yet it is estimated that over 47% of the population in the region <a href="https://beamexchange.org/uploads/filer_public/73/ff/73ffbabd-2447-4924-8a85-0a43f6f266dc/made-nigeria-poverty-assessment-report-final_compressed.pdf#page=4">lives</a> below the poverty line. </p>
<p>We study the economic aspects of environmental issues, and in a recent <a href="https://www.researchgate.net/profile/Otekenari-Elisha/publication/353741948_DESTRUCTION_OF_COASTAL_ECOSYSTEMS_AND_THE_VICIOUS_CYCLE_OF_POVERTY_IN_NIGER_DELTA_REGION/links/610d9423169a1a0103e569f4/DESTRUCTION-OF-COASTAL-ECOSYSTEMS-AND-THE-VICIOUS-CYCLE-OF-POVERTY-IN-NIGER-DELTA-REGION.pdf">paper</a> set out to understand the relationship between the destruction of coastal ecosystems in this region and the economic hardship the people faced.</p>
<p>We found that marine ecosystems had been badly affected by a number of factors, including an increasing population, pollution, over-fishing, damaging fishing techniques and global warming.</p>
<p>The degradation of the environment affects the poor the most as they depend on natural resources like seafood and wood for survival and energy. And they do not earn enough to relocate from polluted areas. </p>
<h2>The destruction of an ecosystem</h2>
<p>We identified a few areas where the Niger Delta ecosystem had been badly affected. The environmental problems in communities like Bille, Andoni, Okirika, Emohua and Ibaa in Rivers State are caused by oil spills, gas flaring, human activities and water pollution, among others. </p>
<p>Between 1976 and 2006, there were at least <a href="http://large.stanford.edu/courses/2017/ph240/nwagbo1/">7,000 oil spills</a> in the region, affecting an area of more than 2,500 square kilometres. These oil spills have polluted the soil, water and air, and they have had a <a href="https://www.aljazeera.com/features/2022/9/9/niger-delta-oil-spills-bring-poverty-low-crop-yields-to-farmers">devastating impact</a> on the people who live in the region. The destruction of the ecosystem has led to environmental problems like flooding and soil erosion, which destroys homes and crops, leading to further poverty. The lack of a healthy ecosystem has led to <a href="https://www.sciencedirect.com/science/article/abs/pii/S0013935121000190#:%7E:text=Lung%20and%20skin%20cancers%20are,et%20al.%2C%202015">health problems</a> for the people living in the region. </p>
<p>Gas flaring is the process of burning off excess natural gas that is produced during oil drilling. More than 2.5 billion cubic feet of natural gas are <a href="https://www.amisdelaterre.org/wp-content/uploads/2019/10/gas-flaring-nigeria.pdf#page=4">flared</a> every day in the Niger Delta. This process <a href="https://www.iea.org/energy-system/fossil-fuels/gas-flaring">emits greenhouse gases</a> and other pollutants into the atmosphere, and it also wastes a valuable resource that could be used to generate electricity or heat homes.</p>
<p>Mangroves are being lost <a href="https://www.researchgate.net/profile/Otekenari-Elisha/publication/366371709_Asian_Journal_of_Current_Research_COMMUNITY-BASED_INTERVENTION_IN_THE_CONTROL_OF_ARTISANAL_REFINING_AGAINST_THE_ENVIRONMENT_IN_NIGER_DELTA_REGION_NIGERIA/links/639d793e095a6a77743755d0/Asian-Journal-of-Current-Research-COMMUNITY-BASED-INTERVENTION-IN-THE-CONTROL-OF-ARTISANAL-REFINING-AGAINST-THE-ENVIRONMENT-IN-NIGER-DELTA-REGION-NIGERIA.pdf#page=8">because of water pollution</a>. Mangrove forests are an important source of food and income for local communities, and their loss has led to a decline in fish stocks and other marine resources. This has damaged the livelihoods of fishers and increased the price of fish in local markets. </p>
<p>The environmental consequences of the destruction of mangroves include erosion and increased vulnerability to storms and flooding.</p>
<p>Natural resources such as nutrient-rich soil, water, trees and fossil fuels abound in marine ecosystems. Excessive exploitation of these resources through mining, logging and oil drilling has had a negative impact.</p>
<p>Animals in an ecosystem keep the food chain in balance. Due to overfishing and hunting, many animals are disappearing from the Niger Delta. Manatees, sea turtles, dolphins, monkeys, antelope and others are under threat. </p>
<p>The destruction of the ecosystem in the Niger Delta has led to a cycle of poverty:</p>
<ul>
<li><p>depletion of resources means people can’t make a living</p></li>
<li><p>environmental problems like flooding and soil erosion destroy homes and crops</p></li>
<li><p>human health depends on a healthy ecosystem.</p></li>
</ul>
<p>There is <a href="https://www.es.amnesty.org/fileadmin/noticias/Niger_Delta_Campaign_Digest_01.pdf">evidence</a> that destruction of the ecosystem has led to poverty in the Niger Delta region. Increasing soil sterility and diminishing agricultural output have <a href="https://www.researchgate.net/profile/Otekenari-Elisha/publication/353741948_DESTRUCTION_OF_COASTAL_ECOSYSTEMS_AND_THE_VICIOUS_CYCLE_OF_POVERTY_IN_NIGER_DELTA_REGION/links/610d9423169a1a0103e569f4/DESTRUCTION-OF-COASTAL-ECOSYSTEMS-AND-THE-VICIOUS-CYCLE-OF-POVERTY-IN-NIGER-DELTA-REGION.pdf#page=10">forced</a> farmers to move or seek illicit sources of living. The degradation of traditional fishing grounds has worsened hunger and poverty in fishing communities.</p>
<h2>Protecting and restoring ecosystems</h2>
<p>The impact of environmental degradation will only worsen if nothing is done to protect and restore degraded ecosystems.</p>
<p>In our paper we made the following suggestions.</p>
<ul>
<li><p>Regulate human activities: Fishing and hunting in the region should be controlled to prevent the depletion of fish and wildlife. Industrial activities, such as oil drilling and shipping, should also be regulated to prevent further pollution of the air, water and soil.</p></li>
<li><p>Restore degraded ecosystems: Mangrove forests can be replanted in areas where they have been destroyed. Another example is restoring wildlife populations through captive breeding programmes and releasing animals back into their natural habitats.</p></li>
<li><p>Build the capacity of local communities to manage their natural resources: This is essential for the long-term protection of the region. One example is providing training to community members on sustainable fishing and hunting practices. Another example is giving local communities a say in how their natural resources are managed.</p></li>
<li><p>Establish marine protected areas: This would help to conserve marine life and ensure that coastal communities can continue to benefit from the resources they depend on. One example is the Calabar-Oron Marine Protected Area in Cross River and Akwa Ibom states. It is home to a variety of marine life, including dolphins, turtles and whales. The area is used for sustainable fishing, ecotourism and research.</p></li>
</ul>
<p>We also recommend steps to address the root causes of poverty and inequality.</p>
<ul>
<li><p>Provide access to quality education and healthcare: Education can help to create greater awareness about environmental issues, and lead to economic opportunities. Availability of these social services could reduce the appeal of rebel groups that promise economic and social benefits.</p></li>
<li><p>Address marginalisation: Groups like women and ethnic minorities can be given equal access to resources and opportunities through inclusive decision-making at the local, state and national levels. Development programmes should target their specific needs. </p></li>
</ul>
<p>Finally, renewed efforts should be made to address conflict and insecurity in the Niger Delta by strengthening governance and the rule of law. Improved governance can lead to stronger enforcement of environmental laws and regulations, which can protect ecosystems from further degradation. In addition, it can protect land rights and create a more stable environment that offers economic opportunities.</p><img src="https://counter.theconversation.com/content/214598/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Otekenari David Elisha 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>Environmental degradation of Nigeria’s Niger Delta region is causing poverty as well as food insecurity, increased crime and conflict.Otekenari David Elisha, Environmental Economist, Ignatius Ajuru University of Education Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2163242023-10-25T21:10:59Z2023-10-25T21:10:59ZToxic diets: Canadian orcas face high risks of pollution-related health effects<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/toxic-diets-canadian-orcas-face-high-risks-of-pollution-related-health-effects" width="100%" height="400"></iframe>
<p>Killer whales, also called orcas, are known for their intelligence and striking presence. They are also enduring a silent but persistent threat beneath the surface of our oceans. </p>
<p>My research investigates killer whales and their diets in the North Atlantic. Previous studies have focused on killer whales in the Pacific Ocean. But until now, no data existed for our killer whales in the North Atlantic, including those in Eastern Canada and the Canadian Arctic. </p>
<p>With other international researchers, I recently published a study in <em>Environmental Science & Technology</em> that reveals a troubling reality: these apex predators are carrying high levels of persistent organic pollutants (POPs) in their blubber. The accumulation of these synthetic contaminants is also <a href="https://doi.org/10.1021/acs.est.3c05516">creating health risks for the killer whales</a>.</p>
<h2>Forever chemicals</h2>
<p>POPs are also known as “forever chemicals” due to their remarkable stability and long-lasting nature. This group includes well-known compounds like <a href="https://www.canada.ca/en/health-canada/services/healthy-living/your-health/environment/pcbs.html">polychlorinated biphenyls (PCBs)</a>, chlorinated pesticides like <a href="https://www.canada.ca/en/environment-climate-change/services/management-toxic-substances/list-canadian-environmental-protection-act/dichlorodiphenyltrichloroethane.html">dichlorodiphenyltrichloroethane (DDT)</a> and <a href="https://www.canada.ca/en/health-canada/services/chemical-substances/fact-sheets/chemicals-glance/polybrominated-diphenyl-ethers-public-summary.html">brominated flame retardants</a>.</p>
<p>In the last century, these chemicals were mass produced and used in a wide range of applications, such as industrial processes or agriculture. But research conducted in Sweden in the late 1960s revealed that <a href="https://doi.org/10.1038/224247a0">these chemicals accumulate in living organisms and persist in the environment</a>. </p>
<p>The chemicals bind to fats and increase in concentration as they move up the food web, impacting dolphins and whales the most. These animals, being top predators, accumulate the largest concentrations and struggle to eliminate these chemicals. This buildup of contaminants through their diets — <a href="https://www.sciencedirect.com/topics/chemistry/biomagnification">known as biomagnification</a> — is especially concerning for marine mammals, as they need ample fat for warmth and energy. </p>
<p>At high concentrations, these chemicals disrupt the mammals’ <a href="https://doi.org/10.1016/j.envint.2015.10.007">immune</a> and <a href="https://doi.org/10.1016/j.envint.2020.105725">hormonal systems</a> but also affect their <a href="https://www.jstor.org/stable/4312230">ability to reproduce</a>, and can even <a href="https://doi.org/10.1016/j.envint.2018.05.020">lead to cancer</a>.</p>
<h2>A gradient of contamination</h2>
<p>Our study, focusing on 160 killer whales, reveals a concerning pattern of PCB contamination accross the North Atlantic. The concentrations <a href="https://doi.org/10.1021/acs.est.3c05516">vary significantly across the North Atlantic</a>, ranging from a staggering 100 mg/kg in the Western North Atlantic, to around 50 mg/kg in the mid-North Atlantic. Intriguingly, killer whales in the Eastern North Atlantic carry lower PCB levels at roughly 10 mg/kg in Norway. </p>
<p>For context, PCB-related immune effects start at 10mg/kg, while reproductive failure <a href="https://www.jstor.org/stable/4312230">was observed at 41 mg/kg</a> in marine mammals. Killer whales in Eastern Canada and the Canadian Arctic have PCB levels exceeding twice the threshold linked to reproductive problems in marine mammals.</p>
<h2>You are what you eat</h2>
<p>Diet plays a pivotal role in this pattern of contamination. Killer whales that primarily feed on fish tend to have lower contaminant levels. On the other hand, those with diets focused on marine mammals, particularly seals and toothed whales, show higher levels of contaminants. </p>
<p>Killer whales with mixed diets — containing both fish and marine mammals — tend to display elevated contaminant levels, particularly in Iceland. </p>
<p>Our research investigates the potential impact of diet preferences on killer whale health. Risk assessments suggest that killer whales in the Western North Atlantic, and specific areas of the Eastern North Atlantic where they have mixed diets, face higher risks, directly linked to what they eat.</p>
<p>Among the emerging contaminants, <a href="https://www.canada.ca/en/health-canada/services/chemical-substances/other-chemical-substances-interest/hexabromocyclododecane.html">hexabromocyclododecane (HBCDD)</a>, a flame retardant, is of particular concern. Concentrations of HBCDD in North Atlantic killer whales are among the highest measured in any marine mammals, surpassing levels found in their North Pacific counterparts.</p>
<h2>Disappearing sea ice</h2>
<p>This reveals the fascinating complexity of killer whale ecology and underscores how their dietary choices significantly impact their exposure to environmental pollutants. </p>
<p>It also raises some concern for <a href="https://doi.org/10.1007/978-90-481-9121-5_6">“Arctic-invading” killer whales</a> that progressively move north due to climate change. Killer whales’ large dorsal fin has traditionally prevented them from navigating dense sea ice. But the melting of sea ice has allowed killer whales to access a new habitat with new prey species.</p>
<p>There, researchers believe that they will hunt more and more marine mammals, like ringed seals, narwhals and belugas. These dietary shifts, influenced by our changing environment, may result in heightened health risks for apex predators.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/analyzing-the-fat-of-killer-whales-reveals-what-they-eat-203497">Analyzing the fat of killer whales reveals what they eat</a>
</strong>
</em>
</p>
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<h2>Maternal transfer means females are less contaminated</h2>
<p>The study also spotlights a sex difference in contaminant concentrations. Male killer whales appear to be more contaminated than their female counterparts, thanks to the <a href="https://doi.org/10.1002/etc.5064">transfer of contaminants</a> from adult females to their offspring during gestation and lactation. </p>
<p>Killer whale mothers use their own energy to produce fatty milk for their calves, helping them grow quickly and stay healthy. This nutritious milk comes from the mother’s blubber, where contaminants are stored. As she feeds her young ones, she may pass on as much as 70 per cent of these stored contaminants.</p>
<h2>Urgent action</h2>
<p>In response to these findings, urgent action is needed to protect North Atlantic killer whales and their ecosystems. <a href="https://chm.pops.int/Home/tabid/2121/Default.aspx">The 2001 United Nations treaty</a>’s objective to phase out and destroy PCBs by 2028 is slipping out of reach. </p>
<p>Substantial quantities of PCB-contaminated waste <a href="https://doi.org/10.1021/acs.est.2c01204">are stored in deteriorating warehouses</a>, risking contaminants ending up in the environment, and further affecting our ecosystems. To compound the issue, as one chemical gets banned, another often emerges, with enough variations to avoid previous regulations, perpetuating a harmful cycle.</p>
<p>To effectively tackle the issue of contaminant accumulation in killer whales, the following actions are necessary:</p>
<ul>
<li>Urgent steps are needed for the proper disposal of PCB-contaminated waste, with an emphasis on international collaboration to support nations lacking the infrastructure for waste management.</li>
<li>It is crucial to prevent the release of potentially more harmful contaminants into the environment by improving toxicity testing of chemicals before they enter the market.</li>
<li>Collaboration among ecotoxicologists, conservation biologists, policymakers and other stakeholders is essential. Effective strategies to mitigate pollution’s adverse effects can only be developed through collective efforts.</li>
<li>Targeted conservation efforts should be directed toward populations at higher risk, such as killer whales in the Eastern Canadian Arctic, and Eastern Canada.</li>
</ul>
<p>Chemical pollution has been identified as <a href="https://doi.org/10.1126/science.1259855">one of the nine global threats to wildlife, as well as human health in modern times</a>. It is time to give our planet — and killer whales — the relief they need by reducing existing contaminants through concrete actions.</p><img src="https://counter.theconversation.com/content/216324/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anaïs Remili 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>The accumulation of synthetic pollutants found in the blubber of killer whales is impacting the marine mammals’ health. Urgent action is needed to tackle the issue.Anaïs Remili, Postdoctoral fellow, Wildlife Ecotoxicology, McGill UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2156522023-10-19T19:24:01Z2023-10-19T19:24:01ZNew class of recyclable polymer materials could one day help reduce single-use plastic waste<figure><img src="https://images.theconversation.com/files/554111/original/file-20231016-23-gcf4fp.jpg?ixlib=rb-1.1.0&rect=79%2C3%2C2038%2C1397&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Single-use plastics. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/various-types-of-plastic-trash-on-the-grass-plastic-royalty-free-image/1325351577?phrase=plastic&adppopup=true">Anton Petrus/Moment</a></span></figcaption></figure><p><a href="https://www.unep.org/interactives/beat-plastic-pollution/">Hundreds of millions of tons</a> of single-use plastic ends up in landfills every year, and even the small percentage of plastic that gets recycled can’t last forever. But our group of materials scientists has developed a new method for creating and deconstructing polymers that could lead to more easily recycled plastics – ones that don’t require you to carefully sort out all your recycling on trash day. </p>
<p>In the century since their conception, people have come to understand the enormous impacts – beneficial as well as detrimental – plastics have on human lives and the environment. As a <a href="https://miyakelab.colostate.edu/">group of polymer scientists</a> dedicated to inventing sustainable solutions for real-world problems, we set out to tackle this issue by rethinking the way polymers are designed and making plastics with recyclability built right in. </p>
<h2>Why use plastics, anyway?</h2>
<p>Everyday items including milk jugs, grocery bags, takeout containers and even ropes are made from a class of <a href="https://www.polymersolutions.com/blog/top-types-of-polyolefins-the-most-common-kind-of-plastics/">polymers called polyolefins</a>. Polyolefins make up around <a href="https://ourworldindata.org/grapher/plastic-waste-polymer">half of the plastics</a> produced and disposed of every year. </p>
<p>These polymers are used in plastics commonly labeled as HDPE, LLDPE or PP, or by their recycling codes #2, #4 and #5, respectively. These plastics are incredibly durable because the <a href="https://doi.org/10.1021/acssuschemeng.9b06635">chemical bonds</a> that make them up are extremely stable. But in a world set up for single-use consumption, this is no longer a design feature but rather a design flaw. </p>
<p><iframe id="2k7dQ" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/2k7dQ/1/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Imagine if half of the plastics used today were recyclable by twice as many processes as they are now. While that wouldn’t get the recycling rate to 100%, a jump from single digits – <a href="https://www.energy.gov/articles/department-energy-releases-plastics-innovation-challenge-draft-roadmap-and-request">currently around 9%</a> – to double digits would make a big dent in the plastics produced, the plastics accumulated in the environment and their capacity for recycling and reuse. </p>
<h2>Recycling methods we already have</h2>
<p>Even the plastics that make it to a recycling facility <a href="https://ellenmacarthurfoundation.org/plastics-and-the-circular-economy-deep-dive">can’t be reused</a> in exactly the same way they were used before – the recycling process degrades the material, so it loses utility and value. Instead of making a plastic cup that is downgraded each time it gets recycled, manufacturers could potentially make plastics once, collect them and reuse them on and on.</p>
<p>Conventional recycling requires careful sorting of all the collected materials, which can be hard with so many different plastics. Here in the U.S., collection happens mainly through <a href="https://www.container-recycling.org/index.php/issues/single-stream-recycling">single stream recycling</a> – everything from metal cans, glass bottles, cardboard boxes and plastic cups end up in the same bin. Separating paper from metal doesn’t require complex technology, but sorting a polypropylene container from a polyethylene milk jug is hard to do without the occasional mistake. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/554113/original/file-20231016-20-hwyi6k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two workers, in bright yellow, stand at a conveyor belt covered in plastics in a recycling facility." src="https://images.theconversation.com/files/554113/original/file-20231016-20-hwyi6k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554113/original/file-20231016-20-hwyi6k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554113/original/file-20231016-20-hwyi6k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554113/original/file-20231016-20-hwyi6k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554113/original/file-20231016-20-hwyi6k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554113/original/file-20231016-20-hwyi6k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554113/original/file-20231016-20-hwyi6k.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">Recycling workers sort through materials.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/OhioRecycling/d1c2014b8c194d55b9f06a328b2dd4a5/photo?Query=recycling%20plant&mediaType=photo&sortBy=&dateRange=Anytime&totalCount=181&currentItemNo=22&vs=true">AP Photo/Mark Gillispie</a></span>
</figcaption>
</figure>
<p>When two different plastics are mixed together during recycling, their useful properties are hugely reduced – to the point of <a href="https://www.scientificamerican.com/article/why-its-so-hard-to-recycle-plastic/">making them useless</a>. </p>
<p>But say you can recycle one of these plastics by a different method, so it doesn’t end up contaminating the recycling stream. When we mixed samples of polypropylene with a polymer we made, we were <a href="https://doi.org/10.1126/science.adh3353">still able to depolymerize</a> – or break down the material – and regain our building blocks without chemically affecting the polypropylene. This indicated that a contaminated waste stream could still recover its value, and the material in it could go on to be recycled, either mechanically or chemically. </p>
<h2>Plastics we need − but more recyclable</h2>
<p>In <a href="https://doi.org/10.1126/science.adh3353">a study published in October 2023</a>, our team developed a series of polymers with only two simple building blocks – one soft polymer and one hard polymer – that mimicked polyolefins but could also be chemically recycled.</p>
<p>Connecting two different polymers together multiple times until they form a single, long molecule creates what’s called a <a href="https://doi.org/10.1021/jacsau.1c00500">multiblock polymer</a>. Just by adjusting how much of each polymer type goes into the multiblock polymer, our team created a wide range of materials with properties that spanned across polyolefin types. But creating these multiblock polymers is easier said than done. </p>
<p>To link these hard and soft polymers, we <a href="https://doi.org/10.1126/science.adh3353">adapted a technique</a> that had previously been used only on very small molecules. This method is improved relative to traditional methods of making polymers in a step-by-step fashion, developed in the 1920s, where the reactive groups on the end of the molecules need to be exactly matched. </p>
<p>In our method, the reactive groups are now the same as each other, meaning we didn’t have to worry about pairing the ends of each building block to make polymers that can compete with the polyolefins we already use. Using the same strategy, applied in reverse by adding hydrogen, we could disconnect the polymers back into their building blocks and easily separate them to use again. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/554857/original/file-20231019-21-9enk8w.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A graph showing a steady increase in single-use plastic use across all plastic types shown, from X to projected in 2050." src="https://images.theconversation.com/files/554857/original/file-20231019-21-9enk8w.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554857/original/file-20231019-21-9enk8w.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=302&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554857/original/file-20231019-21-9enk8w.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=302&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554857/original/file-20231019-21-9enk8w.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=302&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554857/original/file-20231019-21-9enk8w.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=380&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554857/original/file-20231019-21-9enk8w.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=380&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554857/original/file-20231019-21-9enk8w.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=380&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Realized and predicted production of commodity plastics through 2050.</span>
<span class="attribution"><a class="source" href="https://www.energy.gov/sites/default/files/2021/01/f82/Plastics%20Innovation%20Challenge%20Draft%20Roadmap.pdf">International Energy Agency</a></span>
</figcaption>
</figure>
<p>With an almost <a href="https://www.reuters.com/business/environment/plastic-consumption-course-nearly-double-by-2050-research-2023-02-27/">twofold increase in annual plastic use</a> projected through 2050, the complexity and quantity of plastic recycling will only increase. It’s an important consideration when designing new materials and products. </p>
<p>Using just two building blocks to make plastics that have a huge variety of properties can go a long way toward reducing and streamlining the number of different plastics used to make the products we need. Instead of needing one plastic to make something pliable, another for something stiff, and a third, fourth and fifth for properties in between, we could control the behavior of plastics by just changing how much of each building block is there.</p>
<p>Although we’re still in the process of answering some big questions about these polymers, we believe this work is a step in the right direction toward more sustainable plastics. </p>
<p>We were <a href="https://doi.org/10.1126/science.adh3353">able to create materials</a> that mimic the properties of plastics the world relies on, and our sights are now set on creating plastic compositions that you couldn’t with existing methods.</p><img src="https://counter.theconversation.com/content/215652/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Katherine Harry receives funding from RePLACE (Redesigning Polymers to Leverage a Circular Economy) funded by the Office of Science of the US Department of Energy.</span></em></p><p class="fine-print"><em><span>Emma Rettner receives funding from RePLACE (Redesigning Polymers to Leverage a Circular Economy) funded by the Office of Science of the US Department of Energy.</span></em></p>A team of scientists has developed a method for creating a new class of plastic materials that are potentially more recyclable than single-use plastics.Katherine Harry, PhD Student in Chemistry, Colorado State UniversityEmma Rettner, PhD Candidate in Materials Science and Engineering, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2143642023-10-08T19:26:21Z2023-10-08T19:26:21ZThere’s a hidden source of excess nutrients suffocating the Great Barrier Reef. We found it<figure><img src="https://images.theconversation.com/files/551919/original/file-20231003-17-uvt38a.jpg?ixlib=rb-1.1.0&rect=46%2C108%2C5083%2C3337&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Coral impacted by excess nutrients in the Great Barrier Reef.</span> <span class="attribution"><span class="source">Ashly McMahon</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>The Great Barrier Reef is one of Australia’s most important environmental and economic assets. It is estimated to contribute A$56 billion per year and supports about 64,000 full-time jobs, <a href="https://www.barrierreef.org/the-reef/the-value">according to the Great Barrier Reef Foundation</a>. However, the reef is under increasing pressure. </p>
<p>While much public attention is focused on the <a href="https://theconversation.com/severely-threatened-and-deteriorating-global-authority-on-nature-lists-the-great-barrier-reef-as-critical-151275">impacts of climate change</a> on the Great Barrier Reef and the <a href="https://theconversation.com/australian-government-was-blindsided-by-un-recommendation-to-list-great-barrier-reef-as-in-danger-but-its-no-great-surprise-163159">debate around its endangered status</a>, water quality is also crucial to the reef’s health and survival.</p>
<p>Our new study, published today in the journal <a href="https://doi.org/10.1021/acs.est.3c03725.">Environmental Science and Technology</a>, found that previously unquantified groundwater inputs are the largest source of new nutrients to the reef. This finding could potentially change how the Great Barrier Reef is managed.</p>
<h2>Too much of a good thing</h2>
<p>Although nitrogen and phosphorous are essential to support the incredible biodiversity of the reef, <a href="https://www.sciencedirect.com/science/article/abs/pii/S0272771416301469">too much nutrient</a> can lead to losses of coral biodiversity and coverage. It also increases the abundance of algae and the ability of coral larvae to grow into adult coral, and impacts seagrass coverage and health, which is crucial for fisheries and biodiversity. </p>
<p>Nutrient enrichment can also promote the breeding success of <a href="https://link.springer.com/article/10.1007/s00338-010-0628-z">crown-of-thorns starfish</a>, whose increasing populations and voracious appetite for corals have decimated parts of the reef in recent decades. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551916/original/file-20231003-29-k9m16h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A side by side underwater photo collage of vivid healthy coral and pale murky coral" src="https://images.theconversation.com/files/551916/original/file-20231003-29-k9m16h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551916/original/file-20231003-29-k9m16h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=200&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551916/original/file-20231003-29-k9m16h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=200&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551916/original/file-20231003-29-k9m16h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=200&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551916/original/file-20231003-29-k9m16h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=252&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551916/original/file-20231003-29-k9m16h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=252&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551916/original/file-20231003-29-k9m16h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=252&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pristine coral and coral affected by excess nutrient in the Great Barrier Reef.</span>
<span class="attribution"><span class="source">Ashly McMahon</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>What are the sources of nutrients driving the degradation of the reef? Previous studies have <a href="https://www.reefplan.qld.gov.au/__data/assets/pdf_file/0031/45994/2017-scientific-consensus-statement-summary-chap02.pdf">focused on river discharge</a>. According to one estimate, there has been a <a href="https://www.sciencedirect.com/science/article/abs/pii/S0025326X11005583">fourfold increase in riverine nutrient</a> input to the Great Barrier Reef since pre-industrial times.</p>
<p>This past focus on rivers has emphasised reducing surface water nutrient inputs through changing regulations for land-clearing and agriculture, while neglecting other potential sources. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/floods-of-nutrients-from-fertilisers-and-wastewater-trash-our-rivers-could-offsetting-help-203235">Floods of nutrients from fertilisers and wastewater trash our rivers. Could offsetting help?</a>
</strong>
</em>
</p>
<hr>
<p>However, the most recent nutrient budget for the Great Barrier Reef found river-derived nutrient inputs can account for only a <a href="https://www.sciencedirect.com/science/article/abs/pii/S0278434311003025">small proportion of the nutrients</a> necessary to support the abundant life in the reef. This imbalance suggests large, unidentified sources of nutrients to the reef. Not knowing what these are may lead to ineffective management approaches.</p>
<p>With recent government funding of <a href="https://www.barrierreef.org/what-we-do/reef-trust-partnership">more than $200 million to tackle water quality on the reef</a> which is largely focused on managing river water inputs, it is crucial to make sure other nutrient sources are not overlooked.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551905/original/file-20231003-19-ayf7sc.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram listing nutrient sources to the reef" src="https://images.theconversation.com/files/551905/original/file-20231003-19-ayf7sc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551905/original/file-20231003-19-ayf7sc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=270&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551905/original/file-20231003-19-ayf7sc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=270&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551905/original/file-20231003-19-ayf7sc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=270&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551905/original/file-20231003-19-ayf7sc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=339&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551905/original/file-20231003-19-ayf7sc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=339&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551905/original/file-20231003-19-ayf7sc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=339&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 source of potential groundwater inputs to the Great Barrier Reef.</span>
<span class="attribution"><span class="source">Douglas Tait</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>We found a new nutrient source</h2>
<p>Our research team decided to try and track down this missing source of nutrients.</p>
<p>We used natural tracers to track groundwater inputs off Queensland’s coast. This allows us to quantify how much invisible groundwater flows into the Great Barrier Reef, along with the nutrients hitching a ride with this water. Our findings indicate that current efforts to preserve and restore the health of the reef may require a new perspective.</p>
<p>Our team collected data from offshore surveys, rivers and coastal bores along the coastline from south of Rockhampton to north of Cairns. We used the natural groundwater tracer radium to track how much nutrient is transported from the land and shelf sediments via invisible groundwater flows.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-a-disgruntled-scientist-looking-to-prove-his-food-wasnt-fresh-discovered-radioactive-tracers-and-won-a-nobel-prize-80-years-ago-214784">How a disgruntled scientist looking to prove his food wasn't fresh discovered radioactive tracers and won a Nobel Prize 80 years ago</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551907/original/file-20231003-19-ves2t4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A blue and white ship sailing on a calm ocean" src="https://images.theconversation.com/files/551907/original/file-20231003-19-ves2t4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551907/original/file-20231003-19-ves2t4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551907/original/file-20231003-19-ves2t4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551907/original/file-20231003-19-ves2t4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551907/original/file-20231003-19-ves2t4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551907/original/file-20231003-19-ves2t4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551907/original/file-20231003-19-ves2t4.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">The AIMS research vessel, Cape Ferguson.</span>
<span class="attribution"><span class="source">Ashly McMahon</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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</figure>
<p>We found that groundwater discharge was 10–15 times greater than river inputs. This meant roughly one-third of new nitrogen and two-thirds of phosphorous inputs came via groundwater discharge. This was nearly twice the amount of nutrient delivered by river waters.</p>
<p>Past investigations have revealed that groundwater discharge delivers nutrients and affects water quality in a <a href="https://www.nature.com/articles/s43017-021-00152-0">diverse range of coastal environments</a>, including estuaries, coral reefs, coastal embayments and lagoons, intertidal wetlands such as mangroves and saltmarshes, the continental shelf and even the global ocean.</p>
<p>In some cases, this can account for <a href="https://aslopubs.onlinelibrary.wiley.com/doi/abs/10.4319/lo.2011.56.2.0673">90% of the nutrient inputs</a> to coastal areas, which has major implications for global biologic production. </p>
<p>Nevertheless, this pathway remains overlooked in most coastal nutrient budgets and water quality models.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/551909/original/file-20231003-29-npys7a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A beach early in the morning with people digging into the sand" src="https://images.theconversation.com/files/551909/original/file-20231003-29-npys7a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551909/original/file-20231003-29-npys7a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=339&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551909/original/file-20231003-29-npys7a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=339&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551909/original/file-20231003-29-npys7a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=339&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551909/original/file-20231003-29-npys7a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=426&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551909/original/file-20231003-29-npys7a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=426&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551909/original/file-20231003-29-npys7a.jpg?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">The research team sampling groundwater near the Great Barrier Reef.</span>
<span class="attribution"><span class="source">Ashly McMahon</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<h2>A paradigm shift needed?</h2>
<p>Our results suggest the need for a strategic <a href="https://niwa.co.nz/our-science/freshwater/tools/kaitiaki_tools/land-use/agriculture/mitigation">shift in management approaches</a> aimed at safeguarding the Great Barrier Reef from the effects of excess nutrients.</p>
<p>This includes better land management practices to ensure fewer nutrients are entering groundwater aquifers. We can also use ecological (such as seaweed and bivalve aquaculture, enhancing seagrass, oyster reefs, mangroves and salt marsh) and hydrological (increasing flushing where possible) practices at groundwater discharge hotspots to <a href="https://www.frontiersin.org/articles/10.3389/fmars.2018.00470/full">reduce excess nutrients in the water column</a>. </p>
<p><a href="https://medium.com/water-food-nexus/water-recycling-and-reuse-in-agriculture-for-circularity-of-food-and-water-f08fe4b131b3">The reuse of nutrient-rich groundwater</a> for agriculture also needs to be explored as it represents an untapped and inexpensive nutrient source.</p>
<p>Importantly, unlike river outflow, nutrients in groundwater can be <a href="https://www.sciencedirect.com/science/article/abs/pii/S004896972035539X">stored underground for decades</a> before being discharged into coastal waters. This means research and strategies to protect the reef need to be long-term. The potential large lag time may lead to significant problems in the coming decades as the nutrients now stored in underground aquifers make their way to coastal waters regardless of changes to current land use practices.</p>
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<a href="https://images.theconversation.com/files/551908/original/file-20231003-17-z4u9tf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A vivid landscape of colourful corals in an underwater photo" src="https://images.theconversation.com/files/551908/original/file-20231003-17-z4u9tf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551908/original/file-20231003-17-z4u9tf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551908/original/file-20231003-17-z4u9tf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551908/original/file-20231003-17-z4u9tf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551908/original/file-20231003-17-z4u9tf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551908/original/file-20231003-17-z4u9tf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551908/original/file-20231003-17-z4u9tf.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">Pristine corals on the Great Barrier Reef.</span>
<span class="attribution"><span class="source">Ashly McMahon</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>The understanding and ability to manage the sources of nutrients is pivotal in preserving global coral reef systems.</p>
<p>While we need to reduce the impact of climate change on this fragile ecosystem, we also need to adjust our policies to manage nutrient inputs and safeguard the Great Barrier Reef for generations to come.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/out-of-danger-because-the-un-said-so-hardly-the-barrier-reef-is-still-in-hot-water-210787">Out of danger because the UN said so? Hardly – the Barrier Reef is still in hot water</a>
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<img src="https://counter.theconversation.com/content/214364/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors receive funding from the Australian Research Council, the Herman Slade Foundation and the Great Barrier Reef Foundation. </span></em></p><p class="fine-print"><em><span>Damien Maher receives funding from the Australian Research Council, Hermon Slade Foundation, Great Barrier Reef Foundation. </span></em></p>While the Great Barrier Reed needs nutrients to support the ecosystem, it is possible to have too much of a good thing.Douglas Tait, Senior Researcher, Southern Cross UniversityDamien Maher, Professor, Southern Cross UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2151402023-10-06T01:53:35Z2023-10-06T01:53:35Z6 reasons why global temperatures are spiking right now<figure><img src="https://images.theconversation.com/files/552428/original/file-20231006-27-7ho178.jpg?ixlib=rb-1.1.0&rect=25%2C10%2C3424%2C2286&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/6gVvfQEnWtY">Jonas Weckschmied/Unsplash</a></span></figcaption></figure><p>The world is very warm right now. We’re not only seeing record temperatures, but the records are being broken by record-wide margins.</p>
<p>Take the preliminary September global-average temperature anomaly of 1.7°C above pre-industrial levels, for example. It’s an incredible 0.5°C above the previous record.</p>
<p>So why is the world so incredibly hot right now? And what does it mean for keeping our Paris Agreement targets? </p>
<p>Here are six contributing factors – with climate change the main reason temperatures are so high.</p>
<h2>1. El Niño</h2>
<p>One reason for the exceptional heat is we are in a <a href="http://www.bom.gov.au/climate/enso/#tabs=Pacific-Ocean">significant El Niño</a> that is still strengthening. During El Niño we see warming of the surface ocean over much of the tropical Pacific. This warming, and the effects of El Niño in other parts of the world, raises global average temperatures by <a href="https://www.realclimate.org/index.php/archives/2023/01/2022-updates-to-the-temperature-records/">about 0.1 to 0.2°C</a>.</p>
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Read more:
<a href="https://theconversation.com/explainer-el-nino-and-la-nina-27719">Explainer: El Niño and La Niña</a>
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<p>Taking into account the fact we’ve just come out of a triple La Niña, which cools global average temperatures slightly, and the fact this is the first major El Niño in eight years, it’s not too surprising we’re seeing unusually high temperatures at the moment.</p>
<p>Still, El Niño alone isn’t enough to explain the crazily high temperatures the world is experiencing.</p>
<h2>2. Falling pollution</h2>
<p>Air pollution from human activities cools the planet and has offset some of the warming caused by humanity’s greenhouse gas emissions. There have been efforts to reduce this pollution – since 2020 there has been an <a href="https://sdg.iisd.org/news/imo-advances-measures-to-reduce-emissions-from-international-shipping/">international agreement</a> to reduce sulphur dioxide emissions from the global shipping industry.</p>
<p>It has been speculated this cleaner air has contributed to the recent heat, particularly over the record-warm <a href="https://climate.copernicus.eu/record-breaking-north-atlantic-ocean-temperatures-contribute-extreme-marine-heatwaves">north Atlantic</a> and Pacific regions with high shipping traffic.</p>
<p>It’s likely this is contributing to the extreme high global temperatures – but only on the order of hundredths of a degree. <a href="https://www.carbonbrief.org/analysis-how-low-sulphur-shipping-rules-are-affecting-global-warming/">Recent analysis</a> suggests the effect of the 2020 shipping agreement is about an extra 0.05°C warming by 2050.</p>
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<a href="https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A smog shrouded road with motorcycles, trucks and cars barely visible through the pollution" src="https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.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">People pass through the rising pollution on the Delhi-Jaipur Expressway in Gurgaon, Haryana, India, on November 12 2021.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/people-pass-through-rising-pollution-on-2073480677">Shutterstock</a></span>
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<h2>3. Increasing solar activity</h2>
<p>While falling pollution levels mean more of the Sun’s energy reaches Earth’s surface, the amount of the energy the Sun emits is itself variable. There are different solar cycles, but an 11-year cycle is the most relevant one to today’s climate.</p>
<p>The Sun is becoming <a href="https://edition.cnn.com/2023/07/14/world/solar-maximum-activity-2024-scn/index.html">more active</a> from a minimum in late 2019. This is also contributing a small amount to the spike in global temperatures. Overall, increasing solar activity is contributing only hundredths of a degree at most to the recent global heat. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/this-solar-cycle-the-suns-activity-is-more-powerful-and-surprising-than-predicted-209955">This solar cycle, the sun's activity is more powerful and surprising than predicted</a>
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<h2>4. Water vapour from Hunga Tonga eruption</h2>
<p>On January 15 2022 the underwater <a href="https://www.jpl.nasa.gov/images/pia26006-hunga-tonga-hunga-haapai-eruption">Hunga Tonga–Hunga Haʻapai volcano erupted</a> in the South Pacific Ocean, sending large amounts of water vapour high up into the upper atmosphere. Water vapour is a greenhouse gas, so increasing its concentration in the atmosphere in this way does intensify the greenhouse effect.</p>
<p>Even though the eruption happened almost two years ago, it’s still having a small warming effect on the planet. However, as with the reduced pollution and increasing solar activity, we’re talking about hundredths of a degree.</p>
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<h2>5. Bad luck</h2>
<p>We see variability in global temperatures from one year to the next even without factors like El Niño or major changes in pollution. Part of the reason this September was so extreme was likely due to weather systems being in the right place to heat the land surface.</p>
<p>When we have persistent high-pressure systems over land regions, as seen recently over places like <a href="https://www.theguardian.com/environment/2023/oct/01/autumn-heat-continues-in-europe-after-record-breaking-september">western Europe</a> and <a href="https://www.abc.net.au/news/2023-09-19/australia-weather-september-heat-records-tumble/102870294">Australia</a>, we see local temperatures rise and the conditions for unseasonable heat.</p>
<p>As water requires more energy to warm and the ocean moves around, we don’t see the same quick response in temperatures over the seas when we have high-pressure systems.</p>
<p>The positioning of weather systems warming up many land areas coupled with persistent ocean heat is likely a contributor to the global-average heat too.</p>
<h2>6. Climate change</h2>
<p>By far the biggest contributor to the overall +1.7°C global temperature anomaly is human-caused climate change. Overall, humanity’s effect on the climate has been a global warming of <a href="https://www.globalwarmingindex.org/">about 1.2°C</a>.</p>
<p>The record-high rate of greenhouse gas emissions means we should expect global warming to accelerate too.</p>
<p>While humanity’s greenhouse gas emissions explain the trend seen in September temperatures over many decades, they don’t really explain the big difference from last September (when the greenhouse effect was almost as strong as it is today) and September 2023.</p>
<p>Much of the difference between this year and last comes back to the switch from La Niña to El Niño, and the right weather systems in the right place at the right time.</p>
<h2>The upshot: we need to accelerate climate action</h2>
<p>September 2023 shows that with a combination of climate change and other factors aligning we can see alarmingly high temperatures.</p>
<p>These anomalies may appear to be above the 1.5°C global warming level referred to in the Paris Agreement, but that’s about keeping <a href="https://climateanalytics.org/briefings/understanding-the-paris-agreements-long-term-temperature-goal/">long-term global warming</a> to low levels and not individual months of heat.</p>
<p>But we are seeing the effects of climate change unfolding more and more clearly.</p>
<p>The most vulnerable are suffering the biggest impacts as wealthier nations continue to emit the largest proportion of greenhouse gases. Humanity must accelerate the path to net zero to prevent more record-shattering global temperatures and damaging extreme events.</p>
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Read more:
<a href="https://theconversation.com/net-zero-by-2050-too-late-australia-must-aim-for-2035-213973">Net zero by 2050? Too late. Australia must aim for 2035</a>
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<img src="https://counter.theconversation.com/content/215140/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew King receives funding from the National Environmental Science Program. </span></em></p>The preliminary global-average temperature anomaly for September is a shocking 1.7°C. These are the drivers of current record-breaking heat.Andrew King, Senior Lecturer in Climate Science, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.