tag:theconversation.com,2011:/global/topics/india-heatwave-2015-17472/articlesIndia heatwave 2015 – The Conversation2023-04-28T12:08:54Ztag:theconversation.com,2011:article/2045022023-04-28T12:08:54Z2023-04-28T12:08:54ZDeadly heatwaves threaten to reverse India’s progress on poverty and inequality – new research<figure><img src="https://images.theconversation.com/files/523417/original/file-20230428-26-5za89g.jpg?ixlib=rb-1.1.0&rect=0%2C407%2C4484%2C3801&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/new-delhi-india-may-8-2022-2154556927">PradeepGaurs/Shutterstock</a></span></figcaption></figure><p>Record-breaking heatwaves in April 2022 put 90% of people in India at increased risk of going hungry, losing income or premature death, according to our <a href="https://journals.plos.org/climate/article?id=10.1371/journal.pclm.0000156">new study</a>.</p>
<p>After 2022 was designated the hottest in <a href="https://www.vox.com/23057267/india-pakistan-heat-wave-climate-change-coal-south-asia">122 years</a>, extreme heat has appeared early again this year with over <a href="https://www.downtoearth.org.in/news/climate-change/heatwaves-arrive-early-in-2023-hit-11-states-from-march-3-to-april-18-88871#:%7E:text=Over%2060%20per%20cent%20of,Department%20released%20April%2019%2C%202023.">60% of India</a> recording above-normal maximum temperatures for April, according to the country’s Meteorological Department. El Niño, a natural climate event that can increase global temperatures, is also expected to occur this year.</p>
<p>The increasing frequency of such deadly heatwaves could halt or even reverse India’s progress in reducing poverty, food and income security and gender equality, harming the quality of life for over 1.4 billion Indians.</p>
<p>As a natural phenomenon, extreme heat is projected to occur once every <a href="https://theconversation.com/india-heatwave-why-the-region-should-prepare-for-even-more-extreme-heat-in-the-near-future-182452">30 years or so</a> in the Indian subcontinent. This is no longer the case thanks to man-made climate change. India has suffered over <a href="https://journals.plos.org/climate/article?id=10.1371/journal.pclm.0000156">24,000</a> heatwave-related deaths since 1992 alone, with the May 1998 heatwave being one of the most devastating as it claimed over 3,058 lives.</p>
<p>During the May 2010 heatwaves, temperatures in the western city of Ahmedabad reached 47.8°C and raised heat-related hospital admissions of newborns by <a href="https://www.hindawi.com/journals/jeph/2014/946875/">43%</a>, prompting the city to become one of the country’s first to implement a heat action plan meant to guide preparations and emergency responses to heatwaves which has since <a href="https://www.preventionweb.net/news/india-new-evidence-shows-pioneering-heat-action-plan-helps-millions-avoid-killer-heat#:%7E:text=The%20Heat%20Action%20Plan%20in,according%20to%20a%20recent%20study">saved thousands of lives</a>. The 2015 heatwave killed over 2,330 people and prompted the government ministry for disaster management to set guidelines for preventing deaths during heatwaves and push Indian states to develop their own plans.</p>
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<img alt="A person covers a child with a blanket to protect them from the sun on a street in India." src="https://images.theconversation.com/files/523422/original/file-20230428-16-eu8lo4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523422/original/file-20230428-16-eu8lo4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523422/original/file-20230428-16-eu8lo4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523422/original/file-20230428-16-eu8lo4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523422/original/file-20230428-16-eu8lo4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523422/original/file-20230428-16-eu8lo4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523422/original/file-20230428-16-eu8lo4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">People who must work outdoors and those with health conditions are particularly vulnerable to extreme temperatures.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/impact-climate-change-people-trying-save-2147692357">Sudarshan Jha/Shutterstock</a></span>
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<p>Failure to implement these strategies may stymie India’s economic progress. If proper heat action plans are not developed, excessive heat could cost India 2.8% and 8.7% of its GDP by <a href="https://www.mckinsey.com/capabilities/sustainability/our-insights/will-india-get-too-hot-to-work">2050</a> and <a href="https://www.adb.org/publications/assessing-costs-climate-change-and-adaptation-south-asia">2100</a>, respectively. This is a worrying trend, especially given India’s goal of becoming a <a href="https://www.investindia.gov.in/team-india-blogs/indias-growing-strides-towards-10-trillion-dollar-economy#:%7E:text=It%20took%20India%2060%20years,the%20next%2014%2D15%20years.">10-trillion-dollar economy by 2030</a>.</p>
<h2>A ‘real-feel’ measure</h2>
<p>Heat action plans are only useful if they can represent the consequences of heatwaves over the entire population. For Indian authorities to recognise when deadly heat is present (and emergency action is needed), the government has to know how conditions feel for the public.</p>
<p>We used an environmental health measure popular in the US called the heat index to determine how hot the human body is likely to feel in relation to air temperature and humidity levels. This helped us to map how sensitive people were to heatwaves across India and discover that 90% of the country was in danger of severe repercussions during last year’s heatwave.</p>
<p>It’s important to accurately measure India’s vulnerability to lethal temperatures. The metric used by the Indian government, known as the climate vulnerability index, does not account for the physical dangers of heat to human health. Our research showed that combining air temperature and relative humidity levels gave our heat index a “real-feel” measure for extreme heat. In other words, how extreme heat felt for people experiencing it.</p>
<h2>Stop underestimating heatwaves</h2>
<p>Underestimating the effects of extreme heat in India could reduce or even reverse its progress on a range of goals for sustainable development. These include those related to poverty, hunger, health and wellbeing, equality, economic growth and industrial innovation and biodiversity. This is especially concerning given that India’s progress towards achieving these goals has slowed over the last 20 years while the number of extreme weather events has increased. </p>
<p>Extreme heat, for example, can exacerbate drought by drying up the soil and disrupting rainfall patterns, ultimately blighting crop production and food security, which endangers the health and wellbeing of a large portion of Indian society. Being a primarily agricultural economy, productivity losses in this sector threaten the jobs and health of millions of marginal and small landholding farmers, as well as their ability to adapt and take up new livelihoods. Another worrying tendency with heatwaves is increasing <a href="https://nyaspubs.onlinelibrary.wiley.com/doi/full/10.1111/nyas.13950">water-borne and insect-borne diseases</a>, which could further strain India’s already beleaguered public health system.</p>
<p>Every year, millions of people from rural areas migrate to India’s cities in search of a better quality of life. But heatwaves have a disastrous effect on the country’s urban population too. Practically the entire city of Delhi and its 32 million inhabitants were threatened by the 2022 heatwaves. Most migrants are forced to settle in the city’s poorest quarters, where the effects of heatwaves are particularly catastrophic. Sadly, these communities also lack the means to buy air conditioners that might ease their misery.</p>
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<img alt="Two people, one with an umbrella, walking on a hot day with a Hindu temple in the background." src="https://images.theconversation.com/files/523420/original/file-20230428-24-hmppm9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523420/original/file-20230428-24-hmppm9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=428&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523420/original/file-20230428-24-hmppm9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=428&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523420/original/file-20230428-24-hmppm9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=428&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523420/original/file-20230428-24-hmppm9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=538&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523420/original/file-20230428-24-hmppm9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=538&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523420/original/file-20230428-24-hmppm9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=538&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Delhi sweltered under record temperatures in spring 2022.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/new-delhi-india-may-9-2022-2167051459">PradeepGaurs/Shutterstock</a></span>
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<p>Present procedures for assessing the sensitivity of India to climate change will not help people resist the exceptional heat seen in recent years and must be upgraded immediately.</p>
<p>The Intergovernmental Panel on Climate Change <a href="https://www.ipcc.ch/assessment-report/ar6/">estimates</a> that heatwaves in South Asia will grow more powerful and frequent this century. Heat action plans will be crucial in speeding up efforts to mitigate and adapt to the effects, but they must represent the complexity of India’s vulnerabilities to climate change. The emphasis on making Indian cities resilient to extreme heat is critical, since cities will see <a href="https://www.hindustantimes.com/india-news/india-urban-cities-to-see-population-explosion-in-coming-decades-report-101667903294030.html">a population explosion</a> in the next ten years, with 70% of Indian building stock <a href="https://www.theatlantic.com/international/archive/2014/06/70-percent-of-india-has-yet-to-be-built/373656/">yet to be created</a>. There is a chance to incorporate methods for adapting to extreme heat by designing new homes that are easier to keep cool. </p>
<p>With many more people in India <a href="https://theconversation.com/india-heatwave-why-the-region-should-prepare-for-even-more-extreme-heat-in-the-near-future-182452">expected</a> to be hit by even greater heat extremes in the future, finance, urban design and education are necessary to help people adapt.</p>
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<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p class="fine-print"><em><span>Ramit Debnath receives funding from Qudarature Foundation, Keynes Fund, Bill and Melinda Gates Foundation, and Google Cloud Climate Innovation Challenge. </span></em></p><p class="fine-print"><em><span>Ronita Bardhan receives funding from ESRC-GCRF; AHRC; British Academy; Aloborada Fund; EPSRC; British Council; Keynes Fund; Charles Wallace India Trust; Department of Science and Technology, Government of India; MIT-Tata Trust; IUSSTF. </span></em></p>Spring 2022’s record heat put most Indians at greater risk of a premature death.Ramit Debnath, Cambridge Zero Fellow, University of CambridgeRonita Bardhan, Associate Professor of Sustainability in the Built Environment, University of CambridgeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/515882015-12-29T06:18:50Z2015-12-29T06:18:50ZWhy African countries need to make plans to cope with rising temperatures<figure><img src="https://images.theconversation.com/files/106626/original/image-20151218-27875-1p21th7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Health issues from extreme heat are a reality for many in Africa.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Southern Africa has been experiencing high temperatures in recent months. In October, Zimbabwe experienced a <a href="http://allafrica.com/stories/201510120083.html">heatwave</a> with temperatures in Kariba reaching 45°C. In late October, temperatures in Vredendal, South Africa reached a maximum of 48.4°C, breaking the record for the highest worldwide temperature for <a href="https://www.enca.com/south-africa/vredendal-sets-hottest-global-temperature-october">that month</a>. </p>
<p>Southern Africa is not alone. 2015 is the warmest year on <a href="https://www.wmo.int/media/content/wmo-2015-likely-be-warmest-record-2011-2015-warmest-five-year-period">record</a>.</p>
<p>The impact that high temperatures will have on the health of people living in southern Africa is not yet clear. This is particularly worrying since the increases are projected to continue because of climate change. And there are no alert and response systems or tools in place to ensure public health and safety during heatwaves.</p>
<p>According to a new <a href="http://ntww1.csir.co.za/plsql/ptl0002/PTL0002_PGE157_MEDIA_REL?MEDIA_RELEASE_NO=7526949">publication,</a> by the end of the century temperatures in sub-tropical Africa could <a href="http://iopscience.iop.org/article/10.1088/1748-9326/10/8/085004/meta">increase</a> by 4°- 6°C. In tropical Africa there could be rises of between 3°-5°C. Unless greenhouse gas emissions are reduced, these temperatures will become a reality. </p>
<p>These increases in temperature are likely to have a severe impact on health across Africa.</p>
<h2>Health risks</h2>
<p>High temperatures can directly impact health by upsetting the body’s thermoregulatory balance. Heat exhaustion can occur when body temperatures exceed 38°C and heat stroke when body temperatures reach over <a href="http://www.ipcc.ch/pdf/assessment-report/ar5/wg2/WGIIAR5-Chap11_FINAL.pdf">40°C</a>. But studies have also shown that there can be negative health effects and increases in mortality even at lower <a href="http://jech.bmj.com/content/64/9/753.full.pdf">outdoor temperatures</a>. </p>
<p>In general, the relationship between temperature and mortality varies by geographical area and climate, as well as by the characteristics of the population. When temperatures surpass the optimal range, the risk of mortality increases <a href="http://jech.bmj.com/content/64/9/753.full.pdf">rapidly</a>. And, in cases where high temperatures are experienced over multiple days in a row - as in a heatwave - human health can be negatively affected.</p>
<p>For example, in August 2003, Europe experienced the hottest summer in over 500 years. These heatwaves were estimated to have caused up to 45 000 heat-related <a href="https://www.ipcc.ch/pdf/assessment-report/ar4/wg2/ar4-wg2-chapter8.pdf">deaths</a>. In a recent heatwave in India, where temperatures hit around 40°C in some areas, 2,300 people were <a href="https://www.climate.gov/news-features/event-tracker/india-heat-wave-kills-thousands">reported</a> to have died.</p>
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<a href="https://images.theconversation.com/files/106627/original/image-20151218-27894-qkx379.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/106627/original/image-20151218-27894-qkx379.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/106627/original/image-20151218-27894-qkx379.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/106627/original/image-20151218-27894-qkx379.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/106627/original/image-20151218-27894-qkx379.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/106627/original/image-20151218-27894-qkx379.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/106627/original/image-20151218-27894-qkx379.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/106627/original/image-20151218-27894-qkx379.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Men in India lie in mud to cool themselves after a heatwave claimed over 2000 lives in 2015.</span>
<span class="attribution"><span class="source">Jitendra Prakash</span></span>
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<p>Many studies on the effects of heat on health have been done in temperate and industrialised nations. But few have been performed in sub-tropical and tropical climatic regions, and developing countries. This is due to the lack of data, research funding and prioritisation of research to determine the heat-health relationship.</p>
<h2>What is already known about the risk</h2>
<p>Climate projections predict significant <a href="http://www.mdpi.com/1660-4601/12/10/12577/pdf">risk</a> to African <a href="http://ntww1.csir.co.za/plsql/ptl0002/PTL0002_PGE157_MEDIA_REL?MEDIA_RELEASE_NO=7526983">lives</a> from increasing temperatures.</p>
<p>The study used apparent temperature instead of normal temperature. Apparent temperature is an index that combines temperature, relative humidity and wind speed to describe how hot it feels. Because local data were not available, this study assumes the thresholds at which health would be affected. It assumed an apparent temperature threshold of 27°C. Using this threshold and Addis Ababa as an example, the study projected that apparent temperatures in Addis currently go over 27°C on only two days of the year on average. But by the end of the century temperatures in Addis would exceed this on up to 160 days a year.</p>
<p>This increase was seen across Africa. Areas like the Democratic Republic of Congo had much warmer turning points. This is because the country already experiences many extremely hot days. </p>
<p>This research has limitations because of the lack of local data. But the message remains clear. Without strong action to stop climate change, the potential for the health of people in Africa being affected negatively from rising temperatures will increase.</p>
<h2>Response systems would help</h2>
<p>There are some practical steps that can be taken. For example, the Heat Alert and Response <a href="http://www.euro.who.int/en/health-topics/environment-and-health/Climate-change/activities/public-health-responses-to-weather-extremes2/heathealth-action-plans">System</a> combines meteorological forecasting of heat events and heatwaves together with a response plan.</p>
<p>When a heatwave is forecast a few days in advance, communities put out warnings and explain what measures are being put in place to protect public health. The plans are distributed at workplaces and community locations and include information sharing through public alerts via radio, SMSes and TV. Governments are sometimes involved too, providing freely available cooling centres and extra emergency response services focused on vulnerable and isolated people.</p>
<p>Meteorological forecasting systems need to be in place for this to work. For example, advance forecasts of up to 1-3 months give people time to mobilise resources and to put plans in place. </p>
<p>African governments and employers should look at developing a similar response system. </p>
<p>Continuous research and data are also needed to quantify the relationship between heat and health in Africa. It is likely that public health and the health of outdoor workers have already been affected but not yet quantified.</p><img src="https://counter.theconversation.com/content/51588/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rebecca Garland 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>Africa must find ways of dealing with extreme heatwaves or suffer a range of health problems, including fatalities.Rebecca Garland, Senior Researcher in Climate Studies, Modeling and Environmental Health Research Group, Council for Scientific and Industrial ResearchLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/427892015-06-04T05:19:43Z2015-06-04T05:19:43ZHow modern crops can ensure food security in a heatwave<p>India’s heatwave again highlights just how seriously extreme weather conditions threaten our ability to put sufficient nutritious food on all our plates. Headlines have focused on the human deaths – <a href="http://www.independent.co.uk/news/world/asia/minister-blames-indias-heatwave-on-climate-change-as-death-toll-reaches-2500-10294625.html">at least 2,500</a> at last count – but a heatwave can hit farming too. There are reports of <a href="http://www.aljazeera.com/news/2015/05/india-heat-wave-tests-water-supply-deaths-2000-150530032253669.html">scorched crops</a> and livestock struggling to survive in temperatures of 40C or more. More than <a href="http://timesofindia.indiatimes.com/india/Heatwave-kills-millions-of-chickens-prices-soar/articleshow/47505757.cms">17 million chickens have died</a> so far, leading to rapid price increases. </p>
<p>What is not yet so clear is the effect of the current extreme conditions on crop yields and food supply later in the year. Crop scientists the world over are grappling with these questions – but can their work can really protect food security in the face of extreme climate challenges?</p>
<p>Extreme weather like that India is experiencing at the moment presents crops not just with extreme high temperatures, but also with drought. Of those linked challenges, drought is the easier of the two to deal with, at least at first sight. Farmers have been watering crops for millennia, but the scale of modern food production means agriculture is already a major user of freshwater resources in many parts of the world, competing with the demands of other industries and, of course, the need for adequate safe drinking water.</p>
<p>Irrigation water has to come from somewhere. That might be from lakes and rivers, perhaps diverted into reservoirs, or from groundwater. However all these sources are already under intense pressure, both <a href="http://indianexpress.com/article/india/india-others/heat-wave-in-india-the-ready-reckoner/">in India</a> and elsewhere – <a href="http://cida.usgs.gov/ca_drought/">California is another very topical example</a>. </p>
<p>Taking too much water from those sources has knock-on effects on rivers and wetlands. Over-extraction of groundwater can also allow sea water to seep in to groundwater, reducing its quality for both people and crops. So, while irrigation has a part to play, we have to recognise that <a href="http://alokjha.com/thewaterbook/">water is a limited resource</a> in much of the world, and that we need to use it as efficiently as we possibly can. </p>
<p>Poorly managed irrigation, especially using poor quality water, also contributes to the build-up of salts in agricultural soils. Ironically, trying to deal with the heat and drought can introduce a third threat to food production, saline soils. So, beyond irrigation, what options are there?</p>
<h2>GM vs heatwaves</h2>
<p>Producing crops that can grow and yield in the face of high temperature, drought and salty soils is a top priority for crop scientists around the world. </p>
<p>Some employ modern genetic modification techniques to produce new crop varieties that can cope with these harsh growing conditions. There are teams around the world manipulating specific crop traits to do this, but the problem lies in those three words: “specific crop traits”. </p>
<p>GM has given us the means to modify single genes. Whatever your views on GM crops, there is no doubt that changing a single gene can produce crops that are resistant to a herbicide or attack by a particular pest. But heat, drought and salinity damage crops through a range of mechanisms. You may be able to change a gene to reduce one type of damage but that’s just one piece in a complex puzzle. </p>
<p>You could look to combine different traits. Improving root growth for instance can allow a crop to access water deeper in the soil. Leaves might be modified to reduce water loss or to reflect more light to reduce the heat load. Or plant chemistry might be changed, for example to help the plant deal with cellular damage caused by extreme heat, drought or salinity. </p>
<p>Combining these and other possible modifications might ultimately produce much more robust crops. For example the International Rice Research Institute (IRRI) is using these approaches to develop <a href="http://irri.org/our-impact/tackling-climate-change/developing-drought-tolerant-rice">drought resistant rice</a>, but that remains a huge technical challenge and is certainly no “quick fix”. </p>
<p>This “bottom up” combination of specific characteristics actually has many parallels with <a href="http://www.lancaster.ac.uk/news/articles/2013/crop-researchers-sort-the-wheat-from-the-chaff/">traditional breeding</a> – crossing existing crop varieties to combine good characteristics and then screening thousands of offspring under challenging growing conditions to identify those that have improved performance. Again, that’s possible, and is being done now to produce new <a href="http://blog.cimmyt.org/heat-stress-resilient-maize-hybrids-for-asian-farmers/">heat resistant maize varieties for Asian farmers</a>, but it certainly isn’t a quick or easy process, even with modern methods that can accelerate traditional breeding.</p>
<h2>Natural alternatives</h2>
<p>Crop scientists are also looking to alternatives to these genetic methods. For example, we now understand how roots perceive drying soil, and then communicate that to the shoot to induce water-saving changes in the leaves. That understanding has led to new water-efficient irrigation that delivers “<a href="http://www.myscience.org/wire/uk_and_india_collaborate_on_future_proof_crops-2014-lancaster">more crop per drop</a>”, an approach that can be deployed at very low cost even by small farmers. </p>
<p>Understanding how plants regulate their response to heat stress and salinity also provides routes by which we might intervene to boost these responses – a little like boosting our immune system to help prevent disease rather than cure it. There is a great deal of promising research here, and hints that a new generation of <a href="http://www.rsc.org/chemistryworld/News/2008/January/30010801.asp">anti-stress agrochemicals</a> may not be too far away, many based on plant’s own natural defence systems.</p>
<p>Increasing crop losses are one symptom of the weather extremes which are becoming ever more commonplace. Advances in crops and agricultural methods help reduce the severity of that symptom, but we have to be realistic about the limits. Even the best application of crop science can’t make the world’s staple crops able to cope with every extreme of weather. Simply dealing with the symptom is useful, but it can’t be a substitute for a cure to the underlying cause. While we can’t simply link the current heatwave in India with climate change, the message surely isn’t all that hard to read. Let’s hope that’s a message which is heard in Paris this Autumn.</p><img src="https://counter.theconversation.com/content/42789/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nigel Paul receives funding from the UK Biotechnology and Biological Sciences Research Council. </span></em></p>Hardy new grains are being developed that can cope with extreme bursts of heat.Nigel Paul, Professor of Plant Science, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/426362015-06-01T18:04:44Z2015-06-01T18:04:44ZIs India’s heatwave a freak event? A statistician investigates<p>A heatwave over India that started on May 21 and has produced India’s highest recorded temperatures in two decades has claimed <a href="http://www.theguardian.com/weather/2015/may/31/southern-india-heatwave-death-toll-nears-2200-rain-brings-little-relief">more than 2,000 lives</a> and caused widespread devastation. It would be easy to dismiss this as a freak event, something so far out of the norm that there’s little chance of preparing for it. But this isn’t quite true. Even the most extreme events can be predicted – and prepared for.</p>
<p>I specialise in a statistical approach called <a href="http://www.risknet.de/fileadmin/eLibrary/EVT-Paper-Roehrl-Chavez-Demoulin.pdf">extreme value theory</a> which draws inferences about very rare events. Among other uses, it can be used to estimate the <a href="http://www.lancs.ac.uk/%7Ewinterh/research_DH.html">probability of a heatwave occurring</a>. </p>
<p>Where most statistical methods are great at modelling average values – what temperature is it likely to be next week? – they tend to be poor at modelling the extremes (what is the highest temperature we’ll see this decade?). Our model instead focuses on extreme values themselves, in this case the hottest days of the year, which are the values that can cause the greatest devastation.</p>
<p>This also means we can figure out the rough probability of events larger and longer than any that have gone before. Just because we haven’t seen consecutive 40°C days in the UK, or snow in the middle of the Sahara, doesn’t mean it can’t happen. Extreme value theory helps assess these probabilities. </p>
<p>We can use it to assess how likely the current heatwave is by analysing daily temperature maximums for Delhi over the years 1972-2013. Extreme value models can be used to estimate the temperature expected to be attained on average once a year (called the <a href="http://climatica.org.uk/climate-science-information/return-periods-extreme-events">one-year return level</a>). In Delhi the one-year return level is 45°C.</p>
<p>However, single hot days do not have a great impact on excess mortality. Consecutive runs of hot days are more dangerous since the human body is subjected to heat stress over many days without being given the chance to recover. Fortunately the same type of extreme value models can be used to estimate the probability of runs of consecutive days above a certain temperature. </p>
<p>During the current heatwave Delhi recorded <a href="https://theconversation.com/a-heatwave-thats-too-hot-for-india-to-handle-with-more-to-come-42468">seven consecutive days above 44°C</a>. That’s an entire week above an exceptionally high temperature – such an event is expected to happen on average once every 30 years. However, care must be taken with such results since they are often subject to large uncertainty as they are based upon very few rare events in the observational record.</p>
<h2>Blame El Niño?</h2>
<p>An El Niño may make such heatwaves more likely. The El Niño is one of two opposing phases in the El Niño Southern Oscillation (ENSO), a large-scale fluctuation of sea surface temperatures in the equatorial Pacific. Right now a large El Niño (warmer waters) is <a href="https://theconversation.com/el-nino-could-mean-2015-is-even-hotter-than-last-years-scorcher-35837">currently building</a> and will peak later this year. This generally means higher temperatures in India.</p>
<p>Could the current ENSO be contributing to the current heatwave event? Under current conditions, the probability of observing seven days above 44°C in Delhi is slightly increased, with the event expected to happen on average once in every 25 years. But it is difficult to definitively say that El Niño is having an effect since this result is again subject to a great deal of uncertainty.</p>
<p>One important question for decision makers concerns whether heatwaves are going to become more likely under climate change. Answering this question becomes difficult since there are numerous sources of uncertainty – most obviously, we don’t even know exactly what “climate change” will entail.</p>
<p>For example, different scenarios are generated, most famously <a href="https://www.ipcc.ch/pdf/special-reports/spm/sres-en.pdf">by the IPCC</a>, that aim to predict how future emissions will evolve. For each particular scenario, different climate research centres run different models that produce different replications of each future scenario. </p>
<p>The most common way to account for uncertainty is to take an ensemble of many different climate models – yet even this can leave a big margin for error, especially when analysing rare events such as heatwaves.</p>
<h2>Expect more heatwaves</h2>
<p>In 2003 a month-long heatwave struck Europe, causing at least <a href="http://www.metoffice.gov.uk/learning/learn-about-the-weather/weather-phenomena/case-studies/heatwave">20,000 deaths</a> and possibly as many as <a href="http://www.sciencedirect.com/science/article/pii/S1631069107003770">70,000</a>. My colleagues and I have <a href="http://lancs.ac.uk/%7Ewinterh/FST_public_lecture_hugo_winter">previously analysed</a> this particularly hot summer to assess the effect of climate change on heatwaves. We wanted to understand whether such an event would become more likely under future climate change and whether the behaviour of heatwave events would change. </p>
<p>We found that generally temperatures would increase, an increase of 1°C in global temperatures would lead to an increase of, at most, 2.6°C in the one-year return level at Orleans in central France. However, despite the fact heatwaves like in 2003 are expected to become more likely, it is not expected that such events will tend to last longer.</p>
<p>Statistical approaches have great potential to help decision makers mitigate for devastating events such as the current Indian heatwave. By providing reliable estimates of how often they will occur better preparation measures can be undertaken which will reduce the number of deaths. </p>
<p>Looking to the future, the effect of climate change is the largest uncertainty. Further collaborative research between statisticians and climate scientists presents the best chance to understand the potentially devastating effects that climate change will have on all types of extreme event.</p><img src="https://counter.theconversation.com/content/42636/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hugo Winter receives funding from the UK research council EPSRC as part of the STOR-i Centre for Doctoral Training at Lancaster University. He is affiliated and co-funded by the Met Office.</span></em></p>Regular statistics isn’t much good at predicting the improbable.Hugo Winter, Research Student in the Statistics of Meteorological Extremes, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.