tag:theconversation.com,2011:/global/topics/rising-temperatures-6835/articlesRising temperatures – The Conversation2023-11-16T14:47:59Ztag:theconversation.com,2011:article/2156312023-11-16T14:47:59Z2023-11-16T14:47:59ZClimate change and farming: economists warn more needs to be done to adapt in sub-Saharan Africa<p>Sub-Saharan African countries strongly rely on the agricultural and forestry sectors. Agriculture contributes up to <a href="https://data.worldbank.org/indicator/NV.AGR.TOTL.ZS?locations=ZG">60%</a> of some countries’ gross domestic product. But the sector is highly vulnerable to climate change because it relies heavily on climatic factors. This vulnerability is particularly marked in the region because of its slow rate of technological advancement.</p>
<p>As agricultural economists we carried out a <a href="https://www.sciencedirect.com/science/article/abs/pii/S0959652623016451">review</a> of the literature on the climate change challenge for agriculture in sub-Saharan Africa. We explored the distribution of various climatic factors (like rainfall, temperature and extreme weather events) across the region, and their impact on agriculture. We also investigated what rural farmers were doing to respond to climate change. </p>
<p>We found that the implications of climate change for agricultural and economic development are diverse across the region. It is difficult to predict exactly how climate change will affect agriculture and economic development. </p>
<p>But is is clear that sub-Saharan African countries like Nigeria, South Africa, Botswana, and Kenya are <a href="https://www.sciencedirect.com/science/article/abs/pii/S0959652623016451">extremely vulnerable</a> to <a href="https://www.afdb.org/en/cop25/climate-change-africa">climate change</a>. </p>
<p>Farmers are not using effective adaptation strategies. These include planting drought tolerant crop varieties, and conserving water and soil. Limited resources and infrastructure have held them back. Mitigation programmes such as carbon pricing, water management, recycling, afforestation and reforestation have had limited impact. Poor climate change awareness, unstable government policies and political instability have hindered the programmes.</p>
<p>The impact of climate change on vulnerable households will be extreme if adequate measures are not taken in time. Research suggests that countries such as Togo, Nigeria, Congo and Mali will record more agricultural <a href="https://www.ipcc.ch/site/assets/uploads/2018/02/AR5_SYR_FINAL_SPM.pdf#page=13">losses</a> without adaptation. Governments, international organisations, local communities and other stakeholders need to develop strategies to address the diverse needs of rural farmers in sub-Saharan Africa.</p>
<h2>What our review found</h2>
<p>The studies we reviewed indicated that patterns of rainfall, temperature and extreme weather events have changed significantly in the region. This trend is not expected to change in future decades.</p>
<p>Sub-Saharan Africa experiences <a href="https://www.sciencedirect.com/science/article/abs/pii/S0959652623016451">diverse rainfall patterns</a>. Annual rainfall can be as low as 100 millimetres in arid areas in the Sahel and parts of east Africa and over 500 millimetres in tropical areas in central and western Africa. </p>
<p>Temperatures can often exceed 40°C (104°F) during the hottest months. Over the last century, the mean temperature has <a href="https://www.sciencedirect.com/science/article/pii/S2405880722000292">increased</a> by about 0.74°C. </p>
<p>The region <a href="https://www.sciencedirect.com/science/article/pii/S2405880722000292">experiences</a> various extreme weather events, including droughts, floods and heatwaves. Coastal areas, especially in the eastern and southern regions, experience <a href="https://africacenter.org/spotlight/cyclones-more-frequent-storms-threaten-africa/">cyclones or tropical storms</a>.</p>
<p>Many studies show that these conditions affect agricultural production and society in a number of ways:</p>
<ol>
<li><p>Yield reduction: Climate change reduces crop yield. Higher temperatures, changing rainfall patterns, droughts and floods affect harvests. For instance, farmers in Nigeria have seen lower yields caused by new pests, disease outbreaks and the drying up of rivers. </p></li>
<li><p>Food insecurity: Poor agricultural productivity often leads to food insecurity, which affects both rural and urban populations. Lower crop yields can cause prices to rise. Reduced access to food can worsen malnutrition and hunger.</p></li>
<li><p>Income loss and poverty: Lower agricultural output affects the income of smallholder farmers. This can increase poverty levels and economic vulnerability. We found a decline in cereal production over the last decade in Ghana, Congo and South Africa. </p></li>
<li><p>Decreased livestock productivity: Higher temperatures, changes in forage availability, and water scarcity are a challenge for livestock farmers. These make livestock prone to diseases and death. Farmers incur high costs to immunise and treat animals.</p></li>
<li><p>Vulnerability of smallholder farmers: These farmers don’t always have the resources and capacity to adapt to the impact of climate change.</p></li>
</ol>
<h2>Recommendation and policy implications</h2>
<p>The review of studies showed that sub-Saharan Africa could develop economically if rural farmers took more effective measures against climate change.</p>
<p>We made the following recommendations to protect farmers from the impact of climate change:</p>
<ul>
<li><p>Strengthen institutions for policy development and implementation. Coordinating climate change adaptation efforts and sustainable agricultural practices improves farm productivity. </p></li>
<li><p>Improve rural infrastructure. This would promote economic growth, reduce poverty and make rural communities more resilient. </p></li>
<li><p>Initiate public welfare programmes. Improved access to finance, markets, education and climate information would enhance social protection.</p></li>
<li><p>Establish more forest plantations and maintain existing ones. They would help absorb the impact of climate change on agriculture and promote economic development.</p></li>
<li><p>Afforestation and reforestation can also help absorb carbon and conserve biodiversity.</p></li>
</ul><img src="https://counter.theconversation.com/content/215631/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Abeeb Babatunde Omotoso. Researcher at Oyo State College of Agriculture and Technology, Igboora, Nigeria </span></em></p><p class="fine-print"><em><span>Abiodun Olusola Omotayo receives funding from The Climap Africa programme,German Academic Exchange Service (DAAD-Grant Ref: 91838393), Germany and the National Research Foundation’s (NRF), Incentive Funding for Rated Researchers (Grant number: 151680), South Africa. </span></em></p>Smallholder farmers are bearing the brunt of climate change in sub-Saharan Africa. Deliberate steps are required to support them and boost agricultural output,Abeeb Babatunde Omotoso, Postdoctoral research associate, North-West UniversityAbiodun Olusola Omotayo, Senior lecturer/researcher, North-West UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2169332023-11-13T21:21:44Z2023-11-13T21:21:44ZQuébec’s summer 2023 wildfires were the most devastating in 50 years. Is the worst yet to come?<figure><img src="https://images.theconversation.com/files/557286/original/file-20231027-23-ya6je6.jpg?ixlib=rb-1.1.0&rect=6%2C6%2C2032%2C1066&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Forest fires were mostly started by lightning. Their spread was then exacerbated by a lack of precipitation and abnormally high temperatures.</span> <span class="attribution"><span class="source">(Victor Danneyrolles)</span>, <span class="license">Fourni par l'auteur</span></span></figcaption></figure><p>After a summer of exceptional wildfires, the return of cooler temperatures and snowy conditions will provide Québec’s forests a brief respite. </p>
<p>But how long will it last? Are events like these <a href="https://www.cbc.ca/news/climate/quebec-climate-change-wildfires-research-1.6943502">destined to become more frequent?</a></p>
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<p><strong>This article is part of <em>La Conversation Canada’s</em> series <a href="https://theconversation.com/ca-fr/topics/foret-boreale-138017">The boreal forest: A thousand secrets, a thousand dangers</a></strong></p>
<p><br><em>La Conversation Canada invites you to take a virtual walk in the heart of the boreal forest. In this series, our experts focus on management and sustainable development issues, natural disturbances, the ecology of terrestrial wildlife and aquatic ecosystems, northern agriculture and the cultural and economic importance of the boreal forest for Indigenous peoples. We hope you have a pleasant — and informative — walk through the forest!</em></p>
<hr>
<p>As experts in disturbance dynamics occurring in the boreal environment, we are assessing the fires that occurred in Québec in 2023 to provide insights into their causes and consequences.</p>
<h2>Millions of hectares affected</h2>
<p>According to Québec’s <a href="https://sopfeu.qc.ca/en/">Société de protection des forêts contre le feu</a> (Society for the protection of forests against fire, SOPFEU), nearly 700 fires have burned approximately 5.1 million hectares (equivalent to the territory size of Costa Rica), both north and south of the northern forest limit designated by the province — or the boundary that separates northern Québec forests from the southern forests, where logging is conducted.</p>
<p>At the beginning of October, fifteen of the fires that had started in the summer were still active in western Québec. Three of them, although contained, had burned a total of almost 700,000 hectares within the <a href="https://www.pbs.org/newshour/world/canadian-province-of-quebec-looks-for-international-support-to-fight-over-160-wildfires">intensive protection zone</a>, where the SOPFEU systematically fights all fires. </p>
<p>In the <a href="https://sopfeu.qc.ca/lintervention-de-la-sopfeu-dans-les-differentes-zones-de-protection/">northern zone</a>, twelve fires were still under surveillance, some not exceeding 20 hectares, others covering more than a million hectares. Out of the total area burned in 2023 in Québec, three-quarters (3.8 million hectares) were in the northern zone. South of the 50th parallel, within the intensive protection zone, approximately 1.4 million hectares burned, which is more than 80 times the annual average of the past ten years.</p>
<p>When we compare the 2023 fire season to <a href="https://www.donneesquebec.ca/recherche/dataset/feux-de-foret">datasets available since the 1970s</a>, it becomes quite clear that this year was unusual compared to recent decades. Yet, although these fires are impressive and difficult to contain, they are still within the range of “natural variability” observed in previous centuries.</p>
<p>Several <a href="https://doi.org/10.1071/WF22090">studies</a> have shown that particularly intense fire cycles were common in Québec during the period from 1910-1920. These were even more common in the 18th and 19th centuries when warm and dry climatic conditions were particularly conducive to forest fires.</p>
<h2>Exceptional weather conditions</h2>
<p>Like historic forest fires, fire outbreaks in Québec in 2023 were fuelled by <a href="https://www.worldweatherattribution.org/climate-change-more-than-doubled-the-likelihood-of-extreme-fire-weather-conditions-in-eastern-canada/">intense weather conditions</a>. Starting in June, after an already dry month of May, a significant increase in fires was observed in the intensive protection zone. The northern zone was affected throughout the three summer months.</p>
<p>These fires were mainly started by lightning. Their spread was then exacerbated by low precipitation and abnormally high temperatures. <a href="https://www.environnement.gouv.qc.ca/climat/faits-saillants/2023/juin.htm">Temperatures exceeded the 1981-2010 average for the month of June by 2.3°C</a>, setting a record for the warmest June recorded in Québec in at least a hundred years.</p>
<p>These exceptional weather conditions were partly influenced by the El Niño phenomenon, a cyclical warming of the Pacific Ocean known for its impact on terrestrial weather conditions. The trend continued into July, which witnessed exceptionally high average temperatures, well above normal (+2.7°C).</p>
<h2>Multiple consequences</h2>
<p>The simultaneous outbreak of numerous fires and their rapid spread have had multiple effects on wildlife, forests, the climate, and human populations.</p>
<p>The fires have altered the structure and composition of vegetation, causing disruption to wildlife habitats as well as <a href="https://www.cbc.ca/news/canada/montreal/quebec-wildfires-destabilize-quebec-wildlife-1.6867744">displacement and mortality among animals</a>. As a result, the hunting, fishing and harvesting territories of Indigenous communities have been affected.</p>
<p>In addition to representing a direct threat to public safety, the smoke from the fires caused respiratory problems, leading to <a href="https://globalnews.ca/news/9791853/quebec-wildfires-more-evacuations-ordered/">the evacuation of thousands of people in several regions of Québec</a>. The deterioration in air quality was felt not only across Canada and the <a href="https://www.bbc.com/news/world-us-canada-65828469">United States</a>, but also as far as <a href="https://www.cbc.ca/news/canada/montreal/nasa-quebec-fire-smoke-europe-1.6890108">Europe</a>. Fortunately, evacuations were carried out in time, and casualties were avoided. However, there was some material damage.</p>
<p>In terms of their impact on the climate, large fires released several megatons of carbon dioxide stored in trees and soils, <a href="https://cdnsciencepub.com/doi/10.1139/er-2013-0062">contributing to an increase in atmospheric concentrations of greenhouse gases</a> (CO<sub>2</sub>, CH<sub>4</sub>).</p>
<p>While the fires have had significant consequences, <a href="https://theconversation.com/forest-fires-north-americas-boreal-forests-are-burning-a-lot-but-less-than-150-years-ago-201365">they can sometimes be beneficial for certain organisms</a>. We can consider tree species like jack pine, which depend on fires for regeneration, and numerous animal species that thrive in burned forests.</p>
<h2>What can we expect in the future?</h2>
<p>Québec’s forests have been burning and regenerating cyclically for millennia. However, it is imperative to recognize that these cycles can evolve over time.</p>
<p>The 2023 fire season highlights the urgency of preparing for significant changes in disturbance dynamics, including the possibility of such events recurring more frequently.</p>
<p>As climate change progresses, periods of drought could become more frequent if precipitation fails to compensate for rising temperatures, as observed in the 20th century.</p>
<p>This combination of factors increases the likelihood of an increase in the number, size, and intensity of wildfires.</p>
<p>Such changes threaten the natural regeneration of forests and could lead to the formation of treeless areas, victims of too frequent fires <a href="https://www.pnas.org/doi/full/10.1073/pnas.2024872118">for vegetation to have time to regenerate</a>.</p>
<p>These conditions could also be exacerbated by the continued expansion of logging. <a href="https://www.theglobeandmail.com/canada/article-as-canadas-boreal-forests-burn-again-and-again-they-wont-grow-back-the/">Preliminary analyses</a> have shown that more than 300,000 hectares of forests burned in 2023 may not regenerate, mainly due to the effects of logging in recent decades.</p>
<p>The consequences of major forest fires highlight the climate challenges we face. They demonstrate the need to develop mitigation and adaptation measures aimed at protecting vulnerable forest ecosystems and their inhabitants.</p>
<p>It is therefore imperative to learn lessons from the 2023 fire season to strengthen the resilience of forests and communities to climate change and limit damages caused by fires. This involves reducing risk, protecting the most vulnerable areas, and raising awareness among local populations.</p><img src="https://counter.theconversation.com/content/216933/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Yves Bergeron received funding from FRQNT, NSERC and MNRF.</span></em></p><p class="fine-print"><em><span>Dorian M. Gaboriau, Jonathan Lesven et Victor Danneyrolles ne travaillent pas, ne conseillent pas, ne possèdent pas de parts, ne reçoivent pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'ont déclaré aucune autre affiliation que leur poste universitaire.</span></em></p>The forest fires of the summer of 2023 in Québec were devastating. It was the worst year in 50 years. But with climate change, the worst may be yet to come.Dorian M. Gaboriau, Postdoctorant en paléoécologie, Université du Québec en Abitibi-Témiscamingue (UQAT)Jonathan Lesven, Doctorant en paléoécologie, Université du Québec en Abitibi-Témiscamingue (UQAT)Victor Danneyrolles, Professeur-chercheur en écologie forestière, Université du Québec à Chicoutimi (UQAC)Yves Bergeron, Professeur écologie et aménagement forestier, Université du Québec en Abitibi-Témiscamingue (UQAT)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2124922023-09-13T10:55:07Z2023-09-13T10:55:07ZAddis Ababa faces growing climate change risks like heat, drought and floods, study warns<figure><img src="https://images.theconversation.com/files/545484/original/file-20230830-19-8bq04m.jpg?ixlib=rb-1.1.0&rect=0%2C7%2C5000%2C3315&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">About 70% of people in Addis Ababa live in informal settlements that are vulnerable to climate change. Amanuel Sileshi/AFP/</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/muslim-devotees-gather-at-meskel-square-to-break-their-fast-news-photo/1240330823?adppopup=true">Getty Images</a></span></figcaption></figure><p>Addis Ababa, Ethiopia’s capital city, will likely face increased heatwaves, droughts and severe flooding over the next 67 years. These changes will pose risks to public health and infrastructure. They’ll also be felt most acutely by the city’s most vulnerable residents: those living in informal settlements. </p>
<p>Addis Ababa is one of the fastest-growing cities in Africa, and its current metropolitan population of about 5.4 million is projected to reach close to <a href="https://worldpopulationreview.com/world-cities/addis-ababa-population">9 million</a> by 2035.</p>
<p>This increase in the city’s population will be absorbed by informal settlements, the prime destination for most migrants. And informal settlements are characterised by poor or non-existent infrastructure, and face the twin challenges of worsening climate change and poor urban environmental policy.</p>
<p>To investigate the city’s vulnerability to climate change, researchers at <a href="https://www.climatepolicylab.org/">Tufts University</a> and the <a href="https://www.woodwellclimate.org/">Woodwell Climate Research Center</a> analysed flood risk and temperature data for different time periods, projecting from the past to the future.</p>
<p>We predicted that the city’s extreme daily maximum temperatures would increase by about <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">1.7°C over the period 2040-2060</a>, compared with 2000–2020. An increase of 1.7°C would result in a <a href="https://iopscience.iop.org/article/10.1088/1748-9326/aab827">rise</a> in the frequency, duration, and intensity of heatwaves. In addition, higher temperatures contribute to increased water vapour and transpiration. This will <a href="https://report.ipcc.ch/ar6syr/pdf/IPCC_AR6_SYR_LongerReport.pdf#page=16">threaten</a> health, ecosystems, infrastructure, livelihoods, and food supplies.</p>
<p>Certain southern neighbourhoods, such as <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">Akaki-Kaliti, Bole and Nifas Silk-Lafto</a>, have experienced notably higher temperatures, especially during the warm season from March to May. And, looking to the future, temperature projections for <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">Nifas Silk-Lafto suggest an average temperature increase to 26.21°C between 2040 and 2060, and further increase to 27.78°C from 2070 to 2090</a> and <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">27.78°C from 2070 to 2090</a>. </p>
<p>For the warm-season months of March, April, and May, a temperature increase of 1.8°C is projected. This suggests that the peak temperature for the hottest day of the year will rise by an average of 1.8°C compared to recent data. From 2000 to 2020 the average temperature in the Nifas Silk-Lafto sub-city was 24.70°C. </p>
<p>Increases in temperatures of this magnitude will lead to public health challenges such as increased malaria risks, disproportionately affecting vulnerable groups like the elderly, children, and women.</p>
<h2>More droughts</h2>
<p>Over the past two decades, Addis Ababa has endured an average of three months of extreme drought yearly. Using the <a href="https://www.droughtmanagement.info/palmer-drought-severity-index-pdsi/">Palmer Drought Severity Index</a> to assess temperature and precipitation data in a geographical area, our analysis suggests that extreme drought events will become more frequent between 2040 and 2060. The city is expected to experience an additional 1.6 months of extreme drought annually, a 53% increase compared with 2000-2020. </p>
<p>This rising frequency of droughts, along with the city’s growing population, is intensifying water insecurity. Groundwater reserves for drought emergencies are already being <a href="https://onlinelibrary.wiley.com/doi/10.1002/tqem.21512">depleted</a>. </p>
<p>These droughts will affect health, hydroelectric energy production and urban agriculture. </p>
<h2>Flooding</h2>
<p>Too much rainfall, particularly if it occurs within a short period of time in an urban area, leads to flooding. Flooding poses a significant environmental risk to Addis Ababa, especially because the city has developed around three primary rivers. </p>
<p>Climate change will increase water-related challenges by affecting the flow of rivers and the replenishment of groundwater. </p>
<p>Currently, <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">67%</a> of the population in Addis lives in flood prone areas. The parts of the city that are most at risk include central Addis, which has the greatest density of impervious surfaces like tarmac and concrete. These contribute to flood risk because water can’t seep into the ground.</p>
<p>Other <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">parts of the city that are at risk</a> include the southern half – where the slope is relatively flatter, so water doesn’t flow away – and the Nifas Silk-Lafto region, where considerable development has taken place in the floodplain. </p>
<p>Several factors will add to the flooding challenge. The city has <a href="https://www.sciencedirect.com/science/article/pii/S2214581819301843">inadequate sewerage infrastructure</a> and <a href="https://onlinelibrary.wiley.com/doi/10.1111/jfr3.12629">weak drainage systems</a> which are often obstructed by solid waste. </p>
<h2>The impact</h2>
<p>The effects on the city’s residents will be substantial. </p>
<p>Health is just one example. </p>
<p>Our data show that average temperatures in the city will make year-round <a href="https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.2003489#:%7E:text=This%20model%20suggests%20a%20temperature,climate%20change%20on%20malaria%20transmission">malaria transmission</a> a risk. There will have to be sustained policy measures to deal with the risk.</p>
<p>Older adults and pregnant women are particularly vulnerable to the health impacts of climate change. The elderly are more <a href="https://www.ohchr.org/en/climate-change/impact-climate-change-rights-older-persons">sensitive</a> to heat and pollution due to existing health conditions, limited mobility, and compromised immune systems. Pregnant women face <a href="https://www.sciencedirect.com/science/article/pii/S0015028222003831">risks</a> from thermal variations and mosquito-borne illnesses like malaria and Zika. </p>
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Read more:
<a href="https://theconversation.com/climate-change-will-cause-more-african-children-to-die-from-hot-weather-188609">Climate change will cause more African children to die from hot weather</a>
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<p>Many urban residents will be prone to increasing floods. Already <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">10%</a> of the city’s newly developed areas are within a 100-year floodplain, threatening lives and infrastructures.</p>
<p>People living in informal settlements are particularly at risk – that’s about <a href="https://unhabitat.org/ethiopia-addis-ababa-urban-profile">70%</a> of Addis Ababa’s residents. These settlements crop up in limited and unused spaces, such as riverbanks. They are at a higher <a href="https://gsdrc.org/topic-guides/urban-governance/key-policy-challenges/informal-settlements/">risk</a> of flood impact, and the risk is growing.</p>
<p>Our data shows that currently the percentage difference in vulnerability between formal and informal settlements is <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">0.6%</a>. The figure illustrates the extent to which buildings within formal and informal settlements would be affected by flooding events. It is expected to rise to <a href="https://www.woodwellclimate.org/climate-risk-assessment-addis-ababa-ethiopia/">1.3% by 2050 and 1.6% by 2080</a>. </p>
<h2>Policy recommendations</h2>
<p>There’s an urgent need for policies that can rise to these challenges. We suggest:</p>
<ul>
<li><p>the government should establish a climate adaptation and resilience office, to integrate <a href="https://www.c2es.org/document/what-is-climate-resilience-and-why-does-it-matter/">climate resilience</a> into <a href="https://theconversation.com/cape-towns-climate-strategy-isnt-perfect-but-every-african-city-should-have-one-149287">urban planning</a></p></li>
<li><p>an independent body should then assess policies in practice</p></li>
<li><p>a water management strategy to ensure equitable access and sustainable <a href="https://waterfdn.org/sustainable-water-management-swm-profile/#:%7E:text=Sustainable%20water%20management%20means%20using,those%20needs%20in%20the%20future.">use of water</a></p></li>
<li><p>the city should invest in <a href="https://environment.ec.europa.eu/topics/nature-and-biodiversity/green-infrastructure_en">green infrastructure</a> </p></li>
</ul>
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Read more:
<a href="https://theconversation.com/global-climate-finance-leaves-out-cities-fixing-it-is-critical-to-battling-climate-change-194375">Global climate finance leaves out cities: fixing it is critical to battling climate change</a>
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<ul>
<li><p>upgrading infrastructure and improving waste management</p></li>
<li><p>public awareness campaigns and <a href="https://www.unesco.org/en/climate-change/education#:%7E:text=Education%20is%20crucial%20to%20promote,act%20as%20agents%20of%20change.">school</a> education on climate change impacts</p></li>
<li><p>developing mechanisms for effective <a href="https://coastadapt.com.au/how-to-pages/collaboration-and-partnerships-climate-change-adaptation">collaboration</a> among government departments, non-governmental organisations and international agencies.</p></li>
</ul><img src="https://counter.theconversation.com/content/212492/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Abay Yimere 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>Climate change is putting pressure on Ethiopia’s largest city, Addis Ababa, and exposing people to disease and natural disasters.Abay Yimere, Postdoctoral Scholar in International Environment and Resource Policy, The Fletcher School, Tufts UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2093852023-07-11T19:06:20Z2023-07-11T19:06:20ZGlobal temperature rises in steps – here’s why we can expect a steep climb this year and next<figure><img src="https://images.theconversation.com/files/536708/original/file-20230711-27-hedyc9.jpg?ixlib=rb-1.1.0&rect=45%2C182%2C6028%2C3478&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Getty Images</span></span></figcaption></figure><p>Global warming took off in the mid-1970s when the rise in global mean surface temperature exceeded natural variability. Every decade after the 1960s has been warmer than the one before and the 2010s were the <a href="https://www.ipcc.ch/">warmest on record</a>. But there can be a lot of variability from one year to the next.</p>
<p>Now, in 2023, all kinds of records are being broken. The highest daily temperatures ever recorded globally occurred in early July, alongside the largest sea surface temperature anomaly ever.</p>
<figure class="align-center ">
<img alt="This graph shows daily estimates of global surface temperatures (top) and sea-surface temperatures (bottom). The 2023 values are dark and 2022 are orange." src="https://images.theconversation.com/files/536694/original/file-20230710-21-cyxb2s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/536694/original/file-20230710-21-cyxb2s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=523&fit=crop&dpr=1 600w, https://images.theconversation.com/files/536694/original/file-20230710-21-cyxb2s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=523&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/536694/original/file-20230710-21-cyxb2s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=523&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/536694/original/file-20230710-21-cyxb2s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=658&fit=crop&dpr=1 754w, https://images.theconversation.com/files/536694/original/file-20230710-21-cyxb2s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=658&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/536694/original/file-20230710-21-cyxb2s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=658&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Temperatures on land and the ocean surface are breaking records this year, as shown in these graphs of daily estimates of global surface temperatures (top) and sea-surface temperatures (bottom).</span>
<span class="attribution"><span class="source">Author provided, based on NOAA analyses, processed by University of Maine</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>June had its highest global mean surface temperature, according to preliminary analysis. The extent of Antarctica’s sea ice has been at a record low. Meanwhile, atmospheric carbon dioxide concentrations continue to increase at rates that show no sign of slowing. </p>
<p>Evident consequences include torrential downpours in some parts of the world which contrast with excessive heatwaves and wildfires in other locations, notably recently in Canada.</p>
<p>But global mean surface temperature does not continue relentlessly upwards. The biggest increases, and warmest years, tend to happen in the latter stages of an El Niño event. </p>
<p>Human-induced climate change is relentless and largely predictable. But at any time, and especially locally, it can be masked by weather events and natural variability on interannual (El Niño) or decadal time scales. </p>
<p>The combination of decadal variability and the warming trend from rising greenhouse gas emissions makes the temperature record look more like a <a href="https://doi.org/10.1126/science.aac9225">rising staircase</a>, rather than a steady climb.</p>
<figure class="align-center ">
<img alt="This graph shows global mean surface temperatures, annual departures from 20th-century averages, with pre-industrial values indicated by a dashed line. Green lines depict approximate regimes stepping to higher and higher values, with an expected upward step at the end." src="https://images.theconversation.com/files/536696/original/file-20230710-23-g0gc4z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/536696/original/file-20230710-23-g0gc4z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=313&fit=crop&dpr=1 600w, https://images.theconversation.com/files/536696/original/file-20230710-23-g0gc4z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=313&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/536696/original/file-20230710-23-g0gc4z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=313&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/536696/original/file-20230710-23-g0gc4z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=393&fit=crop&dpr=1 754w, https://images.theconversation.com/files/536696/original/file-20230710-23-g0gc4z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=393&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/536696/original/file-20230710-23-g0gc4z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=393&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Rather than rising steadily, global temperatures climb in steps, usually at the end of an El Niño event.</span>
<span class="attribution"><span class="source">Author provided, based on NOAA data</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-are-so-many-climate-records-breaking-all-at-once-209214">Why are so many climate records breaking all at once?</a>
</strong>
</em>
</p>
<hr>
<h2>Sources of variability</h2>
<p>Atmospheric carbon dioxide concentrations continue to climb relentlessly upwards despite the Paris Agreement and the many countries and organisations (cities, companies) that have made good on their commitments to cut emissions. </p>
<p>Unfortunately for the planet, some nations, including China and India, have continued to burn coal and install coal-fired power stations whose emissions <a href="https://theconversation.com/china-is-pumping-out-carbon-emissions-as-if-covid-never-happened-thats-bad-news-for-the-climate-crisis-207933">more than offset gains elsewhere</a>.</p>
<p>But the rise in temperature follows a step-like progression. The warmest year in the 20th century was 1998, following the 1997-98 major El Niño. Then the <a href="https://doi.org/%2010.002/2013EF000165">warming paused</a> and the so-called “hiatus” in global warming from 2001 to 2014 led climate change deniers to become vociferous in proclaiming global warming was a myth. </p>
<p>The major El Niño event in 2015-16 changed that. 2015 became the warmest year on record, ending the hiatus, only to be surpassed by 2016, which remains the warmest calendar year so far in many records.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/global-average-sea-and-air-temperatures-are-spiking-in-2023-before-el-nino-has-fully-arrived-we-should-be-very-concerned-207731">Global average sea and air temperatures are spiking in 2023, before El Niño has fully arrived. We should be very concerned</a>
</strong>
</em>
</p>
<hr>
<p>A lot of year-to-year variability is associated with El Niño events. But it is more than that. Further analysis reveals that the Pacific decadal variability, sometimes referred to as the Pacific Decadal Oscillation or Inter-decadal Pacific Oscillation, resulted in changes in the amount of heat sequestered at various ocean depths. </p>
<p>The Pacific Decadal Oscillation may be thought of as a <a href="https://doi.org/10.1126/science.aac9225">northern-hemisphere version</a> of the Inter-decadal Pacific Oscillation.</p>
<p>With the Pacific Decadal Oscillation, there were major changes in Pacific trade winds, sea-level pressure, sea level, rainfall and storm locations throughout the Pacific and Pacific-rim countries. These changes extended into the southern oceans and across the Arctic into the Atlantic. </p>
<p>The effects are greatest in winter in each hemisphere. There is good but incomplete evidence that changes in winds alter ocean currents, ocean convection and overturning, resulting in changes in the amount of heat sequestered deep in the ocean during the <a href="https://doi.org/10.1038/NCLIMATE2341">negative phase of the Pacific Decadal Oscillation</a>.</p>
<p>Accordingly, during the positive phase of the Pacific Decadal Oscillation, more heat is deposited in the upper 300m of the ocean, where it can influence global temperatures. During the negative phase, more heat is dumped below 300m, contributing to the overall warming of the oceans but lost to the surface. </p>
<p>During El Niño, heat stored at depth in the western tropical Pacific is moved around and returns to the atmosphere, providing a mini global warming.</p>
<h2>Temperatures rising</h2>
<p>Research shows that ocean heat content increases more steadily than surface air warming and is a <a href="https://doi.org/10.1029/2017EO081839">better metric to show that global warming continues</a>. </p>
<p>Sea-level rise comes from both the expansion of the ocean as it warms and the melting of land-based ice (glaciers and ice sheets in Greenland and Antarctica). This puts more water into the oceans. Fluctuations occur as rainfall is partitioned differently between land and the ocean, with more rain on land during La Niña events.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/ocean-heat-is-off-the-charts-heres-what-that-means-for-humans-and-ecosystems-around-the-world-207902">Ocean heat is off the charts – here's what that means for humans and ecosystems around the world</a>
</strong>
</em>
</p>
<hr>
<p>The ocean covers 70% of the Earth. Because most of it is in the southern hemisphere, which experiences winter in June to August, the highest values for sea-surface temperatures occur in March, at the end of southern summer. But as land temperature variations are much larger, the highest global mean surface temperatures occur about July.</p>
<p>With a new El Niño emerging and prospects that it could be another major event, are we about to experience the next step up the stairs? Already in 2023, sea-surface temperatures emerged in April as the highest on record and values are running 0.2°C above previous highs. </p>
<p>This set the stage for June to have record high surface air temperatures globally. In early July, they hit the highest values on record.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1677080394745753600"}"></div></p>
<p>We can expect 2023 to emerge as the warmest year to date. But sea-surface temperatures during El Niño events tend to peak about December and have the <a href="https://doi.org/10.1175/1520-0477(1997)078%3C2771:TDOENO%3E2.0.CO;2">greatest influences in the subsequent two months</a>. That sets the stage for 2024 jumping up the staircase to the next level, perhaps to 1.4°C above pre-industrial levels, with likely daily incursions over 1.5°C. </p>
<p>Once the next La Niña event comes along, there’ll again be a pause in the rise, but values will never quite go back to previous levels.</p><img src="https://counter.theconversation.com/content/209385/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kevin Trenberth 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>Climate change is relentless and largely predictable, but it is influenced by natural variability. This means the largest temperature rise usually comes at the end of an El Niño event.Kevin Trenberth, Distinguished Scholar, NCAR; Affiliate Faculty, University of Auckland, Waipapa Taumata RauLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1944942022-11-20T15:22:31Z2022-11-20T15:22:31ZOntario’s Bill 23 proposes more homes built faster, but this comes at an environmental cost<figure><img src="https://images.theconversation.com/files/496224/original/file-20221118-11-nh9620.jpg?ixlib=rb-1.1.0&rect=0%2C242%2C3540%2C2252&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Bill 23 proposes to eliminate or weaken many housing development regulations including site plan controls, which keep us and our natural environment safe from the negative effects of poorly controlled development
</span> <span class="attribution"><span class="source"> THE CANADIAN PRESS/Nathan Denette</span></span></figcaption></figure><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/ontario-s-bill-23-proposes-more-homes-built-faster--but-this-comes-at-an-environmental-cost" width="100%" height="400"></iframe>
<p>The Ontario government recently <a href="https://www.cbc.ca/news/canada/toronto/ontario-new-housing-legislation-1.6630186">proposed a new bill, the More Homes Built Faster Act, or Bill 23</a>. This bill contains some positive elements, like the removal of duplicate plan approval requirements and adding measures aimed at increasing urban density and housing mix.</p>
<p>However, Bill 23 also proposes weakening or eliminating many housing development regulations, such as site plan controls, that protect us and our natural environment from the negative effects of poorly built development. If implemented as tabled, the bill will severely disrupt the province’s environmental housing regulations.</p>
<p>The housing sector is one of the largest contributors to Ontario’s greenhouse gas emissions. It contributes <a href="https://publications.gc.ca/collections/collection_2020/eccc/En81-4-2018-3-eng.pdf">23 per cent of total greenhouse gas emissions of the province, second only to transportation</a>.</p>
<p>Poorly regulated housing <a href="https://www.orea.com/%7E/media/Files/Downloads/GreenPolicyPaper.pdf">can lead to more greenhouse gas emissions</a> through energy loss, increased energy requirements and greater exposure to weather extremes. This would contribute to accelerating climate change, exposing many Ontario residents to the accompanying risks to human health, well-being and property. </p>
<h2>Climate change and housing</h2>
<p>A recent poll showed that <a href="https://legermarketing.wpenginepowered.com/wp-content/uploads/2022/10/Legers-North-American-Tracker-October-13th-2022.pdf">74 per cent of Ontario residents are worried about climate change.</a> Sixty-eight per cent of the province’s population agree that climate change is caused by human activities; over half said that they personally have experienced the consequences of climate change. Therefore, climate change should be central to the policies that shape our province’s future. </p>
<p>Recent research has demonstrated that substantial amounts of urban green spaces and trees — more than 40 per cent tree canopy cover — <a href="https://doi.org/10.1073/pnas.1817561116">may be required to help us protect urban communities against excess heat</a>. However, <a href="https://www150.statcan.gc.ca/n1/pub/16-002-x/2021001/article/00002-eng.htm">most Canadian cities, including those in Ontario, continue to lose green spaces and trees</a>.</p>
<p>Research also shows that our most disadvantaged and vulnerable populations are disproportionately exposed to climate change risks. Green spaces in Canadian cities are not evenly distributed. </p>
<figure class="align-center ">
<img alt="Aerial view of a green neighbourhood" src="https://images.theconversation.com/files/495094/original/file-20221114-24-r5uyoz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/495094/original/file-20221114-24-r5uyoz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/495094/original/file-20221114-24-r5uyoz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/495094/original/file-20221114-24-r5uyoz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/495094/original/file-20221114-24-r5uyoz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/495094/original/file-20221114-24-r5uyoz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/495094/original/file-20221114-24-r5uyoz.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">Wealthier neighbourhoods often have more green spaces.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p><a href="https://ici.radio-canada.ca/info/2022/07/ilots-chaleur-villes-inegalites-injustice-changements-climatiques/en">Wealthier neighbourhoods and those with fewer immigrants enjoy more green spaces and the benefits they provide</a> in comparison to <a href="https://doi.org/10.3389/frsc.2022.919724">poorer neighbourhoods and those with more immigrants</a>. </p>
<p>In Toronto, recent research confirms that <a href="https://doi.org/10.3389/frsc.2022.919724">the poorest neighbourhoods are the most vulnerable to flooding due to a lack of vital natural infrastructure such as bodies of water and green spaces</a>. These <a href="https://doi.org/10.1073/pnas.1917213116">environmental injustices</a> should be a main concern addressed by new policy.</p>
<p>In addition, recent research reveals that <a href="https://doi.org/10.1002/met.2084">high air temperatures are connected to increased risk of hospital admissions</a>. By 2050, summer temperatures increased by climate change are expected to lead to significant growth in the demand for in-patient hospital care. </p>
<h2>Worsening climate risks</h2>
<p>Unfortunately, Bill 23, as currently conceived, may make all of this worse. It removes all municipal controls over exterior design of residential developments. </p>
<p>First, this may lead to poorly regulated housing and compromised visual quality and appeal that would inevitably detract from, instead of increase, property value. Over time, this would put the financial investment of owners in their property at risk. </p>
<p>Second, removing all sustainable site plan controls may encourage the increase of impervious surfaces that significantly amplify the risk of urban floods from rainwater runoff. This is exacerbated by Bill 23’s reduction of parkland dedication requirements by half, which is likely to cause a loss of the green spaces and bodies of water that we need to cope with climate-related risks like heat and flooding. </p>
<p>Worse still, by curbing the authority of conservation authorities, Bill 23 may endanger people’s lives and property when their houses are built in areas exposed to risks from flooding and pollution. Bill 23’s environmental peril is compounded with the proposed changes that will <a href="https://news.ontario.ca/en/statement/1002453/ontario-launches-consultation-on-proposed-changes-to-the-greenbelt">open up the Greenbelt for development</a>.</p>
<p>While the housing crisis clearly needs to be addressed, Bill 23 proposes to solve one crisis (housing) at the expense of another (climate change). Despite the bill’s positive components, the removal of many environmental regulations will saddle future homeowners with <a href="https://climatechoices.ca/wp-content/uploads/2021/09/Infrastructure-English-FINAL-Sep29.pdf">the costs of having to upgrade and repair their houses when their properties get flooded</a> or when it turns out that <a href="https://doi.org/10.1016/j.landurbplan.2021.104046">their land doesn’t have trees and other plants that help protect against increasing urban heat</a>.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1592291547441152002"}"></div></p>
<p>These are not just concerns of a few environmental groups that can be easily ignored in the political calculus. In the future, all Ontario residents may have to pay the price for some of the worrying policy choices that are included in Bill 23.</p>
<p>For Ontario municipalities and conservation authorities to continue their work <a href="https://conservationontario.ca/conservation-authorities/about-conservation-authorities">to protect, expand and maintain urban green spaces, forests and bodies of water</a>, Bill 23 must be amended. </p>
<p>There are land developers who make great efforts to build residential developments that are meeting or exceeding sustainability standards, regardless of whether they’re required by environmental regulations. These progressive businesses deserve our support. However, a wholesale removal or weakening of environmental regulations opens the door for an increase in housing developments that do not meet these standards.</p>
<p>We cannot afford to lose our urban green spaces and bodies of water. These natural spaces are not a luxury, but are vital infrastructure needed to help protect our communities against the worst effects of climate change.</p><img src="https://counter.theconversation.com/content/194494/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Drescher receives funding from the Social Sciences and Humanities Research Council of Canada, Environment and Climate Change Canada, and the Municipal Natural Assets Initiative.</span></em></p><p class="fine-print"><em><span>Luna Khirfan receives funding from the Social Sciences and Humanities Research Council (SSHRC) of Canada. She is also an elected Governing Board Member of the Association of Collegiate Schools of Planning (ACSP). </span></em></p>Poorly regulated housing is leading to more greenhouse gas emissions through energy loss, increased energy requirements and greater exposure to weather extremes.Michael Drescher, Associate Professor, School of Planning, University of WaterlooLuna Khirfan, Associate professor, School of Planning, University of WaterlooLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1898152022-09-08T17:32:09Z2022-09-08T17:32:09ZPakistan needs a national development program to combat future floods and droughts<figure><img src="https://images.theconversation.com/files/483376/original/file-20220908-9663-lpex5t.jpg?ixlib=rb-1.1.0&rect=0%2C5%2C3603%2C2270&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Pakistani women wade through floodwaters as they take refuge on Sep. 2, 2022. </span> <span class="attribution"><span class="source">(AP Photo/Fareed Khan)</span></span></figcaption></figure><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/pakistan-needs-a-national-development-program-to-combat-future-floods-and-droughts" width="100%" height="400"></iframe>
<p>Pakistan is suffering from the aftermath of yet another massive flood covering about <a href="https://timesofindia.indiatimes.com/world/pakistan/pakistan-floods-key-points-third-of-country-under-water-right-now/articleshow/93858586.cms">one-third of its landmass</a>. This time it has affected more than 33 million people in the Indus River valley, with extensive damage to life, property, crops and livestock. </p>
<p>The Indus River valley contains a rich and multicultural history with enormous human potential, all of which is centred around an agricultural economy. With this flood, the economic backbone of the nation is shattered — rehabilitation of agriculture around the Indus River will take years, if not decades.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/wUllSWVpynI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Al Jazeera English reports on the economic implications of the floods in Pakistan.</span></figcaption>
</figure>
<p>This is at least the fourth major flood within a generation; previous floods occurred in <a href="https://reliefweb.int/report/pakistan/pakistan-floods-sep-1992-un-dha-situation-reports-1-8">1992</a>, <a href="https://reliefweb.int/report/pakistan/pakistan-floods-jul-1993-un-dha-information-reports-1-2">1993</a> and <a href="https://www.britannica.com/event/Pakistan-Floods-of-2010">2010</a>. An increased frequency of such events in the country must be attributed to global temperature rise, particularly since the 1970s. Although Pakistan is responsible for only one per cent of global carbon emissions, it is the <a href="https://www.germanwatch.org/sites/germanwatch.org/files/2021-01/cri-2021_table_10_countries_most_affected_from_2000_to_2019.jpg">eighth most climate change-affected nation on earth</a>.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/pakistan-floods-what-role-did-climate-change-play-189833">Pakistan floods: what role did climate change play?</a>
</strong>
</em>
</p>
<hr>
<h2>Climate change impacts</h2>
<p>The <a href="https://climateknowledgeportal.worldbank.org/country/pakistan/climate-data-historical">climate in most of Pakistan</a> is arid, with the exception of the mountainous region (north and northwest) that is classified as cold. This region serves as the main water storage for the country, <a href="https://www.washingtonpost.com/world/asia_pacific/pakistan-has-more-glaciers-than-almost-anywhere-on-earth-but-they-are-at-risk/2016/08/11/7a6b4cd4-4882-11e6-8dac-0c6e4accc5b1_story.html">with at least 7,253 glaciers</a> containing more ice than anywhere else on earth outside of the polar areas. </p>
<p>The northern areas also receive snow in winter that melts by early spring. Rising global temperatures are accelerating glacial meltdown, depleting a water source and placing the glaciers at a risk of being permanently wiped out. </p>
<p><a href="https://d-nb.info/1201881048/34">Monsoon rains</a> across most of the country are even more critical because these can result in larger amounts of overland flow in a very short time. With increased evaporation from the Indian Ocean due to <a href="https://doi.org/10.1038/d41586-022-02813-6">intense heatwaves</a>, such as the one that happened this year, the number of rainy days and the total amount of rain are expected to increase in the future. </p>
<p>Most of the precipitation (glacial meltdown, snow thawing or rainfall) will continue to end up as surface runoff. This is because of the steep and rocky terrain in the mountainous areas and the mostly dry open fields and urban ground cover in the plains.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/483377/original/file-20220908-9639-659s2n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="an ice-covered mountain range." src="https://images.theconversation.com/files/483377/original/file-20220908-9639-659s2n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/483377/original/file-20220908-9639-659s2n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/483377/original/file-20220908-9639-659s2n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/483377/original/file-20220908-9639-659s2n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/483377/original/file-20220908-9639-659s2n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/483377/original/file-20220908-9639-659s2n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/483377/original/file-20220908-9639-659s2n.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">Pakistan is home to the largest number of glaciers — like the Minapin glacier shown here — outside of the polar regions.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Water management in Pakistan</h2>
<p>The Indus River runs through the length of Pakistan. It originates in the Himalayas and meanders to the west through high altitudes. When it reaches the plains, it mainly flows southward and is successively joined by its western tributaries (Kabul, Kurram and Gomal) followed by its eastern tributaries (Jhelum, Chenab, Ravi and Sutlej). Thereafter, it eventually drains into the Arabian Sea. </p>
<p>Along the Indus River’s flow path, <a href="https://www.britannica.com/place/Indus-River/Irrigation">dams, barrages and a canal system are used to manage water flow</a>. Likewise, several dams and barrages have been constructed along the various tributaries with some of these joined by major canals. </p>
<p>This irrigation infrastructure is not adequate to manage flash floods or long periods of droughts. Existing dams are not very many and do not have enough depth to store water in case of excessive floods. Flowing water carries along with it suspended particles from the mountains and deposits it in the plains. This reduces the storage capacity of the reservoirs and clogs the waterways, resulting in overflows. </p>
<p>It is estimated that the canal system is running at <a href="https://pecongress.org.pk/images/upload/books/107-114-302%20Managing%20flod%20Asad%20Sarwar%20Qureshi.pdf">30 per cent lower efficiency</a>. The overflow water usually drains into the ocean, which means that not enough water is available during droughts while there is a lot of it during floods.</p>
<h2>Awareness and responsibility</h2>
<p>There is a general lack of social awareness and responsibility within the society for reasons ranging from education to poverty and from governance to politics. The result is that people in Pakistan are not prepared to face the force of water, let alone prepare for it. </p>
<p>Encroachment of construction within rivers is quite common across the country. In the town of Bahrain, for example, hotels and shops constructed within the riverbed were <a href="https://www.samaaenglish.tv/news/40015678">washed away during the current floods</a>. </p>
<p><a href="https://doi.org/10.3808/jeil.201900002">The effects of land features</a> such as ground cover, river slope and soil type on floods and droughts are not widely understood by the public. Additionally, a flood warning system does not exist in the country. </p>
<p>Similarly, awareness at the scale of individual farms is limited when it comes to adopting nature-based solutions such as protecting wetlands, re-grading of ground to alter water flow or creating dugouts to store water.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/483379/original/file-20220908-18-xe2kj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A damaged mosque is surrounded by floodwaters" src="https://images.theconversation.com/files/483379/original/file-20220908-18-xe2kj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/483379/original/file-20220908-18-xe2kj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/483379/original/file-20220908-18-xe2kj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/483379/original/file-20220908-18-xe2kj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/483379/original/file-20220908-18-xe2kj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/483379/original/file-20220908-18-xe2kj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/483379/original/file-20220908-18-xe2kj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&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 damaged mosque is surrounded by floodwaters in Bahrain, Pakistan.</span>
<span class="attribution"><span class="source">(AP Photo/Sherin Zada)</span></span>
</figcaption>
</figure>
<h2>Committed leadership is required</h2>
<p>Pakistan needs a proactive approach to enhancing the country’s infrastructure, as opposed to exclusively focusing on disaster risk reduction activities. A national strategy is required to develop and implement programs such as effective <a href="https://www.oecd.org/cfe/regionaldevelopment/governance-of-land-use-policy-highlights.pdf">land-use zoning</a>, <a href="https://www.mdpi.com/2073-4441/14/12/1920">soil-climate modelling</a>, <a href="https://www.oecd.org/environment/cc/policy-perspectives-climate-resilient-infrastructure.pdf">resilient infrastructure development</a> and <a href="https://www.mdpi.com/2412-3811/5/12/109">adaptive asset management</a>. Although expensive and time-consuming, the construction of large dams is inevitable.</p>
<p>A national development program requires committed leadership at various levels of governments and the society. Such a strategy should focus on building local capacity over a long period, and must include public education and incentive schemes.</p><img src="https://counter.theconversation.com/content/189815/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Shahid Azam receives research funding from NSERC and TransGas Limited. He has also consulted with Clifton Associates Limited.</span></em></p>Climate change will increase the frequency of both floods and droughts in Pakistan. To address these challenges, enhancing infrastructure, building dams and educating the public are necessary.Shahid Azam, Professor, Geotechnical and Geoenvironmental Engineering, University of ReginaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1873332022-07-20T12:22:30Z2022-07-20T12:22:30ZHow record-setting heat waves in cities across UK, US and mainland Europe could punish economies already reeling from inflation<figure><img src="https://images.theconversation.com/files/474973/original/file-20220719-12-ooexrc.jpg?ixlib=rb-1.1.0&rect=161%2C161%2C5829%2C3952&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A runner tries to beat the heat by working out in the morning. </span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/EuropeHeatPhotoGallery/6650aed45af1472392f1f79f19ce3c34/photo?Query=heat&mediaType=photo&sortBy=arrivaldatetime:desc&dateRange=Anytime&totalCount=112379&currentItemNo=45">AP Photo/Michael Probst</a></span></figcaption></figure><p>Hundreds of millions of people struggled to keep cool amid a sweltering summer heat wave as cities across the <a href="https://www.cnn.com/2022/06/22/weather/heat-wave-southeast-wednesday/index.html">U.S.</a> and <a href="https://www.cnn.com/2022/07/14/weather/western-europe-heat-wave-wildfires-intl/index.html">mainland Europe</a> experienced <a href="https://www.washingtonpost.com/climate-environment/2022/07/19/heat-wave-europe-climate-change/">record-high temperatures</a>. In the <a href="https://www.usatoday.com/story/news/nation/2022/07/19/europe-heatwave-uk-temperature-record-broken/10094289002">U.K.</a>, thermometers topped 104 Fahrenheit (40 degrees Celsius) on July 19, 2022, the highest ever recorded.</p>
<p>While all this broiling heat is surely punishing on a personal level, it also has significant impacts on the broader economy.</p>
<p>As an <a href="https://www.dereklemoine.com">economist who has studied</a> the <a href="http://scholar.google.com/citations?user=614D6AEAAAAJ">effects of weather and climate change</a>, I have examined a large body of work that links heat to economic outcomes. Here are four ways extreme heat hurts the economy. </p>
<h2>1. Growth takes a hit</h2>
<p>Research has found that extreme heat can directly hurt economic growth. </p>
<p>For example, a 2018 study found that the economies of U.S. states <a href="https://doi.org/10.1111/jmcb.12574">tend to grow at a slower pace</a> during relatively hot summers. The data shows that annual economic growth falls 0.15 to 0.25 percentage points for every 1 degree Fahrenheit (0.56 C) that a state’s average summer temperature is above normal. </p>
<p>Laborers in weather-exposed industries such as construction <a href="https://doi.org/10.1086/671766">work fewer hours</a> when it’s hotter. But higher summer temperatures also reduce growth in many industries that tend to involve indoor work, including retail, services and finance. Workers are less productive when it’s hotter out.</p>
<h2>2. Crop yields drop</h2>
<p>Agriculture is obviously exposed to weather: After all, crops grow outdoors. </p>
<p>While temperatures up to around 85 F to 90 F (29-32 C) can benefit crop growth, <a href="https://doi.org/10.1073/pnas.0906865106">yields fall sharply</a> when thermostats rise further. Some of the crops that can be hit hard by extreme heat include corn, soybeans and cotton. These reductions in yields could be costly for U.S. agriculture.</p>
<p>For example, a recent study I conducted found that an additional 2 degrees C (3.6 F) of global warming <a href="https://www.nber.org/papers/w25008">would eliminate profits</a> from an average acre of farmland in the eastern U.S. </p>
<p>A prominent example of this was the <a href="https://www.reuters.com/article/us-russia-heat-fires/russia-swelters-in-heatwave-many-crops-destroyed-idUSTRE66F2LX20100716">collapse of the Russian wheat harvest</a> in response to the country’s 2010 heat wave, which raised wheat prices throughout the world.</p>
<h2>3. Energy use soars</h2>
<p>Of course, when it’s hot, <a href="https://www.washingtonpost.com/posteverything/wp/2016/07/22/your-air-conditioner-is-making-the-heat-wave-worse/">energy use goes up</a> as <a href="https://www.eia.gov/todayinenergy/detail.php?id=48796">people and businesses run their air conditioners</a> and other cooling equipment at full blast. </p>
<p>A <a href="https://doi.org/10.1257/app.3.4.152">2011 study found</a> that just one extra day with temperatures above 90 F (32 C) increases annual household energy use by 0.4%. <a href="https://doi.org/10.3386/w24397">More recent research</a> shows that energy use increases the most in places that tend to be hotter, probably because more households have air conditioning. </p>
<p>This increase in electricity use on hot days stresses electric grids right when people depend on them most, as seen in <a href="https://www.vox.com/2020/8/15/21370128/california-blackouts-rolling-power-outage">California</a> and <a href="https://www.nytimes.com/2021/06/15/climate/texas-heat-wave-electricity.html">Texas</a> during past heat waves. Blackouts can be quite costly for the economy, as inventories of food and other goods can spoil and many businesses either have to run generators or shut down. For instance, the 2019 California blackouts <a href="https://www.energy.senate.gov/public/index.cfm/files/serve?File_id=93BBC3A5-E6FA-4053-A1A0-532A9714BFC4">cost an estimated US$10 billion</a>. </p>
<h2>4. Education and earnings suffer</h2>
<p>A long-term impact of increasingly hotter weather involves how it affects children’s ability to learn – and thus their future earnings. </p>
<p>Research has shown that hot weather during the school year reduces test scores. <a href="https://doi.org/10.1086/694177">Math scores decrease more and more</a> as the temperature rises beyond 70 F (21 C). Reading scores are more resistant to high temperatures, which this research claims is consistent with how different regions of the brain respond to heat.</p>
<p>One study suggested that students in schools that lack air conditioning <a href="https://doi.org/10.1257/pol.20180612">learn 1% less</a> for every 1 degree Fahrenheit (0.56 C) increase in the school year’s average temperature. It also found that minority students are especially affected by hotter school years, as their schools are more likely to lack air conditioning. </p>
<p>Lost learning results in <a href="https://doi.org/10.1016/S1573-4463(99)03011-4">lower lifetime earnings</a> and <a href="https://www.doi.org/10.1257/jel.39.4.1101">hurts future economic growth</a>.</p>
<p>The impact of extreme heat on development, in fact, begins before we’re even born. <a href="https://doi.org/10.1073/pnas.1702436114">Research has found</a> that adults who were exposed to extreme heat as fetuses <a href="https://doi.org/10.1016/j.jeem.2018.10.001">earn less during their lifetimes</a>. Each extra day with average temperature above 90 F (32 C) reduces earnings 30 years later <a href="https://doi.org/10.1073/pnas.1702436114">by 0.1%</a>. </p>
<h2>Air conditioning can help – to a point</h2>
<p>Air conditioning can offset some of these effects. </p>
<p>For example, studies have found that having a working air conditioner means <a href="https://doi.org/10.1086/684582">fewer people die</a>, <a href="https://doi.org/10.1257/pol.20180612">student learning isn’t compromised</a> and <a href="https://doi.org/10.1073/pnas.1702436114">extreme heat outside during pregnancy doesn’t hurt fetuses</a>. </p>
<p>Not everyone has air conditioners, however, especially in states such as <a href="https://slate.com/technology/2021/07/oregon-washington-heat-conditioner.html">Oregon</a> and countries such as the <a href="https://www.nytimes.com/2022/07/18/world/europe/britain-uk-air-conditioning-heat.html">U.K.</a> that have more temperate climates but have nonetheless recently experienced unusually extreme temperatures. And many people <a href="https://www.wnyc.org/story/life-new-york-public-housing-no-air-conditioning/">can’t afford</a> to own or operate them. Survey data from 2017 found that <a href="https://www.eia.gov/todayinenergy/detail.php?id=31312">around half of homes in the U.S. Pacific Northwest</a>
lacked air conditioning. And <a href="https://doi.org/10.1257/pol.20180612">about 42% of U.S. classrooms</a> lack an air conditioner. </p>
<p>While heat waves are shown to <a href="https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3892429">induce more households</a> to install air conditioning, it’s hardly a panacea. By 2100, higher use of air conditioning could <a href="https://www.pnas.org/content/112/19/5962.short">increase residential energy consumption by 83% globally</a>. If that energy comes from fossil fuels, it could end up amplifying the heat waves that are causing the higher demand in the first place.</p>
<p>And in the U.S. South, where air conditioning is omnipresent, hotter-than-usual summers still <a href="https://doi.org/10.1111/jmcb.12574">take the greatest toll</a> on states’ economic growth.</p>
<p>In other words, as temperatures rise, economies will continue to suffer.</p>
<p><em>This is an updated version of an <a href="https://theconversation.com/4-ways-extreme-heat-hurts-the-economy-164382">article originally published</a> on Aug. 2, 2021.</em></p><img src="https://counter.theconversation.com/content/187333/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Derek Lemoine 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>The UK recorded blistering hot temperatures as the US and Europe also experienced sweltering heat waves.Derek Lemoine, Associate Professor of Economics, University of ArizonaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1812312022-04-21T18:44:57Z2022-04-21T18:44:57ZClimate change is altering the seasonal rhythm of plant life-cycle events<figure><img src="https://images.theconversation.com/files/458261/original/file-20220414-12-lyqvov.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Changes in climate affect the timings of various points in the life cycle of plants, including when flowers bloom in spring and when leaves wither in autumn.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>“<em>Si sta come d’autunno sugli alberi le foglie</em>.” </p>
<p>“We are like autumn leaves on branches,” <a href="https://cultura.biografieonline.it/soldati-ungaretti/">Italian poet Giuseppe Ungaretti wrote in his 1918 poem <em>Soldati</em></a> (Soldiers), on the tragedy of human life and war.</p>
<p>If the popular image of autumn is <a href="https://doi.org/10.1177%2F039219216201003804">decadence and nostalgia</a> after the summer heat, spring is the season of rebirth after the darkness and cold of winter. The transformative passing of seasons has historically represented a powerful mental image, rich in symbolism. The seasonal timings of biological events are also an essential aspect of <a href="https://doi.org/10.1016/j.tree.2007.04.003">plant adaptation</a> and can also be of crucial <a href="https://doi.org/10.1007/978-90-481-3335-2_4">economic relevance</a>. </p>
<p>However, as forest ecologists, we have observed that climate change has been modifying the timing of recurrent plant life-cycle events, thus critically affecting the ecosystem. </p>
<h2>The plant’s clock</h2>
<p>In spring, flowers bloom. In summer, fruits ripen. In autumn, leaves change colour and fall. In winter, plants rest. This is <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/phenology">phenology</a> — the study of the timing of recurring life-cycle events. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/W0jjyf7sRY8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The life-cycle of plants, animals and all life forms depends on the environment around them.</span></figcaption>
</figure>
<p>So how do plants recognize the passage of time and the right moment to accomplish growth and reproduction? Like people, plants have their own calendar. A plant’s clock is represented by cycles in the environmental conditions, and the timing of phenological events is <a href="https://doi.org/10.1111/gcb.14619">controlled by climate</a>. </p>
<p>Specifically, plants use a set of triggers to synchronize the timings of growth and reproduction with favourable environmental conditions. </p>
<p>Depending on the species, phenological events are triggered by temperature (autumn and winter chilling and spring warming), photoperiod (length of day), precipitation or, often, a combination of these.</p>
<h2>If climate changes, phenology changes</h2>
<p>Phenology is one of the most sensitive biological indicators of the changing climate. Under the progressive rise in temperature experienced in the last century and the variations in seasonal distribution of rainfall events, the <a href="https://doi.org/10.1111/gcb.14619">environmental triggers usually occur earlier and earlier</a>. </p>
<p>This is why phenological shifts have been observed worldwide, and contextually, it seems that phenological events are occuring earlier year by year. </p>
<p>Japan’s <em>Sakura</em> or cherry blossom season is one of the <a href="https://doi.org/10.1007/s00484-019-01719-9">most evident proofs</a> of this shift. Dating back to the ninth century, the date of flowering, which defines the festival’s timing, has been anticipated in the last century by the rise in average temperatures. </p>
<h2>What is the problem? Spring is cool, right?</h2>
<p>American poet <a href="https://www.goodreads.com/quotes/136895-if-we-had-no-winter-the-spring-would-not-be">Anne Bradstreet</a> said, “If we had no winter, the spring would not be so pleasant.” While this is hyperbolic, we still need to consider that the timings of flowers blooming, fruits ripening and other such phenological events result from a long-lasting adaptation of each species to its surrounding environment.</p>
<figure class="align-center ">
<img alt="A lone green plant in a barren land stretch with dried plants." src="https://images.theconversation.com/files/458682/original/file-20220419-18-z0vdiu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/458682/original/file-20220419-18-z0vdiu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458682/original/file-20220419-18-z0vdiu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458682/original/file-20220419-18-z0vdiu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458682/original/file-20220419-18-z0vdiu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458682/original/file-20220419-18-z0vdiu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458682/original/file-20220419-18-z0vdiu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Changes in the environment can have economic consequences as it affects the quantity and quality of agriculture and forestry products.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>The timing of phenological events are calibrated to ensure the perfect environmental condition needed to accomplish the annual cycles of a plant’s life while <a href="https://doi.org/10.1016/j.foreco.2020.118483">minimizing the risk of damage</a>. Changes in these conditions can have ecological as well as economic consequences as they can affect the quantity and quality of agriculture and forestry products. </p>
<p>At the end of the growing season, plants develop dormant buds to protect the sensitive <a href="https://www.britannica.com/science/meristem">meristematic cell layer</a> — tissue in which cells maintain the ability to divide throughout the life of the plant — and suspend activity. Dormancy is an adaptation mechanism evolved in climates with seasons to escape harsh winter conditions. </p>
<p>Warm spring temperatures (called forcing), the increase in day length during spring (photoperiod), and the length and intensity of winter temperatures (<a href="https://doi.org/10.1098/rstb.2011.0186">chilling</a>) reactivate the growth of the <a href="https://www.biologyonline.com/dictionary/apical-bud">apical buds</a> — the buds located at the top of the plant — in the spring. Clearly, temperature has a central and leading role in this process. For this reason, warming can trigger an <a href="https://doi.org/10.1093/treephys/tpaa096">earlier reactivation in spring</a> and a delayed cessation in autumn, or both, <a href="https://doi.org/10.1016/j.foreco.2019.01.005">lengthening the growing season</a>.</p>
<p>Some believe that a longer growing season could enhance carbon uptake and, therefore, the productivity of forests. In some places, such as regions in the northern latitudes or elevated altitudes, trees have profited from a <a href="https://doi.org/10.1016/j.foreco.2020.118483">longer growing season</a> and, more generally, more favourable climatic conditions under global warming. </p>
<figure class="align-center ">
<img alt="Snow and ice cover on a blooming cherry tree." src="https://images.theconversation.com/files/458260/original/file-20220414-26-5wo0gn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/458260/original/file-20220414-26-5wo0gn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458260/original/file-20220414-26-5wo0gn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458260/original/file-20220414-26-5wo0gn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458260/original/file-20220414-26-5wo0gn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458260/original/file-20220414-26-5wo0gn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458260/original/file-20220414-26-5wo0gn.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">Late frosts in spring and early frosts in autumn, that often accompany longer growing seasons, increase the risk for damage to plants and trees.</span>
<span class="attribution"><span class="source">(AP Photo/Carolyn Kaster)</span></span>
</figcaption>
</figure>
<p>However, an earlier growth reactivation increases the risk of damage due to <a href="https://doi.org/10.1016/j.foreco.2019.01.005">late spring frosts, and lengthening of the growing season increases the risk of damage by early autumn frosts</a>. </p>
<p>If trees cannot adapt, or re-adapt, their phenology with the new climatic conditions, the fitness and growth performance of local populations could be dramatically affected.</p>
<h2>If phenology changes, species interaction changes</h2>
<p>Ecosystems are generally complex and the species within them interact with each other as well as their surrounding environment. Different species can react differently to the changing climatic conditions, potentially leading to dangerous new phenological matches or mismatches. </p>
<p>For example, current climatic conditions create new phenological matches between prey and predators. <a href="https://doi.org/10.1111/gcb.14991">Black spruce may become a key host for the spruce budworm</a> given that the timing of maximum larvae activity could be better synchonized with the timing of yearly shoots development, which increases the risk of severe defoliations for one of the most profitable boreal species in North America. </p>
<p>Climate change can also cause mismatches between plants and their pollinators. Bumblebees represent one of the <a href="https://doi.org/10.1126/science.aaa7031">most important pollinators</a> for several wild species and many varieties of enormous agricultural interest. Bumblebees, given their low heat and cold tolerance, are particularly sensitive to environmental conditions. For this reason, the projected climatic risk for this species is <a href="https://doi.org/10.1126/science.aaa7031">extremely high</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/458284/original/file-20220414-14135-yes4wi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A bumblebee sits on a wild flower." src="https://images.theconversation.com/files/458284/original/file-20220414-14135-yes4wi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/458284/original/file-20220414-14135-yes4wi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=516&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458284/original/file-20220414-14135-yes4wi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=516&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458284/original/file-20220414-14135-yes4wi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=516&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458284/original/file-20220414-14135-yes4wi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=648&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458284/original/file-20220414-14135-yes4wi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=648&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458284/original/file-20220414-14135-yes4wi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=648&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Bumblebees are extremely sensitive to climate change.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>The mutually beneficial plant-pollinator relationship is an essential ecosystem service, specially considering that the pollination done by insects contributes to <a href="https://doi.org/10.1016/j.ecolecon.2008.06.014">9.5 per cent of global food production</a>.</p>
<h2>Action must be taken</h2>
<p>As the climate continues to change, affecting all kinds of ecosystems in the process, we need to be aware of plant phenology and think about how these shifts may directly affect our lives and businesses. </p>
<p>Scientists, today, use observational data to determine how species, populations and communities are vulnerable to these ongoing and projected future changes in climate. This research can be the foundation for essential human intervention, which may influence <a href="https://doi.org/10.1016/j.foreco.2019.01.005">plant distribution through assisted migration</a>, which is the human-assisted movement of species to areas far outside their established range. This will help tree species resynchronize their phenology to the current climatic condition. </p>
<p>Plant phenology is the result of an adaptation. However, adaptation requires time, an amount of time we do not have given the magnitude and rate at which we are observing climate changes. Constantly monitoring the phenological shifts worldwide will allow us to develop sound strategies to protect the most vulnerable ecosystems as well as our businesses. </p>
<p>Besides, we are like autumn leaves on branches, but at least we should try not to fall!</p><img src="https://counter.theconversation.com/content/181231/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Roberto Silvestro received the Merit scholarship for international PhD students (PBEEE) assigned by the Fonds de Recherche du Québec - Nature et Technologies (FRQNT). </span></em></p><p class="fine-print"><em><span>Sergio Rossi receives funding from Natural Sciences and Engineering Research Council of Canada, Fonds de recherche du Québec - Nature et technologie, Ministère des Forêts, de la Faune et des Parcs du Québec</span></em></p>Climate change is modifying the timing of recurrent life-cycle events with critical consequences on ecological and economic levels.Roberto Silvestro, PhD candidate, biology, Université du Québec à Chicoutimi (UQAC)Sergio Rossi, Professor, Département des Sciences Fondamentales, Université du Québec à Chicoutimi (UQAC)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1647612021-09-30T12:30:36Z2021-09-30T12:30:36ZAs heat waves intensify, tens of thousands of US classrooms will be too hot for students to learn in<figure><img src="https://images.theconversation.com/files/423171/original/file-20210924-25-1obzni.jpg?ixlib=rb-1.1.0&rect=6%2C6%2C4498%2C2985&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Climate change means more schools will need to install or upgrade cooling systems.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/hot-schools-a-fan-attempts-to-cool-the-classroom-of-east-news-photo/1316260189">Bill Uhrich/MediaNews Group/Reading Eagle via Getty Images</a></span></figcaption></figure><p>Rising temperatures <a href="https://www.ipcc.ch/report/sixth-assessment-report-working-group-i/">due to climate change</a> are causing more than just uncomfortably hot days across the United States. These high temperatures are placing serious stress on <a href="https://nca2014.globalchange.gov/highlights/report-findings/infrastructure">critical infrastructure</a> such as water supplies, airports, roads and bridges.</p>
<p>One category of critical infrastructure being severely affected is the nation’s K-12 schools. </p>
<p>Ideally, the nation’s more than <a href="https://www.edweek.org/leadership/education-statistics-facts-about-american-schools/2019/01">90,000 public K-12 schools</a>, which serve over <a href="https://www.edweek.org/leadership/education-statistics-facts-about-american-schools/2019/01">50 million students</a>, should protect children from the sometimes dangerous elements of the outdoors such as severe storms or extreme temperatures.</p>
<p>But since so many of America’s schools are old and dilapidated, it’s the school buildings themselves that need protection – or at least to be updated for the 21st century.</p>
<p><a href="https://nces.ed.gov/surveys/frss/publications/1999048/">Twenty-eight percent</a> of the nation’s public schools were built from 1950 through 1969, federal data shows, while just 10% were built in 1985 or later.</p>
<p>As a <a href="https://scholar.google.com/citations?user=vWMMEkwAAAAJ&hl=en&oi=sra">researcher who studies</a> the impact of climate change, I have measured its effects on infrastructure and health for over a decade. During that time, I’ve seen little attention focused on the effects of climate change on public schools. </p>
<p>Since 2019, climate scientist Sverre LeRoy, at the <a href="https://climateintegrity.org/I%20have%20worked%20with">Center for Climate Integrity</a>, and I have worked to determine if the nation’s schools are prepared for the heat waves on the approaching horizon.</p>
<p>Comparing the climate conditions under which U.S. schools were built with the projected conditions over the next two decades, we looked at the vulnerability of all K-12 schools to increasing temperatures. We determined whether current schools have air conditioning or not and whether they would be required to add air conditioning in the future. </p>
<p>The results of our study, “<a href="https://coolingcrisis.org/">Hotter Days, Higher Costs: The Cooling Crisis in America’s Classrooms</a>,” show that by 2025, more than 13,700 schools will need to install air conditioning, and another 13,500 will need to upgrade their existing systems. </p>
<figure class="align-center ">
<img alt="Woman wearing hat and holding umbrella walks by school sign showing temperature is 104 degrees" src="https://images.theconversation.com/files/423170/original/file-20210924-15-16epykl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/423170/original/file-20210924-15-16epykl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=343&fit=crop&dpr=1 600w, https://images.theconversation.com/files/423170/original/file-20210924-15-16epykl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=343&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/423170/original/file-20210924-15-16epykl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=343&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/423170/original/file-20210924-15-16epykl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=431&fit=crop&dpr=1 754w, https://images.theconversation.com/files/423170/original/file-20210924-15-16epykl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=431&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/423170/original/file-20210924-15-16epykl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=431&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Excessively hot days are occurring more regularly during the school year than in previous decades.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/the-temperature-reads-104f-degrees-at-mark-keppel-high-news-photo/1228811840">Frederic J. Brown/AFP via Getty Images</a></span>
</figcaption>
</figure>
<h2>Hot classrooms</h2>
<p>Research has shown that high classroom temperatures can make it <a href="https://www.hks.harvard.edu/publications/heat-and-learning">harder to learn</a>. Hot school days cause difficulty in concentrating, sleepiness, a decrease in energy and even reduced memory capacity. </p>
<p><a href="https://txssc.txstate.edu/tools/weather-toolkit/drought">Local school districts have policies</a> for <a href="http://www.idph.state.il.us/public/hb/hbheatschools.htm">extreme heat events</a>. However, rising temperatures mean these guidelines are no longer limited to rare occurrences.</p>
<p>Over the past several years, schools across the U.S. are increasingly forced to take “<a href="https://www.nytimes.com/2018/09/06/nyregion/heat-day-schools-extreme-climate-change.html">heat days</a>,” cutting school days short because of classrooms that are too hot for students to effectively learn.</p>
<p>This is happening in places that range from <a href="https://denvergazette.com/news/education/multiple-dps-schools-will-close-or-release-early-on-friday-due-to-potential-record-breaking/article_d82c0020-119a-11ec-ad8a-ab4bf39991e0.html">Denver</a> to <a href="https://www.baltimoresun.com/maryland/baltimore-city/bs-md-ci-city-schools-ac-early-20210829-i5ihvrzjdjep3g7uubymptblwa-story.html">Baltimore</a> and <a href="https://www.cleveland.com/metro/2021/08/cleveland-other-schools-announce-early-dismissals-closures-for-tuesday-because-of-heat.html">Cleveland</a>.</p>
<p>Compounding the increase in temperatures is the national trend that seasonal temperatures are rising in both the <a href="https://www.epa.gov/climate-indicators/climate-change-indicators-seasonal-temperature">spring and the fall</a>. For example, both Rhode Island and New Jersey have seen average spring and fall temperatures rise over 3 degrees Fahrenheit (1.7 Celsius). Rather than high temperatures only occurring when students are on summer break, these heat events now occur regularly during the school year too. Students today in a greater number of cities are beginning and ending the school year in classrooms that often <a href="https://www.washingtonpost.com/education/2019/08/16/when-is-it-too-hot-go-school/">exceed 80 F</a> (27 C). </p>
<h2>Expensive upgrades</h2>
<p>The problem of more hot days is due to average temperatures increasing over the past <a href="https://science2017.globalchange.gov/chapter/6/">40 years</a>. The <a href="https://science2017.globalchange.gov/chapter/6/">number of days</a> with high temperatures has risen across the country, with notable increases in <a href="https://coolingcrisis.org/">large northern cities</a>. For example, Chicago has seen the number of days over 80 degrees during the school year increase from 27 in 1970 to <a href="https://www.accuweather.com/en/us/chicago/60608/may-weather/348308?year=2021">32 in 2020</a> and a projected <a href="https://coolingcrisis.org/">38 by 2025</a>. These increases affect schools in two distinct ways. </p>
<p>Schools in the traditionally cooler north – especially older schools – will need to be retrofitted with new air conditioning systems at an accumulated cost of <a href="https://coolingcrisis.org/">US$40 billion</a> by 2025. For schools in the traditionally warmer South and West, many existing systems will need to be upgraded at a projected cost <a href="https://coolingcrisis.org/">exceeding $400 million</a>. </p>
<p>Temperature increases are especially costly in large cities such as Philadelphia, Chicago and Los Angeles, where existing efforts and continued needs will result in outlays exceeding <a href="http://climatecrises.org/">$500 million, $1.5 billion and $600 million</a>, respectively. These large districts have a greater number of older buildings that require upgrades in electrical and structural systems to support new air conditioning systems.</p>
<p>For all schools – even ones that don’t require system upgrades – the additional costs of operating air conditioning systems to meet the new demands will exceed <a href="https://coolingcrisis.org/">$1.4 billion per year</a>.</p>
<h2>An equity issue</h2>
<p>Since school districts are dependent on local taxes or bond measures to finance the school system, districts in affluent areas have a greater opportunity to obtain funds through tax increases or voter-approved bond measures.</p>
<p>In contrast, districts located in less affluent counties – including <a href="https://www.bell.kyschools.us/">Bell County</a>, Kentucky; <a href="https://www.scottcounty.net/">Scott County</a>, Tennessee; and <a href="https://www.dekalbk12.org/">DeKalb County</a>, Alabama – face the challenge of creating safe learning environments without a financial safety net. With household incomes for the entire district in the bottom 20% of national averages, or less than <a href="https://www.census.gov/data/tables/time-series/demo/income-poverty/historical-income-households.html">$43,000 per year</a>, these districts are unable to absorb significant tax increases.</p>
<p>In this regard, classroom environments become an equity issue. While the increase in temperature may affect all children, the relative impact of the increase and the ability to adapt is not equal. </p>
<figure class="align-center ">
<img alt="Four people hold signs protesting high temperatures in school classrooms" src="https://images.theconversation.com/files/423179/original/file-20210924-18-2jmpuf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/423179/original/file-20210924-18-2jmpuf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/423179/original/file-20210924-18-2jmpuf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/423179/original/file-20210924-18-2jmpuf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/423179/original/file-20210924-18-2jmpuf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/423179/original/file-20210924-18-2jmpuf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/423179/original/file-20210924-18-2jmpuf.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">Protesters in 2019 demand equity for Denver students who go to school in old buildings without air conditioning.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/margaret-bobb-second-from-left-a-retired-dps-secondary-news-photo/1170401741">Helen H. Richardson/The Denver Post</a></span>
</figcaption>
</figure>
<h2>Unsustainable solutions</h2>
<p>Increasingly, school districts are turning to individual window units to <a href="https://pbcchicago.com/projects-by-sister-agency/cps/cps-air-conditioning-program/">address classroom overheating</a>. However, window units do not cool interior offices, cannot circulate and exchange air within the classrooms, and will not meet expected lifespans due to extensive use. Furthermore, they create uneven cooling patterns and classroom disturbance due to noise. While these solutions are popular from an initial budget perspective, they ultimately fail to solve the hot classroom crisis.</p>
<p>Where mechanical systems are not an option due to budgetary constraints, school districts are looking at altering the school year to <a href="https://www.theadvocate.com/baton_rouge/news/communities/article_55af8f32-e38c-5826-a17c-d1c228c5624c.html">start later</a> or <a href="https://www.twincities.com/2021/06/08/st-paul-school-year-ends-three-days-early-because-of-high-temperatures/">end earlier</a>. However, there are limits to this approach because there are minimum requirements for the number of days that are in the school year. Some schools are even experimenting with <a href="https://www.startribune.com/heat-prompts-some-minneapolis-schools-to-move-to-distance-learning/600065654/">remote learning as a response</a> when extreme temperatures are an issue.</p>
<p>The bottom line for schools and their surrounding communities is that rising temperatures from climate change are a growing threat to school infrastructure. Schools will need additional funding to install or upgrade air conditioning systems, pay for increased energy usage or redesign school buildings to enhance natural cooling. <a href="https://insideclimatenews.org/news/17012020/climate-change-fossil-fuel-company-lawsuits-timeline-exxon-children-california-cities-attorney-general/">Various cities and states</a> argue that fossil fuel companies have a duty to pay these infrastructure costs associated with climate change.</p>
<p>The only other choice is for America’s students to continue to endure classrooms where it’s simply too hot to learn. </p>
<p>[<em>Like what you’ve read? Want more?</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=likethis">Sign up for The Conversation’s daily newsletter</a>.]</p><img src="https://counter.theconversation.com/content/164761/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Chinowsky receives funding from the Center for Climate Integrity. </span></em></p>America’s public schools, which are over 40 years old on average, are not equipped to handle rising temperatures due to climate change, a new study reveals.Paul Chinowsky, Professor of Environmental Design, University of Colorado BoulderLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1643822021-08-02T12:39:12Z2021-08-02T12:39:12Z4 ways extreme heat hurts the economy<figure><img src="https://images.theconversation.com/files/414001/original/file-20210730-19-1v35wkw.jpg?ixlib=rb-1.1.0&rect=307%2C0%2C4574%2C3249&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Corn yields can suffer in high heat. </span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/WholesalePrices/8c2c2c03df9f41298d1e7624bb1de30b/photo?Query=heat%20wave%20farm&mediaType=photo&sortBy=arrivaldatetime:desc&dateRange=Anytime&totalCount=101&currentItemNo=34">AP Photo/Seth Perlman</a></span></figcaption></figure><p>Summer 2021 <a href="https://weather.com/news/climate/news/2021-07-22-americas-hottest-summer-2021">will likely be one of the hottest on record</a> as dozens of cities in the West <a href="https://www.climate.gov/news-features/event-tracker/astounding-heat-obliterates-all-time-records-across-pacific-northwest">experience all-time high temperatures</a>. The extreme heat being felt throughout many parts of the U.S. is <a href="https://www.npr.org/2021/07/17/1016415960/as-extreme-heat-kills-hundreds-oregon-steps-up-push-to-protect-people">causing hundreds of deaths</a>, <a href="https://www.nytimes.com/live/2021/07/27/us/climate-change">sparking wildfires</a> and <a href="https://droughtmonitor.unl.edu">worsening drought conditions</a> in over a dozen states. </p>
<p>How does all this broiling heat affect the broader economy?</p>
<p>As an <a href="https://www.dereklemoine.com">economist who has studied</a> the <a href="http://scholar.google.com/citations?user=614D6AEAAAAJ">effects of weather and climate change</a>, I have examined a large body of work that links heat to economic outcomes. Here are four ways extreme heat hurts the economy – and a little good news. </p>
<h2>1. Growth takes a hit</h2>
<p>Research has found that extreme heat can directly hurt economic growth. </p>
<p>For example, a 2018 study found that the economies of U.S. states <a href="https://doi.org/10.1111/jmcb.12574">tend to grow at a slower pace</a> during relatively hot summers. The data shows that annual growth falls 0.15 to 0.25 percentage points for every 1 degree Fahrenheit that a state’s average summer temperature was above normal. </p>
<p>Laborers in weather-exposed industries such as construction <a href="https://doi.org/10.1086/671766">work fewer hours</a> when it’s hotter. But higher summer temperatures reduce growth in many industries that tend to involve indoor work, including retail, services and finance. Workers are less productive when it’s hotter out.</p>
<h2>2. Crop yields drop</h2>
<p>Agriculture is obviously exposed to weather: After all, crops grow outdoors. </p>
<p>While temperatures up to around 85 F to 90 F (29-32 C) can benefit crop growth, <a href="https://doi.org/10.1073/pnas.0906865106">yields fall sharply</a> when thermostats rise further. Some of the crops hit hard by extreme heat include corn, soybeans and cotton. These reductions in yields could be costly for U.S. agriculture.</p>
<p>For example, a recent study I conducted found that an additional 2 degrees Celsius of global warming <a href="https://www.nber.org/papers/w25008">would eliminate profits</a> from an average acre of farmland in the Eastern U.S. </p>
<p>A prominent example of this was the <a href="https://www.reuters.com/article/us-russia-heat-fires/russia-swelters-in-heatwave-many-crops-destroyed-idUSTRE66F2LX20100716">collapse of the Russian wheat harvest</a> in response to the country’s 2010 heat wave, which raised wheat prices throughout the world.</p>
<h2>3. Energy use soars</h2>
<p>Of course, when it’s hot, <a href="https://www.washingtonpost.com/posteverything/wp/2016/07/22/your-air-conditioner-is-making-the-heat-wave-worse/">energy use goes up</a> as <a href="https://www.eia.gov/todayinenergy/detail.php?id=48796">people and businesses run their air conditioners</a> and other cooling equipment at full blast. </p>
<p>A <a href="https://doi.org/10.1257/app.3.4.152">2011 study found</a> that just one extra day with temperatures above 90 F increases annual household energy use by 0.4%. <a href="https://doi.org/10.3386/w24397">More recent research</a> shows that energy use increases the most in places that tend to be hotter, probably because more households have air conditioning. </p>
<p>This increase in electricity use on hot days stresses electric grids right when people depend on them most, as seen in <a href="https://www.vox.com/2020/8/15/21370128/california-blackouts-rolling-power-outage">California</a> and <a href="https://www.nytimes.com/2021/06/15/climate/texas-heat-wave-electricity.html">Texas</a> during recent heat waves. Blackouts can be quite costly for the economy, as inventories of food and other goods can spoil and many businesses either have to run generators or shut down. For instance, the 2019 California blackouts <a href="https://www.energy.senate.gov/public/index.cfm/files/serve?File_id=93BBC3A5-E6FA-4053-A1A0-532A9714BFC4">cost an estimated $10 billion</a>. </p>
<h2>4. Education and earnings suffer</h2>
<p>A long-term impact of increasingly hotter weather involves how it affects children’s ability to learn – and thus their future earnings. </p>
<p>Research has shown that hot weather during the school year reduces test scores. <a href="https://doi.org/10.1086/694177">Math scores decrease more and more</a> as the temperature rises beyond 70 F (21 C). Reading scores are more resistant high temperatures, which this research claims is consistent with how different regions of the brain respond to heat.</p>
<p>One study suggested that students in schools that lack air conditioning <a href="https://doi.org/10.1257/pol.20180612">learn 1% less</a> for every 1 degree Fahrenheit increase in the school year’s average temperature. It also found that minority students are especially affected by hotter school years, as their schools are especially likely to lack air conditioning. </p>
<p>Lost learning results in <a href="https://doi.org/10.1016/S1573-4463(99)03011-4">lower lifetime earnings</a> and <a href="https://www.aeaweb.org/articles?id=10.1257/jel.39.4.1101">hurts future economic growth</a>.</p>
<p>The impact of extreme heat on development, in fact, begins before we’re even born. <a href="https://doi.org/10.1073/pnas.1702436114">Research has found</a> that adults who were exposed to extreme heat as fetuses <a href="https://doi.org/10.1016/j.jeem.2018.10.001">earn less during their lifetimes</a>. Each extra day with average temperature above 90 F (32 C) reduces earnings 30 years later <a href="https://doi.org/10.1073/pnas.1702436114">by 0.1%</a>. </p>
<h2>Air conditioning can help – to a point</h2>
<p>Air conditioning can offset some of these effects. </p>
<p>For example, studies have found that having a working air conditioner means <a href="https://doi.org/10.1086/684582">fewer people die</a>, <a href="https://doi.org/10.1257/pol.20180612">student learning isn’t compromised</a> and <a href="https://doi.org/10.1073/pnas.1702436114">extreme heat outside during pregnancy doesn’t hurt fetuses</a>. </p>
<p>Not everyone has air conditioning, however, especially in normally cooler areas like Oregon, Washington and Canada that have experienced unusually extreme temperatures this year. And many people <a href="https://www.wnyc.org/story/life-new-york-public-housing-no-air-conditioning/">can’t afford</a> to own or operate them. Survey data from 2017 found that <a href="https://www.eia.gov/todayinenergy/detail.php?id=31312">around half of homes in the Pacific Northwest</a>
lacked air conditioning. And <a href="https://doi.org/10.1257/pol.20180612">about 42% of U.S. classrooms</a> lack an air conditioner. </p>
<p>While heat waves are shown to <a href="https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3892429">induce more households</a> to install air conditioning, it’s hardly a panacea. By 2100, higher use of air conditioning could <a href="https://www.pnas.org/content/112/19/5962.short">increase residential energy consumption by 83% globally</a>. If that energy comes from fossil fuels, it could end up amplifying the heat waves that caused the higher demand in the first place.</p>
<p>[<em>Over 100,000 readers rely on The Conversation’s newsletter to understand the world.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=100Ksignup">Sign up today</a>.]</p>
<p>And in the U.S. South, where air conditioning is omnipresent, hotter-than-usual summers <a href="https://doi.org/10.1111/jmcb.12574">take the greatest toll</a> on states’ economic growth.</p>
<p>In other words, as temperatures rise, economies will continue to suffer.</p><img src="https://counter.theconversation.com/content/164382/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Derek Lemoine 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>Much of the US has been experiencing heat waves in recent weeks. An economist explains how the often record-high temperatures can affect the economy.Derek Lemoine, Associate Professor of Economics, University of ArizonaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1617612021-06-01T14:17:14Z2021-06-01T14:17:14ZOne in three heat deaths since 1991 linked to climate change – here’s how else warming affects our health<p>Since 1991, 37% of lives lost due to extreme heat globally can be attributed to climate change on average. That’s according to <a href="https://www.nature.com/articles/s41558-021-01058-x">a new study</a> which gathered data from 732 locations across 43 countries and calculated how often local temperatures exceeded what is ideal for human health.</p>
<p>The researchers simulated heat conditions with and without emissions to isolate the effect of human-induced warming on heat-related deaths. They found that climate change made a much bigger contribution to the total number of heat deaths (more than 50%) in central and South America and south-east Asia, and countries in southern and western Asia like Iran and Kuwait.</p>
<p>Even as researchers who study the effects of climate change on our health, these are alarming statistics. The sad reality however is that they are almost certain to be underestimates.</p>
<h2>The fingerprint of global warming</h2>
<p>Despite including all inhabited continents, the study missed out large swathes of Africa and Asia, continents which, since 1991, have had the fastest growing <a href="https://www.pewresearch.org/fact-tank/2019/07/10/for-world-population-day-a-look-at-the-countries-with-the-biggest-projected-gains-and-losses-by-2100/">populations</a>. As the study points out, this is a significant limitation that highlights the need for more accessible data in these regions.</p>
<p>The researchers also estimated death rates using a combination of modelling and a statistic called <a href="https://www.cdc.gov/csels/dsepd/ss1978/lesson3/section3.html">crude mortality</a>, which is the total number of deaths in proportion to the population size over a set time. Previous studies have used mortality modelling in this way <a href="https://link.springer.com/content/pdf/10.1007/s12199-013-0354-6.pdf">successfully</a>, but these modelled estimates are never a perfect reflection of reality.</p>
<p>It’s very difficult to pinpoint the <a href="https://www.sciencedirect.com/science/article/pii/S1353829218301205">effects of heat</a> on the cause of death. People with heart or lung disease are among the most <a href="https://www.lancetcountdown.org/data-platform/climate-change-impacts-exposures-and-vulnerability/1-1-health-and-heat/1-1-3-exposure-of-vulnerable-populations-to-heatwaves">vulnerable to heat</a>, but these pre-existing conditions also make it difficult to separate the influence of heat from their cause of death. </p>
<p>As a result, many cases of heat-related death go <a href="https://insideclimatenews.org/news/16052021/extreme-heat-risks-climate-change/">unreported</a>. At the same time, what we do know suggests heat extremes – particularly when they coincide with <a href="https://theconversation.com/days-with-both-extreme-heat-and-extreme-air-pollution-are-becoming-more-common-which-cant-be-a-good-thing-for-global-health-139957">high levels of air pollution</a> – are among <a href="https://www.undrr.org/publication/2020-non-covid-year-disasters">the deadliest weather hazards</a>.</p>
<p>But climate deniers often argue that the prospect of fewer deaths related to cold weather means that global heating, on balance, actually <a href="https://theconversation.com/overshadowed-by-covid-the-deadly-extreme-weather-of-2020-151237">saves lives</a>. This might seem logical, but it’s wrong. The reality is much more <a href="https://www.wunderground.com/cat6/Which-Kills-More-People-Extreme-Heat-or-Extreme-Cold">complicated</a>.</p>
<h2>Climate change and health</h2>
<p><a href="https://www.researchgate.net/publication/345668632_Heatwaves_An_invisible_risk_in_UK_policy_and_research">Our own research</a> has revealed the manifold ways in which heat affects health. The more frequent and intense heatwaves caused by climate change are perhaps the most obvious examples. But extreme heat can also <a href="https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(20)30037-1/fulltext">stunt growth</a> in children and increase the <a href="https://www.nature.com/articles/s41598-021-81496-x">likelihood of stillbirths</a>. The health effects of climate change encompass far more than just heat of course. Diseases carried by mosquitoes are <a href="https://www.who.int/bulletin/archives/78(9)1136.pdf">expanding</a> across the Earth as temperatures rise.</p>
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Read more:
<a href="https://theconversation.com/malaria-new-map-shows-which-areas-will-be-at-risk-because-of-global-warming-144783">Malaria: new map shows which areas will be at risk because of global warming</a>
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<p>Other natural hazards caused by climate change offer serious challenges to health and wellbeing, even though they may not be seen as such and are rarely <a href="https://publichealthmatters.blog.gov.uk/2014/01/06/flooding-and-the-publics-health-looking-beyond-the-short-term/">addressed in that manner</a>. People are often evacuated during a serious flood only to be tormented by the outbreak of waterborne illnesses like Cholera, which happened in <a href="https://reliefweb.int/report/democratic-republic-congo/crisisinsight-weekly-picks-26-may-2021">Somalia in May 2021</a>.</p>
<p>We need to reexamine how we think about climate change. Its effects are not so remote and impersonal as melting glaciers might for instance seem. It affects <a href="https://www.climaterealityproject.org/blog/how-climate-change-affecting-our-lives">our lives</a> in ways we may not even be aware of. Even in more affluent and insulated parts of the world, these effects are creeping up.</p>
<p>Climate change will play havoc with the supply chains of products like tea, much of which comes from Kenya where yield is <a href="https://www.preventionweb.net/news/view/77706">projected to fall</a>. Millions of people rely on rice for their daily meal, but its yield too is likely to be <a href="http://www.fao.org/forestry/15526-03ecb62366f779d1ed45287e698a44d2e.pdf">affected by climate change</a>.</p>
<figure class="align-center ">
<img alt="Farmers sift through a parched field." src="https://images.theconversation.com/files/403784/original/file-20210601-13-1y3tqaf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403784/original/file-20210601-13-1y3tqaf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403784/original/file-20210601-13-1y3tqaf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403784/original/file-20210601-13-1y3tqaf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403784/original/file-20210601-13-1y3tqaf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403784/original/file-20210601-13-1y3tqaf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403784/original/file-20210601-13-1y3tqaf.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">Continuous high temperatures are already causing rice crop failures in south-east Asia.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/rice-field-affected-by-continuous-high-709382947">Vietnam Stock Images/Shutterstock</a></span>
</figcaption>
</figure>
<p>Other recent research suggests the world has a <a href="https://public.wmo.int/en/media/press-release/new-climate-predictions-increase-likelihood-of-temporarily-reaching-15-%C2%B0c-next-5#:%7E:text=Geneva%2C%2027%20May%202021%20(WMO,by%20the%20World%20Meteorological%20Organization%20(">40% chance</a> of reaching the 1.5°C warming threshold in the next five years. With every passing temperature increment, the consequences for human health <a href="https://climate.nasa.gov/news/2865/a-degree-of-concern-why-global-temperatures-matter/">will only grow</a>.</p>
<p>The world has no time to waste in cutting emissions. For every 0.1°C of warming avoided, thousands of lives can be spared.</p><img src="https://counter.theconversation.com/content/161761/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chloe Brimicombe receives funding from NERC through the SCENARIO DTP and the University of Reading. She is seconded to ECMWF and works as an analyst with the HIDALGO project. She is associated with the Walker Institute and Evidence for Development. </span></em></p><p class="fine-print"><em><span>Hannah Cloke advises the Environment Agency, the European Centre for Medium-range Weather Forecasts, the Copernicus Emergency Management Service, local and national governments and humanitarian agencies on the forecasting and warning of natural hazards. She is a Council member of the UKRI Natural Environment Research Council, a fellow of the European Centre for Medium-range Weather Forecasts, a fellow of the Centre for Natural Hazards & Disaster Science in Sweden and is also affiliated to Uppsala University in Sweden. Her research is funded by the UKRI Engineering & Physical Sciences Research Council, the UKRI Natural Environment Research Council and the Foreign, Commonwealth & Development Office. </span></em></p>Climate change has profound, but often overlooked, consequences for human health.Chloe Brimicombe, PhD Candidate in Climate Change and Health, University of ReadingHannah Cloke, Professor of Hydrology, University of ReadingLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1519482020-12-15T14:21:16Z2020-12-15T14:21:16ZA tropical fish evolved to endure rising temperatures – but it may not be fast enough to survive climate change<figure><img src="https://images.theconversation.com/files/374934/original/file-20201214-21-6k6xmj.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2000%2C1125&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Zebrafish are small, freshwater fish native to South Asia.</span> <span class="attribution"><span class="source">Per Harald Olsen/NTNU</span>, <span class="license">Author provided</span></span></figcaption></figure><p>The climate is changing, and heatwaves are becoming more common and intense as a result. For the Great Barrier Reef, the <a href="https://oceanservice.noaa.gov/facts/gbrlargeststructure.html#:%7E:text=The%20Great%20Barrier%20Reef%20is,reef%20system%20in%20the%20world.">world’s largest structure</a> of living tissue, the consequences are clear. The reef suffered its <a href="https://www.theguardian.com/environment/2020/mar/26/great-barrier-reefs-latest-bleaching-confirmed-by-marine-park-authority#:%7E:text=Guardian%20Australia%20revealed%20on%20Wednesday,nine%2Dday%20aerial%20survey%20trip.">third mass coral bleaching</a> event in five years in 2020, caused by prolonged periods with high water temperatures. Conservation scientists recently downgraded the ecosystem’s condition to “<a href="https://www.theguardian.com/environment/2020/dec/03/great-barrier-reef-outlook-critical-as-climate-change-called-number-one-threat-to-world-heritage">critical</a>”.</p>
<p>You might expect mobile animals like fish to fare better, but their body temperatures closely match that of the surrounding water. Fish can of course swim and escape high temperatures to an extent – and many species have <a href="https://www.nature.com/articles/nclimate1539">shifted their ranges poleward</a> or into deeper, cooler waters. But migration isn’t always possible. Freshwater fish, for instance, are restricted to their native rivers or lakes. Their ability to adapt to high temperatures may decide whether or not they endure.</p>
<p>Whether an organism does survive a heatwave may depend on its <a href="https://www.nature.com/articles/s41598-018-25593-4">upper thermal tolerance</a> – the temperature at which the organism can no longer function. Some fish populations are already living in water close to their temperature limits and so only have a small margin of additional warming they can safely tolerate. As heatwaves become more extreme and <a href="https://science.sciencemag.org/content/305/5686/994">maximum temperatures increase</a>, those species that cannot evolve fast enough to tolerate them may go extinct.</p>
<p>In <a href="https://www.pnas.org/cgi/doi/10.1073/pnas.2011419117">a recent study</a>, colleagues at the Norwegian University of Science and Technology and I measured the evolution of thermal tolerance using a wild population of zebrafish. Working in a lab, we selectively bred fish which excelled at resisting high temperatures. Over six generations we selected more than 20,000 of these zebrafish in an experiment lasting three years.</p>
<h2>Climate change is outpacing evolution</h2>
<p>Zebrafish are the lab rats of the aquatic world, but <a href="https://www.liebertpub.com/doi/full/10.1089/zeb.2019.1778">in the wild</a>, they can be found in shallow ponds and streams in South Asia, at temperatures very <a href="https://academic.oup.com/conphys/article/7/1/coz036/5521853">close to their thermal limits</a>. Shallow water can heat up rapidly during heatwaves, so zebrafish are an ideal species to help us understand whether evolution will keep up with rising temperatures.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/375102/original/file-20201215-18-5w5bfn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Panorama of a shallow mountain stream in the Indian jungle." src="https://images.theconversation.com/files/375102/original/file-20201215-18-5w5bfn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/375102/original/file-20201215-18-5w5bfn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=255&fit=crop&dpr=1 600w, https://images.theconversation.com/files/375102/original/file-20201215-18-5w5bfn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=255&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/375102/original/file-20201215-18-5w5bfn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=255&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/375102/original/file-20201215-18-5w5bfn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=320&fit=crop&dpr=1 754w, https://images.theconversation.com/files/375102/original/file-20201215-18-5w5bfn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=320&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/375102/original/file-20201215-18-5w5bfn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=320&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Zebrafish live in shallow freshwater habitats which can overheat quickly.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/panorama-mountain-river-jungle-india-goa-511938031">Mr. Tempter/Shutterstock</a></span>
</figcaption>
</figure>
<p>After breeding zebrafish with the highest levels of thermal tolerance for six generations, we found that this upper limit increased by 0.04°C with each new generation. It’s encouraging that species can evolve this ability, but the rate of change is likely to be too slow for most fishes. And while evolution helped make this species more tolerant of higher temperatures over time, it hindered how well the fish could acclimate. </p>
<p>Acclimation is how animals exposed to environmental change adjust their physiology to cope better in the new conditions. In our experiment, one group of fish acclimated to raised temperatures over two weeks, allowing their thermal tolerance to increase. Acclimation occurs within individuals, while evolution occurs across generations. </p>
<p>But zebrafish cannot keep raising their thermal tolerance infinitely. We found that fish which had evolved to raise their upper thermal tolerance could only acclimate to a smaller amount of further warming. Eventually, their physiology will probably reach a temperature ceiling which they’re unable to overcome, either by evolving or acclimating, making death likely. Zebrafish in their native habitats in India will struggle to keep increasing their tolerance to match the <a href="https://link.springer.com/article/10.1007/s10113-014-0660-6?shared-article-renderer">projected rate of warming</a>.</p>
<p>It’s possible that other tropical species living close to their thermal limits will face a similar situation, and be especially vulnerable to climate change. Temperatures are already exceeding these limits for certain species. Mass deaths following heatwaves have been reported not only for <a href="https://www.pnas.org/content/117/41/25378">fish</a>, but also in warm-blooded animals such as tropical <a href="https://royalsocietypublishing.org/doi/10.1098/rsbl.2009.0702">birds</a> and <a href="https://royalsocietypublishing.org/doi/abs/10.1098/rspb.2007.1385">bats</a>.</p>
<p>Climate change is likely outpacing evolution for many tropical species. Unless we dramatically reduce greenhouse gas emissions, it’s possible that many populations will become extinct over the coming decades.</p><img src="https://counter.theconversation.com/content/151948/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This work was funded by the Research Council of Norway and the Norwegian University of Science and Technology (NTNU).</span></em></p>Species can evolve to tolerate higher temperatures – but there’s a ceiling beyond which adaptation isn’t possible.Rachael Morgan, Postdoctoral Research Associate in Ecophysiology, University of GlasgowLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1499212020-11-26T15:10:21Z2020-11-26T15:10:21ZExtreme heat is a threat to lives in Africa, but it’s not being monitored<figure><img src="https://images.theconversation.com/files/369291/original/file-20201113-13-1ux7epw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Heatwaves pose a huge threat to human health.</span> <span class="attribution"><span class="source">Leolintang/Shutterstock</span></span></figcaption></figure><p>Extreme heat is a <a href="https://www.who.int/globalchange/publications/WMO_WHO_Heat_Health_Guidance_2015.pdf?ua=1">serious hazard</a> to people’s health. It affects the cardiovascular system and is particularly dangerous for the elderly and people with pre-existing health conditions. </p>
<p><a href="https://www.nature.com/articles/s41467-020-16970-7">Recent research</a> has found that since the 1950s, extreme heat has become more frequent and severe, and lasted longer, in nearly all regions of the world. The biggest increases have been seen in the Middle East, South America and parts of Africa. </p>
<p>Because societies in different parts of the world have adapted to varying average temperatures, there’s no universal definition of what temperature range qualifies as extreme. For instance, in the UK temperatures above 25⁰C are rare whereas the Indian Meteorological Service only <a href="https://internal.imd.gov.in/section/nhac/dynamic/FAQ_heat_wave.pdf">considers temperatures above 40⁰C as hot</a>.</p>
<p>But almost everywhere thresholds are now more frequently exceeded and for more days at a time. </p>
<p>More worrying is that climate projections show that such heatwaves over the African continent will become hotter and more dangerous, even if global warming is <a href="https://www.carbonbrief.org/in-depth-qa-ipccs-special-report-on-climate-change-at-one-point-five-c#impacts">kept below 1.5°C</a>. Particularly strong increases in extreme heat are foreseen over Eastern and Southern Africa.</p>
<p>Bearing in mind changes in populations, the number of people exposed to dangerous heat in African cities is expected to increase <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018EF001020">at least 20-fold by the end of the century</a>.
Yet extreme heatwaves aren’t systematically monitored in many countries in the sub-Saharan Africa region. </p>
<p>As we explain in a <a href="https://www.nature.com/articles/s41558-020-0851-8">recent paper</a>, this means the effects of extreme heat are under-reported – putting even more people in harm’s way. </p>
<p>In most countries in sub-Saharan Africa there are no early warnings and no heat action plans. Unnecessary, premature deaths aren’t counted. And there are <a href="https://reliefweb.int/report/world/european-summer-heatwaves-most-lethal-disaster-2019-says-international-research-group">very few adaptation efforts</a> for the fastest growing hazard in a changing climate.</p>
<h2>Gaps in the records</h2>
<p>There’s a near-complete absence of reported heatwave events over sub-Saharan Africa in disaster databases. The largest of these databases, <a href="https://www.emdat.be/">EM-DAT</a>, lists technological and environmental disasters across the world. It records events like earthquakes and oil spills and their impact on lives, livelihoods and economies. </p>
<p>EM-DAT lists only two heatwaves in sub-Saharan Africa since 1900. These have led to 71 recorded premature deaths. By contrast, 83 heatwaves were recorded in Europe over the last 40 years alone. Other inventories of weather-related disasters contain similarly stark discrepancies.</p>
<p>Heatwaves in Africa are not reported by governments, weather services or public health agencies, though they are obviously happening. Exposure and vulnerability to extreme weather is also <a href="https://www.ipcc.ch/site/assets/uploads/2018/02/WGIIAR5-Chap22_FINAL.pdf">more pronounced</a> in many sub-Saharan African countries when compared with European countries. This is mainly due to <a href="https://link.springer.com/article/10.1007/s10584-018-2211-5">higher poverty levels, informal settlements and the need for outdoor work</a>. </p>
<p>Hence, there’s likely to be an even larger number of premature deaths from severe heat. But they have never been registered, so the number is unknown.</p>
<h2>Reporting and observing</h2>
<p>A lack of reporting on deaths associated with heatwaves means there’s little awareness that extreme heat can be deadly. It was only after the 2003 European heatwave <a href="https://doi.org/10.1016/j.crvi.2007.12.001">killed more than 70,000 people</a> that countries and cities began to <a href="https://doi.org/10.1093/ije/dym253">plan</a> for such times. </p>
<p>The Indian city of Ahmedabad <a href="https://www.hindawi.com/journals/jeph/2018/7973519/">implemented a heatwave plan</a> after an extremely hot and deadly pre-monsoon season in 2010. This resulted in the country reporting fewer deaths after an even more intense heatwave in 2015.</p>
<p>This type of planning is impossible if heatwaves aren’t recorded. </p>
<figure class="align-center ">
<img alt="An old wooden fishing boat on a dried up river bed." src="https://images.theconversation.com/files/371017/original/file-20201124-13-77dm5l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/371017/original/file-20201124-13-77dm5l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/371017/original/file-20201124-13-77dm5l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/371017/original/file-20201124-13-77dm5l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/371017/original/file-20201124-13-77dm5l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/371017/original/file-20201124-13-77dm5l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/371017/original/file-20201124-13-77dm5l.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">Heatwaves are possibly unreported as they may occur along with other extreme weather events such as droughts.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Since heatwave mortality is rarely reported in sub-Saharan Africa, we don’t know the precise temperature thresholds that result in heat-related mortality. Yet this information is crucial for local communities to adapt. </p>
<p>In Ahmedabad, for example, the <a href="https://en.climate-data.org/asia/india/gujarat/ahmedabad-2828/">average daily maximum temperatures are usually around 40°C in April and May</a>. In Western Europe such temperatures would constitute <a href="https://www.worldweatherattribution.org/human-contribution-to-the-record-breaking-july-2019-heat-wave-in-western-europe/">a severe heatwave</a>. The consequences would be deadly if the temperatures remained at this level for several consecutive days.</p>
<p>One reason for this uneven reporting of extreme heat lies in which entities report the impact of extreme weather. In most developed countries, national governments provide numbers about affected people, mortality rates and even economic losses for extreme weather events. But for many lower-income countries, these reports are provided by different NGOs as an unsystematic by-product of their disaster relief work. </p>
<p>Reporting standards differ depending on the NGO and usually have little or no connection to meteorological services. There’s no central place that records the nature of the event and its impact.</p>
<p>Another reason heatwaves aren’t reported could be that they might occur in combination with droughts. They can often lead to food insecurity and humanitarian crises. So most observations and response mechanisms developed by NGOs and governments are tailored to the adverse outcomes of drought.</p>
<h2>What needs to be done</h2>
<p>In our paper we identified several key areas where improvements can occur quickly.</p>
<p>First, early warning systems and heat action plans can be beneficial. At first they might have to be based on information from other countries with similar climates. More analysis of historical periods of extreme heat in sub-Saharan Africa from a purely meteorological standpoint can help to build a useful definition of heatwaves for the region and improve warnings.</p>
<p>Second, collaborations between local researchers, hospitals and epidemiologists can identify direct health impacts of extreme heat. There have been successful pilot projects in <a href="https://journals.lww.com/environepidem/Fulltext/2019/10001/The_influence_of_apparent_temperature_on_mortality.901.aspx">Ghana</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7141168.2/">The Gambia</a>. </p>
<p>Heatwaves are killers. But relatively simple measures such as opening public buildings to provide cool rooms, distributing free drinking water, informing people about the dangers of heat and early warning can reduce the danger dramatically. </p>
<p>Combining data with local expertise, the effects of heatwaves can be understood and future risks minimised even though the hazard itself is increasing.</p><img src="https://counter.theconversation.com/content/149921/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Luke Harrington receives funding from BNP Paribas climate foundation and FORMAS. </span></em></p><p class="fine-print"><em><span>Friederike Otto receives funding amongst others from the BNP Paribas climate foundation, Newton foundation, FORMAS. </span></em></p>Extreme heatwaves aren’t systematically monitored in most countries in sub-Saharan Africa. This leads to unnecessary and premature deaths which are often unrecorded.Luke Harrington, Senior Research Fellow in Climate Science, Te Herenga Waka — Victoria University of WellingtonFriederike Otto, Associate Director, Environmental Change Institute, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1415892020-06-29T04:49:57Z2020-06-29T04:49:57ZAnger is all the rage on Twitter when it’s cold outside (and on Mondays)<figure><img src="https://images.theconversation.com/files/344418/original/file-20200629-104516-1eoie2u.jpg?ixlib=rb-1.1.0&rect=54%2C0%2C5952%2C4007&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>The link between hot weather and aggressive crime is <a href="https://doi.org/10.1007/s00484-019-01689-y">well established</a>. But can the same be said for online aggression, such as angry tweets? And is online anger a predictor of assaults?</p>
<p>Our study <a href="https://journals.sagepub.com/doi/10.1177/0013916520937455">just published</a> suggests the answer is a clear “no”. We found angry tweet counts actually increased in cooler weather. And as daily maximum temperatures rose, angry tweet counts decreased.</p>
<p>We also found the incidence of angry tweets is highest on Mondays, and perhaps unsurprisingly, angry Twitter posts are most prevalent after big news events such as a leadership spill.</p>
<p>This is the first study to compare patterns of assault and social media anger with temperature. Given <a href="https://doi.org/10.1371/journal.pone.0110184">anger spreads</a> through online communities faster than any other emotion, the findings have broad implications – especially under climate change.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/344431/original/file-20200629-104484-19vl5a0.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/344431/original/file-20200629-104484-19vl5a0.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=778&fit=crop&dpr=1 600w, https://images.theconversation.com/files/344431/original/file-20200629-104484-19vl5a0.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=778&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/344431/original/file-20200629-104484-19vl5a0.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=778&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/344431/original/file-20200629-104484-19vl5a0.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=977&fit=crop&dpr=1 754w, https://images.theconversation.com/files/344431/original/file-20200629-104484-19vl5a0.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=977&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/344431/original/file-20200629-104484-19vl5a0.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=977&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A caricature of US President Donald Trump, who’s been known to fire off an angry tweet.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Algorithms are watching you</h2>
<p>Of Australia’s 24.6 million people, 18 million, or 73%, <a href="https://wearesocial.com/au/blog/2019/02/digital-report-australia">are active social media users</a>. Some 4.7 million Australians, or 19%, use Twitter. This widespread social media use provides researchers with valuable opportunities to gather information. </p>
<p>When you publicly post, comment or even <a href="https://theconversation.com/ai-can-now-read-emotions-should-it-128988">upload a selfie</a>, an algorithm can scan it to estimate your mood (positive or negative) or your emotion (such as anger, joy, fear or surprise). </p>
<p>This information can be linked with the date, time of day, location or even your age and sex, to determine the “mood” of a city or country in near real time.</p>
<p>Our study involved 74.2 million English-language Twitter posts – or tweets – from 2015 to 2017 in New South Wales.</p>
<p>We analysed them using the publicly available <a href="http://wefeel.csiro.au/#/">We Feel</a> tool, developed by the <a href="https://data61.csiro.au/">CSIRO</a> and the <a href="https://www.blackdoginstitute.org.au/">Black Dog Institute</a>, to see if social media can accurately map our emotions.</p>
<p>Some 2.87 million tweets (or 3.87%) contained words or phrases considered angry, such as “vicious”, “hated”, “irritated”, “disgusted” and the very popular “f*cked”.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1275559505871335424"}"></div></p>
<h2>Hot-headed when it’s cold outside</h2>
<p>On average, the number of angry tweets were highest when the temperature was below 15°C, and lowest in warm temperatures (25-30°C). </p>
<p>The number of angry tweets slightly increased again in very high temperatures (above 35°C), although with fewer days in that range there was less certainty about the trend.</p>
<p>On the ten days with the highest daily maximum temperatures, the average angry tweet count was 2,482 per day. Of the ten coldest days, the average angry tweet count was higher at 3,354 per day. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/meet-sara-sharon-and-mel-why-people-spreading-coronavirus-anxiety-on-twitter-might-actually-be-bots-134802">Meet ‘Sara’, ‘Sharon’ and 'Mel': why people spreading coronavirus anxiety on Twitter might actually be bots</a>
</strong>
</em>
</p>
<hr>
<p>The pattern of angry tweets was opposite to that of physical assaults, which are more prevalent in hotter weather – with some evidence of a decline in extreme heat.</p>
<p>So why the opposite patterns? We propose two possible explanations.</p>
<p>First, <a href="https://theconversation.com/how-rising-temperatures-affect-our-health-123016">hot</a> and <a href="https://theconversation.com/forget-heatwaves-our-cold-houses-are-much-more-likely-to-kill-us-83030">cold</a> weather triggers a physiological response in humans. Temperature affects our heart rate, the amount of oxygen to our brain, hormone regulation (including testosterone) and our <a href="https://theconversation.com/too-hot-to-sleep-heres-why-11492">ability to sleep</a>. In some people, this in turn affects physical aggression levels.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/344439/original/file-20200629-96691-y5qqik.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/344439/original/file-20200629-96691-y5qqik.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/344439/original/file-20200629-96691-y5qqik.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/344439/original/file-20200629-96691-y5qqik.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/344439/original/file-20200629-96691-y5qqik.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/344439/original/file-20200629-96691-y5qqik.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/344439/original/file-20200629-96691-y5qqik.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">Hot weather means more socialising, and potentially less time for tweeting.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Second, weather triggers changes to our routine. <a href="https://doi.org/10.1177/0013916503255565">Research suggests</a> aggressive crimes increase because warmer weather encourages behaviour that fosters assaults. This includes more time outdoors, increased socialising and drinking alcohol.</p>
<p>Those same factors – time outdoors and more socialising – may reduce the opportunity or motivation to tweet. And the effects of alcohol (such as reduced mental clarity and physical precicion) make composing a tweet harder, and therefore less likely.</p>
<p>This theory is supported by our finding that both angry tweet counts, as well as overall tweet counts, were lowest on weekends, holidays and the hottest days, </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/car-accidents-drownings-violence-hotter-temperatures-will-mean-more-deaths-from-injury-129628">Car accidents, drownings, violence: hotter temperatures will mean more deaths from injury</a>
</strong>
</em>
</p>
<hr>
<p>It’s possible that as people vent their frustrations online, they <a href="https://link.springer.com/referenceworkentry/10.1007%2F978-1-4419-1428-6_573">feel better</a> and are then less inclined to commit an assault. However, this theory <a href="https://doi.org/10.1080/10926771.2019.1575303">isn’t well supported</a>.</p>
<p>The relationship is more likely due to the vastly different demographics of Twitter users and assault offenders.</p>
<p><a href="https://www.parliament.nsw.gov.au/researchpapers/Documents/A%20statistical%20snapshot%20of%20crime%20and%20justice%20in%20NSW.pdf">Assault offenders</a> are most likely to be young men from low socio-economic backgrounds. In contrast, about half of <a href="https://www.pewresearch.org/fact-tank/2019/04/10/share-of-u-s-adults-using-social-media-including-facebook-is-mostly-unchanged-since-2018/">Twitter users</a> are female, and they’re more likely to be middle-aged and in a higher income bracket compared with other social media users.</p>
<p>Our study did not consider why these two groups differ in response to temperature. However, we are currently researching how age, sex and other social and demographic factors influence the relationships between temperature and aggression.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/344436/original/file-20200629-96639-1rvg2a7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/344436/original/file-20200629-96639-1rvg2a7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/344436/original/file-20200629-96639-1rvg2a7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/344436/original/file-20200629-96639-1rvg2a7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/344436/original/file-20200629-96639-1rvg2a7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/344436/original/file-20200629-96639-1rvg2a7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/344436/original/file-20200629-96639-1rvg2a7.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">Twitter users are more likely to be middle aged.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>The Monday blues</h2>
<p>Our study primarily set out to see whether temperatures and angry tweet counts were related. But we also uncovered other interesting trends. </p>
<p>Average angry tweet counts were highest on a Monday (2,759 per day) and lowest on weekends (Saturdays, 2,373; Sundays, 2,499). This supports research that found an <a href="https://doi.org/10.1145/2661829.2662090">online mood slump on weekdays</a>.</p>
<p>We determined that <a href="https://journals.sagepub.com/doi/suppl/10.1177/0013916520937455">major news events</a> correlated with the ten days where the angry tweet count was highest. These events included:</p>
<ul>
<li><p>the federal leadership spill in 2015 when Malcolm Turnbull replaced Tony Abbott as prime minister</p></li>
<li><p>a severe storm front in NSW in 2015, then a major cold front a few months later</p></li>
<li><p>two mass shootings in the United States: Orlando in 2016 and Las Vegas in 2017</p></li>
<li><p>sporting events including the Cricket World Cup in 2015.</p></li>
</ul>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/344447/original/file-20200629-155303-137dhdh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/344447/original/file-20200629-155303-137dhdh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=383&fit=crop&dpr=1 600w, https://images.theconversation.com/files/344447/original/file-20200629-155303-137dhdh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=383&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/344447/original/file-20200629-155303-137dhdh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=383&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/344447/original/file-20200629-155303-137dhdh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=482&fit=crop&dpr=1 754w, https://images.theconversation.com/files/344447/original/file-20200629-155303-137dhdh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=482&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/344447/original/file-20200629-155303-137dhdh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=482&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Days with high angry tweet counts correlated with major news events.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Twitter in a warming world</h2>
<p>Our study was limited in that Twitter users are not necessarily representative of the broader population. For example, Twitter is a preferred medium for <a href="https://books.google.com.au/books?hl=en&lr=&id=ZcVxGdegAJ8C&oi=fnd&pg=PR5&dq=Parmelee+%26+Bichard,+2011&ots=TM3BMSQQiZ&sig=NO-Aj_IEUR-t_da_629TVDt3O7o">politicians</a>, <a href="https://doi.org/10.1002/meet.14504701201">academics</a> and <a href="https://doi.org/10.1007/978-3-642-20161-5_34">journalists</a>. These users may express different emotions, or less emotion, in their posts than other social media users.</p>
<p>However, the influence of temperature on social media anger has broad implications. Of all the emotions, <a href="https://doi.org/10.1371/journal.pone.0110184">anger spreads</a> through online communities the fastest. So temperature changes and corresponding social media anger can affect the wider population.</p>
<p>We hope our research helps health and justice services develop more targeted measures based on temperature. </p>
<p>And with climate change likely to affect <a href="https://doi.org/10.3386/w20598">assault rates </a>and <a href="https://doi.org/10.1016/j.apgeog.2015.06.017">mood</a>, more research in this field is needed.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/nine-things-you-love-that-are-being-wrecked-by-climate-change-127099">Nine things you love that are being wrecked by climate change</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/141589/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ivan Charles Hanigan receives funding from the National Health and Medical Research Council. </span></em></p><p class="fine-print"><em><span>Heather R. Stevens, Paul Beggs, and Petra Graham 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>The study examined patterns of Twitter rage in hot and cold weather. Given anger spreads through online communities faster than any other emotions, the findings are important.Heather R. Stevens, Doctoral student in Environmental Sciences, Macquarie UniversityIvan Charles Hanigan, Data Scientist (Epidemiology), University of SydneyPaul Beggs, Associate Professor and Environmental Health Scientist, Macquarie UniversityPetra Graham, Senior Research Fellow, Macquarie Business School, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1393002020-06-03T20:09:55Z2020-06-03T20:09:55ZWe dug up Australian weather records back to 1838 and found snow is falling less often<figure><img src="https://images.theconversation.com/files/338663/original/file-20200530-78845-10bl8yn.jpeg?ixlib=rb-1.1.0&rect=0%2C72%2C1022%2C712&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">State Library of South Australia</span></span></figcaption></figure><p>As we slowly emerge from lockdown, local adventures are high on people’s wish lists. You may be planning a trip to the ski fields, or even the nearby hills to revel in the white stuff that occasionally falls around our southern cities after an icy winter blast. </p>
<p>Our <a href="https://link.springer.com/article/10.1007/s00382-020-05298-z">new research</a> explores these low-elevation snowfall events. We pieced together weather records back to 1838 to create Australia’s longest analysis of daily temperature extremes and their impacts on society. </p>
<p>These historical records can tell us a lot about Australia’s pre-industrial climate, before the large-scale burning of fossil fuels tainted global temperature records.</p>
<p>They also help provide a longer context to evaluate more recent temperature extremes. </p>
<p>We found snow was once a regular feature of the southern Australian climate. But as Australia continues to warm under climate change, cold extremes are becoming less frequent and heatwaves more common. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/338667/original/file-20200530-78871-12zrq21.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/338667/original/file-20200530-78871-12zrq21.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/338667/original/file-20200530-78871-12zrq21.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/338667/original/file-20200530-78871-12zrq21.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/338667/original/file-20200530-78871-12zrq21.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/338667/original/file-20200530-78871-12zrq21.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/338667/original/file-20200530-78871-12zrq21.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">Heatwaves in Adelaide are becoming more common.</span>
<span class="attribution"><span class="source">David Mariuz/AAP</span></span>
</figcaption>
</figure>
<h2>Extending Australia’s climate record</h2>
<p>Data used by the Bureau of Meteorology to study long-term weather and climate dates back to the early 1900s. This is when good coverage of weather stations across the country began, and observations were taken in a <a href="https://theconversation.com/why-scientists-adjust-temperature-records-and-how-you-can-too-36825">standard way</a>.</p>
<p>But many <a href="https://theconversation.com/delving-through-settlers-diaries-can-reveal-australias-colonial-era-climate-72652">older weather records exist</a> in national and state archives and libraries, as well as local historical societies around the country.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/some-say-weve-seen-bushfires-worse-than-this-before-but-theyre-ignoring-a-few-key-facts-129391">Some say we've seen bushfires worse than this before. But they're ignoring a few key facts</a>
</strong>
</em>
</p>
<hr>
<p>We analysed daily weather records from the coastal city of Adelaide and surrounding areas, including the Adelaide Hills, back to 1838. Adelaide is the Australian city <a href="https://www.sciencedirect.com/science/article/pii/S1462901114000999">worst affected by heatwaves</a>, and the capital of our nation’s driest state, South Australia. </p>
<p>To crosscheck the heatwaves and cold extremes identified in our historical temperature observations, we also looked at newspaper accounts, model simulations of past weather patterns, and palaeoclimate records. </p>
<p>The agreement was remarkable. It demonstrates the value of historical records for improving our estimation of future climate change risk.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/338729/original/file-20200601-78867-g4kckq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/338729/original/file-20200601-78867-g4kckq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=330&fit=crop&dpr=1 600w, https://images.theconversation.com/files/338729/original/file-20200601-78867-g4kckq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=330&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/338729/original/file-20200601-78867-g4kckq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=330&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/338729/original/file-20200601-78867-g4kckq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=415&fit=crop&dpr=1 754w, https://images.theconversation.com/files/338729/original/file-20200601-78867-g4kckq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=415&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/338729/original/file-20200601-78867-g4kckq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=415&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Weather journal of Adelaide’s historical climate held by the National Archives of Australia.</span>
<span class="attribution"><span class="source">National Archives of Australia</span></span>
</figcaption>
</figure>
<h2>‘Limpness to all mankind’</h2>
<p>While most other historical climate studies have looked at annual or monthly values, the new record enabled us to look at daily extremes. </p>
<p>This is important, because global temperature increases are most clearly detected in changes to extreme events such as heatwaves. Although these events may only last a few days, they have very real impacts on human health, agriculture and infrastructure.</p>
<p>Our analysis focused on the previously undescribed period before 1910, to extend the Bureau of Meteorology’s official record as far as possible. </p>
<p>Using temperature observations, we identified 34 historical heatwaves and 81 cold events in Adelaide from 1838–1910. We found more than twice as many of these “snow days” by conducting an independent analysis of snowfall accounts in historical documents.</p>
<p>Almost all the events in the temperature observations were supported by newspaper reports. This demonstrated our method can accurately identify historical temperature extremes. </p>
<p>For example, an outbreak of cold air on June 22, 1908, delivered widespread snow across the hills surrounding Adelaide. <a href="https://trove.nla.gov.au/newspaper/article/208824714/22917235#">The Express and Telegraph</a> newspaper reported: </p>
<blockquote>
<p>Many people made a special journey from Adelaide by train, carriage, or motor to revel in the unwonted delight of gazing on such a wide expanse of real snow, and all who did so felt that their trouble was amply rewarded by the panorama of loveliness spread out before their enraptured eyes.</p>
</blockquote>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/337783/original/file-20200526-106866-mkst5p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/337783/original/file-20200526-106866-mkst5p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/337783/original/file-20200526-106866-mkst5p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/337783/original/file-20200526-106866-mkst5p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/337783/original/file-20200526-106866-mkst5p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/337783/original/file-20200526-106866-mkst5p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/337783/original/file-20200526-106866-mkst5p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Snowballing at Mount Lofty 29 August 1905.</span>
<span class="attribution"><span class="source">Source: State Library of South Australia</span></span>
</figcaption>
</figure>
<p>From December 26-30, 1897, Adelaide was gripped by a heatwave that produced five days above 40°C. Newspapers reported heat-related deaths, agricultural damage, animals dying in the zoo, bushfires and even “burning hot pavements scorching the soles of people’s shoes”. As <a href="https://bit.ly/36wzczi">The Advertiser</a> reported:</p>
<blockquote>
<p>When the mercury reaches its “century” (100°F or 37.6°C) there must be a really uncomfortable experience for everyone. One such day can be struggled with; but six of them in a fortnight, three in succession — that is a thing to bring limpness to all mankind. </p>
</blockquote>
<p>On December 31, 1897, the <a href="https://bit.ly/3enOrNS">South Australian Register</a> wrote prophetically of future Australian summers:</p>
<blockquote>
<p>May Heaven preserve us from being here when the “scorchers” try and add a few degrees to the total.</p>
</blockquote>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/337800/original/file-20200527-141316-juv7cy.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/337800/original/file-20200527-141316-juv7cy.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=473&fit=crop&dpr=1 600w, https://images.theconversation.com/files/337800/original/file-20200527-141316-juv7cy.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=473&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/337800/original/file-20200527-141316-juv7cy.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=473&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/337800/original/file-20200527-141316-juv7cy.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=594&fit=crop&dpr=1 754w, https://images.theconversation.com/files/337800/original/file-20200527-141316-juv7cy.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=594&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/337800/original/file-20200527-141316-juv7cy.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=594&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Newspaper account of a deadly heatwave published in the South Australian Register on Friday 31 December 1897.</span>
<span class="attribution"><span class="source">National Library of Australia</span></span>
</figcaption>
</figure>
<h2>A longer view</h2>
<p>While Australia has a long history of hot and cold extremes, our extended analysis shows that their frequency and intensity is changing. </p>
<p>The quality of the very early part of the record is still uncertain, so the information from the 1830s and 1840s must be treated with caution. That said, there is excellent agreement with newspaper and other historical records.</p>
<p>Our research suggests low-elevation snow events around Adelaide have become less common over the past 180 years. This can be seen in both temperature observations and independent newspaper accounts. For example, snowfall was exceptionally high in the 1900s and 1910s — more than four times more frequent than other decades.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/black-skies-and-raging-seas-how-the-first-fleet-got-a-first-taste-of-australias-unforgiving-climate-94168">Black skies and raging seas: how the First Fleet got a first taste of Australia's unforgiving climate</a>
</strong>
</em>
</p>
<hr>
<p>We also found heatwaves are becoming more frequent in Adelaide. The decade 2010–19 has the highest count of heatwaves of any decade in the record. Although recent heatwaves are not significantly longer than those of the past, our analysis showed heatwaves of up to ten days are possible.</p>
<p>Previous Australian studies have identified an increase in extreme heat and a corresponding <a href="https://theconversation.com/sure-winter-felt-chilly-but-australia-is-setting-new-heat-records-at-12-times-the-rate-of-cold-ones-35607">decrease in cold events</a>. However, this is the longest analysis in Australia, and the first to systematically combine instrumental and documentary information. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/337963/original/file-20200527-20250-2av1df.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/337963/original/file-20200527-20250-2av1df.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=420&fit=crop&dpr=1 600w, https://images.theconversation.com/files/337963/original/file-20200527-20250-2av1df.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=420&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/337963/original/file-20200527-20250-2av1df.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=420&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/337963/original/file-20200527-20250-2av1df.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=528&fit=crop&dpr=1 754w, https://images.theconversation.com/files/337963/original/file-20200527-20250-2av1df.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=528&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/337963/original/file-20200527-20250-2av1df.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=528&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Number of heatwaves identified in Adelaide from January 1838 to August 2019. No digitised temperature observations are available from 1 January 1848 – 1 November 1856, so these decades are shown in lighter shades.</span>
<span class="attribution"><span class="source">Author supplied</span></span>
</figcaption>
</figure>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/338728/original/file-20200601-78845-1oycbje.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/338728/original/file-20200601-78845-1oycbje.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/338728/original/file-20200601-78845-1oycbje.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/338728/original/file-20200601-78845-1oycbje.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/338728/original/file-20200601-78845-1oycbje.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=377&fit=crop&dpr=1 754w, https://images.theconversation.com/files/338728/original/file-20200601-78845-1oycbje.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=377&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/338728/original/file-20200601-78845-1oycbje.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=377&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Number of extreme cold days identified in Adelaide from January 1838 to August 2019. No digitised temperature observations are currently available from 1 January 1848 – 1 November 1856, so these decades are shaded grey.</span>
<span class="attribution"><span class="source">Author supplied</span></span>
</figcaption>
</figure>
<h2>Learning from the past</h2>
<p>This study shows we can use historical weather records to get a better picture of <a href="https://climatehistory.com.au">Australia’s long-term weather and climate history</a>. By using different sources of information, we can piece together the significant events in our climate history with greater certainty. </p>
<p>Historical records tell us about more than just exciting day trips of the past. They also hold the key to understanding impacts of extreme events, such as heat-related deaths or agricultural damage, in the future.</p>
<p>A better understanding of these pre-industrial extremes will help emergency management services better adapt to increased climate risk, as Australia continues to warm.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/just-how-hot-will-it-get-this-century-latest-climate-models-suggest-it-could-be-worse-than-we-thought-137281">Just how hot will it get this century? Latest climate models suggest it could be worse than we thought</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/139300/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Joelle Gergis has received funding from the Australian Research Council in the past. She currently receives funding from the Australian National University and the Australian Government's Department of the Environment and Energy.</span></em></p><p class="fine-print"><em><span>Linden Ashcroft has received funding from the Australian Research Council in the past. </span></em></p>Older records can tell us a lot about Australia’s pre-industrial climate, before the large-scale burning of fossil fuels tainted global temperature records.Joelle Gergis, Senior Lecturer in Climate Science, Australian National UniversityLinden Ashcroft, Lecturer in climate science and science communication, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1326732020-03-02T19:03:42Z2020-03-02T19:03:42ZFrom crocodiles to krill, a warming world raises the ‘costs’ paid by developing embryos<figure><img src="https://images.theconversation.com/files/317925/original/file-20200301-166528-1r4a03y.jpg?ixlib=rb-1.1.0&rect=5%2C0%2C952%2C718&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><p>Apart from mammals and birds, most animals develop as eggs exposed to the vagaries of the outside world. This development is energetically “costly”. Going from a tiny egg to a fully functioning organism can deplete up to 60% of the energy reserves provided by a parent.</p>
<p>In cold-blooded animals such as marine invertebrates (including sea stars and corals), fish and reptiles, and even insects, embryonic development is very sensitive to changes in the temperature of the environment.</p>
<p>Thus, in a warming world, many cold-blooded species face a new challenge: developing successfully despite rising temperatures. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-do-eggs-have-a-yolk-111605">Curious Kids: why do eggs have a yolk?</a>
</strong>
</em>
</p>
<hr>
<p>For our research, <a href="https://www.nature.com/articles/s41559-020-1114-9">published today in Nature Ecology and Evolution</a>, we mined existing literature for data on how temperature impacts the metabolic and development rates of 71 different species, ranging from tropical crocodiles to Antarctic krill. </p>
<p>We found over time, species tend to fine-tune their physiology so that the temperature of the place they inhabit is the temperature needed to minimise the “costs” of their embryonic development. </p>
<p>Temperature increases associated with global warming could substantially impact many of these species.</p>
<h2>The perfect weather to grow an embryo</h2>
<p>The energy costs of embryonic development are determined by two key rates. The “metabolic” rate refers to the rate at which energy is used by the embryo, and the “development” rate determines how long it takes the embryo to fully develop, and become an independent organism. </p>
<p>Both of these rates are heavily impacted by environmental temperature. Any change in temperature affecting them is therefore costly to an embryo’s development. </p>
<p>Generally, a 10°C increase in temperature will cause an embryo’s development and metabolic rate <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/ele.13213">to more than triple</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/317926/original/file-20200301-166503-7r63z2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/317926/original/file-20200301-166503-7r63z2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/317926/original/file-20200301-166503-7r63z2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/317926/original/file-20200301-166503-7r63z2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/317926/original/file-20200301-166503-7r63z2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/317926/original/file-20200301-166503-7r63z2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/317926/original/file-20200301-166503-7r63z2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/317926/original/file-20200301-166503-7r63z2.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">This photo shows a developing sea urchin, from egg (top left) to larva, to a metamorphosed (matured into adult form) individual.</span>
<span class="attribution"><span class="source">Dustin Marshall</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>These effects partially cancel each other out. Higher temperatures <a href="https://www.nature.com/articles/s41559-020-1114-9">increase the rate at which energy is used (metabolic), but shorten the developmental time</a>.</p>
<p>But do they balance out effectively?</p>
<h2>What are the costs?</h2>
<p>For any species, there is one temperature that achieves the perfect energetic balance between relatively rapid development and low metabolism. <a href="https://www.nature.com/articles/s41559-020-1114-9">This optimal temperature,</a> also called the <a href="https://www.abc.net.au/news/science/2016-02-22/goldilocks-zones-habitable-zone-astrobiology-exoplanets/6907836">“Goldilocks”</a> temperature, is neither too hot, nor too cold.</p>
<p>When the temperature is too cold for a certain species, development takes a long time. When it’s too hot, development time decreases while the metabolic rate continues to rise. An imbalance on either side can negatively impact a natural population’s resilience and ability to replenish. </p>
<p>As an embryo’s developmental costs increase past the optimum, mothers must invest more resources into each offspring to offset these costs. </p>
<p>When offspring become more costly to make, mothers make fewer, larger offspring. These offspring start life with fewer energy reserves, reducing their chances of successfully reproducing as adults themselves.</p>
<p>Thus, when it comes to embryonic development, higher-than ideal temperatures pack a nasty punch for natural populations. </p>
<p>Since the temperature dependencies of metabolic rate and development rate are fairly similar, the slight differences between them <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/ele.13213">had gone unnoticed until recently</a>.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-cold-blooded-animals-dont-need-to-wrap-up-to-keep-warm-29618">Why cold-blooded animals don’t need to wrap up to keep warm</a>
</strong>
</em>
</p>
<hr>
<h2>Embryos at risk</h2>
<p>For each species in our study, we found a narrow band of temperatures that minimised developmental cost. Temperatures that were too high or too low caused massive blow-outs in the energy budget of developing embryos.</p>
<p>This means temperature increases associated with global warming are <a href="https://www.nature.com/articles/s41559-020-1114-9">likely to have bigger impacts than previously predicted</a>.</p>
<p>Predictions of how future temperature changes will affect organisms are often based on estimates of how temperature affects embryo survival. These measures suggest <a href="https://www.nature.com/articles/s41559-020-1114-9">small temperature increases (1°C-2°C) do not reduce embryo survival by much</a>.</p>
<p>But our study found the developmental costs are about twice as high, and we had underestimated the impacts of subtle temperature changes on embryo development.</p>
<h2>In the warming animal kingdom, there are winners and losers</h2>
<p>Some good news is our research suggests not all species are facing rising costs with rising temperatures, at least initially. </p>
<p>We’ve created a mathematical <a href="https://www.nature.com/articles/s41559-020-1114-9">framework called the Developmental Cost Theory</a>, which predicts some species will actually experience slightly lower developmental costs with minor increases in temperature.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/flipping-the-genetic-switch-that-makes-many-animals-look-alike-as-embryos-55631">Flipping the genetic ‘switch’ that makes many animals look alike as embryos</a>
</strong>
</em>
</p>
<hr>
<p>In particular, aquatic species (fish and invertebrates) in cool temperate waters seem likely to experience lower costs in the near future. In contrast, certain tropical aquatic species (including coral reef organisms) are already experiencing temperatures that exceed their optimum. <a href="https://www.nature.com/articles/s41559-020-1114-9">This is likely to get worse.</a></p>
<p>It’s important to note that for all species, increasing environmental temperature will eventually come with costs. </p>
<p>Even if a slight temperature increase reduces costs for one species, too much of an increase will still have a negative impact. This is true for all the organisms we studied.</p>
<p>A key question now is: how quickly can species evolve to adapt to our warming climate?</p><img src="https://counter.theconversation.com/content/132673/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dustin Marshall receives funding from the Australian Research Council. </span></em></p>When offspring become more “costly” to make, mothers make fewer of them. And these offspring start life with fewer energy reserves.Dustin Marshall, Professor, Marine Evolutionary Ecology, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1203692019-07-30T11:51:20Z2019-07-30T11:51:20ZWe tracked South Africa’s sardine run over 66 years: here’s what we found<figure><img src="https://images.theconversation.com/files/284689/original/file-20190718-116579-1pygnd0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">shutterstock</span> </figcaption></figure><p>The <a href="https://www.shark.co.za/Pages/Sardinerun">sardine run</a> is well known among residents of the KwaZulu-Natal coastline that runs along South Africa’s east coast. Every year in winter, sardines migrate close to the shoreline. The event is well documented in the local press. </p>
<p>The sardine run is of great economic importance because it provides prime fishing opportunities and attracts large numbers of tourists who come for dolphin and shark sightings. Similar migration patterns are seen in <a href="https://www.sciencedirect.com/science/article/pii/S0079661111001418">Sweden</a>, <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2419.2012.00632.x">Chile</a>, and the <a href="https://science.sciencemag.org/content/299/5604/217">Pacific Ocean</a>.</p>
<p>The sardine run is what scientists term a “phenological event” – a biological event that occurs at the same time every year. Phenological events are standard for plants and include the appearance of leaf and flower buds, blossoming, fruit development, fruit harvest and leaf colouration and fall. </p>
<p>For animals, the events are more varied and include hibernation, hatching, animal calls, moulting, and in the case of birds, game and fish (among others) migration.</p>
<p>Scientists have become very interested in phenology over the past few decades, because it’s one of the most sensitive biological indicators of climate change. As temperatures increase, the plants or animals experience their triggers for spring earlier and their triggers for winter later. As a result, many of these phenological events are occurring at different times of the year.</p>
<p>In a recently published <a href="https://doi.org/10.17159/sajs.2019/5887">paper</a> in the South African Journal of Science, we examined newspaper articles written between 1946 and 2012 that reported on the South African sardine run. From these articles we established an annual date of the peak of the sardine run. </p>
<p>We then explored how the dates of the sardine run have changed over the 65-year period, and statistically examined oceanographic and climatological factors to determine the cause of this change. We did this because there are very few phenological records for South Africa and consequently, the rate of phenological shifts and the associated climate signal is largely unknown. </p>
<p>Phenology is highly species and location <a href="https://journals.sagepub.com/doi/full/10.1177/0309133315578940">specific</a>, and so it’s important to reconstruct records for as many locations and as many plants and animals as possible. It’s also known that climate <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2005.3356">affects</a> the timing of phenological events globally, including <a href="https://www.nature.com/articles/nature02808">marine environments</a>. </p>
<p>Our research sought to determine changes in the pattern of the sardine run and, possibly, what might be behind them. The hope is that this can help fisheries plan for delays or failed migrations which are happening more <a href="https://www.dw.com/en/our-beautiful-planet-south-africas-sardine-run/a-44071241-0">frequently</a>. </p>
<h2>Nature’s biological clock</h2>
<p>Phenological shifts are specific to species and location. For example, Granny Smith apple trees are flowering approximately four days earlier for each 1°C increase in temperature in <a href="https://www.agriculturejournals.cz/publicFiles/49_2008-HORTSCI.pdf">Poland</a>. In <a href="https://www.sciencedirect.com/science/article/pii/S0168192310002893">South Africa</a>, these Granny Smith apples are flowering two days earlier for each 1°C increase in temperature.</p>
<p>For many species these events are happening earlier. This is because they are spring events and, under climate change, the temperatures that are perceived by plants and animals to be the onset of spring are occurring in late winter. For events that occur in autumn, the events are often occurring later, because the cooling that marks the start of winter has not yet occurred.</p>
<p>This is the case for the South African sardines. </p>
<p>We found that over the 66-year period, sardines arrived off the coast of Durban increasingly late – at a rate of 1.3 days later per decade. Over the six decades this has meant the date has changed from arrivals as early as mid-June at the beginning of the record to dates as late as mid-July in the last decade. </p>
<p>Through statistical analysis comparing the constructed phenological record with climate and ocean data, we hypothesise that the delay could be caused by two things. </p>
<p>First, the ocean water is warmer. Sardines can tolerate a maximum surface temperature of 21°C. But this temperature isn’t being reached consistently at the same time every year due to changes in ocean temperature.</p>
<p>The second factor is mid-latitude cyclones. There have been an increasing number of these in the east coast region. The relationship between them and the sardine run is complex and difficult to pin down. But this has also been <a href="https://www.ncbi.nlm.nih.gov/pubmed/28948709">recorded</a> for sardine migration in the North Pacific. </p>
<h2>Why it matters</h2>
<p>The delay is concerning. First, the large influx of sardines is important for the fishery industry. If the sardine run occurs at an unexpected time, or doesn’t occur at all, supply chains are disrupted and fishermen are placed at economic risk. </p>
<p>The unpredictability is also a problem for tourism. The sardine run attracts visitors who are keen on shark and dolphin sightings and may leave disappointed. </p>
<p>The delays in the sardine run also result in food shortages for predators such as sharks, which feed on the sardines. This is termed a species mismatch, and is increasingly observed as a result of climate change induced phenological shifts, where predators and their prey are no longer in the same place at the same time. This is because each species has its own unique trigger for a particular activity.</p><img src="https://counter.theconversation.com/content/120369/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jennifer Fitchett receives funding from the DST-NRF Centre of Excellence in Palaeoscience. </span></em></p><p class="fine-print"><em><span>Stefan Grab 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>South Africa’s annual sardine run is occurring increasingly late, and there have been instances where it doesn’t happen at all. Here’s why.Jennifer Fitchett, Senior Lecturer in Physical Geography, University of the WitwatersrandStefan Grab, Professor of Historical climate and weather, University of the WitwatersrandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1113892019-02-25T14:15:26Z2019-02-25T14:15:26ZHow environmental health workers can help climate change mitigation<figure><img src="https://images.theconversation.com/files/259900/original/file-20190220-148533-jsdsu6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Environmental health practitioners promote health, safety and well-being.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>All <a href="https://epic.awi.de/id/eprint/37530/">the evidence</a> <a href="https://www.who.int/globalchange/en/">tells us</a> that the world’s changing climate will affect more than the environment. It will have serious consequences for people’s health too.</p>
<p>Southern Africa is in the eye of the climate change storm. In the next 80 years it’s likely to experience an <a href="https://epic.awi.de/id/eprint/37530/1/IPCC_AR5_SYR_Final.pdf">increase in temperature</a> that exceeds the global average. But little is known about whether vulnerable groups in the region are equipped to deal with these changes and the resulting <a href="https://www.ncbi.nlm.nih.gov/pubmed/21730992">health problems</a>. </p>
<p>One of the ways they can be assisted, in South Africa at least, is through the work of <a href="https://www.hpcsa.co.za/PBEnviromental">environmental health practitioners</a>. There are <a href="https://www.hpcsa.co.za/Publications/Statistics">3 833</a> practitioners registered with the <a href="https://www.hpcsa.co.za/">Health Professions Council of South Africa</a> across the country. They operate at the interface between government and communities, dealing with environmental safety and community health in local government districts.</p>
<p>Environmental health practitioners work <a href="https://www.ufs.ac.za/docs/librariesprovider25/cpd-documents/cpd-health-professions-act-56-of-1974-1018-eng.pdf?sfvrsn=0">in the areas</a> of water quality, food control, waste management, health surveillance of premises, surveillance and prevention of communicable diseases, vector control (methods to limit or eradicate disease pathogens transmitted via mammals, birds, insects or other arthropods) and environmental pollution control. They spend time in communities doing environmental monitoring, disease surveillance (for example during rabies outbreaks) as well as awareness and educational campaigns.</p>
<p>In 2011, the <a href="http://www.energy.gov.za/cop%2017/default.html">Conference of the Parties (COP)-17</a> meeting hosted in South Africa highlighted the importance of involving environmental health and health care practitioners in helping communities increase their capacity to respond to the impact of climate change. <a href="https://www.sanbi.org/documents/national-climate-change-response-white-paper/">Local legislation</a> echoes this. But in reality, this isn’t happening.</p>
<p>Our <a href="https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-018-6378-5">study</a> looked at the role that environmental health practitioners play in helping communities adapt to climate change. The participants acknowledged that climate change poses a serious threat to public health. But they said there was no clarity on what their role should be in preventing adverse risks from a changing climate. </p>
<p>From these findings we concluded that implementing climate change adaptation plans, and considering appropriate climate services, could become part of environmental health practitioners’ work. Practitioners should receive formal training on climate change. </p>
<h2>The research</h2>
<p>The health practitioners we spoke to identified a number of areas in which they could help communities guard their health in the face of a changing climate. These included encouraging tree planting and vegetable gardening, improving storm water drainage systems, strengthening climate and health research programmes and developing community early warning systems. </p>
<p>Two-thirds of the 48 respondents said their role in this work should be supportive, rather than leading. And 42% believed that climate change adaptation action was best dealt with at a global level. This suggests that the practitioners may not yet have identified or clarified their role in climate change adaptation among local communities, where the effects are felt most.</p>
<p>This may be because when it comes to climate change there’s a lack of information on community level policy, regulations and standards, budgetary matters, research, training and education. </p>
<p>Some municipalities did have climate change, health strategies and policies in place. These included the City of Cape Town and eThekwini (Durban) municipalities. But human capacity and financial constraints were identified as challenges to educating and encouraging practitioners to advocate for climate change health and adaptation practices. </p>
<h2>What needs to be done</h2>
<p>There needs to be a debate about the role that environmental health practitioners can play to help communities manage climate threats. Resources have to be made available to support these efforts. </p>
<p>There are examples of where this has happened successfully. The city of Rustenburg in the North West province, in partnership with the South African Medical Research Council, is in the process of developing a Heat and Health Plan for its citizens. </p>
<p>The effort was prompted by Rustenburg being declared as a vulnerable location in 2016 after about <a href="https://www.pressreader.com/south-africa/sunday-times-1107/20160110/281492160306134">40 people died</a> during a single heatwave. The climate and health adaptation measures, which were suggested by stakeholders during a consultative workshop in Rustenburg, echo those mentioned in our <a href="https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-018-6378-5">study</a>. </p>
<p>The establishment of an <a href="https://www.jst.go.jp/global/english/kadai/h2509_southafrica.html">iDEWS (infectious Diseases Early Warning System)</a> Bureau to predict malaria, diarrhoea and pneumonia in Limpopo province is another success story. </p>
<p>As climate change takes hold, environmental health practitioners may have an important role to play in ensuring that the environments – especially built environments – in which people live are fit to promote health, safety and well-being. This should be a national priority to ensure that their role is clarified.</p><img src="https://counter.theconversation.com/content/111389/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>South Africa’s environmental health workers play a vital role in helping communities respond to climate change.Busisiwe Shezi, Senior Scientist, South African Medical Research CouncilCaradee Yael Wright, Specialist Scientist (Public Health), South African Medical Research CouncilRenee Street, Specialist scientist, South African Medical Research CouncilLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1073752019-01-07T14:28:55Z2019-01-07T14:28:55ZClimate change: effect on sperm could hold key to species extinction<figure><img src="https://images.theconversation.com/files/252638/original/file-20190107-32139-y9hdya.jpg?ixlib=rb-1.1.0&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/skull-on-desert-58522480?src=5RTUr9LQgKjOeuj47ESMcw-1-5">Wong Yu Liang/Shutterstock</a></span></figcaption></figure><p>Since the 1980s, <a href="https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(17)30082-7/fulltext">increasingly frequent and intense heatwaves</a> have contributed to more deaths than any other extreme weather event. The fingerprints of extreme events and climate change are widespread in the natural world, where populations are showing stress responses.</p>
<p>A common fingerprint of a warmer world is a range shift, where the distribution of a species moves to higher altitudes or migrates toward the poles. A review of several hundred studies found an <a href="https://www.ncbi.nlm.nih.gov/pubmed/21852500">average shift of 17km poleward, and 11 metres upslope</a>, every decade. However, if temperature changes are too intense or lead species to geographic dead ends, local extinctions occur in the heat.</p>
<p>In 2003, <a href="https://www.ncbi.nlm.nih.gov/pubmed/12511952" title=") of climate change on natural populations. [Significant and simultaneous stress responses](https://www.ncbi.nlm.nih.gov/pubmed/22257223 "">80% of relevant studies found the fingerprints</a> were seen among species, from grasses to trees and molluscs to mammals. Some migrated, some changed colour, some altered their bodies and some shifted their life cycle timings. A recent review of more than 100 studies found <a href="http://science.sciencemag.org/content/348/6234/571">8-50% of all species</a> will be threatened by climate change as a result. </p>
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</figure>
<h2>High temperatures and extinctions</h2>
<p>Currently, we have a <a href="https://www.ncbi.nlm.nih.gov/pubmed/23075836">disturbingly limited knowledge</a> of which biological traits are sensitive to climate change and therefore responsible for local extinctions. However, a potential candidate is male reproduction, because a range of medical and agricultural studies <a href="https://pdfs.semanticscholar.org/2291/2f5bb3a55579381a5e92cab3a142f94639a1.pdf">in warm blooded animals</a> have shown that male infertility happens during heat stress.</p>
<p>However, until recently this had <a href="https://www.ncbi.nlm.nih.gov/pubmed/16033555">rarely been explored outside fruit flies</a> in cold blooded animals. This is despite the fact that ectotherms – organisms that rely on heat in their environment to maintain a suitable body temperature – comprise most of biodiversity. Astonishingly, nearly <a href="https://www.ncbi.nlm.nih.gov/pubmed/26034274">25% of all species</a> are thought to be a beetle.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/252633/original/file-20190107-32124-12s9wfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/252633/original/file-20190107-32124-12s9wfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/252633/original/file-20190107-32124-12s9wfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=753&fit=crop&dpr=1 600w, https://images.theconversation.com/files/252633/original/file-20190107-32124-12s9wfx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=753&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/252633/original/file-20190107-32124-12s9wfx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=753&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/252633/original/file-20190107-32124-12s9wfx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=946&fit=crop&dpr=1 754w, https://images.theconversation.com/files/252633/original/file-20190107-32124-12s9wfx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=946&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/252633/original/file-20190107-32124-12s9wfx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=946&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 red flour beetle. The ubiquity of beetles prompted biologist J.B.S. Haldane to say that God has ‘an inordinate fondness for beetles’.</span>
<span class="attribution"><span class="source">Martin Taylor</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The red flour beetle (<em>Tribolium castaneum</em>) is a useful ectotherm for <a href="https://www.ncbi.nlm.nih.gov/pubmed/18429767">large experiments on reproduction</a>, as they can go from egg to adult in a month at 30°C. Females can store male sperm in specialised organs called spermathecae and they only need to keep 4% of a single ejaculate to enable them to produce offspring for up to 150 days.</p>
<p>To look at the <a href="https://www.nature.com/articles/s41467-018-07273-z">impact of heatwaves on reproduction</a>, beetles were exposed to either standard control conditions or five-day heatwave temperatures, which were 5°C to 7°C above their preferred temperature. Afterwards, beetles mated and a variety of experiments looked for damage to their reproductive success, sperm form and function, and offspring quality.</p>
<p>We found that 42°C heatwave temperatures halved the number of offspring males could produce relative to 30°C, with some males failing to produce any and mature sperm in female storage also experiencing damage from heatwaves. However, the reproductive output of pairs where only the females endured a five-day heatwave event was similar in all temperatures.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/249969/original/file-20181211-76971-k69dg2.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/249969/original/file-20181211-76971-k69dg2.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/249969/original/file-20181211-76971-k69dg2.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=250&fit=crop&dpr=1 600w, https://images.theconversation.com/files/249969/original/file-20181211-76971-k69dg2.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=250&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/249969/original/file-20181211-76971-k69dg2.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=250&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/249969/original/file-20181211-76971-k69dg2.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=314&fit=crop&dpr=1 754w, https://images.theconversation.com/files/249969/original/file-20181211-76971-k69dg2.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=314&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/249969/original/file-20181211-76971-k69dg2.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=314&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Heated males (B) had less sperm (stained green) and relatively more dead sperm (stained red) than control males (A).</span>
<span class="attribution"><span class="source">Kris Sales</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The decline was likely due to a combination of males becoming worse at mating, less sperm being transferred, less sperm transferred being alive, less sperm being kept in the females’ spermathecae and more sperm being damaged and infertile.</p>
<p>Two results were particularly concerning. These beetles, and many cold-blooded animals, can live for years and are likely to see multiple heatwaves. When we exposed males to two heatwave events, ten days apart, their offspring production was less than 1% of that of unheated males. </p>
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<em>
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Read more:
<a href="https://theconversation.com/wildlife-winners-and-losers-in-britains-summer-heatwave-100408">Wildlife winners and losers in Britain's summer heatwave</a>
</strong>
</em>
</p>
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<p>This suggests that successive heatwaves can compound the damage of previous ones. The damage to offspring longevity and male fertility was another effect which was compounded over successive generations, and could lead to spiralling population declines.</p>
<p>Knowing what aspects of biology higher temperatures could compromise is essential to understanding how climate change affects nature. Hopefully, this new knowledge can help predict which species are most likely to be vulnerable, allowing conservationists to prepare for the trouble ahead.</p><img src="https://counter.theconversation.com/content/107375/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kris Sales 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>Climate change threatens to cause mass extinctions – but how, exactly? New research suggests male fertility may be the weakest link.Kris Sales, PhD Candidate in evolution, behaviour, ecology and entomology, University of East AngliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1050282018-10-22T10:38:37Z2018-10-22T10:38:37Z3 dangers of rising temperatures that could affect your health now<figure><img src="https://images.theconversation.com/files/240878/original/file-20181016-165897-1fiqujl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Members of a ground crew In Phoenix wrapped wet towels around their necks to cool off when the temperature reached a record of 116°F.</span> <span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Southwest-Heat/b5c7bf55642648fc82db38955564739a/47/0">Matt York/AP Photo</a></span></figcaption></figure><p>I read the <a href="https://www.ipcc.ch/pdf/session48/pr_181008_P48_spm_en.pdf">news</a> about the urgency of addressing climate change, and as a mathematician who studies climate change, I was not surprised. Very worried, but not surprised.</p>
<p>A few days before Christmas last year, I took a picture of a blooming cherry tree along the Charles River in Boston. As a scientist at Tufts University studying seasonal patterns, I saw the tree as an anomaly resulting from increasing temperature, another piece of evidence for climate change. As a human, I was amused by the contrast of color and moved on.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/241245/original/file-20181018-67164-ubamzu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/241245/original/file-20181018-67164-ubamzu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=343&fit=crop&dpr=1 600w, https://images.theconversation.com/files/241245/original/file-20181018-67164-ubamzu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=343&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/241245/original/file-20181018-67164-ubamzu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=343&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/241245/original/file-20181018-67164-ubamzu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=432&fit=crop&dpr=1 754w, https://images.theconversation.com/files/241245/original/file-20181018-67164-ubamzu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=432&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/241245/original/file-20181018-67164-ubamzu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=432&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A cherry tree blooming by the Charles River in Boston, Dec. 17, 2017.</span>
<span class="attribution"><span class="source">Elena Naumova</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>This exceptionally hot summer <a href="https://www.bostonglobe.com/metro/2018/08/23/this-summer-has-set-records-for-heat-boston/22Cn9YweZXuq6gOYwlW7ZJ/story.html">set several records</a> in the Boston area. I had the luxury to budget some extra money for air conditioning, spend some time in Maine and move a business trip to South India from August to January, when I can function well. What if a person doesn’t have this luxury? </p>
<p>Last summer, I spent time editing a paper on the effect of heat on health. It took me 15 years to secure funds, find students, assemble the data, build the model and scrutinize the model so that I could defend the finding “beyond reasonable doubt” and finally <a href="https://doi.org/10.1038/srep39581">publish the results</a>. </p>
<p>In that paper, we showed that in Boston for about 10 days in the summer when night-time temperature is above 65.5 degrees Fahrenheit for three consecutive nights, we Bostonians paid the price of about 14 older people being hospitalized due to heatstroke, a fully preventable condition. Is it too much or what we should expect? Over 15 years in the Boston metropolitan area, these preventable hospitalizations contributed over US$5 million in medical charges, which is almost equivalent to the annual state budget allocated to supportive senior housing of $5.5 million for 2015.</p>
<p>It’s not only older people who are vulnerable, however. So are you. </p>
<h2>Higher risk of heatstroke</h2>
<p>The human body of a healthy adult has a remarkable capacity to maintain <a href="https://www.reference.com/science/body-temperature-maintained-e11e175f9cbb833">stable core temperature</a> in the narrow range between 36.6 and 37.7 degrees Celsius (98°F and 100°F) despite large variability in ambient temperature. The core body temperature is controlled by complex physiological feedback loops and maintained by a delicate balance between heat production, conservation and dissipation that depends on environmental conditions. Failure to dissipate enough heat causes <a href="https://www.mayoclinic.org/diseases-conditions/heat-stroke/symptoms-causes/syc-20353581">heatstroke</a>, or an uncontrollable rise in the core body temperature above the healthy levels. </p>
<p>When <a href="https://www.ncbi.nlm.nih.gov/pubmed/11988377">core body temperature</a> reaches 40.5°C (105°F) due to a failure of the internal body’s temperature control system, it causes adverse health consequences, such as complications involving the central nervous system and cardiovascular and respiratory systems failure, leading to morbidity and mortality.</p>
<p><a href="https://www.ncbi.nlm.nih.gov/pubmed/19758453">Older adults</a> suffer disproportionately more during heat waves due to weakening of thermoregulatory mechanisms, potential side effects of medications and limited mobility. Furthermore, people with a high perspiration threshold combined with increased blood viscosity, elevated cholesterol level and diminished ability to detect changes in body temperature <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4397690/">may further contribute </a>to severe heat-related health conditions. </p>
<h2>Some illnesses worsened, some people caught off-guard</h2>
<p>Heat waves <a href="https://doi.org/10.1186/1476-069X-8-40">threaten the health of vulnerable populations</a>, especially of those who are who are less capable to cope and adapt to the thermal extremes, such as individuals with preexisting conditions like asthma or diabetes and people who need routine support, like dialysis or oxygen. Heatstroke occurs at rates that are <a href="https://ehp.niehs.nih.gov/doi/10.1289/ehp.1205223">12–23 times higher</a> in persons 65 and older compared with other age groups, indicating the high degree of inability to cope with climate stressors. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/241251/original/file-20181018-67182-1e8r30l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/241251/original/file-20181018-67182-1e8r30l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/241251/original/file-20181018-67182-1e8r30l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/241251/original/file-20181018-67182-1e8r30l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/241251/original/file-20181018-67182-1e8r30l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/241251/original/file-20181018-67182-1e8r30l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/241251/original/file-20181018-67182-1e8r30l.jpg?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">People in cooler climates may have a harder time adjusting to extreme heat waves.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/warning-extreme-heat-vintage-rusty-metal-1086468626?src=LUJpPHV0oSsJ76eYXq8aVA-2-37">Ducu59us/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>The issue with <a href="https://www.ncbi.nlm.nih.gov/pubmed/11772788">superhot days</a> is that the increase of one degree from, say, 100°F to 101°F will produce a more devastating effect than one degree in increase at a low temperature base, say from 90°F to 91°F. </p>
<p>While populations in the southern regions, characterized by hotter climate, are better acclimatized to handle high seasonal temperature, the effects of poverty, substandard infrastructure and limited access to health care could easily wipe out the advantages of regional adaptation.</p>
<h2>Outdoor work becomes more dangerous</h2>
<p>Short heat waves resolve into cooling nights, offering a highly desired relief. Extended heat waves, however, accrue the impact and start to affect healthy people who might well <a href="https://doi.org/10.1186/1476-069X-11-58">tolerate short periods</a> of heat. Extended heat waves, in particular, threaten the health of people highly exposed to elements, such as construction workers or farmers. About <a href="https://www.cdc.gov/disasters/extremeheat/index.html">600 deaths</a> a year are considered officially due to extreme heat, but that number may not reflect all heat-related deaths. For example, studies have shown that hundreds of deaths from <a href="https://www.epa.gov/climate-indicators/climate-change-indicators-heat-related-deaths">Chicago’s heat wave in 1995</a> may not have been captured on death certificates. Other reasons, such as cardiac failure, may instead be reported, even if heat may have led to them. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/241254/original/file-20181018-67170-1f28t4i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/241254/original/file-20181018-67170-1f28t4i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/241254/original/file-20181018-67170-1f28t4i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/241254/original/file-20181018-67170-1f28t4i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/241254/original/file-20181018-67170-1f28t4i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/241254/original/file-20181018-67170-1f28t4i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/241254/original/file-20181018-67170-1f28t4i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dry soil can contribute to increased temperatures, a European study suggested. Here, a dirt road during the 2018.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/long-dusty-dry-dirt-road-during-1142326478?src=yABGvSXusbZwK3ZKAqtv_g-2-14">Simon Annable/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>A study in Europe suggested that high surface temperature that arise from <a href="https://doi.org/10.1016/j.wace.2015.05.001">dry soils may contribute to anomalously high overnight temperatures</a>, a feature of extreme heatwaves. </p>
<h2>A real and growing crisis</h2>
<p>Average temperatures compared to preindustrial times have already risen almost <a href="https://earthobservatory.nasa.gov/WorldOfChange/DecadalTemp">1°C</a>, and in the most recent IPCC report, climate scientists said preventing an increase of 1.5°C is <a href="https://www.dw.com/en/15c-degree-goal-extremely-unlikely-ipcc/a-42154601">very unlikely</a>.</p>
<p>How does one define how a 1.5°C increase in global temperature affects me personally? It is not like you bake a cake in an oven set to 350°F and now you bake it at 351.5°F and wonder if the cake turned out well. It is also not like a child had a fever of 102°F and now it is at 103.5°F and you need to choose the best course of action to save a child. It is more like trying to understand that we live in interconnected world where “small” things matter, even if the cause and effects are not so visible. The seasonal patterns are changing, and a heat wave arriving too early and late in a season can catch you off guard and leave people scrambling for solutions. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/241259/original/file-20181018-67182-1geqllg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/241259/original/file-20181018-67182-1geqllg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/241259/original/file-20181018-67182-1geqllg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/241259/original/file-20181018-67182-1geqllg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/241259/original/file-20181018-67182-1geqllg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/241259/original/file-20181018-67182-1geqllg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/241259/original/file-20181018-67182-1geqllg.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">What would Copernicus say? A statue of the astronomer in his hometown of Torun, Poland.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/monument-great-astronomer-nicolaus-copernicus-torun-618122798?src=iNzCpOFOEXwG-h9e-2_jdg-1-0">Lukasz Janyst/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>These global issues demand seeing a picture at a different scale. I wonder how Galileo and Copernicus would reply if asked to provide an example how a person might feel if he or she places the sun rather than Earth at the center of the universe. Maybe they will continue to believe scientists, because regardless of their feelings, Earth is moving around the sun. As an educator, I wonder what we missed in our education to allow for a dangerous mix of ignorance and arrogance to gamble with the future, which we are affecting daily. </p>
<p>In order to measure the effect of heat wave in a timely and accurate manner, I believe we need a national surveillance system. Such a system should employ features that already exist in the national and global surveillance for flu or other notifiable infections, including report standardization, distributed network of credible regional units, routing reporting and analysis. </p>
<p>So far, timely systematic and comprehensive reports for heat wave effects are rare. During natural disasters, the reporting of health effects is limited for obvious reasons, as the first responders’ attention is focused on saving lives. So far heat waves are not treated like a state of emergency but more like a seasonal nuisance. We are beginning to see – and feel – the effects.</p><img src="https://counter.theconversation.com/content/105028/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Elena N. Naumova receives funding from the National Institutes of Health.</span></em></p>Rising temperatures will not only hurt people in the future. Many are feeling the effects now. Those who work outdoors, those who have certain chronic conditions and the elderly are vulnerable.Elena N. Naumova, Professor, Tufts UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1003652018-08-01T10:39:45Z2018-08-01T10:39:45ZOverhydrating presents health hazards for young football players<figure><img src="https://images.theconversation.com/files/229839/original/file-20180730-106514-1k69i9e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Thomas Johnson drinks Gatorade at a 'Beat the Heat' event the company sponsored in Fort Worth, Texas, June 10, 2013.</span> <span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/inVision-Brandon-Wade-Invision-AP-a-ENT-CPAENT-/ffc008b459e745f1b91f7b8215e0e7dc/3/0">Brandon Wade/Invision for Gatorade/AP Photo</a></span></figcaption></figure><p>With August football practice fast approaching, every coach’s favorite cheer will be to “stay hydrated” and “keep urine clear” during the summer heat. </p>
<p>In 2017, a University of Texas football coach created a urine-based “<a href="https://www.usatoday.com/story/sports/ftw/2017/10/05/herman-explains-logic-texas-hydration-chart/106335964/">Longhorn Football Hydration Chart</a>,” which labeled players with yellow urine as “selfish teammates” and those with brown urine as “bad guys.” This “hydration shaming” practice has permeated high school sports, thereby encouraging a sporting culture which equates <a href="https://usatodayhss.com/2017/true-colors-using-the-texas-longhorns-chart-and-other-hydration-tips">superior performance with superior hydration</a>. </p>
<p>Overzealous obedience to this hydration advice has uncovered a dark underbelly to superior hydration practices: overhydration. When high school football player <a href="http://www.msnewsnow.com/story/26364634/jackson-prep-football-player-dies">Walker Wilbanks</a> died in Mississippi in August 2014 from overhydration, the doctor said that the cause of death was an “<a href="https://www.clarionledger.com/story/prepsreport/2014/08/25/walker-wilbanks-cause-of-death-related-to-over-hydration/14598215/">unpredictable freak occurrence</a>.” </p>
<p>Two weeks prior, another <a href="https://www.ajc.com/news/update-douglas-county-football-player-has-died/G73yyxV1Sxo4N1IMdcibQO/">high school football player from Georgia drank “two gallons of water and two gallons of Gatorade</a>” after football practice to prevent muscle cramps and then died. Thus, over the last four years, two high school football players have died during August football practice from overhydrating - a medical condition known as <a href="https://www.ncbi.nlm.nih.gov/pubmed/26102445">exercise-associated hyponatremia</a>. </p>
<p>Conversely, no football player has ever been known to die from dehydration, although seven died during this same four-year period from <a href="https://nccsir.unc.edu/files/2013/10/Annual-Football-2017-Fatalities-FINAL.pdf">heatstroke</a>, which may be related, but not always. </p>
<p>How do I know about that overhydration kills athletes? I watched runners almost die after <a href="https://www.ncbi.nlm.nih.gov/pubmed/12544163">drinking 100 cups of water during a marathon</a> because they were scared of becoming “dehydrated.” So, I got interested in thirst. </p>
<p>Turns out, the neuroendocrine thirst circuit dates back 700 million years and is found in most animals, including bugs and worms. Thirst activates the same conscious area of the brain that tells us we’re hungry or have to pee. To say we need to stay “ahead of thirst” (or die) is like saying we need to pee every hour to stay ahead of imminent bladder explosion (or die). The molecular and <a href="https://www.ncbi.nlm.nih.gov/pubmed/14657368">neural circuits that govern fluid intake (and micturition) in real-time are absolutely exquisite</a>.</p>
<p>It’s remarkable to think that animals survive without water bottles and urine charts – they drink when they are thirsty, and we should too.</p>
<h2>Too much water, too little salt</h2>
<p>Hyponatremia is caused by drinking too much water or sports drinks, which dilutes blood salt levels below the normal range. Any sudden drop in blood salt levels, from drinking more than the body can excrete, can cause all cells in the body to swell. Brain swelling from hyponatremia can cause headaches and vomiting, while muscle cell swelling can trigger whole-body muscle cramping.</p>
<p>What is most frightening, however, is that these <a href="https://www.ncbi.nlm.nih.gov/pubmed/28902757">symptoms mimic those of dehydration</a> They are often treated by medical staff with more fluids. </p>
<p>So, which hydration imbalance – dehydration and overhydration – is the lesser of two evils? </p>
<p>Dehydration is undeniably harmful to human health and performance. <a href="https://www.ncbi.nlm.nih.gov/pubmed/9480411">Wrestlers have died</a> from trying to “make weight,” through vigorous dehydration practices. A recent meta-analysis of 33 studies verified that more than <a href="https://www.ncbi.nlm.nih.gov/pubmed/29933347">2 percent dehydration impairs cognition</a>. Dehydration can impair performance and increase core body temperature, as per the American College of Sports Medicine’s latest <a href="https://www.ncbi.nlm.nih.gov/pubmed/17277604">position statement</a>. All of these statements underscore the vital importance of staying hydrated. </p>
<p>But I fear that many coaches ignore the finer points that support those conclusions. For example, three wrestlers who died of dehydration rapidly lost about 15 percent of body weight by withholding fluids while exercising in a hot environment in a rubber suit. Similarly, to achieve 3 percent dehydration, which impairs cognition, individuals need to withhold fluids for 24 hours. And that’s without exercise. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/229843/original/file-20180730-106514-1861gwl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/229843/original/file-20180730-106514-1861gwl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/229843/original/file-20180730-106514-1861gwl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/229843/original/file-20180730-106514-1861gwl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/229843/original/file-20180730-106514-1861gwl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/229843/original/file-20180730-106514-1861gwl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/229843/original/file-20180730-106514-1861gwl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dehydration can occur in the desert when one runs out of water, but dehydration is less likely where fluids are readily available.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/man-walking-alone-sunny-desert-he-766046011?src=eM5FT04JqkXAOxNqT6uOEw-1-36">Koldunova Anna/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>These dehydration protocols do not necessarily represent “free-living” situations. When hikers die from dehydration in the desert, most if not all had become lost or had run out of fluids. Thus, thirst – or the “<a href="https://www.ncbi.nlm.nih.gov/pubmed/6727142">deep-seated desire for water</a>” – is rarely “broken” when healthy people die from dehydration. Morbidity and mortality occur when there is no fluid available, fluids are withheld, as in lab studies, or when athletes refuse to drink for other reasons, such as “making weight.” </p>
<h2>When do athletes and others need to drink?</h2>
<p>So how much fluid should football players – and all other humans for that matter – drink? If you ask fluid balance experts who perform basic science research on the <a href="https://www.ncbi.nlm.nih.gov/pubmed/29129925">brain</a> or <a href="https://www.ncbi.nlm.nih.gov/pubmed/25830425">kidney</a>, or <a href="https://www.ncbi.nlm.nih.gov/pubmed/25551526">clinicians who specialize in fluid balance disorders</a>, researchers who perform <a href="https://www.ncbi.nlm.nih.gov/pubmed/29311314">brain scans on dehydrated and overhydrated humans</a>, or even <a href="https://www.ncbi.nlm.nih.gov/pubmed/24058873">worm</a> investigators, they all agree that water balance is tightly regulated and that all land mammals need to drink when thirsty. </p>
<p>Drinking when you are thirsty is not “too late,” because the thirst mechanism is hardwired into the nervous system to protect against scarcity. Thirst represents the highly individualized signal which protects the balance between water and salt regardless of size, activity or ambient temperature and is encoded in <a href="https://www.ncbi.nlm.nih.gov/pubmed/24058873">most invertebrate and all vertebrate DNA</a>. Babies are born with this innate behavioral drive. </p>
<p>Then, what about the need for eight glasses of water per day? There is <a href="https://www.ncbi.nlm.nih.gov/pubmed/12376390">no evidence</a> to support this. What about peeing until our urine is clear? Dark colored urine merely reflects <a href="https://www.ncbi.nlm.nih.gov/pubmed/29464103">water conservation</a> by the kidney, rather than water lack by the body. </p>
<h2>What’s a football player to do?</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/229840/original/file-20180730-106530-177mhi2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/229840/original/file-20180730-106530-177mhi2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=414&fit=crop&dpr=1 600w, https://images.theconversation.com/files/229840/original/file-20180730-106530-177mhi2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=414&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/229840/original/file-20180730-106530-177mhi2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=414&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/229840/original/file-20180730-106530-177mhi2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=521&fit=crop&dpr=1 754w, https://images.theconversation.com/files/229840/original/file-20180730-106530-177mhi2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=521&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/229840/original/file-20180730-106530-177mhi2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=521&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Kirtland, Ohio, football players pour ice over head coach Tiger Laverde after a major playoff win Dec. 6, 2013. Pouring ice or water over their own heads could be a good option to stay cool.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Div-6-Wayne-Trace-Kirtland-Football/6e3833ab0f244ee38e5965f5c0d9fbc8/15/0">David Richard/AP Photo</a></span>
</figcaption>
</figure>
<p>Football players absolutely need water, but they should be warned not to overdo it. </p>
<p>In the modern era, where fluid is widely available, in order to stay adequately hydrated, the following must occur: </p>
<ol>
<li><p>A variety of fluids needs to be freely available to football players, and </p></li>
<li><p>The players should be given the freedom to drink whenever they feel thirsty.</p></li>
</ol>
<p>And when the players get hot, they need the opportunity to pour generous amounts of ice water over their heads instead of into their mouths to promote evaporative cooling, rather than dilute sodium levels. Better yet, they should be allowed to go inside and cool off. </p>
<p>We should recognize who the “true champions” may be with regards to most modern day hydration advice. According to the latest figures, bottled water sales have increased to <a href="https://www.beveragedaily.com/Article/2018/06/01/Bottled-water-takes-top-spot-in-US-in-2017">US$18.5 billion dollars, up 8.8 percent</a> from the previous year. This revenue does not include the vast array of purified, infused, oxygenized, sparkled, distilled, intravenous and reverse osmosis versions that compete for attention on the market. </p>
<p>While we all need water, drinking until our “urine is clear” is money (and water) flushed away. And with the threat of overdrinking high in motivated athletes, I ask coaches/trainers to reconsider before enforcing the urine color chart in athlete locker rooms: Is it worth the risk?</p><img src="https://counter.theconversation.com/content/100365/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tamara Hew-Butler DPM, PhD, FACSM receives royalties from UpToDate, for her ongoing contributions to the topic of Exercise-Associated-Hyponatremia. </span></em></p>Yes, it’s hot outside. And football practice is starting for thousands of kids. But coaches and parents should be careful about tellings kids to drink more water. That has been deadly.Tamara Hew-Butler, Associate Professor of Exercise and Sports Studies, Wayne State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/970882018-06-24T19:51:06Z2018-06-24T19:51:06ZAustralian cities are lagging behind in greening up their buildings<figure><img src="https://images.theconversation.com/files/223983/original/file-20180620-137734-1d98wbz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Green rooftops give a backyard feel to smaller housing units in Sydney </span> <span class="attribution"><span class="source">Author Provided </span>, <span class="license">Author provided</span></span></figcaption></figure><p>Covering roofs and walls of buildings with vegetation is a good way of reducing greenhouse gas emissions. And these green roofs and walls make cities look nicer. Toronto’s central business district <a href="https://web.toronto.ca/wp-content/uploads/2017/08/8f15-Report-on-the-Environmental-Benefits-and-Costs-of-Green-Roof-Technology-for-the-City-of-Toronto-Chapter-2.pdf">adopted a policy</a> of establishing green roofs on around half of all city buildings in 2009. Research shows this could reduce maximum city temperatures by up to 5°C. </p>
<p>We spent the past 12 months analysing the case for more greenery on Australian city buildings, drawing on international comparisons. We’ve shown that a mandatory policy, coupled with incentives to encourage new and retrofitted green roofs and walls, will provide environmental, social and business benefits. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/green-roofs-and-walls-a-growth-area-in-urban-design-23911">Green roofs and walls – a growth area in urban design</a>
</strong>
</em>
</p>
<hr>
<p>These include improved air quality, energy conservation and <a href="http://www.rics.org/uk/knowledge/research/research-reports/sustainable-urban-drainage/">reductions in stormwater run-off</a> from buildings, which would decrease flash flooding. Green roofs and walls also become new habitats for biodiversity and can be <a href="https://www.researchgate.net/publication/314527276_THE_IMPACT_OF_HORTICULTURE_THERAPY_ON_MENTAL_HEALTH_CARE_CONSUMERS_ON_A_RETROFITTED_ROOF">pleasant spaces</a> for social interaction in dense urban areas.</p>
<p>We found numerous <a href="https://www.sciencedirect.com/science/article/pii/S0360132306001752">studies</a> confirming that greenery on inner-city buildings reduces the <a href="https://www.epa.gov/sites/production/files/2014-06/documents/basicscompendium.pdf">urban heat island</a> effect, which is when city centres are hotter than surrounding suburban and outer-urban areas.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/223984/original/file-20180620-137746-jb859j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/223984/original/file-20180620-137746-jb859j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/223984/original/file-20180620-137746-jb859j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/223984/original/file-20180620-137746-jb859j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/223984/original/file-20180620-137746-jb859j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/223984/original/file-20180620-137746-jb859j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/223984/original/file-20180620-137746-jb859j.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">Green roofs are great social spaces.</span>
<span class="attribution"><span class="source">Author provided</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>What other countries are doing</h2>
<p>We <a href="https://www.researchgate.net/publication/325734547_Expanding_The_Living_Architecture_in_Australia_Project_Expanding_The_Living_Architecture_in_Australia_GC15001">examined international case studies</a> of cities embracing green roofs and walls to review policy frameworks which could be suitable for Australia. A range of measures and policies exist and vary depending on building types (buildings need specific features to host vegetation) and the degree to which policies can be enforced.</p>
<p>Singapore is leading in this area. It <a href="http://eresources.nlb.gov.sg/history/events/a7fac49f-9c96-4030-8709-ce160c58d15c">markets itself</a> as a “garden city” to attract investment, visitors and commerce. Green roofs and walls are a vital and visual manifestation of this policy. </p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/223985/original/file-20180620-137720-o4cmgn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/223985/original/file-20180620-137720-o4cmgn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/223985/original/file-20180620-137720-o4cmgn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/223985/original/file-20180620-137720-o4cmgn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/223985/original/file-20180620-137720-o4cmgn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/223985/original/file-20180620-137720-o4cmgn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/223985/original/file-20180620-137720-o4cmgn.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">Green walls are aesthetically pleasing.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Greenery is ingrained in Singapore’s development sector and is boosted by incentives, grants, awards, certification schemes and government-led development. Through this voluntary-heavy (yet supported) effort, Singapore increased its number of green roofs and spaces nine-fold between 2006 and 2016.</p>
<p>Rotterdam’s efforts weren’t as extensive as Singapore’s, but the city more than doubled its green roof area from 2012-2017 through incentives, grants, tax benefits and demonstration projects.</p>
<p>London increased its total green-roof area more than four-fold from 2005-2016. This was partially achieved through a <a href="https://www.lbhf.gov.uk/sites/default/files/section_attachments/city_of_london_2016-2020.pdf">biodiversity action plan</a>.</p>
<p>And Toronto has the second-largest area of green roofs of the four cities we studied. This has been delivered through a <a href="https://www.toronto.ca/city-government/planning-development/official-plan-guidelines/green-roofs/green-roof-bylaw/">mandatory policy</a>, introduced in 2009, that requires all new developments with roofs of 2,000m² or more to install green roofs. </p>
<h2>The case in Australia</h2>
<p>We modelled what could be delivered in the City of Sydney and the City of Melbourne based on the measures taken in Singapore (which is voluntary-heavy), London (voluntary-light), Rotterdam (voluntary-medium) and Toronto (mandatory). </p>
<p>We combined this with data on actual green building projects in 2017 in Sydney and Melbourne to show the potential increase of projects in each city based on the four policies. </p>
<p>In the Sydney local government area, 123 green roof and wall projects were under way in 2016. The below table uses this base to estimate what the numbers of such projects would be for three time periods, based on the policies in the four scenarios modelled.</p>
<iframe src="https://datawrapper.dwcdn.net/7ff2z/3/" scrolling="no" frameborder="0" allowtransparency="true" width="100%" height="357"></iframe>
<p>In the Melbourne local government area, 28 green roof and wall projects were under way in 2016. The table below shows how these could increase based on policies of the four case studies modelled.</p>
<iframe src="https://datawrapper.dwcdn.net/s2Efy/1/" scrolling="no" frameborder="0" allowtransparency="true" width="100%" height="357"></iframe>
<h2>How Australia can get on board</h2>
<p>Sydney and Melbourne have green roof and green wall policies aligned with their 2030 and 2040 sustainability targets, launched in 2012 and 2015 respectively. Sydney has the <a href="https://greenroofsaustralasia.com.au/sites/default/files/sponsors/files/CoS_Green-Roofs-and-Walls-Policy-Implementation-Plan-Adopted_0.pdf">Green Roofs and Walls Policy Implementation Plan</a>, while Melbourne has the <a href="http://www.growinggreenguide.org/">Growing Green Guide 2014</a>. </p>
<p>These policies appear most aligned with the voluntary-light approach adopted in London. Sydney had a 23% increase in green roofs since its policy launch, although this was from a very low starting point. Melbourne also reports an increase in green roofs and walls, though the amount of uptake isn’t publicly available.</p>
<p>There are, of course, barriers to greening up buildings. These include costs as well as lack of experience in the industry, especially in terms of construction and management. Professional capacity for green roofs is still in a developing phase and further training and skill development are needed. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/224163/original/file-20180621-137750-i347f7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/224163/original/file-20180621-137750-i347f7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/224163/original/file-20180621-137750-i347f7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/224163/original/file-20180621-137750-i347f7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/224163/original/file-20180621-137750-i347f7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/224163/original/file-20180621-137750-i347f7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/224163/original/file-20180621-137750-i347f7.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">Green wall adds vegetation to an aged care home in Sydney.</span>
</figcaption>
</figure>
<p>Around 87% of the building stock Australia will have in 2050 is already here, and a large <a href="https://www.wiley.com/en-gb/Retrofitting+Cities+for+Tomorrow%27s+World-p-9781119007210">proportion of existing buildings</a> could be retrofitted. We recommend a voluntary approach using a mix of initiatives for building owners, such as tax benefits and credits in green building tools.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/if-planners-understand-its-cool-to-green-cities-whats-stopping-them-55753">If planners understand it's cool to green cities, what's stopping them?</a>
</strong>
</em>
</p>
<hr>
<p>Focusing on new buildings is likely to lead to more modest growth rates in the short to medium term, relative to alternative approaches such as retrofitting. The annual growth rate of new stock is around 1-3%, which means that policies focusing on new stock will have a substantial impact over the long term. </p>
<p>However, in the short to medium term, a retrofit policy would have greater impact given the numbers of existing buildings suitable for this. </p>
<p>Local government areas can also promote the evidence showing the lift in <a href="https://www.aecom.com/content/wp-content/uploads/2017/04/Green-Infrastructure-vital-step-brilliant-Australian-cities.pdf">property values</a> in areas with more green infrastructure – in some instances up to 15%. This should encourage voluntary uptake.</p><img src="https://counter.theconversation.com/content/97088/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sara Wilkinson receives funding from Horitculture Innovation Australia. </span></em></p><p class="fine-print"><em><span>Paul Brown received funding from Horticulture Innovation Australia. </span></em></p><p class="fine-print"><em><span>Sumita Ghosh received funding from Horticulture Innovation Australia. She works for University of Technology Sydney. </span></em></p>Research shows if Australia encourages greenery on buildings, it will reduce temperatures in the city, as well as potential for flash flooding. It also creates new habitats and socialising spaces.Sara Wilkinson, Associate Professor, School of the Built Environment, University of Technology SydneyPaul J Brown, Senior Lecturer – Creative Intelligence | Faculty of Transdisciplinary Innovation & Senior Lecturer – Accounting | UTS Business School, University of Technology SydneySumita Ghosh, Senior Lecturer, School of the Built Environment, University of Technology SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/970982018-06-11T17:09:01Z2018-06-11T17:09:01ZWhy Africa stands to benefit if rise in global temperatures is kept to 1.5°C<figure><img src="https://images.theconversation.com/files/221950/original/file-20180606-137301-bcluaq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">It would be in Africa’s best interests to limit a rise in global temperature.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>At the end of the century, if <a href="http://www.ipcc.ch/pdf/assessment-report/ar5/syr/SYR_AR5_FINAL_full_wcover.pdf">carbon emissions aren’t reduced faster</a>, the global temperature is likely to be 2.6°C to 4.8°C higher than it was in 1986–2005. Africa could be even hotter than that, to the tune of between <a href="https://doi.org/10.1017/CBO9781107415386.002">3°C and 6°C</a>.</p>
<p>If the world doesn’t make a bigger effort to cut emissions than it does now, global warming might have a severe effect <a href="http://www.ipcc.ch/pdf/assessment-report/ar5/syr/SYR_AR5_FINAL_full_wcover.pdf">on sub-tropical Africa</a>. </p>
<p>Our <a href="https://www.nature.com/articles/s41558-018-0145-6">research</a> has found that for Africa, it would make an important difference to limit a rise in global temperature to 1.5°C. That limit would shrink the likelihood of extreme climate events like heatwaves. And that would be good for societies and economies.</p>
<p>A global mean temperature of 2°C above pre-industrial levels has been under discussion for years as a threshold for <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/wcc.457">danger</a>. Many countries already experiencing extreme climate events have raised concerns, though, that a 2°C target is insufficient to shield them from <a href="https://www.nature.com/articles/nclimate2572">these extremes</a>.</p>
<p>These countries welcomed the 2015 <a href="https://doi.org/10.1038/nclimate2939">Paris Agreement</a> on efforts to confine global warming and reduce risks of climate change in the future. </p>
<p>Africa is a <a href="https://doi.org/10.1017/CBO9781107415386.002">climate change hotspot</a>. But there has been little research on how much difference a lower temperature target would make. </p>
<p>To fill this gap, we explored potential benefits for Africa from limiting global warming to <a href="https://doi.org/10.1038/s41558-018-0145-6">1.5°C compared to 2°C</a>. We used a model that enabled us to simulate how heat and hydrological extremes might change in Africa under stabilised 1.5°C and 2°C scenarios. We focused on the likelihood of seeing a repeat of record-breaking seasons that have already happened.</p>
<p>We found that keeping global warming to 1.5°C could significantly decrease the frequency of extreme climate events across the continent. In particular, the probability of events like the southern African hot December–February <a href="https://doi.org/10.1038/s41558-018-0145-6">1991/1992</a> and the heatwave in North Africa in <a href="http://library.wmo.int/pmb_ged/wmo_1074_en.pdf">December–February 2009/2010</a> would be a lot lower. </p>
<h2>Severe high temperatures</h2>
<p>Over the past decade, Africa has recorded <a href="http://library.wmo.int/pmb_ged/wmo_1167_en.pdf">severe high temperatures</a>. </p>
<p>It was particularly hot in North Africa between <a href="http://library.wmo.int/pmb_ged/wmo_1074_en.pdf">December 2009 and April 2010</a>. The region observed <a href="https://go.nature.com/2Jngrm0">new records</a> of 47.6°C for Faya-Largeau in Chad, 48.2°C for Bilma in Niger and 49.6°C for Dongola in Sudan in 2010. In 2015 Egypt’s Luxor reached 48.4°C and South Africa’s Vredendal observed a record <a href="http://library.wmo.int/pmb_ged/wmo_1167_en.pdf">high of 47.6°C</a>. </p>
<p>We established that if global warming were to be limited to 1.5°C instead of 2°C, the chances of extreme heat events in Africa might be reduced. Specifically, the likelihood of annual high temperatures that exceed the 2015 record is estimated to be 100% under 2°C level, but 91% under 1.5°C levels.</p>
<p>Under a 2°C scenario, we projected that there is a 30% chance of occurrence for extreme high temperatures similar to that of 2009/2010 in North Africa. But if temperatures were kept at a projected 1.5°C, there would be only an 11% chance of such an extreme occurring. </p>
<h2>Flooding and droughts</h2>
<p>In February 2000, there was a <a href="https://journals.ametsoc.org/doi/abs/10.1175/1520-0434%282004%29019%3C0789%3ATCEAIU%3E2.0.CO%3B2">tropical cyclone</a> that brought <a href="https://doi.org/10.1038/s41558-018-0145-6">unusually high rainfall</a> to southeast Africa and as far west as Namibia. It was also a year when Namibia experienced its wettest summer <a href="https://journals.ametsoc.org/doi/abs/10.1175/1520-0434%282004%29019%3C0789%3ATCEAIU%3E2.0.CO%3B2">since 1976</a>. It resulted in devastating floods and <a href="https://journals.ametsoc.org/doi/abs/10.1175/1520-0434%282004%29019%3C0789%3ATCEAIU%3E2.0.CO%3B2">loss of life</a>. </p>
<p>Global climate model simulations in our study estimated that similar extreme events in this region will be rare under low global warming scenarios in the future, with slight difference in occurrence between 1.5°C and 2°C warming levels. But in general, global climate models have been known to draw differing results in terms of the direction of future precipitation. That’s why our confidence levels are higher for temperature projections than <a href="http://www.ipcc.ch/pdf/assessment-report/ar5/syr/SYR_AR5_FINAL_full_wcover.pdf">precipitation projections</a>. </p>
<p>Almost all subsistence farmers in Africa who practise rain-fed agriculture are affected by <a href="https://doi.org/10.1088/1748-9326/10/8/085004">natural climate variability</a>. Increased frequency and severity of droughts is projected in the 21st century over most of the continent <a href="https://doi.org/10.1017/CBO9781107415386.002">because of climate change</a>. </p>
<p>Using rainfall deficits and high temperatures as drought indicators, we explored the likelihood of droughts similar to the 1991/1992 one in southern Africa under <a href="https://doi.org/10.1038/s41558-018-0145-6">low warming scenarios</a>. We found that, even though the rainfall would be similar in both the scenarios, the high temperatures might increase the probability of such droughts.</p>
<h2>Benefits of a low-warming world</h2>
<p>Our <a href="https://doi.org/10.1038/s41558-018-0145-6">study</a> projects that limiting global warming to 1.5°C instead of 2°C would have considerable paybacks for Africa. In particular, extreme heat events like the ones in 2015 and 2009/2010 might be reduced by 10% and 20% respectively under 1.5°C of global warming level compared to under 2°C level. </p>
<p>Temperatures as high as those in the December–February 1991/1992 southern African drought are estimated to be 25% less likely under 1.5°C of global warming level compared to under 2°C level. </p>
<p>So, continued efforts to limit warming to 1.5°C may offer considerable benefits to Africa in terms of reduced occurrence of heat extremes.</p><img src="https://counter.theconversation.com/content/97098/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Shingirai Nangombe 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>Keeping global warming to 1.5°C could significantly decrease the frequency of extreme climate events across Africa.Shingirai Nangombe, Doctor of Philosophy, Chinese Academy of SciencesLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/932482018-03-15T14:16:02Z2018-03-15T14:16:02ZWhat a century of climate change has done to France’s biggest glacier<figure><img src="https://images.theconversation.com/files/210384/original/file-20180314-113485-11wuxpw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Dundee University</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Like a one-man Google Earth, Swiss aviation pioneer <a href="http://monovisions.com/eduard-spelterini-biography-pioneer-aerial-photographer/">Eduard Spelterini</a> flew a gas-filled balloon from the French town of Chamonix to Switzerland on August 8, 1909 – a distance of 100 miles over the Alps. While the flight was extraordinary for being the first aerial crossing of the central Alps from west to east, it now holds a special significance of which Spelterini was unaware. The balloonist was also a photographer who captured a series of <a href="https://www.cbsnews.com/news/photographys-era-of-glass-plate-negatives/">glass-plate images</a> of the <a href="https://www.britannica.com/place/Mer-de-Glace">Mer de Glace</a> (“sea of ice”) glacier that descends from the <a href="https://www.chamonix.net/english/mountaineering/mont-blanc-range">Mont Blanc Massif</a> in a dramatic sweep.</p>
<p>Spelterini’s interest in recording the alpine landscape was both scientific and aesthetic, and the results are striking. This <a href="https://www.helveticarchives.ch/detail.aspx?ID=226144">collection</a> of images survives today as a record of the glacier that is unique in its detail and antiquity. But crucially, they can be used to measure how much this landscape has changed in the intervening years. In 1909, no one could have guessed how significant these glaciers would become to environmental science, or just how rapidly they would be affected by <a href="https://www.nasa.gov/topics/earth/features/upsDownsGlobalWarming.html">rising temperatures</a> in the century that followed.</p>
<h2>Digital analysis</h2>
<p>The flight over the Mer de Glace was unusual because Spelterini’s aerial photographs rarely focused on the glaciers, instead more often framing the peaks and other geological features. He was also unaware that the distribution of his photographs along the balloon’s flight path, pictured below, would make excellent material for digital analysis more than 100 years later.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/210378/original/file-20180314-113472-15v4z77.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/210378/original/file-20180314-113472-15v4z77.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/210378/original/file-20180314-113472-15v4z77.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/210378/original/file-20180314-113472-15v4z77.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/210378/original/file-20180314-113472-15v4z77.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/210378/original/file-20180314-113472-15v4z77.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/210378/original/file-20180314-113472-15v4z77.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">The flight path of Eduard Spelterini’s balloon in 1909.</span>
<span class="attribution"><span class="source">James Gentles</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>By identifying common features in the photographs, which can in turn be linked to surveyed features in the landscape, a 3D representation of both the balloon flight and the historical topography can be reconstructed using <a href="http://www.photogrammetry.com/">photogrammetry</a> – the science of taking measurements from photography. While the oblique angle of the photographs limits the measurable accuracy of the resulting data, compared to the vertical mapping photographs taken in the decades that followed, they still provide a unique and compelling glimpse into a past landscape. </p>
<p>In Spelterini’s image below, the oblique aerial view taken at a sideways angle towards the horizon gives a sense of place that is part way between the familiar ground level view and the high vertical perspective like that of a map. In the foreground the newly completed <a href="https://www.chamonet.com/lifts/summer/montenvers--mer-de-glace-cog-railway-train-40000">Montenvers cogwheel railway</a> is visible, perched over the voluminous Mer de Glace glacier which leads the eye to the spires of the Mont Blanc Massif in the background.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/210381/original/file-20180314-113482-1jj88lx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/210381/original/file-20180314-113482-1jj88lx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=451&fit=crop&dpr=1 600w, https://images.theconversation.com/files/210381/original/file-20180314-113482-1jj88lx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=451&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/210381/original/file-20180314-113482-1jj88lx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=451&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/210381/original/file-20180314-113482-1jj88lx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=567&fit=crop&dpr=1 754w, https://images.theconversation.com/files/210381/original/file-20180314-113482-1jj88lx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=567&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/210381/original/file-20180314-113482-1jj88lx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=567&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Montenverscog railway in the foreground was recently completed when Spelterini took this photograph.</span>
<span class="attribution"><span class="source">Eduard Spelterini</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The photographs are carefully composed, designed to serve as both record and artwork. Their oblique angle makes them less abstracted and more relatable, despite their height above the ground and the scale of the landscape they depict. All of these factors make them an ideal point of reference for visualising the changing nature of the alpine landscape.</p>
<h2>Follow that balloon</h2>
<p>In October 2017, a team of photographers and researchers from the University of Dundee returned to Chamonix to replicate the path of the historic flight and recreate the sequence of photographs using a helicopter. Spelterini’s balloon rapidly ascended to around 2,000m above the Chamonix valley before passing Mer de Glace. Such heights are virtually inaccessible to unmanned drones, meaning that a manned aircraft was needed.</p>
<p>The results are documented in <a href="https://bifrostonline.org/the-100-year-time-lapse/">The 100-year Time-Lapse Project</a>. GPS coordinates derived digitally from Spelterini’s photographs were used to return to the same locations to capture current-day equivalents of both his individual photographs and the 3D surface reconstruction. While the rate of change in the Mer de Glace glacier has been <a href="https://www.unige.ch/forel/files/1514/1691/5961/Chamonix_Eng0.pdf">studied</a> in great detail, using digital technology in this way allows for a visual comparison of the landscape then and now to reveal the staggering reduction in the ice surface that has taken place over the last century.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/DKMvNjvzAdU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Kieran Baxter and Kieran Duncan/YouTube.</span></figcaption>
</figure>
<p>Today, visitors alighting at the Montenvers railway station are no longer confronted with the Mer de Glace <a href="https://www.bloomberg.com/news/features/2015-09-25/climate-change-on-mont-blanc-the-vanishing-mer-de-glace">at close range</a>, but instead look down upon a largely empty valley and debris-covered glacier far below. Here the ice surface has dropped around 100 metres compared to its height in 1909. Scientists have <a href="https://www.researchgate.net/publication/285863081_Fluctuations_of_the_Mer_de_Glace_Mont_Blanc_area_France_AD_1500-2050_an_interdisciplinary_approach_using_new_historical_data_and_neural_network_simulations">calculated</a> that, overall, the glacier has lost around 700m cubic metres of water since the beginning of the 20th century.</p>
<p>While the facts and figures alone should be enough to narrate the impact that the previous century of greenhouse gas emissions have had on our climate and environment, images like these help drive the point home. Eduard Spelterini was not just a pioneer of aviation but also of aerial photography as a way of better understanding the natural world. His images capture an emotive sense of place while providing insights into aspects of the landscape that are not available from the ground.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/0zWI0xXDCSc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Kieran Baxter/YouTube.</span></figcaption>
</figure>
<p>Today, despite the heavy carbon footprint that comes with manned aviation, we continue to rely on aerial views to interpret our environment, from <a href="https://landsat.gsfc.nasa.gov/about/">Landsat satellite</a> imagery to low-level drone photography. By repurposing archival aerial photographs and continuing the legacy of photographers like Spelterini, with the help of current technology, we can explore new and compelling ways to visualise our rapidly changing glacial landscapes.</p>
<p>As well as serving to convince hearts and minds in the present political debates surrounding climate change, these images will also form a poignant record of magnificent landscapes that will no longer be around for future generations to experience.</p><img src="https://counter.theconversation.com/content/93248/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kieran Baxter 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>A heritage landscape researcher used the work of a Victorian aerial photographer to map a century of glacial loss in the Alps – and the results are staggering.Kieran Baxter, Research assistant, 3DVisLab, Duncan of Jordanstone College of Art and Design, University of DundeeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/574892016-04-21T01:44:24Z2016-04-21T01:44:24ZBuilding cool cities for a hot future<figure><img src="https://images.theconversation.com/files/119063/original/image-20160418-23625-1yxxtx1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Some materials and surfaces radiate much more heat (red areas) than others, as can be seen in this thermal image of Arncliffe Street in Wolli Creek, Sydney.</span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><blockquote>
<p>Another hot and humid day in Sydney tomorrow with a maximum of 32 degrees in the city and 38 in the western suburbs.</p>
</blockquote>
<p>How many times have we heard that on TV or radio weather reports? </p>
<p>But what would you think about the following forecast?</p>
<blockquote>
<p>Temperatures in Wattle Street, Ultimo, will spike at 37 degrees around 10 am. Further up the hill at Point Street we can expect a top of 40 degrees shortly after 1 pm. Meanwhile, at the Observatory Hill weather station the 3 pm maximum will struggle to pass 32 degrees.</p>
</blockquote>
<p>We are unlikely ever to be able to forecast temperatures to such pinpoint accuracy. Still, the above exercise reflects the very real differences in temperature – and thermal comfort – at the scale of the individual street, indeed individual block, within our cities. </p>
<p>The driver of this surprising variability is the interaction between urban form and the heat energy of the sun. Building heights and materials, width and orientation of streets, and presence or absence of vegetation all affect local temperatures across the city. And if we drive to work, the heat from our vehicle’s engine and exhaust might be adding a degree or two.</p>
<p>Recent media reports have highlighted the <a href="https://theconversation.com/sydney-so-hot-right-now-whats-behind-the-citys-record-run-of-warm-weather-55756">bizarre weather patterns</a> in Sydney over January, February and March 2016. Some reports have linked evidence of temperature extremes to urbanisation and the loss of shading and moisture that vegetation provides. This is known as the <a href="https://theconversation.com/if-planners-understand-its-cool-to-green-cities-whats-stopping-them-55753">Urban Heat Island (UHI) effect</a>. </p>
<p>A research collaboration between the UNSW Faculty of Built Environment and the Universities of South Australia and Melbourne has collected further evidence for the highly localised effects of building form, surface materials and street orientation on outdoor microclimate and pedestrian thermal comfort. The aim is to build a solid evidence base to inform design, planning and policy across Australian cities.</p>
<p>Meteorological data collected during the 2015-16 summer in Sydney reveals that air temperatures in the street “canyon” may vary by up to 5°C from those the Bureau of Meteorology records at Observatory Hill.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/119034/original/image-20160418-23606-mjsnwt.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/119034/original/image-20160418-23606-mjsnwt.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=810&fit=crop&dpr=1 600w, https://images.theconversation.com/files/119034/original/image-20160418-23606-mjsnwt.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=810&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/119034/original/image-20160418-23606-mjsnwt.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=810&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/119034/original/image-20160418-23606-mjsnwt.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1018&fit=crop&dpr=1 754w, https://images.theconversation.com/files/119034/original/image-20160418-23606-mjsnwt.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1018&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/119034/original/image-20160418-23606-mjsnwt.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1018&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
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<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Even more worrying are the surface temperatures measured on building facades. These may exceed 70°C in the sun. </p>
<p>The vertical surfaces of multi-storey buildings account for much of the urban surface in contact with the surrounding air. Hotter surface temperatures elevate nearby air temperatures during the day. </p>
<p>Then, due to the thermal mass of typically dense and dark building materials, building facades continue to emit radiant heat well after sunset. This slows the cooling of local outdoor air temperature. </p>
<p>Without night-time cooling, human thermal discomfort is prolonged. Consecutive nights of elevated air temperatures have severe impacts on human health. This includes <a href="https://www.nccarf.edu.au/business/sites/www.nccarf.edu.au.business/files/attached_files_publications/Loughnan-ExtremeHeatEventsinAustralianCapitalCities-HighRes.pdf">increasing heat-related mortality and morbidity</a>.</p>
<p>More extreme heat days projected from climate change on top of localised heating due to urban design <a href="https://www.nccarf.edu.au/sites/default/files/attached_files_publications/HEATWAVE_A4-Webview.pdf">elevates the health risks from future heatwaves</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/119033/original/image-20160418-23629-4gkckn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/119033/original/image-20160418-23629-4gkckn.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1003&fit=crop&dpr=1 600w, https://images.theconversation.com/files/119033/original/image-20160418-23629-4gkckn.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1003&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/119033/original/image-20160418-23629-4gkckn.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1003&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/119033/original/image-20160418-23629-4gkckn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1261&fit=crop&dpr=1 754w, https://images.theconversation.com/files/119033/original/image-20160418-23629-4gkckn.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1261&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/119033/original/image-20160418-23629-4gkckn.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1261&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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</figure>
<h2>Urban temperatures vary with design</h2>
<p>Our research sought to quantify the effects of typical urban form and materials on street microclimate and outdoor thermal comfort. We recorded building surface temperatures and ambient air temperatures using a thermal camera and mobile weather station in various locations in metropolitan Sydney. </p>
<p>Preliminary results suggest that business-as-usual architectural and urban design are exacerbating urban heat and creating hotter cities. This is alarming when considering the <a href="http://infrastructureaustralia.gov.au/policy-publications/publications/files/Australian-Infrastructure-Audit-Executive-Summary.pdf">current and projected population</a> of Australia’s major cities, particularly the <a href="http://www.treasury.gov.au/%7E/media/Treasury/Publications%20and%20Media/Publications/2015/2015%20IGR%20Overview/Downloads/PDF/2015IGR_Overview.ashx">growing proportion of vulnerable elderly</a>.</p>
<p>On January 14, 2016 – <a href="http://www.bom.gov.au/climate/dwo/201601/html/IDCJDW2124.201601.shtml">Sydney’s hottest day that month</a> – the 9AM and 3PM air temperatures recorded at Observatory Hill were 30.8°C and 32.4°C respectively. </p>
<p>On the same day, pedestrian-height air temperatures were recorded mid-morning in Wattle Street, Ultimo – 32.34°C at 9am – and mid-afternoon in Point Street, Pyrmont – 36.34°C around 3pm. These temperatures in Wattle and Point streets were 1.54°C and 3.94°C higher – or up to 12.2% greater – than the maximums at Observatory Hill. </p>
<p>Prior studies have reported a <a href="http://www.ncbi.nlm.nih.gov/pubmed/18058138">significant increase in mortality</a> for every 1°C rise in air temperatures above a mortality-temperature threshold (typically around 32°C for Australian cities). This applies particularly for the <a href="http://www.ncbi.nlm.nih.gov/pubmed/20797898">population aged 65 years and older</a>. Conversely, every degree of cooling has health and economic benefits for urban residents.</p>
<p>The surface temperatures of nearby building facades confirm a potential source of localised heating. The seven-storey, northeast-facing Wattle Street facade recorded a maximum spot temperature of 65°C and a mean surface temperature of 46°C around 9AM. The eight-storey, northwest-facing Point Street facade recorded an average surface temperature of 42.4°C and a spot maximum of 54°C mid-afternoon. </p>
<p>Notwithstanding measurement uncertainty due to emissivity (how well a material emits heat energy), the higher daytime building facade temperatures suggest an influential relationship with observed near-facade air temperatures. </p>
<p>By taking into account the design drivers – including orientation and solar exposure, material albedo (reflectance) and emissivity, and views of opposite buildings and the sky – building designers can help cool our cities through “cool facades”.</p>
<h2>Buildings hold key to outdoor comfort</h2>
<p>We also calculated the effects of material properties on outdoor air temperatures and thermal comfort for January 14. </p>
<p>Footpath albedos (reflectance) in Wattle Street and Point Street ranged from 0.033 to 0.050 for rough weathered bitumen and smoother grey stone pavers respectively. Superficially the footpath materials appear to be the same colour. However, the rougher bitumen has a lower reflectance and therefore absorbs more solar radiation (and becomes hotter) than the smoother stone tile.</p>
<p>Prior studies have <a href="http://eetd.lbl.gov/publications/content/reflective-surfaces-cooler-buildings-and-cities">linked surface roughness to reflectance characteristics</a>. The potentially contradictory effects of footpath surface reflectance on air temperatures and thermal comfort are evident in the grey globe thermometer (GGT) measurements. </p>
<p>The GGT measures only radiant heating to which humans are particularly sensitive. Cooler air temperatures are often correlated with higher albedo surfaces, but greater reflectance may increase the radiant load on pedestrians, increasing thermal discomfort. </p>
<p>The GGT 10-minute mean between 8.30AM and 10.30AM in Wattle Street was 36.95°C and the ten-minute mean air temperature for the same period was 33.70°C. Between 1PM and 2.30PM in Point Street, the GGT ten-minute mean was 43.0°C and the ten-minute mean air temperature was 38.57°C. </p>
<p>The relative differences between ambient and GGT temperatures are 4.87°C and 6.05°C. This greater GGT temperature difference confirms the additional radiant heating from the more reflective footpath surface and nearby hot facade.</p>
<p>The conclusion? Weather is not simply what the bureau tells us. As higher urban temperatures occur at the scale in which people actually live – the building, the street, the block – the implications for our health and well-being are profound. </p>
<p>By informing those involved in city planning, management and design about the implications of their design decisions on urban microclimate, this research provides the evidence base for a “cool” urban future.</p><img src="https://counter.theconversation.com/content/57489/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Osmond receives funding for this research from the Co-operative Research Centre (CRC) for Low Carbon Living (LCL).</span></em></p><p class="fine-print"><em><span>Jonathan Fox receives research funding for this research from the Cooperative Research Centre (CRC) for Low Carbon Living (LCL).</span></em></p>Hot spots occur at the scale of where people live – the building, the street, the block – which means urban design and building materials have profound implications for our health and well-being.Paul Osmond, Senior Lecturer and Director, Sustainable Built Environment program, UNSW SydneyJonathan Fox, PhD Research Candidate, Urban Climates Research, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.