tag:theconversation.com,2011:/ca/topics/el-nino-5638/articlesEl Nino – The Conversation2024-03-11T10:04:45Ztag:theconversation.com,2011:article/2185452024-03-11T10:04:45Z2024-03-11T10:04:45ZEast Africa must prepare for more extreme rainfall during the short rainy season – new study<p>East Africa has recently had an <a href="https://earthobservatory.nasa.gov/images/150712/worst-drought-on-record-parches-horn-of-africa">unprecedented series of failed rains</a>. But some rainy seasons are bringing the opposite: huge amounts of rainfall. </p>
<p>In the last few months of 2023, the rainy season, known as the “short rains”, was much wetter than normal. It brought severe flooding to Kenya, Somalia and Tanzania. In Somalia, <a href="https://news.un.org/en/story/2023/11/1144202">more than</a> 2 million people were affected, with over 100 killed and 750,000 displaced from their homes. Tens of thousands of people in northern Kenya <a href="https://www.euronews.com/green/2023/12/15/floods-have-washed-away-entire-villages-kenyas-rains-made-twice-as-intense-by-climate-chan">lost</a> livestock, farmland and homes. </p>
<p>The very wet short rainy seasons are linked to a climate event known as a positive Indian Ocean Dipole (known as the “IOD”). And climate model projections <a href="https://www.nature.com/articles/s41558-020-00943-1">show an increasing trend</a> of extreme Indian Ocean dipoles. </p>
<p>In a <a href="https://doi.org/10.1029/2023GL105258">new research paper</a>, we set out to investigate what effect more frequent extreme Indian Ocean Dipole events would have on rainfall in east Africa. We did this using a large number of climate simulations and models.</p>
<p>Our results show that they increase the likelihood of very wet days – therefore making very wet seasons. </p>
<p>This could lead to extreme weather events, even more extreme than the floods of 1997, which led to <a href="https://www.fao.org/3/w7832e/w7832e00.htm">10 million people requiring emergency assistance</a>, or those of 2019, when <a href="https://fews.net/east-africa/special-report/january-2020">hundreds of thousands were displaced</a>.</p>
<p>We recommend that decision-makers plan for this kind of extreme rainfall, and the resulting devastating floods.</p>
<h2>How the Indian Ocean Dipole works</h2>
<p>Indian Ocean Dipole events tend to occur in the second half of the year, and can last for months. They have two phases: positive and negative. </p>
<p>Positive events occur when the temperature of the sea surface in the western Indian Ocean is warmer than normal and the temperature in the eastern Indian Ocean is cooler than normal. Put simply, this temperature difference <a href="https://www.nature.com/articles/43854">happens when</a> winds move warmer water away from the ocean surface in the eastern region, allowing cooler water to rise. </p>
<p>In the warmer western Indian Ocean, more heated air will rise, along with water vapour. This forms clouds, bringing rain. Meanwhile, the eastern part of the Indian Ocean will be cooler and drier. This is why flooding in east Africa can happen at the same time as <a href="https://theconversation.com/indian-ocean-linked-to-bushfires-and-drought-in-australia-20893">bushfires in Australia</a>.</p>
<p>The opposite is true for negative dipole events: drier in the western Indian Ocean and wetter in the east. </p>
<p>Under climate change we’re expecting to see more frequent and more extreme positive dipole events – bigger differences between east and west. This is <a href="https://www.carbonbrief.org/guest-post-why-climate-change-will-cause-more-strong-indian-ocean-dipole-events/">shown by climate model projections</a>. They are believed to be driven by different paces of warming across the tropical Indian Ocean – with western and northern regions projected to warm faster than eastern parts.</p>
<p>Often heavy rain seasons in east Africa are attributed to El Niño, but <a href="https://rmets.onlinelibrary.wiley.com/doi/10.1002/asl.1015">recent research</a> has shown that the direct impact of El Niño on east African rainfall is actually relatively modest. El Niño’s principal influence lies in its capacity to bring about positive dipole events. This occurs since El Niño events tend to cool the water in the western Pacific Ocean – around Indonesia – which also helps to cool down the water in the eastern Indian Ocean. These cooler temperatures then help kick-start a positive Indian Ocean Dipole.</p>
<h2>Examining unprecedented events</h2>
<p>Extreme positive Indian Ocean Dipole events are rare in the recent climate record. So to examine their potential impacts on rainfall extremes, we used a large set of climate simulations. The data allowed us to diagnose the sensitivity of rainfall to larger Indian Ocean Dipole events in a statistically robust way.</p>
<p>Our results show that as positive dipole events become more extreme, more wet days during the short rains season can be expected. This effect was found to be largest for the frequency of extremely wet days. Additionally, we found that as the dipole strength increases, the influence on the most extreme days becomes even larger. This means that dipole events which are even slightly “record-breaking” could lead to unprecedented levels of seasonal rainfall. </p>
<p>Ultimately, if positive Indian Ocean Dipole seasons increase in frequency, as predicted, regular seasons of flooding impacts will become a new normal.</p>
<p>One aspect not included in our analysis is the influence of a warmer atmosphere on rainfall extremes. A warmer atmosphere <a href="https://www.carbonbrief.org/explainer-what-climate-models-tell-us-about-future-rainfall/">holds more moisture</a>, allowing for the development of more intense rain storms. This effect could combine with the influence of extreme positive dipoles to bring unprecedented levels of rainfall to the Horn of Africa. </p>
<p>2023 was <a href="https://wmo.int/media/news/wmo-confirms-2023-smashes-global-temperature-record">a year of record-breaking temperatures driven both by El Niño and global warming</a>. We might expect that this warmer air could have intensified rain storms during the season. Indeed, evidence from <a href="https://www.worldweatherattribution.org/climate-change-indian-ocean-dipole-compounding-natural-hazards-and-high-vulnerability-increased-severity-of-flooding-in-the-horn-of-africa/">a recent assessment</a> suggests that climate change-driven warming is highly likely responsible for increased rainfall totals. </p>
<h2>Responding to an unprecedented future</h2>
<p>Policymakers need to plan for this. </p>
<p>In the long term it is crucial to ensure that any new infrastructure is robust to withstand more frequent and heavier rains, and that government, development and humanitarian actors have the capacity to respond to the challenges.</p>
<p>Better use of technology, such as innovations in <a href="https://fastaweather.com/">disseminating satellite rainfall monitoring via mobile phones</a>, can communicate immediate risk. <a href="https://www.science.org/content/article/ai-churns-out-lightning-fast-forecasts-good-weather-agencies">New frontiers in AI-based weather prediction</a> could improve the ability to anticipate localised rain storms, including <a href="https://www.wfp.org/publications/2023-machine-learning-early-warning-systems">initiatives focusing on eastern Africa</a> specifically. </p>
<p><a href="https://www.youtube.com/watch?v=9g_06jBU-ag">Linking rainfall information with hydrological models designed for dryland environments</a> is also essential. These will help to translate weather forecasts into impact forecasts, such as identifying risks of flash flooding down normally dry channels or bank overflow of key rivers in drylands.</p>
<p>These technological improvements are crucial. But better use of the forecast information we already have can also make a big difference. For instance, initiatives like <a href="https://www.climatecentre.org/priority_areas/fbf-ibf/">“forecast-based financing”</a>, pioneered by the Red Cross Red Crescent movement, link forecast triggers to pre-approved financing and predefined action plans, helping communities protect themselves before hazards have even started.</p>
<p>For these endeavours to succeed, there must be dialogue between the science and practitioner communities. The scientific community can work with practitioners to integrate key insights into decisions, while practitioners can help to ensure research efforts target critical needs. With this, we can effectively build resilience to natural hazards and resist the increasing risks of our changing climate.</p><img src="https://counter.theconversation.com/content/218545/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Erik W. Kolstad receives funding from the European Union’s Horizon 2020 programme through the CONFER project (grant 869730)</span></em></p><p class="fine-print"><em><span>Katerina Michaelides receives funding from EU H2020, the FCDO and the Leverhulme Trust. </span></em></p><p class="fine-print"><em><span>Michael Singer receives funding from the European Union's Horizon 2020 Programme. </span></em></p><p class="fine-print"><em><span>David MacLeod 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>Projections show that there’ll be Indian Ocean dipoles in the future – and that means more rainy days, and more extreme rainfall.David MacLeod, Lecturer in Climate Risk, Cardiff UniversityErik W. Kolstad, Research professor, Uni ResearchKaterina Michaelides, Professor of Dryland Hydrology, School of Geographical Sciences, University of BristolMichael Singer, Professor of Hydrology and Geomorphology, Cardiff UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2249742024-03-05T13:13:04Z2024-03-05T13:13:04ZDry weather hits southern Africa’s farmers, putting key maize supplies at risk: how to blunt the impact<p><a href="https://www.news24.com/news24/africa/news/south-africa-and-the-region-face-grain-strain-despite-record-harvests-20231128">South Africa</a>, <a href="https://apnews.com/article/drought-national-disaster-emergency-electricity-4cc6a2105f4641efe17e10a5b75f78a5">Zambia</a> and <a href="https://english.news.cn/20240229/c7454e0f49e74fd6b891519993f943b9/c.html">Zimbabwe</a> have recently published reports indicating a potential decline in grain harvest because of intense El Niño-induced dryness. These developments could put the entire Southern Africa maize supply chain at risk, with Zambia and South Africa hard hit by heatwaves and dryness. The neighbouring small producers such as Zimbabwe, Botswana, Lesotho and Namibia are also struggling with dryness.</p>
<p>Given that South Africa, Zambia and Zimbabwe <a href="https://apps.fas.usda.gov/psdonline/circulars/production.pdf#page=29">are among the largest maize producers </a> within the Southern Africa region, a potential decline in the harvest in these countries suggests there could be an increase in the risk of food insecurity. This would necessitate imports to meet the shortfall in the region’s maize supplies.</p>
<p>The dryness in an El Niño event is not unexpected in the <a href="https://reliefweb.int/report/madagascar/southern-africa-el-nino-positive-indian-ocean-dipole-forecast-and-humanitarian-impact-october-2023#:%7E:text=El%20Ni%C3%B1o%2Drelated%20climate%20variability,during%20the%20November%20%2D%20April%20season.">Southern Africa region as this weather phenomenon is typically accompanied by dryness</a>. The year started favourably, with excellent rains. But the dryness intensified from the end of January. Major damage has been <a href="https://www.aljazeera.com/news/2024/2/29/zambia-declares-national-disaster-after-drought-devastates-agriculture">caused</a> to crops since then. The unusual pattern may be part of the broader climate change challenges.</p>
<p>Based on research into <a href="https://agbiz.co.za/content/open/sa-2023-24-summer-crop-production-forecasts-lowered-notably-72">grains markets</a> in the region, and recent observations from our field work across the summer crop growing regions of South Africa, it is clear that the region faces a difficult time ahead.</p>
<p>While the extent of the impact of the heatwave and dryness on crops changes daily, the pattern thus far is clear that the whole Southern Africa region has taken strain and will see a significant reduction in the volume of the crop produced.</p>
<p>Although the domestic hunger challenges may rise in some countries, as we already see in the forecasts in <a href="https://fews.net/sites/default/files/2024-01/FAOB-January%202024_1.pdf">Zimbabwe </a> and <a href="https://reliefweb.int/report/zambia/statement-unicef-zambia-situation-children-following-recent-emergency-declaration">Zambia</a>, the governments in the region must be careful about the response policies and programmes. For example, they should avoid export restrictions and maize price caps. And they should make sure that any government support should be at the household level.</p>
<h2>South Africa</h2>
<p>In South Africa, <a href="https://www.grainsa.co.za/news-headlines/press-releases/climate-conditions-problematic-for-grain-producers">a recent farmers’ survey</a> by <a href="https://www.grainsa.co.za/pages/about-grain-sa/overview">Grain South Africa</a>, a lobby group for the sector, found that extreme heat and dry conditions had caused the grain and oil-seeds harvest to deteriorate much faster than initially expected. </p>
<p>These challenges have probably worsened since the survey was completed towards the end of February.</p>
<p>The Crop Estimates Committee in South Africa – a grouping of scientists, economists and statisticians from the government, private sector, academia and independent research organisations – also fears the possible decline in the summer grains and oilseed harvest. <a href="https://agbiz.co.za/content/open/south-africas-summer-crop-production-prospects-remain-bleak-363">In its latest production estimate</a> for the 2023/24 season, the Committee placed the summer grains and oilseed harvest at 15.8 million tonnes, down 21% on 2023.</p>
<p>This is primarily a function of lower expected yields rather than a reduction in the acreage planted, thus reflecting a negative impact of the drier weather conditions and heatwave. This is an overall production figure, and the decline varies crop by crop. Still, a positive aspect of South Africa is that the expected harvest will still be enough to meet the country’s domestic consumption, leaving some volume for exports, albeit significantly down from the previous seasons.</p>
<p>There has not been a lot of talk about other value chains outside summer grains and oilseed, primarily because of higher dam levels from the past few years and earlier rains in the season. With all of South Africa’s commercial fruit and vegetable production under irrigation, the improved water levels in the dams assist farmers in coping with the current heatwave. The livestock industry is still in a relatively better place as the grazing veld has generally improved, and there were large maize and soybean supplies from the 2022/23 season. </p>
<p>The field crops are <a href="https://sa-tied-archive.wider.unu.edu/article/climate-uncertainty-and-agricultural-vulnerability-south-africa-0">primarily rainfed</a>, leaving a large percentage at the mercy of the natural rains, which have been scarce since the start of February.</p>
<h2>Zambia under drought stress</h2>
<p>In late February Zambia’s President, Mr Hakainde Hichilema, <a href="https://www.aljazeera.com/news/2024/2/29/zambia-declares-national-disaster-after-drought-devastates-agriculture">declared Zambia’s severe drought a national disaster and emergency</a>. There is crop damage in the majority of the summer crop-producing regions of the country because of the El Niño-induced drought. </p>
<p>Worryingly, the government reported that the drought <a href="https://apnews.com/article/drought-national-disaster-emergency-electricity-4cc6a2105f4641efe17e10a5b75f78a5">has destroyed nearly 1 million hectares of maize</a>. Given that the overall commercial maize area planting in the country is about 1.9 million hectares, this would mean half of the production has been destroyed. <a href="https://apps.fas.usda.gov/newgainapi/api/Report/DownloadReportByFileName?fileName=Zambia%20Maintains%20its%20Status%20as%20a%20Net%20Exporter%20of%20Corn%20_Pretoria_Zambia_ZA2023-0001.pdf">It could have significant negative consequences on food production</a>.</p>
<p>Zambia is one of southern Africa’s main producers and exporters of maize. This means if the maize harvest is down notably in the country, there will be no volume for exports to neighbouring countries that also need supplies. This happens at a time when South Africa, although potentially with sufficient supplies for domestic consumption, would have a massive decline in the volume of maize available for exports. </p>
<h2>Zimbabwe’s grain production also strained</h2>
<p>At the start of this year, there were reports of roughly <a href="https://apnews.com/article/zimbabwe-hunger-food-aid-el-nino-climate-aa25b4d2ee6405a792d75a0d4d12d505">2.7 million Zimbabweans potentially at risk of hunger</a> because of the drought impact in their summer grain fields. Moreover, Reuters <a href="https://www.nasdaq.com/articles/zimbabwe-targets-1.1-mln-tons-of-maize-imports-state-media-reports">reported</a> that “Zimbabwe plans to import 1.1 million metric tons of maize over the next year”.</p>
<p>It is unclear how much of this volume has thus far already been imported into the country. The volume speaks to the pressures of maize supplies in Southern Africa. Typically, when Zimbabwe needs such large maize imports, South Africa and Zambia are the primary suppliers. With Zambia potentially out of the export market this year, the pressure is now on South Africa to supply Zimbabwe.</p>
<p>Still, suppose all the required maize is of the white varietal, South Africa may not be in a position to provide Zimbabwe with the total required volume, particularly if we consider that the likes of Namibia, Botswana, Lesotho, Mozambique, Madagascar, and even Zambia will also require maize imports to supplement their domestic annual needs.</p>
<h2>Policy considerations</h2>
<p>There are several key points that policy makers should consider. These include:</p>
<ul>
<li><p>Avoiding export restrictions and maize price caps. While restricting exports seems a good approach for cushioning households in the near term, such an intervention disincentivises production for the next year as the farm-level prices would be artificially depressed. This is particularly important as farmers are not protected from higher input costs and pay world prices for all the imported inputs such as fertilisers, agrochemicals and some seeds.</p></li>
<li><p>Ensure interventions are at the household level through various support packages with fiscal space used to implement such programmes.</p></li>
<li><p>The regional governments should also engage with the World Food Programme to prepare to assist the least well-off countries with maize imports from the world market.</p></li>
<li><p>The governments should also engage, collectively with the private sector, the likes of Mexico that produce white maize, to assess if they would have space to export to the Southern Africa region if the need arises.</p></li>
</ul><img src="https://counter.theconversation.com/content/224974/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Wandile Sihlobo is the Chief Economist of the Agricultural Business Chamber of South Africa (Agbiz) and a member of the Presidential Economic Advisory Council (PEAC).</span></em></p>The whole southern Africa region has taken strain and will see a significant reduction in the volume of the crop produced.Wandile Sihlobo, Senior Fellow, Department of Agricultural Economics, Stellenbosch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2241332024-02-22T18:11:17Z2024-02-22T18:11:17ZClimate change is fanning the flames of NZ’s wildfire future. Port Hills is only the beginning<p>Last week, <a href="https://www.rnz.co.nz/news/national/509653/police-find-witnesses-to-650-hectare-port-hills-blaze">wildfire burnt through 650 hectares</a> of forest and scrub in Christchurch’s Port Hills. This is not the first time the area has faced a terrifying wildfire event. </p>
<p>The <a href="https://assets.stuff.co.nz/interactives/2017/firestorm/">2017 Port Hills fires</a> burnt through almost 2,000 hectares of land, claiming one life and 11 homes. It took 66 days before the fires were fully extinguished. </p>
<p>It is clear New Zealand stands at a pivotal juncture. The country faces an increasingly severe wildfire climate. And our once relatively “safe” regions are now under threat. </p>
<p>At all levels of government, New Zealand needs to consider whether our current investment to combat fires will be enough in the coming decades. </p>
<p><a href="https://doi.org/10.1029/2022EF002853">Our research</a> integrating detailed climate simulations with daily observations reveals a stark forecast: an uptick in both the frequency and intensity of wildfires, particularly in the inland areas of the South Island. </p>
<p>It is time to consider what this will mean for Fire and Emergency New Zealand (FENZ), and how a strategic calibration of resources, tactics and technologies will help New Zealand confront this emerging threat.</p>
<h2>The climate drivers of wildfires</h2>
<p>Last year was the <a href="https://www.ecmwf.int/en/about/media-centre/news/2024/2023-was-hottest-year-record-copernicus-data-show">warmest year on record</a> by a large margin. And with <a href="https://niwa.co.nz/climate/seasonal-climate-outlook/seasonal-climate-outlook-january-2024-march-2024">El Niño at full throttle into 2024</a>, conditions in late-summer Aotearoa New Zealand are hot and dry. There is also plenty of vegetation fuel from the <a href="https://www.rnz.co.nz/news/national/485129/saying-goodbye-to-la-nina-what-to-expect-from-autumn-s-weather">departing wet La Niña</a>. </p>
<p>The tinder-dry scrub and grass vegetation in the Port Hills – an area that was around 30% above “extreme” drought fire danger thresholds – drove the flammability of the region. And on February 13, when the latest fires started, a strong gusty northwesterly wind was blowing 40-50kph with exceptionally dry relative humidity values.</p>
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Read more:
<a href="https://theconversation.com/human-exposure-to-wildfires-has-more-than-doubled-in-two-decades-who-is-at-risk-might-surprise-you-207903">Human exposure to wildfires has more than doubled in two decades – who is at risk might surprise you</a>
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<p>These conditions resulted in the extreme wildfire behaviour. Only the rapid and coordinated response of FENZ on the ground and in the air prevented this fire from becoming much worse. </p>
<p>While conditions are already bad, our study revealed a concerning trend: the widespread emergence of a new wildfire climate, with regions previously unaffected by “very extreme” wildfire conditions now facing unprecedented threats. </p>
<p>The most severe dangers are projected for areas like the Mackenzie Country, upper Otago and Marlborough, where conditions similar to <a href="https://theconversation.com/200-experts-dissected-the-black-summer-bushfires-in-unprecedented-detail-here-are-6-lessons-to-heed-198989">Australia’s “Black Summer” fires</a> could occur every three to 20 years. </p>
<p>This shift is not merely an environmental concern, it is a socioeconomic one. The increased threat of wildfires will affect communities, the government’s tree-planting initiatives and financial investments in carbon forests.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1759978874950255032"}"></div></p>
<h2>Enhanced resources and agile response</h2>
<p>New Zealand’s firefighting strategy emphases speed and manoeuvrability, especially in the initial attack phase, to prevent wildfires from escalating into large-scale disasters.</p>
<p>Approximately NZ$10 million is allocated annually to general firefighting aviation services, translating into around 11,000 flight hours. The aerial battle over the Port Hills peaked on Thursday and Friday. This effort cost over $1 million, with up to 15 helicopters active over the two days.</p>
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Read more:
<a href="https://theconversation.com/how-wildfires-affect-climate-change-and-vice-versa-158688">How wildfires affect climate change — and vice versa</a>
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<p>FENZ operations are primarily funded by property insurance levies. However, with the severity and frequency of wildfires on the rise, it may be necessary to review this funding model to match the evolving risk portfolio. </p>
<p>Climate change is already driving insurance retreat – a phenomenon whereby coastal properties are <a href="https://www.climatesigma.com/projects/insurance-retreat">unable to renew their insurance</a> due sea level rise. It is plausible insurance companies could take a similar stance in extremely fire-prone areas.</p>
<p>The agility of FENZ and associated rural fire teams, coupled with the investment and integration of advanced technologies and modelling for better wildfire prediction and management, can significantly enhance the effectiveness of firefighting efforts. </p>
<h2>Policy adjustments and community engagement</h2>
<p>Adjustments in policy and regulatory frameworks are also crucial in mitigating wildfire risks, and should be explored by experts. </p>
<p>To significantly reduce the ignition of new fires, there needs to be greater implementation of restrictions on access, and banning of high-risk activities, when areas are under “extreme fire risk”. </p>
<p>Moreover, community engagement and preparedness initiatives are vital. One successful example is <a href="https://www.scionresearch.com/about-us/about-scion/corporate-publications/scion-connections/past-issues-list/scion-connections-issue-42,-february-2023/accessible-information-vital-in-extending-knowledge-of-wildfire-risk">Mt Iron, Wanaka</a>, where a model was developed after interviews, focus groups and workshops with residents identified wildfire risk awareness and mitigation actions. </p>
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Read more:
<a href="https://theconversation.com/living-with-wildfire-how-to-protect-more-homes-as-fire-risk-rises-in-a-warming-climate-208652">Living with wildfire: How to protect more homes as fire risk rises in a warming climate</a>
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<p>Educating vulnerable communities about their wildfire risks and preparedness strategies can also <a href="https://www.ruralfireresearch.co.nz/__data/assets/pdf_file/0004/78664/RFR_tech_note_45.pdf">enhance community resilience and safety</a>.</p>
<p>The emergence of a more severe wildfire climate in New Zealand calls for a unified response, integrating increased investment in FENZ, strategic planning and community involvement. </p>
<p>By embracing a multifaceted approach that includes technological innovation, enhanced resource, and community empowerment, New Zealand can navigate the complexities of this new era with resilience and foresight.</p><img src="https://counter.theconversation.com/content/224133/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nathanael is the founding director of Climate Prescience. He has received government funding from MBIE NZ to research the effect of climate change on wildfire risk. The opinions expressed here are his own.</span></em></p>The recent Port Hills fires highlight the increasing wildfire risks caused by climate change. Reducing the threat is going to take a shift in strategy, investment and community engagement.Nathanael Melia, Adjunct Senior Research Fellow – Climate Science, Te Herenga Waka — Victoria University of WellingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2236472024-02-16T13:19:35Z2024-02-16T13:19:35ZForest Service warns of budget cuts ahead of a risky wildfire season – what that means for safety<figure><img src="https://images.theconversation.com/files/575790/original/file-20240215-20-28tft.jpg?ixlib=rb-1.1.0&rect=79%2C144%2C1867%2C1217&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Members of the Snake River Hotshot crew monitor a prescribed fire near Roberts, Idaho.
</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/nifc/52530463314/">Austin Catlin/BLM</a></span></figcaption></figure><p>A wet winter and spring followed by a hot, dry summer can be a dangerous combination in the Western U.S. The rain fuels bountiful vegetation growth, and when summer heat dries out that vegetation, it can <a href="https://www.publish.csiro.au/wf/wf12064">leave grasses and shrubs ready to burn</a>. Drier than normal conditions, like many regions are experiencing in 2024, also raises the fire risk.</p>
<p>In years like this, controlled burns and prescribed fire treatments are crucial to help protect communities against wildfires. Well-staffed fire crews ready to respond to blazes are essential, too.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576093/original/file-20240215-16-etn253.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A forecast map shows above average temperatures likely across the US in July- August-September period for 2024, but particularly in the Western US." src="https://images.theconversation.com/files/576093/original/file-20240215-16-etn253.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576093/original/file-20240215-16-etn253.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=464&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576093/original/file-20240215-16-etn253.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=464&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576093/original/file-20240215-16-etn253.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=464&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576093/original/file-20240215-16-etn253.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=583&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576093/original/file-20240215-16-etn253.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=583&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576093/original/file-20240215-16-etn253.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=583&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 National Oceanic and Atmospheric Administration Climate Prediction Center’s long-range seasonal forecast for summer 2024.</span>
<span class="attribution"><a class="source" href="https://www.cpc.ncep.noaa.gov/products/predictions/long_range/seasonal.php?lead=6">NOAA</a></span>
</figcaption>
</figure>
<p>However, on Feb. 8, U.S. Forest Service Chief Randy Moore told agency employees to <a href="https://www.fs.usda.gov/inside-fs/leadership/fy2024-budget-overview">expect budget cuts</a> from Congress in 2024. His letter was thin on details. However, taken at face value, budget cuts could be interpreted as a reduction in the firefighting workforce, compounding recruitment and retention challenges that the Forest Service is already facing.</p>
<p>So what does this mean for the coming fire season? We <a href="https://scholar.google.com/citations?hl=en&user=XgAzk2EAAAAJ">study wildfire policy</a> and fire ecology, and one of us, <a href="https://scholar.google.com/citations?user=g2KEhV4AAAAJ&hl=en">Camille Stevens-Rumann</a>, has worked as a wildland firefighter. Here are a few important things to know.</p>
<h2>The fire funding fix</h2>
<p>While Moore’s letter raises concerns, the financial reality for fighting fires this year is likely less dire than it might otherwise be for one key reason.</p>
<p>The 2018 Consolidated Appropriations Act included what is known as the “<a href="https://www.govinfo.gov/content/pkg/PLAW-115publ141/pdf/PLAW-115publ141.pdf">fire funding fix</a>.” It introduced a new budget structure, creating a separate disaster fund accessible during costly wildfire seasons. The fire funding fix allows federal firefighting agencies to access up to US$2.25 billion in additional disaster funding a year starting in 2020 and increasing to $2.95 billion in 2027.</p>
<p>Prior to the fire funding fix, fighting fires – suppression expenditures – consumed <a href="https://www.americanprogress.org/article/defining-success-wildfire-funding-fix/">nearly 50% of the U.S. Forest Service budget</a>. As bad fire years worsened, that left less funding for the agency’s other services, including conducting fuel treatments, such as prescribed burns, to reduce the risk of wildfires spreading.</p>
<p><iframe id="DyoBq" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/DyoBq/2/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>The fix protects agency budgets, ensuring that a high-cost fire season will not completely consume the budget, and that allows more funding for preventive efforts and all the other programs of the Forest Service.</p>
<h2>Prevention is a rising priority</h2>
<p>The Forest Service has also made fire prevention a <a href="https://www.fs.usda.gov/sites/default/files/Wildfire-Crisis-Implementation-Plan.pdf">higher priority in recent years</a>.</p>
<p>In 2022, it released a <a href="https://www.fs.usda.gov/sites/default/files/Wildfire-Crisis-Implementation-Plan.pdf">Wildfire Crisis Strategy and Implementation Plan</a> that included ramping up fuel treatments to reduce the potential for large uncontrollable fires, as the West had seen in previous years. It called for treating up to an additional 50 million acres over 10 years.</p>
<p>That work <a href="https://doi.org/10.1093/jofore/fvac042">won’t be completed before the 2024 fire season</a>, but fuel treatments will be underway. They include prescribed burning to remove dry grasses, twigs, logs and other fuels in a controlled way and the use of heavy equipment to thin dense forest areas and create fire breaks by removing trees and vegetation. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/575801/original/file-20240215-18-mmzoyk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/575801/original/file-20240215-18-mmzoyk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/575801/original/file-20240215-18-mmzoyk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/575801/original/file-20240215-18-mmzoyk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/575801/original/file-20240215-18-mmzoyk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/575801/original/file-20240215-18-mmzoyk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/575801/original/file-20240215-18-mmzoyk.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">A wildland firefighter conducts a controlled burnout to help stop a fire near Spokane, Wash., in 2022.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/nifc/52530781658/">Sienna Falzetta/BLM</a></span>
</figcaption>
</figure>
<p>Prescribed burning must be done when conditions are safe to limit the potential for the fire to get out of control, usually in the spring and early summer. However, climate change is expected to <a href="https://www.nature.com/articles/s43247-023-00993-1">shorten the prescribed burning window</a> in the western U.S.</p>
<h2>Staffing is still a concern</h2>
<p>Doing this work requires staff, and the Forest Service’s challenges in recruiting and retaining qualified firefighters may hinder its ability to accomplish all of its objectives. </p>
<p>In 2023, over 18,000 people were employed as federal wildland firefighters. While the Forest Service and Department of the Interior have not specified precise staffing targets, Moore has mentioned that “<a href="https://www.theguardian.com/world/2023/sep/14/us-forest-service-wildfire-fighters-low-pay">some crews have roughly half the staff they need</a>.”</p>
<p>A recent Government Accountability Office report found that low wages and poor work-life balance, among other challenges, were <a href="https://www.gao.gov/products/gao-23-105517">barriers commonly cited</a> by federal firefighting employees. The government boosted firefighters’ pay in 2021, but that increase is set to expire <a href="https://www.fs.usda.gov/inside-fs/delivering-mission/excel/firefighter-pay">unless Congress votes</a> to make it permanent. So far, firefighters have kept the same level of pay each time Congress pushed back acting on the 2024 budget, but it’s a precarious position.</p>
<p>The agency has started many initiatives to recruit and retain permanent employees, but it is too early to assess the results. A recent study involving one of us, Jude Bayham, found that highly qualified firefighters were <a href="https://doi.org/10.1016/j.forpol.2023.103115">more likely to remain</a> with the agency after active seasons, during which they earn more money.</p>
<h2>Everyone has a role in fire protection</h2>
<p>Even with optimal funding and staffing, the firefighting agencies cannot protect every area from wildfire. Some of the defensive work will have to be <a href="https://theconversation.com/living-with-wildfire-how-to-protect-more-homes-as-fire-risk-rises-in-a-warming-climate-208652">done by residents</a> in high-risk areas.</p>
<p>Homeowners can reduce the fire risk to their own properties by <a href="https://csfs.colostate.edu/wildfire-mitigation/protect-your-home-property-from-wildfire/">following defensible space recommendations</a>. </p>
<p>These include keeping flammable vegetation away from buildings and reducing other fire hazards such as wood shingles, flammable debris in yards and pine needles in gutters. People should also pay attention to burn bans and avoid risky activities, such as leaving campfires unattended, setting off fireworks and using equipment that can spark fires on hot, dry, windy days.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/VusWu3Y4cgY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Clearing away dead trees and brush within 100 feet of homes can help reduce fire risk.</span></figcaption>
</figure>
<p>The federal government and states have increased funds to help people reduce wildfire hazards on their property. The <a href="https://www.doi.gov/pressreleases/secretary-haaland-announces-nearly-50-million-wildfire-mitigation-and-resilience">Bipartisan Infrastructure Law</a> of 2021 included millions of dollars to support fire prevention on <a href="https://www.fs.usda.gov/news/releases/usda-announces-new-round-of-investments-in-wildfire-protection-cwdg">state, tribal and private lands</a>. Several <a href="https://www.fire.ca.gov/what-we-do/grants/wildfire-prevention-grants">states also have programs</a>, such as Colorado’s Forest Restoration and Wildfire Risk Mitigation Grant Program to support <a href="https://csfs.colostate.edu/grants/forest-restoration-wildfire-risk-mitigation/">community investment in wildfire mitigation</a>.</p>
<p><a href="https://theconversation.com/the-year-the-west-was-burning-how-the-2020-wildfire-season-got-so-extreme-148804">Recent disastrous wildfire seasons</a> have shown how important it is to manage the fire risk. Consistent funding is crucial, and homeowners can help by taking defensive action to reduce wildfire risk on their property.</p><img src="https://counter.theconversation.com/content/223647/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Camille Stevens-Rumann receives funding from US Forest Service, the Bureau of Land Management, and the US department of Agriculture. She used to work for the US Forest Service and works closely with Federal, State, and non-profit organizations that help manage forests across the western US</span></em></p><p class="fine-print"><em><span>Jude Bayham receives funding from the United States Forest Service. He is on the Protect Our Winters Science Alliance. </span></em></p>A hot, dry summer on the heels of a wet winter raises the risk of wildfires.Camille Stevens-Rumann, Associate Professor of Forest and Rangeland Stewardship, Colorado State UniversityJude Bayham, Associate Professor of Agricultural and Resource Economics, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2230132024-02-08T13:40:00Z2024-02-08T13:40:00ZEl Niño is starting to lose strength after fueling a hot, stormy year, but it’s still powerful − an atmospheric scientist explains what’s ahead for 2024<figure><img src="https://images.theconversation.com/files/574206/original/file-20240207-16-vnmp3w.jpg?ixlib=rb-1.1.0&rect=0%2C23%2C5107%2C3298&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">In California, El Niño helped fuel a wet 2023 and early 2024.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/person-walks-through-flood-waters-as-a-powerful-long-news-photo/1986231877">Mario Tama/Getty Images</a></span></figcaption></figure><p>Wild weather has been <a href="https://theconversation.com/2023s-extreme-storms-heat-and-wildfires-broke-records-a-scientist-explains-how-global-warming-fuels-climate-disasters-217500">roiling North America</a> for the past few months, thanks in part to a strong El Niño that sent temperatures surging in 2023. The climate phenomenon fed <a href="https://theconversation.com/what-is-an-atmospheric-river-with-flooding-and-mudslides-in-california-a-hydrologist-explains-the-good-and-bad-of-these-storms-and-how-theyre-changing-222249">atmospheric rivers</a> drenching the West Coast and contributed to <a href="https://theconversation.com/summer-2023-was-the-hottest-on-record-yes-its-climate-change-but-dont-call-it-the-new-normal-213021">summer’s extreme heat</a> in the South and Midwest and fall’s <a href="https://theconversation.com/2023s-extreme-storms-heat-and-wildfires-broke-records-a-scientist-explains-how-global-warming-fuels-climate-disasters-217500">wet storms across the East</a>.</p>
<p>That strong El Niño is now <a href="https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml">starting to weaken</a> and will likely be gone by late spring 2024.</p>
<p>So, what does that mean for the months ahead – and for the 2024 hurricane season?</p>
<h2>What is El Niño?</h2>
<p>Let’s start with a quick look at what an El Niño is.</p>
<p>El Niño and its opposite, La Niña, are <a href="https://oceanservice.noaa.gov/facts/ninonina.html">climate patterns that influence weather</a> around the world. El Niño tends to raise global temperatures, as we saw in 2023, while La Niña events tend to be slightly cooler. The two result in global temperatures fluctuating above and below the <a href="https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature">warming trend set by climate change</a>. </p>
<p>El Niño starts as warm water builds up along the equator in the eastern tropical Pacific Ocean, off South America.</p>
<figure class="align-center ">
<img alt="A colored map shows temperature differences with a warm area just west of South America along the equator." src="https://images.theconversation.com/files/574240/original/file-20240207-18-ojnwih.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/574240/original/file-20240207-18-ojnwih.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=325&fit=crop&dpr=1 600w, https://images.theconversation.com/files/574240/original/file-20240207-18-ojnwih.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=325&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/574240/original/file-20240207-18-ojnwih.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=325&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/574240/original/file-20240207-18-ojnwih.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=408&fit=crop&dpr=1 754w, https://images.theconversation.com/files/574240/original/file-20240207-18-ojnwih.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=408&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/574240/original/file-20240207-18-ojnwih.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=408&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Reds and yellows show where Pacific waters were warmer in 2024 than in 2022. The abnormally warmer region along the equator is what we call El Niño. Weak El Niño events occur every few years, with strong events like this averaging once every 10 to 20 years.</span>
<span class="attribution"><span class="source">NOAA</span></span>
</figcaption>
</figure>
<p>Typically, tropical Pacific winds blow from the east, exposing cold water along the equator and building up warm water in the western Pacific. Every <a href="https://www.noaa.gov/understanding-el-nino">three to seven years or so</a>, however, these winds relax or turn to blow from the west. When that happens, warm water rushes to the east. The warmer-than-normal water drives more rainfall and alters winds around the world. <a href="https://www.youtube.com/watch?v=MPok2G9Fyno">This is El Niño</a>.</p>
<p>The water stays warm for several months until, ultimately, it cools or is driven away from the equator by the return of the trade winds.</p>
<p><iframe id="aOiS8" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/aOiS8/17/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>When the eastern Pacific region along the equator becomes abnormally cold, La Niña has emerged, and global weather patterns change again.</p>
<h2>What to expect from El Niño in 2024</h2>
<p>While the 2023-24 El Niño event <a href="https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml">likely peaked in December</a>, it is still strong.</p>
<p>For the rest of winter, forecasts suggest that strong El Niño conditions will likely continue to favor unusual warmth in Canada and the northern United States and occasional stormy conditions across the southern states.</p>
<figure class="align-center ">
<img alt="Two maps of typical winter conditions under El Nino and La Nina show the Southwest wetter and the Northwest and upper Midwest generally warmer under El Nino." src="https://images.theconversation.com/files/574242/original/file-20240207-24-syjmnk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/574242/original/file-20240207-24-syjmnk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=853&fit=crop&dpr=1 600w, https://images.theconversation.com/files/574242/original/file-20240207-24-syjmnk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=853&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/574242/original/file-20240207-24-syjmnk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=853&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/574242/original/file-20240207-24-syjmnk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1072&fit=crop&dpr=1 754w, https://images.theconversation.com/files/574242/original/file-20240207-24-syjmnk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1072&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/574242/original/file-20240207-24-syjmnk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1072&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Typical winters under El Niño and La Niña show the striking differences between the two patterns. Not all El Niños turn out this way.</span>
<span class="attribution"><a class="source" href="https://www.climate.gov/news-features/understanding-climate/el-ni%C3%B1o-and-la-ni%C3%B1a-frequently-asked-questions">NOAA Climate.gov</a></span>
</figcaption>
</figure>
<p>El Niño is likely to end in late spring or early summer, shifting briefly to neutral. There’s a good chance we will see La Niña conditions this fall. But forecasting when that happens and what comes next is harder.</p>
<h2>How an El Niño ends</h2>
<p>While it’s easy to tell when an El Niño event reaches its peak, predicting when one will end depends on how the wind blows, and everyday weather affects the winds.</p>
<p>The warm area of surface water that defines El Niño typically becomes more shallow toward spring. In mid-May 1998, at the end of an <a href="https://www.youtube.com/watch?v=9rPqIuXlWuA">even stronger El Niño event</a>, there was a time when people fishing in the warm surface water in the eastern tropical Pacific could have touched the cold water layer a few feet below by just jumping in. At that point, it took only a moderate breeze to pull the cold water to the surface, ending the El Niño event.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/WPA-KpldDVc?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">How El Niño develops in the equatorial Pacific Ocean.</span></figcaption>
</figure>
<p>But exactly when a strong El Niño event reverses varies. A <a href="https://www.washingtonpost.com/news/capital-weather-gang/wp/2015/06/12/how-the-super-el-nino-of-1982-83-kept-itself-a-secret/">big 1983 El Niño</a> didn’t end until July. And the <a href="https://doi.org/10.1126/science.241.4862.192">El Niño in 1987</a> retreated into the central Pacific but did not fully reverse until December.</p>
<p>As of early February 2024, strong westerly winds were driving warm water from west to east across the equatorial Pacific.</p>
<p>These winds tend to make El Niño last a little longer. However, they’re also likely to drive what little warm water remains along the equator out of the tropics, up and down the coasts of the Americas. The more warm water that is expelled, the greater the chances of full reversal to La Niña conditions in the fall.</p>
<h2>Summer and the hurricane risk</h2>
<p>Among the more important El Niño effects is its tendency to reduce <a href="https://www.climate.gov/news-features/blogs/enso/impacts-el-ni%C3%B1o-and-la-ni%C3%B1a-hurricane-season">Atlantic hurricane activity</a>.</p>
<p>El Niño’s Pacific Ocean heat affects upper level winds that blow across the Gulf of Mexico and the tropical Atlantic Ocean. That <a href="https://www.accuweather.com/en/weather-news/what-is-wind-shear-and-how-does-it-impact-hurricanes-other-tropical-cyclones/330987">increases wind shear</a> - the change in wind speed and direction with height – which can tear hurricanes apart.</p>
<p>The 2024 hurricane season likely won’t have El Niño around to help weaken storms. But that doesn’t necessarily mean an active season.</p>
<p>During the <a href="https://www.noaa.gov/news-release/2023-atlantic-hurricane-season-ranks-4th-for-most-named-storms-in-year">2023 Atlantic hurricane season</a>, El Niño’s effect on the winds was more than offset by abnormally warm Atlantic waters, which fuel hurricanes. The season ended with more storms than average.</p>
<h2>The strange El Niño of 2023-24</h2>
<p>Although the 2023-24 El Niño event wasn’t the strongest in recent decades, many aspects of it have been unusual.</p>
<p>It followed three years of La Niña conditions, which is unusually long. It also emerged quickly, from March to May 2023. The combination led to weather extremes unseen <a href="https://yaleclimateconnections.org/2020/04/a-horrific-drought-in-the-1870s-offers-a-warning-for-today/">since perhaps the 1870s</a>. </p>
<figure class="align-center ">
<img alt="Two cars are trapped up to their widows in a mudslide that poured through a Los Angeles neighborhood. One car is parked in its driveway," src="https://images.theconversation.com/files/574187/original/file-20240207-30-4e5k3b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/574187/original/file-20240207-30-4e5k3b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/574187/original/file-20240207-30-4e5k3b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/574187/original/file-20240207-30-4e5k3b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/574187/original/file-20240207-30-4e5k3b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/574187/original/file-20240207-30-4e5k3b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/574187/original/file-20240207-30-4e5k3b.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">Extreme rainfall in early 2024 sent mudslides into dozens of Los Angeles-area neighborhoods.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/APTOPIXCaliforniaStorms/b49e6373657e41f9964a64a6a631e5b6/photo">AP Photo/Marcio Jose Sanchez</a></span>
</figcaption>
</figure>
<p>La Niña cools the tropics but stores warm water in the western Pacific. It also warms the middle latitude oceans by weakening the winds and allowing more sunshine through. After three years of La Niña, the rapid emergence of El Niño helped make the Earth’s surface <a href="https://www.noaa.gov/news/2023-was-worlds-warmest-year-on-record-by-far">warmer than in any recent year</a>.</p><img src="https://counter.theconversation.com/content/223013/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Roundy receives funding from the National Science Foundation and National Oceanic and Atmospheric Administration. </span></em></p>The strong El Niño that started in 2023 will still have big impacts at least through March. Here’s what to watch for next.Paul Roundy, Professor of Atmospheric and Environmental Sciences, University at Albany, State University of New YorkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2214962024-01-23T18:59:54Z2024-01-23T18:59:54ZDid the BOM get it wrong on the hot, dry summer? No – predicting chaotic systems is probability, not certainty<figure><img src="https://images.theconversation.com/files/570789/original/file-20240123-15-btnti9.jpg?ixlib=rb-1.1.0&rect=37%2C6%2C4123%2C2763&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>What happened to the <a href="https://media.bom.gov.au/releases/1205/the-bureau-forecasts-an-unusually-warm-summer/">scorching El Niño summer</a> we were bracing for? Why has the east coast of Australia been drenched while the north and west gets the heat? </p>
<p>For beachgoers, a wrong weather forecast is annoying. For farmers, it can be very expensive. And for northern Queensland residents surprised by flooding after Cyclone Jasper, it can be devastating. Small wonder there’s <a href="https://www.adelaidenow.com.au/news/south-australia/farmers-roast-bom-forecasts-but-it-says-its-top-five-in-the-world/news-story/c945a38830fd6ea189e253b91b03fd36">been plenty</a> of <a href="https://indaily.com.au/news/2023/12/20/bom-criticised-for-queensland-rain-forecasts/">criticism</a> levelled at the Bureau of Meteorology and other forecasting agencies this summer. </p>
<p>The criticism is understandable. But is it fair? No. The reason is that weather forecasting is inherently not about certainty but probability. Our atmosphere and oceans do not behave in simple, easily predictable ways. They are <a href="https://www.bbc.com/future/article/20230203-why-the-world-feels-so-unstable-right-now">non-linear, chaotic systems</a>. That means we can only predict large weather features such as highs and lows or bands of storms with relative certainty and even then only for a few days in advance. </p>
<h2>We want certainty – but we have to settle for probability</h2>
<p>Let’s say you check your weather app and see your location has a 60% chance of rain at midday. What does this actually mean? </p>
<p>It means if this forecast was issued 100 times, you should get wet 60 times and stay dry 40 times.</p>
<p>To forecast rainfall <a href="http://www.bom.gov.au/climate/outlooks/#/overview/summary">for a whole season ahead</a>, meteorologists generally calculate the chance of exceeding average conditions, rather than stating that we will have a dry or wet summer with certainty. </p>
<p>So if we predict a 25% chance of above-average rain during an El Niño summer, we would expect that one out of every four times we make this prediction, we would observe higher rainfall than the average. </p>
<p>So how then do we know if we are making good forecasts? Given that a 60% chance of rain can mean wet or dry, albeit with different odds, we certainly won’t be able to judge the forecast quality based on a single event. Instead, we assess many forecasts of 60% rain made in the past to see if the 60 to 40 split of wet and dry eventuated. If it did for this and all other possible probabilities, the forecasts work well. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/570791/original/file-20240123-19-axi289.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="storms entering sydney" src="https://images.theconversation.com/files/570791/original/file-20240123-19-axi289.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/570791/original/file-20240123-19-axi289.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=396&fit=crop&dpr=1 600w, https://images.theconversation.com/files/570791/original/file-20240123-19-axi289.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=396&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/570791/original/file-20240123-19-axi289.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=396&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/570791/original/file-20240123-19-axi289.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=498&fit=crop&dpr=1 754w, https://images.theconversation.com/files/570791/original/file-20240123-19-axi289.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=498&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/570791/original/file-20240123-19-axi289.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=498&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Big weather events such as bands of storms are easier to predict with some certainty. But other weather is much harder.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>This isn’t what we’d like. Many of us find probabilistic forecasts confusing. Intuitively, we would prefer to simplify them into absolute statements. </p>
<p>Take a picnic you have planned for tomorrow. If you read the statement “there will be thunderstorms at noon tomorrow at Picnic Spot,” you will feel confident it’s best to cancel the event. But the statement “there’s a 60% chance of thunderstorms at noon tomorrow at Picnic Spot” is far more accurate. The first gives false certainty, by vastly oversimplifying what we really know. </p>
<p>Let’s not forget, there is a 40% chance it will stay dry, which the first statement completely ignores. And if it does stay dry, how will your friends react to the cancelled picnic? How much risk are you willing to take?</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-how-do-people-know-what-the-weather-will-be-108295">Curious Kids: how do people know what the weather will be?</a>
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</em>
</p>
<hr>
<p>When we criticise weather forecasts for their inaccuracy, we are usually being unfair. You can’t actually say a weather forecast was wrong if you experienced rain when the forecast was for a high chance of being dry. It’s simply not possible to tell from a single day or even a season how well our forecasts are working because of the nature of how our atmosphere and oceans behave. We’ve known about this <a href="https://journals.ametsoc.org/view/journals/atsc/20/2/1520-0469_1963_020_0130_dnf_2_0_co_2.xml">for 60 years</a>. </p>
<p>That is why the Bureau of Meteorology’s seasonal forecasts come in likelihoods, such as the <a href="http://www.bom.gov.au/climate/ahead/outlooks/archive/20230928-outlook.shtml">rainfall outlook for October to December</a> issued on September 28th. It predicted that “October to December rainfall was likely (60 to 80% chance) to be below median for much of Australia excluding most of central and northwestern WA and south-west Tasmania.” Note that the forecast had a 20-40% chance for the wetter than usual conditions which some parts of Australia ended up experiencing. </p>
<p>But beware: We can’t declare the success or failure of a likelihood forecast from a single season. What the likelihood gives us is the ability to make better decisions based on the best information we have. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1747819013646987638"}"></div></p>
<h2>Less than certain but far better than nothing</h2>
<p>Given these constraints, how can we best use probabilistic forecasts in making decisions? </p>
<p>Here, weather and climate forecasting alone cannot provide the answers. The use and value of a particular forecast strongly depend on what decisions need to be made, our values, and what economic circumstances decisions are made in. </p>
<p>A very simple example is to <a href="https://rmets.onlinelibrary.wiley.com/doi/10.1002/qj.49712757715">assess how much</a> it would cost to protect ourselves against, say, a flood, and the loss we would incur if we did not protect ourselves and then the event happened. </p>
<p>If the cost of protection is very low and the loss very large, the answer is simple: protect yourself all the time. High protection costs and low losses imply we should never protect ourselves. Both statements can be made without bringing in the forecast probability. But in the middle, it gets tricky. How much should you spend on a highly damaging event with a low probability of occurring? </p>
<p>Deterministic weather forecasts giving certainty are only possible for a week or two, and only for the large features of the weather. This means longer term forecasts and those for intense weather systems such as thunderstorms or tropical cyclones will only ever be possible by assessing how likely different outcomes are, and giving us a probability. </p>
<p>It’s fine to complain about the weather. But we can’t complain about the forecasting based on a single event. We want to know what’s coming our way, but the weather doesn’t work like that. We owe it to society to provide and use the best information we have to protect and save property and lives. There is too much at stake to keep it simple. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/extreme-weather-is-outpacing-even-the-worst-case-scenarios-of-our-forecasting-models-216562">Extreme weather is outpacing even the worst-case scenarios of our forecasting models</a>
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<img src="https://counter.theconversation.com/content/221496/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christian Jakob receives funding from the Australian Research Council. </span></em></p>We crave certainty in our weather forecasts. But that’s only possible for big weather events such as cyclones and major storms. Everything else is probability.Christian Jakob, Director, ARC Centre of Excellence for the Weather of the 21st Century, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2143072024-01-04T20:01:53Z2024-01-04T20:01:53ZBecome a beach scientist this summer and help monitor changing coastlines<figure><img src="https://images.theconversation.com/files/565647/original/file-20231213-17-zlgqzp.jpg?ixlib=rb-1.1.0&rect=35%2C11%2C3958%2C2257&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">CoastSnap</span></span></figcaption></figure><p>When you arrive at your favourite beach these summer holidays, you may notice something different about the coast. </p>
<p>With the triple-dip La Niña now <a href="https://media.bom.gov.au/releases/1205/the-bureau-forecasts-an-unusually-warm-summer/">making way for El Niño</a>, our beaches have been through a rollercoaster ride. Some beaches have been completely stripped of sand, while others have grown very wide. </p>
<p>In the past, such changes went mostly unrecorded. However, thanks to a project <a href="https://www.coastsnap.com/">known as CoastSnap</a>, coastal data is now being collected like never before. Using designated camera cradles installed at beach viewpoints, CoastSnap uses community snapshots taken on smartphones to track beach change. </p>
<p>Almost <a href="https://www.spotteron.com/coastsnap/">50,000 photos</a> have been collected so far. They have revealed a varying picture in recent years: from <a href="https://www.abc.net.au/news/2020-02-12/tropical-cyclone-uesi-bring-dangerous-conditions-nsw-coast/11955628">dramatic beach loss during La Niña storms three years ago</a>, to <a href="https://www.smh.com.au/environment/climate-change/the-sydney-beach-that-s-grown-by-59-metres-since-last-summer-20230921-p5e6id.html">60 metres of beach growth in recent months</a>. So with smartphones as commonplace as towels and sunscreen in the beach bag, why not add coastal data collection to your list of holiday activities this summer?</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/563079/original/file-20231203-29-n4laod.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="CoastSnap stainless steel camera cradle with smartphone placed in it, overlooking Manly beach" src="https://images.theconversation.com/files/563079/original/file-20231203-29-n4laod.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563079/original/file-20231203-29-n4laod.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563079/original/file-20231203-29-n4laod.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563079/original/file-20231203-29-n4laod.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563079/original/file-20231203-29-n4laod.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563079/original/file-20231203-29-n4laod.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563079/original/file-20231203-29-n4laod.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">A CoastSnap community beach monitoring station at Manly Beach in Sydney, Australia.</span>
<span class="attribution"><span class="source">Larry Paice</span></span>
</figcaption>
</figure>
<h2>Turning beach snaps into scientific data</h2>
<p>Through CoastSnap, we installed a network of stainless-steel camera cradles along coastal trails all around the world. These camera cradles are positioned at a perfect vantage point for tracking changes to the coast – whether it be due to rising sea levels, extreme storms or other factors.</p>
<p>All you need to do is place your camera in the cradle, take a photo and upload it using the QR code at the station. Because the position and angle of the photo is always the same, over time these snaps reveal how the beach is changing.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/millions-of-satellite-images-reveal-how-beaches-around-the-pacific-vanish-or-replenish-in-el-nino-and-la-nina-years-198505">Millions of satellite images reveal how beaches around the Pacific vanish or replenish in El Niño and La Niña years</a>
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<hr>
<p>As well as being a powerful visual record, <a href="https://www.sciencedirect.com/science/article/pii/S0278434322001492">sophisticated algorithms</a> turn each photo into miniature satellite images that are used to precisely measure shoreline position. This is done using a <a href="https://en.wikipedia.org/wiki/Photogrammetry">process known as photogrammetry</a>, in which pixels in the image are rearranged as though they had been taken from space. </p>
<p>This aerial view enables beach change to be easily measured. Also, since the exact time of photo capture is recorded, the effects of tides as they vary throughout the day can be accounted for.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/563240/original/file-20231204-17-8678xw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="CoastSnap photo of beach (left) and equivalent photo converted to an aerial photo with a red line to mark out the shoreline" src="https://images.theconversation.com/files/563240/original/file-20231204-17-8678xw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563240/original/file-20231204-17-8678xw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=317&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563240/original/file-20231204-17-8678xw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=317&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563240/original/file-20231204-17-8678xw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=317&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563240/original/file-20231204-17-8678xw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=398&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563240/original/file-20231204-17-8678xw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=398&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563240/original/file-20231204-17-8678xw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=398&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">CoastSnap photos are converted to a miniature satellite image using a process known as photogrammetry.</span>
<span class="attribution"><span class="source">Mitchell Harley</span></span>
</figcaption>
</figure>
<h2>From local to global: a network of community beach monitoring</h2>
<p>From its beginnings on the Northern Beaches of Sydney in 2017, new CoastSnap stations have been rolled out all around the world. We now have more than 350 CoastSnap stations in 31 countries and across five continents. </p>
<p>This makes it the largest coordinated network of coastal monitoring worldwide – and all the data is collected by the community.</p>
<p>In Ghana, West Africa, students from local schools are using CoastSnap to <a href="https://theconversation.com/ghanas-fishing-industry-has-a-golden-seaweed-problem-how-citizen-science-can-help-203007">better understand how the “golden seaweed” sargassum impacts fishing communities</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/like-20-tip-trucks-pouring-sand-on-every-metre-wide-strip-how-extreme-storms-can-replenish-beaches-not-just-erode-them-182039">‘Like 20 tip trucks pouring sand on every metre-wide strip’: how extreme storms can replenish beaches, not just erode them</a>
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<hr>
<p>On Prince Edward Island in Canada, CoastSnap captured the <a href="https://www.cbc.ca/news/canada/prince-edward-island/pei-fiona-coastal-climate-change-1.6599408">damage done by Hurricane Fiona last year</a>. The same stations are now being used to track the post-hurricane dune recovery.</p>
<p>In Australia, there are currently 125 CoastSnap stations around the country. This enables a big-picture assessment of the coastal consequences of large-scale weather events. For example, during <a href="https://theconversation.com/the-east-coast-rain-seems-endless-where-on-earth-is-all-the-water-coming-from-178316">last year’s record rainfall in eastern Australia</a>, extreme erosion was observed at CoastSnap stations from Queensland to southern New South Wales. The images reveal scouring by floodwaters was the main cause of beach erosion in many locations, rather than wave action as is usually the case.</p>
<p><div data-react-class="TiktokEmbed" data-react-props="{"url":"https://www.tiktok.com/@coastsnap/video/7192798251588898049"}"></div></p>
<h2>Monitoring the present to plan for the future</h2>
<p>Data on coastal change is crucial for managing coastlines into the future. This is particularly important as sea levels continue to rise, storm tracks shift, and beaches come under increasing pressure from overdevelopment.</p>
<p>With several CoastSnap stations already operating for over six years now, this growing record is beginning to observe longer-term changes to the coast. This data is being fed into numerical models that help coastal researchers predict what the coastline will be like in the coming decades – and plan accordingly.</p>
<p>Smart coastal planning will help buffer climate change impacts. This will go some way to ensure future generations can enjoy the coast like we do today. </p>
<p>So as you head out to the beach this summer, look out for your nearest CoastSnap station and help monitor the coastline – it really is a “snap”!</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/storms-or-sea-level-rise-what-really-causes-beach-erosion-209213">Storms or sea-level rise – what really causes beach erosion?</a>
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</p>
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<img src="https://counter.theconversation.com/content/214307/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mitchell Harley receives funding from the Australian Research Council. He is also the New South Wales Chair of the Australian Coastal Society.</span></em></p><p class="fine-print"><em><span>Fred Chaaya works for the University Of New South Wales Water Research Laboratory, which manages the CoastSnap project and network.</span></em></p>With smartphones as commonplace as towels and sunscreen in the beach bag, why not add coastal data collection to your list of holiday activities this summer? Look for the CoastSnap camera cradles.Mitchell Harley, Scientia Senior Lecturer, UNSW SydneyFred Chaaya, Project Engineer, UNSW Water Research LaboratoryLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2164352023-12-12T03:14:39Z2023-12-12T03:14:39ZKoalas suffer in the heat – here’s how to help this summer<figure><img src="https://images.theconversation.com/files/565082/original/file-20231212-21-nxaeys.jpg?ixlib=rb-1.1.0&rect=23%2C5%2C3970%2C2652&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/cute-koala-533590378">Yatra4289, Shutterstock</a></span></figcaption></figure><p>As we brace for an <a href="https://media.bom.gov.au/releases/1205/the-bureau-forecasts-an-unusually-warm-summer/">unusually hot summer</a>, spare a thought for koalas. They will be <a href="https://rcc.news/2018/05/koalas-on-the-move-and-looking-for-love/">out and about in search of love, food and water</a> in the searing heat.</p>
<p>Mother koalas with pouch young are especially vulnerable. Many will be killed or injured on our roads as they attempt to cross. Sometimes joeys are orphaned in the process, but even if they make it to one of Australia’s rehabilitation centres these <a href="https://www.biorxiv.org/content/10.1101/2023.10.09.561560v1">young koalas can be stressed by well-meaning visitors</a> such as potential donors and media.</p>
<p>Hot and dry conditions make gum tree leaves less nutritious, so koalas tend to <a href="https://www.newscientist.com/article/2205561-thirsty-koalas-need-bowls-of-water-to-survive-increasingly-hot-climate/">seek additional water sources</a>. Some diseases can also damage their kidneys, making them drink more. </p>
<p>As habitat loss pushes koalas <a href="https://theconversation.com/koalas-can-learn-to-live-the-city-life-if-we-give-them-the-trees-and-safe-spaces-they-need-112068">into our cities</a>, people frequently encounter these wild animals on roads, in parks and sometimes even in their backyards. So it’s worth knowing how to help keep koalas healthy and what to do if you encounter a koala in distress. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1726843046405276100"}"></div></p>
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<p>
<em>
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Read more:
<a href="https://theconversation.com/koalas-can-learn-to-live-the-city-life-if-we-give-them-the-trees-and-safe-spaces-they-need-112068">Koalas can learn to live the city life if we give them the trees and safe spaces they need</a>
</strong>
</em>
</p>
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<h2>What to do if you encounter a sick or injured koala</h2>
<ol>
<li><p>Put clean water out in a shallow bowl such as an ice-cream container at the base of a gum tree. Thirsty koalas will <a href="https://youtu.be/IFF7m7KWEwA">gently lap up the water</a> using their tongue. <a href="https://www.theweathernetwork.com/en/news/nature/animals/dont-offer-koalas-water-from-water-bottles">Never give a koala water from a bottle</a> because koalas can choke if their heads are tilted back while drinking. </p></li>
<li><p>Avoid any interaction with wild koalas. <a href="https://environment.des.qld.gov.au/wildlife/animals/living-with/koalas/care-and-rescue/rehabilitation-hub">Leave this</a> to veterinarians, wildlife officers, researchers with permits, and licensed rehabilitators. Koalas have strong arms, sharp claws and <a href="https://environment.des.qld.gov.au/wildlife/animals/living-with/koalas/facts">a very tight grip</a>. They also find the presence of humans very stressful. </p></li>
<li><p>If you find a koala on the ground and it lets you approach, there must be a problem. Call your local koala rescue group. The name of the organisation will vary depending on your location. If you don’t know where to begin, Google “wildlife rescue near me”. Dial the number and follow the instructions from the koala rescue team. Do not try to touch, handle or pick up the koala. Also discourage other people from gathering to look on, as it can do more harm. Distressed koalas produce the stress hormone cortisol, which can raise blood pressure, increase heart rate variability and make recovery and rehabilitation more challenging. </p></li>
<li><p>Keep dogs on a leash when you are out and attend to any barking at home. <a href="https://loganwestnews.com.au/train-your-dog-to-respect-wildlife/">Train your dog to respect wildlife</a>. Ensure the dog will come to you when called. Reward good behaviour. </p></li>
<li><p>Koalas can end up in suburban backyards with or without food trees. You might like to install an “escape pole” such as timber log placed vertically against the fence in your yard. Follow these handy <a href="https://www.des.qld.gov.au/policies?a=272936:policy_registry/koala-sensitive-design-guideline.pdf">koala-sensitive design guidelines</a>. </p></li>
<li><p><a href="https://environment.des.qld.gov.au/wildlife/animals/living-with/koalas/threats#koalas_and_swimming_pools">Secure swimming pools</a> so koalas are less likely to fall in and drown. Australia’s largest wildlife rescue organisation, WIRES, suggests <a href="https://www.wires.org.au/blog/wildlife-and-pool-safety">draping something over the edge of the pool</a> so animals can climb out. A length of heavy-duty rope or even a bodyboard, secured at one end to something heavy outside the pool, works well because it does not absorb water and provides a platform for an exhausted animal to rest on. You can also place bricks or large stones to the side of each step, to make it easier for animals to gain a foothold and climb out.</p></li>
</ol>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1693114179576848724"}"></div></p>
<h2>Understanding stress in koalas</h2>
<p>Koalas are well adapted to life in Australian forests. They have insulating fur and an ability to adjust body posture when exposed to environmental challenges – such as rolling up in a ball in high wind and covering their ears. They can stay in the trees even in very windy conditions. </p>
<p>If you wander into the bush at night during <a href="https://www.bushheritage.org.au/species/koalas#:%7E:text=Koalas%20are%20seasonal%20breeders%2C%20mating,sense%20of%20smell%20and%20touch.">breeding season</a> – from spring through to autumn – you may hear the deafening <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/joa.12770">bellowing of male koalas</a> trying to attract females. </p>
<p>Breeding season is a stressful time for wild koalas because there is so much activity involved, including energy expended in the search for mate. </p>
<p>Koalas generally <a href="https://koalaclancy.wordpress.com/category/clancys-family-tree/">keep to their family groups</a>. Mum and joeys usually stay together in the treetops. Adult males <a href="https://koalaclancy.wordpress.com/2017/12/01/five-koala-joeys/">father many joeys</a>, sometimes with different females.</p>
<p>The diseases chlamydia and koala retrovirus are <a href="https://koalahospital.org.au/pages/threats-to-koalas">among the biggest threats</a> to koalas’ survival. <a href="https://koalahospital.org.au/pages/disease">Chlamydia</a> is a bacteria found in many species of bird and mammals worldwide. <a href="https://www.uniprot.org/taxonomy/394239">Koala retrovirus</a> is thought to cause koala immune deficiency syndrome (KIDS), an AIDS-like immunodeficiency that leaves infected koalas more susceptible to infectious disease and cancers. </p>
<p>A lack of appropriate food trees is another source of stress, because koalas rely on fresh gum leaves to <a href="https://koalainfo.com/koalas-love-fresh-eucalyptus-leaves-as-their-food">maintain their body’s water balance</a>. </p>
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<figcaption><span class="caption">Ask An Expert: How Extensive is Chlamydia? (Koala Life)</span></figcaption>
</figure>
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<strong>
Read more:
<a href="https://theconversation.com/testing-the-stress-levels-of-rescued-koalas-allows-us-to-tweak-their-care-so-more-survive-in-the-wild-196224">Testing the stress levels of rescued koalas allows us to tweak their care so more survive in the wild</a>
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<h2>Be a friend to koalas</h2>
<p>Habitat loss, bushfire, drought, heat and pressure to find a mate mean koalas are frequently on the move. Here’s how to help keep them safe and well: </p>
<ul>
<li><p>watch out for <a href="https://www.koala.nsw.gov.au/help-koalas/drive-responsibly">koalas on the road</a> and slow down</p></li>
<li><p>put local koala wildlife rescue group contact numbers in your phone so you know whom to call in an emergency</p></li>
<li><p>report urban koala sightings to your local rescue group – it’s likely to indicate an ongoing problem. Well-informed koala rescue groups can better manage the situation and put appropriate action plans in place</p></li>
<li><p>ask your council about programs available for koalas in your local area and volunteer for food tree planting days and other activities</p></li>
<li><p>support local koala hospitals and donate if you can</p></li>
<li><p>share this article with family and friends.</p></li>
</ul><img src="https://counter.theconversation.com/content/216435/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Edward Narayan 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>Koalas will need our help more than ever this summer as hot, dry conditions force them to seek water. Here’s how to help keep them safe and what to do if you encounter a koala in distress.Edward Narayan, Senior Lecturer in Animal Science, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2182572023-12-08T00:14:27Z2023-12-08T00:14:27ZWhat does El Niño do to the weather in your state?<figure><img src="https://images.theconversation.com/files/564399/original/file-20231207-23-isxdk1.jpg?ixlib=rb-1.1.0&rect=38%2C1702%2C6451%2C4787&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-illustration/surface-planet-earth-viewed-satellite-focused-1609386070">titoOnz, Shutterstock</a></span></figcaption></figure><p>You’ve probably heard El Niño brings hot and dry weather to the eastern states, but what about the rest of Australia? Are we all in for a scorcher this summer? </p>
<p>El Niño is what scientists call a <a href="https://www.climatechangeinaustralia.gov.au/en/overview/climate-system/australian-climate-influences/">climate driver</a>. But it’s just one of many. </p>
<p>These climate drivers control year-to-year variations in the weather. Some years are hotter and drier, while others are cooler and wetter. </p>
<p>Australia is particularly prone to weather whiplash because our continent is buffeted by climate drivers to our north, south, east and west. The dominant driver in your state may be one of the lesser-known influences. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/iVhi1wq2sTY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Understanding Climate Drivers (Bureau of Meteorology)</span></figcaption>
</figure>
<h2>East: El Niño Southern Oscillation</h2>
<p>The El Niño Southern Oscillation (ENSO) is the resident climate driver in the Pacific Ocean and the driver with the biggest influence over Australian weather. Differences in sea surface temperatures and winds across the Pacific determine whether we swing towards El Niño (the boy) or La Niña (the girl).</p>
<p><a href="http://www.bom.gov.au/climate/about/?bookmark=enso">During the El Niño phase</a>, sea surface temperatures near South America are warmer than normal and they are cooler than normal off the coast of eastern Australia. Additionally, trade winds that blow from east to west across the Pacific weaken. </p>
<p>El Niño brings hotter daytime temperatures, but often <a href="http://www.bom.gov.au/climate/enso/#tabs=Pacific-Ocean&pacific=History">cooler nights</a>. That’s because reduced cloud cover allows more heat to escape into space overnight. So the same process that increases the chances of heatwaves can also raise the <a href="https://www.agric.wa.gov.au/climate-weather/historical-frost-and-heat-maps-south-west-land-division">risk of frost</a> in Western Australia, New South Wales, the Australian Capital Territory and Victoria.</p>
<p>Australia as a whole is typically drier during an El Niño event. In the tropical regions, El Niño can delay the <a href="http://www.bom.gov.au/climate/updates/articles/a008-el-nino-and-australia.shtml">onset of the monsoon and reduce the likelihood of tropical cyclones</a>. In the southern states, the hot and dry conditions increase the chance of intense bushfires.</p>
<p>La Niña is the opposite phase. Waters off eastern Australia are warmer than usual, increasing the <a href="http://www.bom.gov.au/climate/enso/#tabs=Pacific-Ocean&pacific=History&enso-impacts=La-Ni%C3%B1a-impacts">chance of tropical cyclones</a> and an earlier start to the monsoon for WA, the Northern Territory and Queensland.</p>
<p>So what does El Niño do to the weather in your state? Hover over your state in the interactive map to find out. </p>
<p><iframe id="tc-infographic-1008" class="tc-infographic" height="400px" src="https://cdn.theconversation.com/infographics/1008/7f37ae91389db072906b320ffd54d0fefd840c0d/site/index.html" width="100%" style="border: none" frameborder="0"></iframe></p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/were-in-an-el-nino-so-why-has-australia-been-so-wet-219111">We're in an El Niño – so why has Australia been so wet?</a>
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</em>
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<h2>West: Indian Ocean Dipole</h2>
<p>The <a href="http://www.bom.gov.au/climate/about/?bookmark=iod">Indian Ocean Dipole</a> is like ENSO’s Indian Ocean cousin. A positive Indian Ocean Dipole is declared when ocean temperatures near Africa are warmer than normal and ocean temperatures off the coast of Sumatra are cooler than usual.</p>
<p>A positive dipole tends to bring warmer and drier conditions, particularly to western and central Australia. A negative Indian Ocean Dipole is the reverse and is associated with wetter than normal weather and an increase in <a href="https://pursuit.unimelb.edu.au/articles/why-more-clouds-can-mean-less-rain-in-australia">northwest cloudbands</a>.</p>
<h2>North: Madden-Julian Oscillation</h2>
<p>The <a href="http://www.bom.gov.au/climate/about/?bookmark=mjo">Madden-Julian Oscillation</a> is a pulse of storms that start in the Indian Ocean, travel over Northern Australia and Indonesia and die in the Pacific Ocean. Ahead of the pulse, the air sinks, causing sunny and dry weather. Under the pulse is high storm activity and typically heavy rainfall.</p>
<p>We describe the Madden-Julian Oscillation based on whether the pulse of storms is <a href="http://www.bom.gov.au/climate/mjo/">active or inactive</a> and where the storm activity is located on its path between the Indian and Pacific Oceans. As well as causing rainfall, the Madden-Julian Oscillation can control the timing of the monsoon onset and <a href="http://www.bom.gov.au/climate/about/?bookmark=tc">tropical cyclone formation</a>.</p>
<h2>South: Southern Annular Mode</h2>
<p>The <a href="http://www.bom.gov.au/climate/about/?bookmark=sam">Southern Annular Mode</a> controls the north and south position of the westerly winds that whizz around the globe in the Southern Ocean. When the winds are further north than usual, we call this the negative phase. But when the westerly wind move towards Antarctica, we call this the positive phase.</p>
<p>The phase of the Southern Annular Mode <a href="https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/joc.1370">affects how many weather systems</a>, like cold fronts, make landfall over southern Australia. A positive mode may also draw tropical moist air south, which happened in 2022 during the extensive flooding over eastern Australia.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1730116714686562507"}"></div></p>
<h2>Climate drivers control the odds, but not the result</h2>
<p>These four key climate drivers affect the weather on average (over months and seasons), but they do not dictate the exact day-to-day weather we experience. As the Gippsland region of Victoria <a href="https://www.theguardian.com/australia-news/2023/oct/05/victoria-floods-flooding-warnings-gippsland-region-flood-and-fires-evacuation">saw in October</a>, heavy rainfall can still occur during an El Niño. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/561494/original/file-20231124-16-ip8fja.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map of Australia showing the difference from normal rainfall during October 2023, with a large wet patch around Gippsland, Victoria." src="https://images.theconversation.com/files/561494/original/file-20231124-16-ip8fja.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/561494/original/file-20231124-16-ip8fja.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=407&fit=crop&dpr=1 600w, https://images.theconversation.com/files/561494/original/file-20231124-16-ip8fja.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=407&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/561494/original/file-20231124-16-ip8fja.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=407&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/561494/original/file-20231124-16-ip8fja.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/561494/original/file-20231124-16-ip8fja.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/561494/original/file-20231124-16-ip8fja.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Difference from normal rainfall during October 2023, showing defined wet area around Gippsland, Victoria surrounded by drier conditions.</span>
<span class="attribution"><span class="source">The Bureau of Meteorology</span></span>
</figcaption>
</figure>
<p>Climate drivers are like a football coach. They can select the best players and develop ingenious strategies, but that doesn’t guarantee a win every time. </p>
<p>Players can get injured on the field or simply have a bad game. These uncontrollable factors are challenging to predict and may change the result from what we would expect. Scientists call this stochasticity. The climate drivers are the football coach, but the day-to-day weather systems are the players.</p>
<p>The Bureau of Meteorology <a href="http://www.bom.gov.au/climate/enso/">releases an update</a> on all of these drivers every two weeks. The update explains which drivers are currently active and the forecast for the next few weeks.</p>
<p>So, if you are wondering why the weather is cooler during summer, or it’s raining in the middle of the dry season, perhaps take a look at which driver is steering Australia’s weather at the moment.</p>
<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>
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</em>
</p>
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<img src="https://counter.theconversation.com/content/218257/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kimberley Reid receives funding from the Australian Research Council. </span></em></p>El Niño looms large as we head into the Australian summer. But can everyone expect hot and dry weather? What drives the weather in your state?Kimberley Reid, Postdoctoral Research Fellow in Atmospheric Sciences, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2191112023-12-04T05:51:16Z2023-12-04T05:51:16ZWe’re in an El Niño – so why has Australia been so wet?<figure><img src="https://images.theconversation.com/files/563213/original/file-20231204-16-c43nop.jpg?ixlib=rb-1.1.0&rect=25%2C8%2C5552%2C3838&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>After three La Niña summers many of us would have been expecting much hotter and drier conditions this spring and summer after the arrival of El Niño. Instead, in many parts of eastern Australia it’s rained and rained over the last few weeks. </p>
<p>El Niño hasn’t gone away. It’s expected to <a href="https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml">continue into 2024</a>. Why the rain? Because even with an El Niño, eastern Australia can still experience significant rain events.</p>
<p>Despite the recent rain, Australia’s summer is much more likely than normal to be a hot one.</p>
<h2>Has it been unusually wet?</h2>
<p>Much of eastern Australia has seen wetter than normal conditions over November. Vigorous low-pressure systems and thunderstorms brought record rain totals and <a href="https://www.abc.net.au/news/2023-11-29/heavy-rain-in-nsw-south-east-after-supercell-storm-in-west/103160380">flooding</a> to parts of Victoria, New South Wales and Queensland.</p>
<p>Overall, this meant November was wetter than average across the continent. But as we had a record dry September and a dry October (apart from in eastern Victoria), spring was <a href="http://www.bom.gov.au/climate/maps/rainfall/?variable=rainfall&map=decile&period=3month&region=nat&year=2023&month=11&day=30">actually drier than average</a> for Australia as a whole.</p>
<h2>Should the recent rain come as a surprise?</h2>
<p>When Australians think of El Niño, we usually think of parched soils and blazing sunshine. But this is not guaranteed. </p>
<p>The El Niño of 1997-98, for instance, was one of the strongest on record. Even so, the spring of 1997 was actually a <a href="http://www.bom.gov.au/climate/maps/rainfall/?variable=rainfall&map=decile&period=3month&region=nat&year=1997&month=11&day=30">bit wetter than normal</a> over parts of South Australia, NSW and southern Queensland.</p>
<p>The El Niño-Southern Oscillation describes changes in the tropical central and east Pacific. These changes can swing between El Niño, neutral and La Niña events. Think of poet Dorothea Mackellar’s description “of droughts and flooding rains” – that’s the type of contrasting extremes that El Niño and La Niña often cause. </p>
<p>It’s not as simple as El Niño hot and dry, La Niña cool and rainy. The influence of this phenomenon is complex and non-linear. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/faster-disaster-climate-change-fuels-flash-droughts-intense-downpours-and-storms-213242">Faster disaster: climate change fuels 'flash droughts', intense downpours and storms</a>
</strong>
</em>
</p>
<hr>
<p>Scientists are more confident in saying La Niña causes unusually wet conditions over eastern Australia than we are in saying El Niño causes unusually dry conditions. That’s because Australia is typically a dry place and just a few wet days can make a big difference to whether a month or season is wetter or drier than average.</p>
<p>When El Niño events are coupled with a second climate driver, a <a href="http://www.bom.gov.au/climate/enso/#tabs=Indian-Ocean">positive Indian Ocean Dipole</a> – where colder water comes up from the deep in the eastern Indian Ocean – we typically see fewer low pressure weather systems causing heavy rainfall over southeastern Australia. </p>
<p>But again, nothing is certain, as we’ve seen. Despite these two climate cycles suggesting less rain was likely, the rain returned. </p>
<p>Why? One reason is the unusually high sea surface temperatures to the south and <a href="https://theconversation.com/a-monster-eddy-current-is-spinning-into-existence-off-the-coast-of-sydney-will-it-bring-a-new-marine-heatwave-216625">southeast of Australia</a>, which can drive more moisture into the air and trigger more rain in the region.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/563235/original/file-20231204-27-cef1p6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="figure showing high sea surface temperatures around most of the world" src="https://images.theconversation.com/files/563235/original/file-20231204-27-cef1p6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563235/original/file-20231204-27-cef1p6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=333&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563235/original/file-20231204-27-cef1p6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=333&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563235/original/file-20231204-27-cef1p6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=333&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563235/original/file-20231204-27-cef1p6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=419&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563235/original/file-20231204-27-cef1p6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=419&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563235/original/file-20231204-27-cef1p6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=419&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">Sea surface temperatures are unusually high around southern Australia as well as in the central and eastern tropical Pacific where the El Niño event is continuing.</span>
<span class="attribution"><span class="source">Bureau of Meteorology</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Many of us were shocked by how intense late November’s rainfall was. But this is a feature of how variable and fickle Australia’s weather can be. </p>
<p>During El Niño events we should still be prepared for floods even if droughts are more likely on average. You might think we would see more thunderstorms during, say, a La Niña event. In fact, that’s not true. Thunderstorms <a href="https://doi.org/10.1007/s00382-020-05167-9">do not have a strong relationship</a> to either of these climate cycles. That matters, because it’s thunderstorms which can drive many of these heavy rain events we see during spring in Australia.</p>
<h2>What does the summer hold?</h2>
<p>During spring, El Niño in the Pacific and conditions in the Indian Ocean typically have their strongest effect on Australia. In December, these influences start to wane as Indian Ocean Dipole events usually begin to decay as we move into summer. </p>
<p>In the summer, more rain falls in small-scale weather systems such as thunderstorms which makes <a href="https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/qj.3789">seasonal outlooks less accurate</a> compared to other times of the year. At present, our seasonal prediction models have a limited ability to simulate thunderstorms.</p>
<p>But we can still make some predictions about the summer ahead. We usually see fewer tropical cyclones during El Niño summers, noting that tropical cyclones can cause extreme rainfall in northern Australia. The <a href="http://www.bom.gov.au/climate/cyclones/australia/">seasonal outlook</a> reflects this, with an 80% chance of a below-average number of tropical cyclones.</p>
<p>What about fire? The recent rains are good news in that they should help reduce the chance of major forest fires in parts of southeast Australia for a while at least, while noting many other factors also contribute to fire risk. However, grass fires could become more likely in some regions, as grass grows fast after rain and can dry out quickly if hot and dry weather returns. </p>
<p>Our overall <a href="https://www.afac.com.au/auxiliary/publications/newsletter/article/seasonal-bushfire-outlook-summer-2023">bushfire outlook</a> points to a heightened fire risk through much of the east of Australia. There have already been <a href="https://www.theguardian.com/australia-news/2023/nov/24/perth-fires-18-homes-destroyed-as-fire-crews-brace-for-more-dangerous-conditions">severe fires near Perth</a> leading to loss of property. It’s very early in the fire season for southern Western Australia to see major fire damage like that.</p>
<p>Earlier in spring we saw <a href="https://cosmosmagazine.com/news/is-australia-in-middle-of-a-flash-drought/">flash droughts</a> start to form. That’s where soils rapidly dry out under hot and sunny conditions. </p>
<p>Where sustained dry conditions return, we could see flash drought conditions follow soon after. </p>
<p>Our high water storage levels mean major droughts and water restrictions like those seen in the 2001-2009 Millennium Drought won’t return for a while longer in the southeast.</p>
<p>As with every summer in Australia, we must be prepared for extreme weather including fire, floods and intense heat. Human-caused climate change is <a href="https://theconversation.com/faster-disaster-climate-change-fuels-flash-droughts-intense-downpours-and-storms-213242">supercharging our extreme weather events</a> and making our summer weather more dangerous than it used to be.</p>
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Read more:
<a href="https://theconversation.com/in-september-we-went-past-1-5-degrees-in-november-we-tipped-over-2-degrees-for-the-first-time-whats-going-on-218228">In September we went past 1.5 degrees. In November, we tipped over 2 degrees for the first time. What's going on?</a>
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<img src="https://counter.theconversation.com/content/219111/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew King receives funding from the National Environmental Science Program. </span></em></p><p class="fine-print"><em><span>Andrew Dowdy receives funding from The University of Melbourne.</span></em></p>El Niño usually brings hot, dry weather to Australia. But the rains that have drenched eastern Australia are normal too.Andrew King, Senior Lecturer in Climate Science, The University of MelbourneAndrew Dowdy, Principal Research Scientist, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2182282023-11-21T03:56:00Z2023-11-21T03:56:00ZIn September we went past 1.5 degrees. In November, we tipped over 2 degrees for the first time. What’s going on?<p>In September, the world passed 1.5°C of warming. Two months later, we <a href="https://twitter.com/CopernicusECMWF/status/1726578518463816078">hit 2°C of warming</a>. It’s fair to wonder what is going on. </p>
<p>What we’re seeing is not runaway climate change. These are daily spikes, not the long-term pattern we would need to say the world is now 2 degrees hotter than it was in the pre-industrial period. </p>
<p>These first breaches of temperature limits are the loudest alarms yet. They come as the United Nations Environment Program warns the world is still on a path to <a href="https://www.theguardian.com/environment/2023/nov/20/world-facing-hellish-3c-of-climate-heating-un-warns-before-cop28">a “hellish” 3°C of warming</a> by the end of the century. </p>
<p>But they do not signal our failure. The sudden spike in warming in 2023 comes from a combination of factors – climate change, a strong El Niño, sea ice failing to reform after winter, reduced aerosol pollution and increased solar activity. There are also minor factors such as the aftermath of the volcanic eruption near Tonga. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1726587990208868841"}"></div></p>
<p><iframe id="tc-infographic-990" class="tc-infographic" height="400px" src="https://cdn.theconversation.com/infographics/990/f56fb3adf64fd2aec673a627f2bfb83c3f55c532/site/index.html" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>How significant are these factors?</h2>
<p><strong>1. Climate change</strong></p>
<p>This is by far the biggest factor. What many of us don’t recognise is how recent our intense period of emissions is. If you were born in 1983, fully 50% of all of humanity’s emissions have gone into the atmosphere <a href="https://news.sky.com/story/climate-change-how-much-carbon-dioxide-has-been-produced-since-you-were-born-enter-your-year-of-birth-to-find-out-12415233">since your birth</a>. Human emissions and other activities have <a href="https://www.globalwarmingindex.org/">so far contributed about 1.2°C of warming</a>. </p>
<p>Greenhouse gases trap heat, which is why the Earth is not a snowball. But the <a href="https://theconversation.com/two-trillion-tonnes-of-greenhouse-gases-25-billion-nukes-of-heat-are-we-pushing-earth-out-of-the-goldilocks-zone-202619">2 trillion tonnes</a> of fossil carbon we’ve taken from underground and put back in the atmosphere are trapping more heat. And more heat. And will continue to do so until we stop burning fossil fuels for heat or power. </p>
<p><iframe id="tc-infographic-992" class="tc-infographic" height="400px" src="https://cdn.theconversation.com/infographics/992/c3cf4c90cc688825c60b538072d66a58749a8bf3/site/index.html" width="100%" style="border: none" frameborder="0"></iframe></p>
<p><strong>2. El Niño</strong></p>
<p>The El Niño-Southern Oscillation climate cycle in the Pacific has the biggest natural influence on climate. That’s because the Pacific is huge, accounting for 30% of Earth’s surface. When in the El Niño phase, the seas off South America heat up. This, in turn, usually makes average global temperatures hotter.</p>
<p>Right now, there’s a dangerous heatwave in Brazil, where heat and humidity combined makes it <a href="https://www.theguardian.com/global-development/2023/nov/19/brazil-temperatures-extreme-heat-danger-climate-change-inequality">feel like 60°C</a>. The intense heat contributed to the <a href="https://www.bbc.com/news/world-latin-america-67465742">death of a fan</a> at Taylor Swift’s Rio concert last week. </p>
<p>El Niño will likely peak in the next two months. But its effects may well persist throughout 2024, driving global average temperatures higher by perhaps 0.15°C.</p>
<p><strong>3. Antarctic sea ice isn’t bouncing back</strong></p>
<p>The declines in Arctic sea ice are well known. But now Antarctic sea ice, too, is <a href="https://theconversation.com/as-antarctic-sea-ice-continues-its-dramatic-decline-we-need-more-measurements-and-much-better-models-to-predict-its-future-213747">failing to recover</a>. Normally, the ring of frozen seawater around the ice continent reaches maximum extent in September. But this year’s maximum is well below any previous year.</p>
<p>As we enter summer, that means more dark water will be exposed. And since dark surfaces absorb more heat while white ones reflect it, it means still more heat will go into the oceans rather than back out to space.</p>
<p><strong>4. Increased solar activity</strong></p>
<p>Our Sun runs on a roughly 11-year cycle, going between lower and higher output. The solar maximum was forecast for 2025 and a clear increase is occurring this year. This brings spectacular auroras – even in the Southern Hemisphere, where residents have seen auroras <a href="https://www.abc.net.au/news/2023-04-24/aurora-australis-southern-lights-south-west-victoria/102259180">as far inland</a> as Ballarat, in Victoria. </p>
<p>Solar maximums add extra heat. But not much – the effect is only <a href="https://theconversation.com/global-temperatures-are-off-the-charts-for-a-reason-4-factors-driving-2023s-extreme-heat-and-climate-disasters-209975#:%7E:text=Earth's%20temperature%20increase%20during%20a,happens%20during%20a%20solar%20minimum.">around 0.05°C</a>, about a third of an El Niño. </p>
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Read more:
<a href="https://theconversation.com/global-temperatures-are-off-the-charts-for-a-reason-4-factors-driving-2023s-extreme-heat-and-climate-disasters-209975">Global temperatures are off the charts for a reason: 4 factors driving 2023's extreme heat and climate disasters</a>
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<p><strong>5. The volcanic hangover</strong></p>
<p>Normally, volcanic eruptions cool the planet, as their vast plumes of aerosols block sunlight. But the largest volcanic eruption this century near Tonga in January 2022 did the opposite.</p>
<p>That’s because the Hunga Tonga-Hunga Ha’apai volcano was under the sea. Its explosive force evaporated vast volumes of seawater – and water vapour is a greenhouse gas. While some sceptics like to point to this eruption as the root cause of our recent spike in warming, the Tonga eruption is a blip – it will add an <a href="https://www.nature.com/articles/s41558-022-01568-2">estimated 0.035°C</a> for about five years. </p>
<p><strong>6. Cutting aerosol pollution</strong> </p>
<p>In 2020, new international shipping rules came into force, mandating low-sulphur fuels. This cut sulphur dioxide emissions by about 10%. That’s good for health. But aerosols in the atmosphere can actually block heat. Cutting pollution may have added to warming. But again, the effect seems small, adding an <a href="https://www.carbonbrief.org/analysis-how-low-sulphur-shipping-rules-are-affecting-global-warming/">estimated 0.05°C of warming</a> by 2050. </p>
<h2>What should we take from this?</h2>
<p>The climate is enormously complex. We should see the first day 2°C warmer than the same day in the pre-industrial period as a stark warning – but not as a sign to give up. </p>
<p>In short, this isn’t a step change. It’s a combination of factors which has driven this surge. Some of those, like El Niño, are cyclical and will switch back. </p>
<p><iframe id="tc-infographic-991" class="tc-infographic" height="400px" src="https://cdn.theconversation.com/infographics/991/69bb78190ac8614652630853dd01bce56f7c5a84/site/index.html" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>But as negotiators prepare for next week’s COP28 climate talks, it’s yet another sign that we cannot relent. </p>
<p>We are – at last – seeing signs of real progress in the clean energy and clean transport roll out. This year, we may even see emissions from power generation <a href="https://www.theguardian.com/environment/2023/oct/05/global-carbon-emissions-electricity-peak-thinktank-report">finally peak</a> and then begin to fall. </p>
<p>So – we haven’t failed, yet. But we are on a rapidly warming planet – and we can now clearly see the effect, even in these new daily temperature records. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/we-just-blew-past-1-5-degrees-game-over-on-climate-not-yet-213364">We just blew past 1.5 degrees. Game over on climate? Not yet</a>
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<img src="https://counter.theconversation.com/content/218228/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew King receives funding from the National Environmental Science Program.
</span></em></p>Daily global temperature records keep breaking. It’s a sign we’re on a rapidly warming planet.Andrew King, Senior Lecturer in Climate Science, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2164402023-11-01T19:25:06Z2023-11-01T19:25:06ZExtreme weather is landing more Australians in hospital – and heat is the biggest culprit<figure><img src="https://images.theconversation.com/files/556795/original/file-20231031-23-y5pgcp.jpg?ixlib=rb-1.1.0&rect=34%2C483%2C5725%2C3350&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/silhouette-of-woman-standing-facing-sunset-LOOKlkcOo5k">Rod Long/Unsplash</a></span></figcaption></figure><p>Hospital admissions for injuries directly attributable to extreme weather events – such as heatwaves, bushfires and storms – have increased in Australia over the past decade.</p>
<p>A new <a href="https://www.aihw.gov.au/reports/injury/extreme-weather-injuries/contents/about">report</a> from the Australian Institute of Health and Welfare (AIHW) shows 9,119 Australians were hospitalised for injuries from extreme weather from 2012-22 and 677 people died from these injuries in the decade up to 2021.</p>
<p>In 2021-22, there were 754 injury hospitalisations directly related to extreme weather, compared to 576 in 2011-12. </p>
<p>Extreme heat is responsible for most weather-related injuries. Exposure to prolonged natural heat can result in physical conditions ranging from mild heat stroke, to organ damage and <a href="https://www.dea.org.au/wp-content/uploads/2021/01/DEA-Fact-Sheet_HeatwavesWEB.pdf">death</a>. </p>
<p>As Australia heads into summer with an El Niño, it’s important to understand and prepare for the health risks associated with extreme weather.</p>
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Read more:
<a href="https://theconversation.com/study-finds-2-billion-people-will-struggle-to-survive-in-a-warming-world-and-these-parts-of-australia-are-most-vulnerable-205927">Study finds 2 billion people will struggle to survive in a warming world – and these parts of Australia are most vulnerable</a>
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<h2>A spike every three years</h2>
<p>Extreme weather-related hospitalisations have spiked at more than 1,000 cases every three years, with the spikes becoming progressively higher. There were:</p>
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<li>1,027 injury hospitalisations in 2013–14</li>
<li>1,033 in 2016–17 </li>
<li>1,108 in 2019–20. </li>
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<p>In each of these three years, extreme heat had the biggest impact on hospital admissions and deaths. </p>
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<p>Extreme heat accounted for 7,104 injury hospitalisations (78% of all injury hospitalisations) and 293 deaths (43% of all injury deaths) in the ten year period analysed. </p>
<p>In 2011-12, there were 354 injury hospitalisations directly related to extreme heat. This rose to 579 by 2021-22. </p>
<h2>El Niño and La Niña</h2>
<p>Over the past three decades, extreme weather events have increased in <a href="https://www.ipcc.ch/report/ar5/syr/">frequency</a> and <a href="http://www.bom.gov.au/state-of-the-climate/">severity</a>.</p>
<p>In Australia, El Niño drives a period of reduced rainfall, warmer temperatures and increased bushfire danger. </p>
<p>La Niña, on the other hand, is associated with above average rainfall, cooler daytime temperatures and increased chance of tropical cyclones and flood events.</p>
<p>Although similar numbers of heatwave-related hospitalisations occurred in El Niño and La Niña years studied, the number of injuries related to bushfires was higher in El Niño years. </p>
<p>During the 2019–20 bushfires, in the week beginning January 5 2020, there were 1,100 more hospitalisations than the previous five-year average, an 11% increase.</p>
<p>Although El Niño hasn’t directly been proved as the cause for these three spikes, according to the Bureau of Meteorology, two of the three years (2016-17 and 2019-20) were El Niño summers. And the other year (2013-14) was the warmest neutral year on record at that time.</p>
<h2>Regional differences</h2>
<p>Exposure to excessive natural heat was the most common cause leading to injury hospitalisation for all the mainland states and territories. From 2019 to 2022, there were 2,143 hospital admissions related to extreme heat, including:</p>
<ul>
<li>717 patients from Queensland</li>
<li>410 from Victoria</li>
<li>348 from NSW</li>
<li>267 from South Australia</li>
<li>266 from Western Australia</li>
<li>73 from the Northern Territory</li>
<li>23 from the ACT </li>
<li>19 from Tasmania. </li>
</ul>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/556987/original/file-20231101-27-3c98xm.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/556987/original/file-20231101-27-3c98xm.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=632&fit=crop&dpr=1 600w, https://images.theconversation.com/files/556987/original/file-20231101-27-3c98xm.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=632&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/556987/original/file-20231101-27-3c98xm.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=632&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/556987/original/file-20231101-27-3c98xm.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=794&fit=crop&dpr=1 754w, https://images.theconversation.com/files/556987/original/file-20231101-27-3c98xm.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=794&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/556987/original/file-20231101-27-3c98xm.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=794&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="attribution"><a class="source" href="https://www.aihw.gov.au/reports-data/latest-reports">AIHW National Hospital Morbidity Database</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>The report also includes state and territory data on hospitalisations related to extreme cold and storms. </p>
<p>During the ten-year period analysed, there were 773 injury hospitalisations and 242 deaths related to extreme cold. Extreme rain or storms accounted for 348 injury hospitalisations and 77 deaths.</p>
<p>From 2019 to 2022, there were 191 hospitalisations related to extreme cold, with Victoria recording the highest number (51, compared to 40 in next-placed NSW). During the same period there were 111 hospitalisations related to rain and storms, with 52 occurring in NSW and 28 in Queensland.</p>
<h2>What about for bushfires?</h2>
<p>Over the ten-year period studied, there were 894 hospitalisations and 65 deaths related to bushfires. </p>
<p>Bushfire-related injury hospitalisations and deaths peaked in 2019–20, an El Niño year with 174 hospitalisations and 35 deaths. The two most common injuries that result from bushfires are smoke inhalation and burns. </p>
<p>During the 2019–20 bushfires, in the week beginning 5 January 2020 there were 1,100 more respiratory hospitalisations than the previous five-year average, an 11% increase. </p>
<p>The greatest increase in the hospitalisation rate for burns was 30% in the week beginning December 15 2019 — 0.8 per 100,000 persons (about 210 hospitalisations), compared with the previous 5-year average of 0.6 per 100,000 (an average of 155 hospitalisations).</p>
<h2>Some people are particularly vulnerable</h2>
<p>Anyone can be affected by extreme weather-related injuries but some population groups are more at risk than others. This includes older people, children, people with disabilities, those with pre-existing or chronic health conditions, outdoor workers, and those with greater <a href="https://www.mdpi.com/2071-1050/15/1/813">socioeconomic disadvantage</a>. </p>
<p>People in these groups may have reduced capacity to avoid or reduce the health impacts of extreme weather conditions, for example older people taking medication may be less able to regulate their body temperature. “Thermal inequity” includes people living in poor quality housing who have difficulty accessing adequate heating and cooling.</p>
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Read more:
<a href="https://theconversation.com/extreme-heat-is-particularly-hard-on-older-adults-an-aging-population-and-climate-change-put-ever-more-people-at-risk-210049">Extreme heat is particularly hard on older adults – an aging population and climate change put ever more people at risk</a>
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<p>For heat-related injuries between 2019–20 and 2021–22, people aged 65 and over were the most commonly admitted to hospital, followed by people aged 25–44. </p>
<p>Across age groups, men had higher numbers of heat related injury hospitalisations than women. This difference was most notable among those aged 25-44 and 45-64 years, where over twice as many men were hospitalised due to extreme heat as women.</p>
<h2>We still don’t have a full picture</h2>
<p>The AIHW data only includes injuries which were serious enough for patients to be admitted to hospital; it doesn’t include cases where patients treated in an emergency department and sent home without being admitted.</p>
<p>It includes injuries that were directly attributable to weather-related events but does not include injuries that were indirectly related. For example, it doesn’t include injuries from road traffic accidents that occur due to wet weather, since the primary cause of injury would be recorded as “transport”. </p>
<p>Improved surveillance of weather-related injuries could help the health system and the community better prepare for responding to extreme weather conditions. For example, better data aids communities in predicting what resources will be needed during periods of extreme weather.</p>
<p>A more complete picture of injuries during weather events could also be used to inform people of actions they can take to protect their own health. Given a predicted hot summer, this could be a matter of life or death. </p>
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Read more:
<a href="https://theconversation.com/drowning-risk-increases-during-heatwaves-in-unexpected-ways-heres-how-to-stay-safe-this-summer-212095">Drowning risk increases during heatwaves in unexpected ways -- here's how to stay safe this summer</a>
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<p><em>This article was co-authored by Sarah Ahmed and Heather Swanston from the Injuries and System Surveillance Unit at the Australian Institute of Health and Welfare.</em></p><img src="https://counter.theconversation.com/content/216440/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Amy Peden receives funding from the National Health and Medical Research Council, Meta Inc, Royal Life Saving Society - Australia and Surf Life Saving Australia. She provided expert review for the Australian Institute of Health and Welfare’s Extreme weather-related injuries report. </span></em></p>As Australia heads into summer with an El Niño, it’s important understand and prepare for the health risks associated with extreme weather.Amy Peden, NHMRC Research Fellow, School of Population Health & co-founder UNSW Beach Safety Research Group, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2153952023-10-12T12:30:45Z2023-10-12T12:30:45ZWhat is a strong El Niño? Meteorologists anticipate a big impact in winter 2023-2024, but the forecasts don’t all agree<figure><img src="https://images.theconversation.com/files/553361/original/file-20231011-29-363wak.png?ixlib=rb-1.1.0&rect=32%2C873%2C3211%2C2058&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The El Niño pattern stands out in the warm sea surface temperature anomalies in the Pacific in 2023</span> <span class="attribution"><a class="source" href="https://www.climate.gov/maps-data/data-snapshots/data-source/sst-enso-region-monthly-difference-average">NOAA Climate.gov</a></span></figcaption></figure><p><em>Meteorologists have been talking for weeks about <a href="https://www.accuweather.com/en/winter-weather/us-winter-forecast-for-the-2023-2024-season/1583853">a snowy season ahead</a> in the southern Rockies and the Sierra Nevada. They anticipate <a href="https://www.powder.com/trending-news/el-nino-huge-snow-east">more storms</a> in the U.S. South and Northeast, and warmer, drier conditions across the already dry Pacific Northwest and the upper Midwest.</em></p>
<p><em>One phrase comes up repeatedly with these projections: <a href="https://www.wcpo.com/weather/weather-101/a-strong-el-nino-expected-this-winter-heres-what-that-means-for-our-weather">a strong El Niño</a> is coming.</em></p>
<p><em>It sounds ominous. But what does that actually mean? We asked <a href="https://scholar.google.com/citations?user=z7CXcXkAAAAJ&hl=en">Aaron Levine</a>, an atmospheric scientist at the University of Washington whose research focuses on El Niño.</em></p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/wVlfyhs64IY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">NOAA explains in animations how El Niño forms.</span></figcaption>
</figure>
<h2>What is a strong El Niño?</h2>
<p>During a normal year, the warmest sea surface temperatures are in the western Pacific and the Indian Ocean, in what’s known as the <a href="https://doi.org/10.1186/s40562-016-0054-3">Indo-Western Pacific warm pool</a>.</p>
<p>But every few years, the trade winds that blow from east to west weaken, allowing that warm water to slosh eastward and <a href="https://www.pmel.noaa.gov/elnino/schematic-diagrams">pile up along the equator</a>. The warm water causes the air above it to warm and rise, fueling precipitation in the central Pacific and shifting atmospheric circulation patterns across the basin.</p>
<p>This pattern is <a href="https://www.pmel.noaa.gov/elnino/what-is-el-nino">known as El Niño</a>, and it can <a href="https://www.climate.gov/media/13628">affect weather around the world</a>.</p>
<figure class="align-center ">
<img alt="An animation shows how warm water builds up along the equator off South America. The box where temperatures are measured is south of Hawaii." src="https://images.theconversation.com/files/553048/original/file-20231010-23-c36xip.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/553048/original/file-20231010-23-c36xip.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=272&fit=crop&dpr=1 600w, https://images.theconversation.com/files/553048/original/file-20231010-23-c36xip.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=272&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/553048/original/file-20231010-23-c36xip.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=272&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/553048/original/file-20231010-23-c36xip.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=342&fit=crop&dpr=1 754w, https://images.theconversation.com/files/553048/original/file-20231010-23-c36xip.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=342&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/553048/original/file-20231010-23-c36xip.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=342&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The box shows the Niño 3.4 region as El Niño begins to develop in the tropical Pacific, from January to June 2023.</span>
<span class="attribution"><a class="source" href="https://www.climate.gov/">NOAA Climate.gov</a></span>
</figcaption>
</figure>
<p>A strong El Niño, in the most basic definition, occurs once the average sea surface temperature in the equatorial Pacific is at least 1.5 degrees Celsius (2.7 Fahrenheit) warmer than normal. It’s measured in an imaginary box along the equator, roughly south of Hawaii, known as the <a href="https://svs.gsfc.nasa.gov/4695">Nino 3.4 Index</a>.</p>
<p>But El Niño is a coupled ocean-atmosphere phenomenon, and the atmosphere also plays a crucial role.</p>
<p>What has been surprising about this year’s El Niño – and still is – is that the atmosphere hasn’t responded as much as we would have expected based on the rising sea surface temperatures.</p>
<h2>Is that why El Niño didn’t affect the 2023 hurricane season the way forecasts expected?</h2>
<p>The 2023 Atlantic hurricane season is a good example. Forecasters often use El Niño as a predictor of <a href="https://www.weather.gov/ilx/swop-springtopics">wind shear</a>, which can tear apart Atlantic hurricanes. But with the atmosphere not responding to the warmer water right away, the impact on Atlantic hurricanes was lessened and it turned out to be a <a href="https://www.nytimes.com/article/tropical-storm-sean-hurricane.html">busy season</a>.</p>
<p><a href="https://doi.org/10.1175/JCLI-D-12-00097.1">The atmosphere is what transmits El Niño’s impact</a>. Heat from the warm ocean water causes the air above it to warm and rise, which fuels precipitation. That air sinks again over cooler water. </p>
<p>The rising and sinking creates giant loops in the atmosphere <a href="https://www.climate.gov/news-features/blogs/enso/walker-circulation-ensos-atmospheric-buddy">called the Walker Circulation</a>. When the warm pool’s water shifts eastward, that also shifts where the rising and sinking motions happen. The atmosphere reacts to this change like ripples in a pond when you throw a stone in. These ripples affect the jet stream, which steers weather patterns in the U.S.</p>
<p>This year, in comparison with other large El Niño events – such as <a href="https://www.climate.gov/news-features/blogs/enso/united-states-el-ni%C3%B1o-impacts-0">1982-83, 1997-98</a> and <a href="https://www.climate.gov/news-features/understanding-climate/2015-state-climate-el-ni%C3%B1o-came-saw-and-conquered">2015-16</a> – we’re not seeing the same change in where the precipitation is happening. It’s taking much longer to develop, and it’s not as strong.</p>
<p>Part of that, presumably, is related to the whole tropics being very, very warm. But <a href="https://doi.org/10.1029/2019GL086182">this is still an emerging field of research</a>.</p>
<p>How El Niño will change with global warming is a big and open question. El Niño <a href="https://www.climate.gov/news-features/understanding-climate/climate-variability-oceanic-nino-index">only happens every few years</a>, and there’s a fair amount of variability between events, so just getting a baseline is tough.</p>
<h2>What does a strong El Niño typically mean for US weather?</h2>
<p>During <a href="https://www.climate.gov/enso">a typical El Niño winter</a>, the U.S. South and Southwest are cooler and wetter, and the Northwest is warmer and drier. The upper Midwest tends to be drier, while the Northeast tends to be a little wetter. </p>
<p>The likelihood and the intensity generally scale with the strength of the El Niño event.</p>
<p>El Niño has traditionally been good for the mountain snowpack in California, which the state relies for a large percentage of its water. But it is often not so good for the Pacific Northwest snowpack.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/553424/original/file-20231012-15-3wfvdw.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two maps showing wetter, cooler weather in the Southeast and drier warmer air in the north during El Nino." src="https://images.theconversation.com/files/553424/original/file-20231012-15-3wfvdw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/553424/original/file-20231012-15-3wfvdw.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=834&fit=crop&dpr=1 600w, https://images.theconversation.com/files/553424/original/file-20231012-15-3wfvdw.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=834&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/553424/original/file-20231012-15-3wfvdw.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=834&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/553424/original/file-20231012-15-3wfvdw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1047&fit=crop&dpr=1 754w, https://images.theconversation.com/files/553424/original/file-20231012-15-3wfvdw.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1047&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/553424/original/file-20231012-15-3wfvdw.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1047&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 jet stream takes a very different path in a typical El Niño vs. La Niña winter weather pattern. But these patterns have a great deal of variability. Not every El Niño or La Niña year is the same.</span>
<span class="attribution"><a class="source" href="https://www.climate.gov/media/14484">NOAA Climate.gov</a></span>
</figcaption>
</figure>
<p>The <a href="https://www.climate.gov/news-features/featured-images/how-el-ni%C3%B1o-and-la-ni%C3%B1a-affect-winter-jet-stream-and-us-climate">jet stream plays a role</a> in that shift. When the polar jet stream is either displaced very far northward or southward, storms that would normally move through Washington or British Columbia are steered to California and Oregon instead.</p>
<h2>What do the forecasts show for the months ahead?</h2>
<p>Whether forecasters think a strong El Niño will develop depends on whose forecast model they trust.</p>
<p>This past spring, the <a href="https://www.weather.gov/media/climateservices/NWS%20Climate%20Forecast%20and%20Tools.pdf">dynamical forecast models</a> were <a href="https://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/?enso_tab=enso-sst_table">already very confident</a> about the potential for a strong El Niño developing. These are big models that solve basic physics equations, starting with current oceanic and atmospheric conditions. </p>
<p>However, statistical models, which use statistical predictors of El Niño calculated from historical observations, were less certain.</p>
<p>Even in the <a href="https://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/?enso_tab=enso-sst_table">most recent forecast model outlook</a>, the dynamical forecast models were predicting a stronger El Niño than the statistical models were.</p>
<p>If you go by just a sea surface temperature-based El Niño index, the forecast is for a fairly strong El Niño. </p>
<p>But the indices that incorporate the atmosphere are not responding in the same way. We’ve seen <a href="https://psl.noaa.gov/enso/enso.current.html">atmospheric anomalies</a> – as measured by cloud height monitored by satellites or sea-level pressure at monitoring stations – on and off in the Pacific since May and June, <a href="https://images.theconversation.com/files/553327/original/file-20231011-15-kprvx9.png">but not in a very robust fashion</a>. Even in September, they were nowhere near as large as they were in 1982, in terms of overall magnitude.</p>
<p>We’ll see if the atmosphere catches up by wintertime, when El Niño peaks.</p>
<h2>How long do El Niños last?</h2>
<p>Often during El Niño events – particularly strong El Niño events – the sea surface temperature anomalies collapse really quickly during the Northern Hemisphere spring. Almost all end in April or May.</p>
<p>One reason is that El Niño sows the seeds of its own demise. When El Niño happens, it <a href="https://doi.org/10.1175/1520-0469(1997)054%3C0811:AEORPF%3E2.0.CO;2">uses up that warm water</a> and the warm water volume shrinks. <a href="https://doi.org/10.1175/1520-0442(2000)013%3C3551:OOWWVC%3E2.0.CO;2">Eventually, it has eroded its fuel</a>.</p>
<p><iframe id="aOiS8" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/aOiS8/14/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>The surface can stay warm for a while, but once the heat from the subsurface is gone and the trade winds return, the El Niño event collapses. At the end of past El Niño events, the sea surface anomaly dropped very fast and we saw conditions typically switch to La Niña – El Niño’s cooler opposite.</p><img src="https://counter.theconversation.com/content/215395/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Aaron Levine receives funding from NOAA and has received funding in the past from the National Research Council. He is a member of the American Geophysical Union </span></em></p>An atmospheric scientist explains how El Niño works, this year’s oddities and why this phenomenon doesn’t last long.Aaron Levine, Atmospheric Research Scientist, CICOES, University of WashingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2150622023-10-10T19:04:09Z2023-10-10T19:04:09ZEarly heat and insect strike are stressing urban trees – even as canopy cover drops<figure><img src="https://images.theconversation.com/files/552275/original/file-20231005-17-de8trl.jpg?ixlib=rb-1.1.0&rect=27%2C0%2C4573%2C3449&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>Have you noticed street trees looking oddly sad? You’re not alone. Normally, spring means fresh green leaves and flowers. But this year, the heat has come early, stressing some trees. </p>
<p>But there’s more going on – insects are on the march. Many eucalypts are showing signs of lerp or <a href="https://ipm.ucanr.edu/PMG/PESTNOTES/pn7423.html">psyllid</a> attack. These insects hide underneath leaves and build little waxy houses for themselves. But as they feed on the sap, they can give the leaves a stressed, pinkish look. When they appear in numbers – as they are this year – they can defoliate a whole tree with a serious infestation. </p>
<p>How did we get here? Milder, wetter summers during three successive La Niña years mean boomtime for insects. This year, we’ve had a warm winter and a warm spring, meaning insects are up and about early and in large numbers.</p>
<p>This summer <a href="http://www.bom.gov.au/climate/enso">will be an El Niño</a>, which usually means drier and hotter weather for most of Australia. For those of us interested in urban trees, these conditions are troubling. </p>
<p>But it’s more than that. The fact our urban trees are in danger should tell us something – we need to value and protect them better. As the world heats up, our urban forests will be <a href="https://theconversation.com/we-need-urban-trees-more-than-ever-heres-how-to-save-them-from-extreme-heat-211414">even more at risk</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/552274/original/file-20231005-19-p8h59k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="lerp insects sucking sap gum tree" src="https://images.theconversation.com/files/552274/original/file-20231005-19-p8h59k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552274/original/file-20231005-19-p8h59k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552274/original/file-20231005-19-p8h59k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552274/original/file-20231005-19-p8h59k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552274/original/file-20231005-19-p8h59k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552274/original/file-20231005-19-p8h59k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552274/original/file-20231005-19-p8h59k.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">Lerps and psyllid sap-sucking insects can stress or even kill a tree.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>What’s different this year?</h2>
<p>In most years, insect infestations arrive later. That gives trees time to produce a flush of new growth. As a result, they’re rarely lethal. Trees can put out more leaves and recover. </p>
<p>But this year, they’re attacking early and in numbers. It also makes it more likely we’ll see more and more infestations over a long summer. End result: stressed trees, and even deaths from sap-sucking and other insect damage.</p>
<p>That’s not ideal for us either. In an El Niño summer, we’ll likely face hotter days. This year is unusually hot, due to unchecked climate change. The heatwaves to come could make us sick, hospitalise us, or even kill. </p>
<p>Urban trees are <a href="https://www.epa.gov/heatislands/using-trees-and-vegetation-reduce-heat-islands">one of our best methods</a> of protecting ourselves. Suburbs with greater tree canopy cover are significantly cooler. Trees shade the ground and their foliage emits water, which cools the air. Good canopy cover can cut temperatures by up to 6°C. </p>
<p>So, it’s not good news for us that our urban trees are looking stressed. Worse is the fact that our urban tree canopy is actually declining, due to bad urban planning of new suburbs with no space for canopy trees coupled with tree loss from subdivisions or apartment builds. Our state governments <a href="https://vpa.vic.gov.au/project-subpage/key-ideas-review-of-guidelines/greener-and-cooler-environments/">talk about this</a> in their planning documents, but efforts to correct the problem don’t seem to be working. </p>
<p>What happens in hot summers with fewer trees? More air conditioner use, sending energy demand and electricity bills soaring. </p>
<p>We can hope this summer <a href="https://theconversation.com/here-are-5-practical-ways-trees-can-help-us-survive-climate-change-129753">acts as a wake up call</a> about the importance of healthy urban trees as we head into ever-hotter years. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/here-are-5-practical-ways-trees-can-help-us-survive-climate-change-129753">Here are 5 practical ways trees can help us survive climate change</a>
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<h2>What can you do for your trees?</h2>
<p>It’s worth <a href="https://theconversation.com/running-out-of-things-to-do-in-isolation-get-back-in-the-garden-with-these-ideas-from-4-experts-134229">looking after your own trees</a> in anticipation of the tough summer ahead. </p>
<p>As soils are already drying out, keep up the moisture and add quality mulch under trees to a good depth. </p>
<p>The longer you can keep them healthy and stress free, the more likely trees are to be able to cope with the summer stress and insect attacks. </p>
<p>If water restrictions are imposed in your town or city, it’s likely irrigating trees and gardens will be the first activity restricted. </p>
<p>If your plants have been kept stress free as long as possible, they are more likely to survive. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-need-urban-trees-more-than-ever-heres-how-to-save-them-from-extreme-heat-211414">We need urban trees more than ever – here's how to save them from extreme heat</a>
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<p>An irony here is that if trees are water-stressed, many species will start to defoliate by shedding leaves. That means we lose both shade and transpirational cooling when we could use them most. </p>
<p>Councils, state governments and water authorities face a dilemma in these situations. Save the water for human use? Or keep urban trees alive and reduce the risk of heat illness and death? </p>
<h2>Time to value our urban trees</h2>
<p>What this summer will show is the need for local and state governments to place greater value on their urban forests and canopy cover. </p>
<p>In many places, urban canopy cover is dropping by <a href="https://treenet.org/resource/taking-it-to-the-streets-celebrating-a-twenty-year-history-of-treenet-responding-to-the-urban-forest-challenge/">about 1-1.5% per year</a>. Many tree removals are <a href="https://treenet.org/resource/defending-and-expanding-the-urban-forest-opposing-unnecessary-tree-removal-requests/">thoughtless and unnecessary</a>. </p>
<p>Sometimes, these losses provoke outcry. Adelaide, for instance, <a href="https://www.abc.net.au/news/2022-12-02/adelaide-tree-canopy-subject-of-new-parliamentary-inquiry/101723682">has been losing</a> an estimated 75,000 trees a year in recent years. That prompted a <a href="https://www.jaynestinson.com.au/news/2022/12/4/media-release-parliamentary-inquiry-into-the-urban-forest#:%7E:text=A%20Parliamentary%20inquiry%20has%20been,severe%20in%20Adelaide's%20inner%20suburbs">parliamentary inquiry</a> into how to better protect urban forests. </p>
<p>For things to change for the better, our local governments need the ability to protect mature trees in the front and back yards of developed sites and to set out minimum areas of green space and numbers of canopy trees for new developments. </p>
<p>In most states, giving councils these powers would require changes to state planning laws. But without them, the urban forest and canopy cover of most major cities, regional centres and country towns will continue to decline. </p>
<p>With proper planning, we can have both new housing and canopy trees. If we simply aim to maximise housing, our towns and suburbs will be economically and environmentally unsustainable. </p>
<p>So when you see sick trees on our streets this spring, see them as a symptom. We need to value them. We would most certainly notice if they were gone. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/urban-patchwork-is-losing-its-green-making-our-cities-and-all-who-live-in-them-vulnerable-187161">Urban patchwork is losing its green, making our cities and all who live in them vulnerable</a>
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<img src="https://counter.theconversation.com/content/215062/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gregory Moore 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>It’s spring, but many street trees look stressed and sick. Heat and insect attack are arriving early. But our cities are also steadily losing canopy cover.Gregory Moore, Senior Research Associate, School of Ecosystem and Forest Sciences, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2151402023-10-06T01:53:35Z2023-10-06T01:53:35Z6 reasons why global temperatures are spiking right now<figure><img src="https://images.theconversation.com/files/552428/original/file-20231006-27-7ho178.jpg?ixlib=rb-1.1.0&rect=25%2C10%2C3424%2C2286&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/6gVvfQEnWtY">Jonas Weckschmied/Unsplash</a></span></figcaption></figure><p>The world is very warm right now. We’re not only seeing record temperatures, but the records are being broken by record-wide margins.</p>
<p>Take the preliminary September global-average temperature anomaly of 1.7°C above pre-industrial levels, for example. It’s an incredible 0.5°C above the previous record.</p>
<p>So why is the world so incredibly hot right now? And what does it mean for keeping our Paris Agreement targets? </p>
<p>Here are six contributing factors – with climate change the main reason temperatures are so high.</p>
<h2>1. El Niño</h2>
<p>One reason for the exceptional heat is we are in a <a href="http://www.bom.gov.au/climate/enso/#tabs=Pacific-Ocean">significant El Niño</a> that is still strengthening. During El Niño we see warming of the surface ocean over much of the tropical Pacific. This warming, and the effects of El Niño in other parts of the world, raises global average temperatures by <a href="https://www.realclimate.org/index.php/archives/2023/01/2022-updates-to-the-temperature-records/">about 0.1 to 0.2°C</a>.</p>
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Read more:
<a href="https://theconversation.com/explainer-el-nino-and-la-nina-27719">Explainer: El Niño and La Niña</a>
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<p>Taking into account the fact we’ve just come out of a triple La Niña, which cools global average temperatures slightly, and the fact this is the first major El Niño in eight years, it’s not too surprising we’re seeing unusually high temperatures at the moment.</p>
<p>Still, El Niño alone isn’t enough to explain the crazily high temperatures the world is experiencing.</p>
<h2>2. Falling pollution</h2>
<p>Air pollution from human activities cools the planet and has offset some of the warming caused by humanity’s greenhouse gas emissions. There have been efforts to reduce this pollution – since 2020 there has been an <a href="https://sdg.iisd.org/news/imo-advances-measures-to-reduce-emissions-from-international-shipping/">international agreement</a> to reduce sulphur dioxide emissions from the global shipping industry.</p>
<p>It has been speculated this cleaner air has contributed to the recent heat, particularly over the record-warm <a href="https://climate.copernicus.eu/record-breaking-north-atlantic-ocean-temperatures-contribute-extreme-marine-heatwaves">north Atlantic</a> and Pacific regions with high shipping traffic.</p>
<p>It’s likely this is contributing to the extreme high global temperatures – but only on the order of hundredths of a degree. <a href="https://www.carbonbrief.org/analysis-how-low-sulphur-shipping-rules-are-affecting-global-warming/">Recent analysis</a> suggests the effect of the 2020 shipping agreement is about an extra 0.05°C warming by 2050.</p>
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<a href="https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A smog shrouded road with motorcycles, trucks and cars barely visible through the pollution" src="https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552429/original/file-20231006-15-4t8dca.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">People pass through the rising pollution on the Delhi-Jaipur Expressway in Gurgaon, Haryana, India, on November 12 2021.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/people-pass-through-rising-pollution-on-2073480677">Shutterstock</a></span>
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<h2>3. Increasing solar activity</h2>
<p>While falling pollution levels mean more of the Sun’s energy reaches Earth’s surface, the amount of the energy the Sun emits is itself variable. There are different solar cycles, but an 11-year cycle is the most relevant one to today’s climate.</p>
<p>The Sun is becoming <a href="https://edition.cnn.com/2023/07/14/world/solar-maximum-activity-2024-scn/index.html">more active</a> from a minimum in late 2019. This is also contributing a small amount to the spike in global temperatures. Overall, increasing solar activity is contributing only hundredths of a degree at most to the recent global heat. </p>
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Read more:
<a href="https://theconversation.com/this-solar-cycle-the-suns-activity-is-more-powerful-and-surprising-than-predicted-209955">This solar cycle, the sun's activity is more powerful and surprising than predicted</a>
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<h2>4. Water vapour from Hunga Tonga eruption</h2>
<p>On January 15 2022 the underwater <a href="https://www.jpl.nasa.gov/images/pia26006-hunga-tonga-hunga-haapai-eruption">Hunga Tonga–Hunga Haʻapai volcano erupted</a> in the South Pacific Ocean, sending large amounts of water vapour high up into the upper atmosphere. Water vapour is a greenhouse gas, so increasing its concentration in the atmosphere in this way does intensify the greenhouse effect.</p>
<p>Even though the eruption happened almost two years ago, it’s still having a small warming effect on the planet. However, as with the reduced pollution and increasing solar activity, we’re talking about hundredths of a degree.</p>
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<h2>5. Bad luck</h2>
<p>We see variability in global temperatures from one year to the next even without factors like El Niño or major changes in pollution. Part of the reason this September was so extreme was likely due to weather systems being in the right place to heat the land surface.</p>
<p>When we have persistent high-pressure systems over land regions, as seen recently over places like <a href="https://www.theguardian.com/environment/2023/oct/01/autumn-heat-continues-in-europe-after-record-breaking-september">western Europe</a> and <a href="https://www.abc.net.au/news/2023-09-19/australia-weather-september-heat-records-tumble/102870294">Australia</a>, we see local temperatures rise and the conditions for unseasonable heat.</p>
<p>As water requires more energy to warm and the ocean moves around, we don’t see the same quick response in temperatures over the seas when we have high-pressure systems.</p>
<p>The positioning of weather systems warming up many land areas coupled with persistent ocean heat is likely a contributor to the global-average heat too.</p>
<h2>6. Climate change</h2>
<p>By far the biggest contributor to the overall +1.7°C global temperature anomaly is human-caused climate change. Overall, humanity’s effect on the climate has been a global warming of <a href="https://www.globalwarmingindex.org/">about 1.2°C</a>.</p>
<p>The record-high rate of greenhouse gas emissions means we should expect global warming to accelerate too.</p>
<p>While humanity’s greenhouse gas emissions explain the trend seen in September temperatures over many decades, they don’t really explain the big difference from last September (when the greenhouse effect was almost as strong as it is today) and September 2023.</p>
<p>Much of the difference between this year and last comes back to the switch from La Niña to El Niño, and the right weather systems in the right place at the right time.</p>
<h2>The upshot: we need to accelerate climate action</h2>
<p>September 2023 shows that with a combination of climate change and other factors aligning we can see alarmingly high temperatures.</p>
<p>These anomalies may appear to be above the 1.5°C global warming level referred to in the Paris Agreement, but that’s about keeping <a href="https://climateanalytics.org/briefings/understanding-the-paris-agreements-long-term-temperature-goal/">long-term global warming</a> to low levels and not individual months of heat.</p>
<p>But we are seeing the effects of climate change unfolding more and more clearly.</p>
<p>The most vulnerable are suffering the biggest impacts as wealthier nations continue to emit the largest proportion of greenhouse gases. Humanity must accelerate the path to net zero to prevent more record-shattering global temperatures and damaging extreme events.</p>
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Read more:
<a href="https://theconversation.com/net-zero-by-2050-too-late-australia-must-aim-for-2035-213973">Net zero by 2050? Too late. Australia must aim for 2035</a>
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<img src="https://counter.theconversation.com/content/215140/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew King receives funding from the National Environmental Science Program. </span></em></p>The preliminary global-average temperature anomaly for September is a shocking 1.7°C. These are the drivers of current record-breaking heat.Andrew King, Senior Lecturer in Climate Science, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2145772023-10-02T19:12:09Z2023-10-02T19:12:09ZFire authorities are better prepared for this summer. The question now is – are you?<figure><img src="https://images.theconversation.com/files/551324/original/file-20231002-15-d4sb4s.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4281%2C2848&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>Last year, campers had to evacuate <a href="https://www.thegreynomads.com.au/caves-2/">because of floods</a>. This year, they’re evacuating because of fire. Over Victoria’s long weekend, campers and residents in Gippsland had to <a href="https://www.abc.net.au/news/2023-10-01/gippsland-fires-burn-briagolong-loch-sport-erica/102922014">flee fast-moving fires</a>, driven by high winds. </p>
<p>The megafires of the 2019–2020 Black Summer came off the back of an earlier El Niño climate cycle. Now, after three years of rain and floods, El Niño is arriving on Australian shores again. With it comes fire weather – hot, dry and windy. </p>
<p>The question is – <a href="https://www.thesaturdaypaper.com.au/comment/topic/2023/09/30/climate-change-and-the-fire-season-ahead#mtr">are we ready?</a> </p>
<p>Last week, emergency management minister Murray Watt moved to reassure an anxious country. “Australia is much better prepared for this season than we were heading into Black Summer,” he said, <a href="https://www.abc.net.au/news/2023-09-24/australia-better-prepared-for-bushfire-threat-than-black-summer/102895018">speaking after</a> a national summit on disaster preparedness. </p>
<p>Yes, authorities are better prepared. But by and large, we as individuals are not. Far too often, Australians think it’s the job of the authorities to be ready, which breeds a false sense of security. </p>
<h2>This fire season may pack a punch</h2>
<p>The Black Summer bushfires of the 2019–20 summer were a stark reminder of how fire prone Australia is. But they were more than that – they <a href="https://theconversation.com/australias-black-summer-of-fire-was-not-normal-and-we-can-prove-it-172506">were not normal</a>. Around 20% of all of our forests went up in flame. </p>
<p>2019 was the <a href="https://www.newscientist.com/article/2019-2019-was-australias-hottest-and-driest-year-on-record/#:%7E:text=Last%20year%20was%20Australia's%20hottest,are%20the%20worst%20on%20record.">hottest and driest</a> year on record for Australia. But 2023 <a href="https://www.theguardian.com/environment/2023/sep/01/australia-records-warmest-winter-caused-by-global-heating-and-sunny-conditions">may break that record</a>, as climate records topple around the world and extreme weather events multiply. This year is likely to be the hottest on record globally, and next year the record <a href="https://www.climatecouncil.org.au/resources/what-the-return-of-el-nino-means/#:%7E:text=Looking%20ahead%20%E2%80%93%20with%20El%20Ni%C3%B1o,above%20the%20pre%2Dindustrial%20average">may well fall again</a>. </p>
<p>Sustained rain from three successive La Niña years has driven widespread vegetation growth across Australia’s 125 million hectares of forest, bush and grasslands. Over the coming weeks, many areas could dry out quickly and become tinder for bushfires. </p>
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Read more:
<a href="https://theconversation.com/worried-about-heat-and-fire-this-summer-heres-how-to-prepare-212443">Worried about heat and fire this summer? Here's how to prepare</a>
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<h2>Climate cycles do give us time to prepare</h2>
<p>Australia’s wet-dry climate cycles have one benefit – during wet years, fire authorities get a reprieve. That lets governments, emergency services and the community <a href="https://www.abc.net.au/news/2023-09-22/bushfire-royal-commission-revisited-after-el-nino-weather/102880144">coordinate, plan and prepare</a> for bushfire seasons ahead. </p>
<p>That’s why Minister Watt can accurately claim Australia is better prepared. The capacity and capability of our emergency services to predict the spread of fires and issue timely warnings to communities is better than it has ever been. In planning and preparedness for natural hazards such as bushfires and floods, we have seen <a href="https://nema.gov.au/about-us/media-centre/Preparedness-Summit-250923">better integration</a> between government, emergency services, civil and private sector organisations.</p>
<p>Planned burning is still a challenge. It’s tough to find the right weather conditions to burn off fuel loads at low intensity, without risking the blaze spreading or threatening property. </p>
<p>But these burns are done much more <a href="https://knowledge.aidr.org.au/resources/ajem-october-2020-searching-for-objectivity-in-burning/">strategically these days</a>. Rather than simply aim to hit a target of hectares burned, authorities are now focused on burning fuel in areas where it could endanger lives and damage critical infrastructure during bushfire season.</p>
<p>These advances give us good reason for confidence. But not for complacency. </p>
<p>Every bushfire is unique. And our fires are, by and large, <a href="https://www.nature.com/articles/s41467-021-27225-4">getting worse</a>. It would be an error to think our investment in <a href="https://reporter.anu.edu.au/all-stories/fighting-fires-from-space-how-satellites-and-other-tech-could-prevent-catastrophic-bushfires">smoke-detecting algorithms and satellite monitoring</a> and the development of the new <a href="https://afdrs.com.au/">Australian Fire Danger Rating System</a> will spare Australia from the loss of life, property and environmental destruction observed during the Black Summer fires. </p>
<p>Why? Decades of bushfires have shown even the best preparation can be found wanting on days of severe bushfire danger when firestorms can develop quickly and behave unpredictably.</p>
<h2>For Australia to be ready, you need to be ready</h2>
<p>While megafires happen – and draw the most headlines – most bushfires are local rather than national events. </p>
<p>That means we must prepare at a local level.</p>
<p>If you’re faced with a bushfire threat, you have only <a href="https://onlinelibrary.wiley.com/doi/10.1111/1467-8500.12592">two options</a>. </p>
<p>You can stay and defend your property – as long as you are physically and mentally prepared, have adequate firefighting resources, and your property is prepared and defensible. </p>
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Read more:
<a href="https://theconversation.com/fire-regimes-around-australia-shifted-abruptly-20-years-ago-and-falling-humidity-is-why-209689">Fire regimes around Australia shifted abruptly 20 years ago – and falling humidity is why</a>
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<p>Or you can leave early, which means making a judgement call about the best time to go in a calm manner. That doesn’t mean panic – if there is time, it can be possible to do things like clear fuels from around the home and dampen the surrounds to give your house a better chance of surviving undefended.</p>
<p>Which should you choose? It depends, in part, on where you live and your personal circumstances. Remember too that most Australians will never experience a bushfire firsthand. </p>
<p>Every community has a different risk profile and people and communities vary considerably in their levels of preparedness and planning. </p>
<p>If a fire does start and head towards your house, you could be taken entirely by surprise if you have no bushfire plan. </p>
<p>To be clear, this is arguably the <a href="https://theconversation.com/how-to-prepare-your-home-for-a-bushfire-and-when-to-leave-50962#:%7E:text=Under%20Catastrophic%20fire%20conditions%20all,of%20bushfires%20and%20their%20unpredictability.">largest gap</a> in Australia’s fire preparedness. </p>
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<a href="https://images.theconversation.com/files/551322/original/file-20231002-15-6vcwli.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5551%2C3650&q=45&auto=format&w=1000&fit=clip"><img alt="burned forest near road" src="https://images.theconversation.com/files/551322/original/file-20231002-15-6vcwli.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5551%2C3650&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/551322/original/file-20231002-15-6vcwli.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/551322/original/file-20231002-15-6vcwli.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/551322/original/file-20231002-15-6vcwli.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/551322/original/file-20231002-15-6vcwli.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/551322/original/file-20231002-15-6vcwli.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/551322/original/file-20231002-15-6vcwli.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Which way out? Planning ahead could save your life.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<h2>Planning is easy – if done ahead</h2>
<p>The question of whether Australia is ready for the fire season should be reframed. The better question is: are Australians ready? </p>
<p>The good news is, it’s easier than you think to make a fire plan. As a household, it might take just 10 minutes. Your state or territory government has a website showing you how: </p>
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<li><a href="https://www.cfa.vic.gov.au/plan-prepare/before-and-during-a-fire/your-bushfire-plan">Victoria</a></li>
<li><a href="https://www.rfs.nsw.gov.au/resources/bush-fire-survival-plan">New South Wales</a></li>
<li><a href="https://bushfire-survival-plan.qfes.qld.gov.au/">Queensland</a></li>
<li><a href="https://www.cfs.sa.gov.au/plan-prepare/before-a-fire-be-prepared/make-a-plan/5-minute-bushfire-plan/">South Australia</a></li>
<li><a href="https://mybushfireplan.wa.gov.au/">Western Australia</a></li>
<li><a href="https://esa.act.gov.au/cbr-be-emergency-ready/bushfires/bushfire-ready">Australian Capital Territory</a></li>
<li><a href="https://securent.nt.gov.au/prepare-for-an-emergency/fires/bushfires/survival-plans">Northern Territory</a></li>
<li><a href="https://www.fire.tas.gov.au/Show?pageId=colbushfirePrepareActSurvive&fbclid=IwAR1mRkwm89K_SlAnUXUm0LYwAQ7Hc8moJ7c9AoNgkmdPVDxxIPx7WMLJzvk">Tasmania</a></li>
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<p>Why plan ahead? Because it is vastly better to have a clear plan at your fingertips rather than frantically trying to figure out where your loved ones are, whether it’s too late to leave and whether you could realistically fight the fire – when the fire is on your doorstep. Faced by the reality of fire, many of us can freeze. </p>
<p>What firefighters <a href="https://theconversation.com/i-can-still-picture-the-faces-black-saturday-firefighters-want-you-to-listen-to-them-not-call-them-heroes-128632">want us to learn</a> is that the critical decisions and actions which save lives and property in a bushfire are taken by us and our communities, not by politicians or agencies. </p>
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Read more:
<a href="https://theconversation.com/australias-black-summer-of-fire-was-not-normal-and-we-can-prove-it-172506">Australia's Black Summer of fire was not normal – and we can prove it</a>
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<p><em>John Schauble contributed significantly to this article. He has worked extensively in bushfire policy and research at state level and has volunteered for over 40 years as a firefighter.</em></p><img src="https://counter.theconversation.com/content/214577/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Graham Dwyer receives funding from Natural Hazards Research Australia and the Australian Research Council. </span></em></p>Many people are asking if Australian authorities are ready for the fire season. The real question to ask is – are we ready as individuals?Graham Dwyer, Course Director, Centre for Social Impact, Swinburne University of Technology, Swinburne University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2139872023-09-28T01:55:39Z2023-09-28T01:55:39Z4 ways to support someone with dementia during extreme heat<figure><img src="https://images.theconversation.com/files/550476/original/file-20230927-21-7h3iw5.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1000%2C666&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/elderly-woman-sitting-soffa-using-hand-2337887847">Shutterstock</a></span></figcaption></figure><p>Our ability to adapt our behaviour to changes in temperature takes a significant amount of thought and decision making. For example, we need to identify suitable clothing, increase our fluid intake, and understand how to best keep the house cool. </p>
<p>A person with dementia may find some or all these things challenging. These and other factors mean, for someone with dementia, extreme heat <a href="https://pubmed.ncbi.nlm.nih.gov/31520832/#:%7E:text=Conclusion%3A%20Heatwaves%20increased%20the%20risk,heat%2Drelated%20Alzheimer's%20disease%20burden.">can be deadly</a>.</p>
<p>But as the temperature rises, friends, relatives and carers can help.</p>
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Read more:
<a href="https://theconversation.com/5-reasons-to-check-on-your-elderly-neighbour-during-a-heatwave-196218">5 reasons to check on your elderly neighbour during a heatwave</a>
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<h2>El Niño means there are challenges ahead</h2>
<p>The recent declaration of <a href="https://www.abc.net.au/news/2023-09-19/bureau-of-meteorology-el-nino-blog/102875154">another El Niño</a> means we need to think about how we can best support those more vulnerable to be safe during the warmer months.</p>
<p>Extreme heat and bushfires bring unique challenges for someone with dementia.</p>
<p>Bushfires have a significant impact on older people’s mental health. But they generally <a href="https://www.health.act.gov.au/sites/default/files/2023-03/PATH_Impact%20of%202019-20%20Bushfires%20on%20a%20Cohort%20of%20Older%20Adults_REPORT_V3_0.pdf">bounce back</a> quickly. </p>
<p>However, for someone with dementia, extreme heat can lead to a <a href="https://www.sciencedirect.com/science/article/pii/S0013935119305110">significant deterioration</a> in their overall health and they may not recover. </p>
<p>Emergency evacuations can also be confusing and distressing for a person with dementia, so it is important to think ahead.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/worried-about-heat-and-fire-this-summer-heres-how-to-prepare-212443">Worried about heat and fire this summer? Here's how to prepare</a>
</strong>
</em>
</p>
<hr>
<h2>Why are people with dementia more at risk?</h2>
<p>Dementia can affect the parts of the brain that help <a href="https://academic.oup.com/brain/article/138/11/3360/332653?login=true">regulate</a> our body temperature. Some <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0243665">medications</a> can also increase someone’s sensitivity to heat. </p>
<p>Problems with memory and thinking associated with dementia <a href="https://www.alzheimers.org.uk/get-support/daily-living/drinking-hydration">means</a> remembering to drink or communicating you are thirsty can be challenging.</p>
<p>Heat can affect everyone’s mood. But if someone with dementia becomes dehydrated this can <a href="https://www.alzdiscovery.org/cognitive-vitality/blog/can-dehydration-impair-cognitive-function">increase</a> confusion and agitation, making it harder for them to know how to cool down.</p>
<p>A person with dementia can also wander and become lost, which can be dangerous in extreme heat.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1585508043772436480"}"></div></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/is-my-medicine-making-me-feel-hotter-this-summer-5-reasons-why-199085">Is my medicine making me feel hotter this summer? 5 reasons why</a>
</strong>
</em>
</p>
<hr>
<h2>4 ways to support someone with dementia</h2>
<p><strong>1. Avoid dehydration and heatstroke</strong></p>
<p>Try to avoid dehydration by encouraging someone to drink throughout the day. It’s better to have <a href="https://pubmed.ncbi.nlm.nih.gov/31769256/">small amounts</a> of liquid regularly instead of a large amount all at once. Little and often will help maximise hydration while avoiding sudden trips to <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/dementia-continence-issues#causes-of-incontinence-in-people-with-dementia">the bathroom</a>.</p>
<p>Try to offer different types of drinks, or ice blocks. Placing drinks in sight can help as a reminder to drink. Choose foods with a high liquid content, such as fruit, salads, cool broths and yoghurt. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/550474/original/file-20230927-15-4jij0o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Older man eating icecream, sitting outside with walking stick" src="https://images.theconversation.com/files/550474/original/file-20230927-15-4jij0o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/550474/original/file-20230927-15-4jij0o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/550474/original/file-20230927-15-4jij0o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/550474/original/file-20230927-15-4jij0o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/550474/original/file-20230927-15-4jij0o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/550474/original/file-20230927-15-4jij0o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/550474/original/file-20230927-15-4jij0o.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">Cooler foods, or ones containing lots of liquid, will help.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/portrait-senior-man-walking-cane-eating-2366409675">Shutterstock</a></span>
</figcaption>
</figure>
<p>Look out for <a href="https://www.nia.nih.gov/health/hot-weather-safety-older-adults#:%7E:text=Signs%20of%20heat%20stroke%20are,as%20under%20shade%20or%20indoors.">signs of heatstroke</a>, such as increased confusion beyond what the person would usually experience. Heatstroke may be more difficult to spot in someone living with dementia so it is important to check in when possible and to help them cool down if needed.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-how-do-i-tell-if-im-dehydrated-107437">Health Check: how do I tell if I'm dehydrated?</a>
</strong>
</em>
</p>
<hr>
<p><strong>2. Cool the home</strong></p>
<p>Try to modify their home to make it easier to stay cool. Some air-conditioners have complex settings so make sure the temperature is set appropriately and the person with dementia knows how to use the controls. </p>
<p>It is important to keep blinds and curtains shut where possible to reduce heat. However, ensure the <a href="https://www.scie.org.uk/dementia/supporting-people-with-dementia/dementia-friendly-environments/lighting.asp">lighting is adequate</a> to avoid falls.</p>
<p>Try to support the person to make suitable clothing choices for the season by having cool, lightweight options easily available.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-delirium-194631">What is delirium?</a>
</strong>
</em>
</p>
<hr>
<p><strong>3. Think about communications early</strong></p>
<p>If someone with dementia lives alone, consider how you will maintain contact in an emergency.</p>
<p>Some people may not realise many landlines don’t work in a power outage, and of course, mobile phones can’t be recharged. Ensure the person with dementia has access to an <a href="https://www.telstra.com.au/support/category/home-phone/uninterruptible-power-supply">uninterruptable power supply</a>. This can help maintain communication for a few hours in a blackout. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/550481/original/file-20230927-21-a77bl1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Older woman using smartphone at home, next to window" src="https://images.theconversation.com/files/550481/original/file-20230927-21-a77bl1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/550481/original/file-20230927-21-a77bl1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/550481/original/file-20230927-21-a77bl1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/550481/original/file-20230927-21-a77bl1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/550481/original/file-20230927-21-a77bl1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/550481/original/file-20230927-21-a77bl1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/550481/original/file-20230927-21-a77bl1.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">You cannot always rely on phones in an emergency.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/old-woman-uses-smart-phone-623448185">Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-people-with-dementia-dont-all-behave-the-same-100960">Why people with dementia don't all behave the same</a>
</strong>
</em>
</p>
<hr>
<p><strong>4. Have an evacuation plan</strong></p>
<p>In case of fire, flash flooding or severe storm, <a href="https://dementiaresearch.org.au/wp-content/uploads/2017/10/2447_DCRC_Prep_natural_disaster_EBook_5.pdf">have an evacuation plan</a>. If the person with dementia attends a day or respite centre, know their plan too.</p>
<p>The situation can change quickly in an emergency, and this can be particularly overwhelming for people with cognitive issues. </p>
<p>Understand that someone with dementia may become distressed when their routine is disrupted. So be prepared with some simple activities or comfort items, current medications, and any specific medical information. </p>
<p>Stay up-to-date with <a href="http://www.bom.gov.au/">current warnings</a> and act early whenever possible.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/floods-and-other-emergencies-can-be-extra-tough-for-people-with-dementia-and-their-carers-heres-how-to-help-193096">Floods and other emergencies can be extra tough for people with dementia and their carers. Here's how to help</a>
</strong>
</em>
</p>
<hr>
<h2>We can all help</h2>
<p>It’s not just carers of people with dementia who can help. We can all ensure people with dementia stay safe and cool this spring and summer. </p>
<p>So remember to check in on your relatives, friends and neighbours or arrange for someone to do so on your behalf.</p><img src="https://counter.theconversation.com/content/213987/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nikki-Anne Wilson receives funding from the Australian Association of Gerontology and the UNSW Ageing Futures Institute. </span></em></p>Extreme heat and bushfires bring unique challenges for someone with dementia. Here’s how we can all play a part in helping them stay safe and cool this spring and summer.Nikki-Anne Wilson, Postdoctoral Research Fellow, Neuroscience Research Australia (NeuRA), UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2114142023-09-24T20:02:08Z2023-09-24T20:02:08ZWe need urban trees more than ever – here’s how to save them from extreme heat<figure><img src="https://images.theconversation.com/files/549744/original/file-20230922-17-ju4303.jpeg?ixlib=rb-1.1.0&rect=701%2C0%2C11902%2C6019&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/blurred-sun-on-hot-climate-red-1650322804">Torychemistry, Shutterstock</a></span></figcaption></figure><p>Australians are bracing for a hot spring and summer. The Bureau of Meteorology has finally <a href="https://media.bom.gov.au/releases/1183/the-bureau-declares-el-nino-and-positive-indian-ocean-dipole-events/">declared El Niño is underway</a>, making warmer and drier conditions more likely for large parts of the country. And we’ve just watched the Northern Hemisphere swelter through their summer, making July 2023 Earth’s <a href="https://public.wmo.int/en/media/news/july-2023-confirmed-hottest-month-record">hottest month on record</a>. </p>
<p>We studied the effects of extreme heat on urban trees in Western Sydney during Australia’s record-breaking summer of 2019–20. So we hold grave concerns for the survival of both native Australian and exotic species in our <a href="https://nph.onlinelibrary.wiley.com/doi/10.1002/ppp3.10240">urban forest</a>. These stands of trees and shrubs – along streets and in parks, gardens, and yards – play vital roles in our cities. Trees improve people’s mental health and wellbeing, lower energy use, and reduce temperatures through shading and evaporative cooling.</p>
<p>In previous research, we compared the <a href="https://www.sciencedirect.com/science/article/pii/S0048969722050148">heat tolerance of different species</a>. Our new research, published in the journal Global Change Biology, assessed their water use. Most of the trees we measured <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.16929">lost more water on hot days than models predicted</a>. </p>
<p>Much like <a href="https://www.scientificamerican.com/article/trees-sweat-to-keep-cool/">sweating in humans</a>, trees <a href="https://doi.org/10.1111/gcb.14037">lose water to keep cool</a>. If there’s not enough water, dieback or tree death occurs. This means access to water will be crucial for the survival of our urban forests during the hot summer ahead.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/549729/original/file-20230922-23-l8zvwg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of a city street in western Sydney showing London plane trees with scorched leaves during the 2019-20 summer." src="https://images.theconversation.com/files/549729/original/file-20230922-23-l8zvwg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/549729/original/file-20230922-23-l8zvwg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=387&fit=crop&dpr=1 600w, https://images.theconversation.com/files/549729/original/file-20230922-23-l8zvwg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=387&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/549729/original/file-20230922-23-l8zvwg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=387&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/549729/original/file-20230922-23-l8zvwg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=487&fit=crop&dpr=1 754w, https://images.theconversation.com/files/549729/original/file-20230922-23-l8zvwg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=487&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/549729/original/file-20230922-23-l8zvwg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=487&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">London plane trees in western Sydney lost leaves during the hot, dry 2019-20 summer.</span>
<span class="attribution"><span class="source">Renee Prokopavicius</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/climate-change-threatens-up-to-100-of-trees-in-australian-cities-and-most-urban-species-worldwide-188807">Climate change threatens up to 100% of trees in Australian cities, and most urban species worldwide</a>
</strong>
</em>
</p>
<hr>
<h2>Trees during heatwaves in Sydney</h2>
<p>During December 2019 and January 2020, Western Sydney had 12 days over 40°C. The city’s record maximum temperature of 48.9°C was set on January 4, 2020.</p>
<p>We <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.16929">measured carbon uptake and water loss</a> from urban tree leaves on these hot summer days. </p>
<p>We found some species had low heat tolerance. Those <a href="https://www.sciencedirect.com/science/article/pii/S0048969722050148">most vulnerable to heatwaves</a> included both native Australian and exotic species. Some trees died, including red maple (<em>Acer rubrum</em>), tulip poplar (<em>Liriodendron tulipifera</em>), coast banksia (<em>Banksia integrifolia</em>) and water gum (<em>Tristaniopsis laurina</em>). Others did not die but suffered to such an extent they were later removed. </p>
<p>In contrast, Chinese elm (<em>Ulmus parvifolia</em>) and ash (<em>Fraxinus excelsior</em>) avoided excessive dieback or death, as did the native weeping bottlebrush (<em>Callistemon viminalis</em>) and kurrajong (<em>Brachychiton populneus</em>).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/549726/original/file-20230922-25-qbsw4a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Closeup photo showing heat damage in maple leaves, which are especially vulnerable because they are large and thin" src="https://images.theconversation.com/files/549726/original/file-20230922-25-qbsw4a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/549726/original/file-20230922-25-qbsw4a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/549726/original/file-20230922-25-qbsw4a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/549726/original/file-20230922-25-qbsw4a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/549726/original/file-20230922-25-qbsw4a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/549726/original/file-20230922-25-qbsw4a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/549726/original/file-20230922-25-qbsw4a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Large, thin maple leaves are particularly vulnerable to damage from heat.</span>
<span class="attribution"><span class="source">Renee Prokopavicius</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/without-urgent-action-these-are-the-street-trees-unlikely-to-survive-climate-change-172758">Without urgent action, these are the street trees unlikely to survive climate change</a>
</strong>
</em>
</p>
<hr>
<h2>Why are some species more vulnerable?</h2>
<p>Some species are inherently less heat and drought tolerant. For example, species with <a href="https://www.sciencedirect.com/science/article/pii/S0048969722050148">large, thin leaves</a> are particularly vulnerable. Large leaves have thicker insulating boundary layers and so release heat more slowly. Thin leaves are less able to buffer against overheating on hot, sunny days when the wind lulls.</p>
<p>But it can be hard to predict how individual trees will respond to heat stress. That’s because access to water is important, but changes over time.</p>
<p>Trees with enough water can usually tolerate high temperatures. Microscopic pores in the leaves called stomata open up, allowing water vapour to pass through. This cools the plant down.</p>
<p>In drought, trees conserve water by closing these pores. This causes tree leaves to heat up. When hot days occur during drought, tree leaves can reach lethal temperatures above 45°C. </p>
<p>Our research found most urban tree species –- even those under drought stress –- <a href="https://onlinelibrary.wiley.com/doi/10.1111/gcb.14037">opened their pores to cool leaves</a> on hot summer days. This results in rapid water loss but may help prevent tree leaves from scorching. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/549722/original/file-20230922-19-k8tzko.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Closeup photo showing Renee Prokopavicius using a thermal camera to measure leaf temperature" src="https://images.theconversation.com/files/549722/original/file-20230922-19-k8tzko.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/549722/original/file-20230922-19-k8tzko.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=372&fit=crop&dpr=1 600w, https://images.theconversation.com/files/549722/original/file-20230922-19-k8tzko.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=372&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/549722/original/file-20230922-19-k8tzko.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=372&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/549722/original/file-20230922-19-k8tzko.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=467&fit=crop&dpr=1 754w, https://images.theconversation.com/files/549722/original/file-20230922-19-k8tzko.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=467&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/549722/original/file-20230922-19-k8tzko.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=467&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Renee Prokopavicius uses a thermal camera to measure leaf temperature.</span>
<span class="attribution"><span class="source">Laura Dillon</span></span>
</figcaption>
</figure>
<h2>Why is water so important during heatwaves?</h2>
<p>As part of the latest research, we grew seedlings in a glasshouse to test how access to water affected heat tolerance. We kept half the plants well watered and exposed the rest to drought conditions. </p>
<p>We found <a href="https://onlinelibrary.wiley.com/doi/10.1111/gcb.14037">water loss was higher</a> than predicted during heatwaves for all plants. </p>
<p>For well-watered trees and shrubs, water loss was 23% higher than predicted. This kept leaves nearly 1°C cooler than the air temperature. </p>
<p>Thirsty plant leaves were more than 1°C hotter than the air temperature.</p>
<p>In urban trees, leaves reached lethal temperatures of 49–50°C for species with the lowest rates of water loss. But when species with low rates of water loss had access to water, there was little heat damage or scorched leaves. For trees that lost foliage due to overheating, their recovery took multiple years after the end of drought and return of average temperatures. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/548691/original/file-20230917-23-d74j1q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo showing Western Sydney University student Nicholas Spurr collecting leaf temperature data on a hot day in Penrith, taken from behind" src="https://images.theconversation.com/files/548691/original/file-20230917-23-d74j1q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/548691/original/file-20230917-23-d74j1q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/548691/original/file-20230917-23-d74j1q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/548691/original/file-20230917-23-d74j1q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/548691/original/file-20230917-23-d74j1q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/548691/original/file-20230917-23-d74j1q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/548691/original/file-20230917-23-d74j1q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Western Sydney University student Nicholas Spurr collecting leaf temperature data on a hot day in Penrith.</span>
<span class="attribution"><span class="source">Renee Prokopavicius</span></span>
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<h2>Preserving our natural air conditioners</h2>
<p>Our research shows access to water is crucial for the survival of urban trees during heatwaves. </p>
<p>That means urban greening programs need to find ways to provide trees with enough water when rainfall is unreliable. </p>
<p>It’s worth exploring new techniques such as <a href="https://wsroc.com.au/projects/project-turn-down-the-heat/turn-down-the-heat-resources-5">passive irrigation storage pits</a> and <a href="https://www.sydneywater.com.au/content/dam/sydneywater/documents/urban-typologies-and-stormwater-management-part-2.pdf">raingardens</a>. Passive irrigation pits capture and store stormwater in underground trenches. This both decreases runoff during storms and provides water for trees. Raingardens also naturally reduce stormwater runoff and use plants to filter pollutants from rainfall. </p>
<p>Providing trees with the water they need to keep cool on hot summer days will not only improve their chances of survival, but also protect people. Cities need trees now more than ever, as these natural air conditioners take the edge off the extremes. </p>
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Read more:
<a href="https://theconversation.com/the-illegal-killing-of-265-trees-on-sydneys-north-shore-is-not-just-vandalism-its-theft-on-a-grand-scale-212844">The illegal killing of 265 trees on Sydney's North Shore is not just vandalism. It's theft on a grand scale</a>
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<p class="fine-print"><em><span>Renée M Prokopavicius receives funding from the Australian Research Council, the New South Wales Government, and Hort Innovation. </span></em></p><p class="fine-print"><em><span>Belinda Medlyn receives funding from the Australian Research Council, the NSW Government, the Victorian Country Fire Authority, Bush Heritage Australia, Arid Recovery, and the Australian Citizen Science Association. She is a member of the Scientific Advisory Panel for Land Life Company. </span></em></p><p class="fine-print"><em><span>David S Ellsworth receives funding from the Australian Research Council, the New South Wales Government, Hort Innovation, and the Herman Slade Foundation.</span></em></p><p class="fine-print"><em><span>Mark G Tjoelker receives funding from the Australian Research Council, the New South Wales Government, Hort Innovation, the Herman Slade Foundation and the Australian Citizen Science Association. He is affiliated with Standards Australia. </span></em></p>New research reveals how trees respond to extreme heat. Most trees lose more water than models predict. Some species cope better than others. Access to water will be critical for the hot summer ahead.Renée M Prokopavicius, Postdoctoral Researcher in Plant Ecophysiology, Western Sydney UniversityBelinda Medlyn, Distinguished Professor, Ecosystem Function and Integration, Western Sydney UniversityDavid S Ellsworth, Professor of Plant Eco-physiology, Western Sydney UniversityMark G Tjoelker, Professor and Associate Director, Hawkesbury Institute for the Environment, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2130212023-09-13T12:29:10Z2023-09-13T12:29:10ZSummer 2023 was the hottest on record – yes, it’s climate change, but don’t call it ‘the new normal’<figure><img src="https://images.theconversation.com/files/547640/original/file-20230911-15-wqiow8.jpg?ixlib=rb-1.1.0&rect=581%2C29%2C4255%2C2815&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Kansas City's baseball stadium ran misters to cool people off in heat near 100 degrees on June 28, 2023.</span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/HeatWaveMissouri/b3807c6f1e034556b1a829164b3f831d/photo">AP Photo/Charlie Riedel</a></span></figcaption></figure><p>Summer 2023 was the <a href="https://public.wmo.int/en/media/press-release/earth-had-hottest-three-month-period-record-unprecedented-sea-surface">hottest on record</a> by <a href="https://www.noaa.gov/news/world-just-sweltered-through-its-hottest-august-on-record">a huge margin</a>. Hundreds of millions of people suffered as <a href="https://climate.copernicus.eu/surface-air-temperature-august-2023">heat waves</a> cooked Europe, Japan, Texas and the Southwestern U.S. <a href="https://www.pbs.org/newshour/nation/phoenix-hit-110-degrees-on-54-days-in-2023-setting-another-heat-record">Phoenix hit 110 degrees Fahrenheit</a> (43 degrees Celsius) for a record 54 days, including a 31-day streak in July. <a href="https://www.aljazeera.com/news/2023/8/23/mapping-the-scale-of-canadas-record-wildfires">Large parts of Canada</a> were on fire. Lahaina, Hawaii, <a href="https://www.washingtonpost.com/weather/2023/08/12/hawaii-fires-climate-change-maui/">burned to the ground</a>.</p>
<p>As <a href="https://www.atmos.colostate.edu/people/faculty/denning/">an atmospheric scientist</a>, I get asked at least once a week if the wild weather we’ve been having is “caused” by climate change. This question reflects a misunderstanding of the <a href="https://www.ncei.noaa.gov/news/weather-vs-climate">difference between weather and climate</a>. </p>
<p>Consider this analogy from the world of sports: Suppose a baseball player is having a great season, and his batting average is twice what it was last year. If he hits a ball out of the park on Tuesday, we don’t ask whether he got that hit because his batting average has risen. His average has gone up because of the hits, not the other way around. Perhaps the Tuesday homer resulted from a fat pitch, or the wind breaking just right, or because he was well rested that day. But if his batting average has doubled since last season, <a href="https://youtu.be/MW3b8jSX7ec?feature=shared">we might reasonably ask if he’s on steroids</a>.</p>
<p>Unprecedented heat and downpours and drought and wildfires aren’t “caused by climate change” – they are climate change. </p>
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<p>The rise in <a href="https://www.climate.gov/news-features/event-tracker/record-breaking-june-2021-heatwave-impacts-us-west">frequency and intensity of extreme events</a> is by definition a change in the climate, just as an increase in the frequency of base hits causes a better’s average to rise. </p>
<p>And as in the baseball analogy, we should ask tough questions about the underlying cause. While El Niño is a contributor to 2023’s extreme heat, <a href="https://theconversation.com/el-nino-is-back-thats-good-news-or-bad-news-depending-on-where-you-live-205974">that warm event</a> has only just begun. The steroids fueling extreme weather are the <a href="https://climate.nasa.gov/causes/">heat-trapping gases from burning coal, oil and gas</a> for energy around the world.</p>
<h2>Nothing ‘normal’ about it</h2>
<p>A lot of commentary uses the framing of a “<a href="https://www.wsj.com/us-news/climate-environment/heat-floods-fire-was-summer-2023-the-new-normal-2df9bc21">new normal</a>,” as if our climate has undergone a step change to a new state. This is deeply misleading and downplays the danger. The unspoken implication of “new normal” is that the change is past and we can adjust to it as we did to the “old normal.” </p>
<p>Unfortunately, warming won’t stop this year or next. The changes will get worse until we stop putting more carbon dioxide and other greenhouse gases into the atmosphere <a href="https://oceanservice.noaa.gov/facts/carbon-cycle.html">than the planet can remove</a>.</p>
<p>The excess carbon dioxide humans have put into the atmosphere raises the temperature – permanently, as far as human history is concerned. Carbon dioxide lingers in the atmosphere for a long time, so long that the carbon dioxide from a gallon of gasoline I burn today will still be warming the climate <a href="https://doi.org/10.1007/s10584-008-9413-1">in thousands of years</a>.</p>
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<p>That warming increases evaporation from the planet’s surface, putting more moisture into the atmosphere to fall as rain and snow. Locally intense rainfall has <a href="https://science2017.globalchange.gov/chapter/7/">more water vapor to work with in a warmer world</a>, so big storms drop more rain, <a href="https://www.nytimes.com/2023/09/05/world/europe/greece-flooding-rain.html">causing dangerous floods</a> and mudslides like the ones we saw in <a href="https://theconversation.com/how-climate-change-intensifies-the-water-cycle-fueling-extreme-rainfall-and-flooding-the-northeast-deluge-was-just-the-latest-209476">Vermont</a>, <a href="https://theconversation.com/epic-snow-from-all-those-atmospheric-rivers-in-the-west-is-starting-to-melt-and-the-flood-danger-is-rising-203874">California</a>, <a href="https://apnews.com/article/india-himalayan-deadly-floods-landslides-rains-9d1c22cb9deb72d4fd40e18fc88252d3">India</a> and other places around the world this year.</p>
<p>By the same token, anybody who’s ever watered the lawn or a garden knows that in hot weather, plants and soils need more water. A hotter world also has <a href="https://www.nasa.gov/feature/warming-makes-droughts-extreme-wet-events-more-frequent-intense">more droughts</a> and <a href="https://www.noaa.gov/noaa-wildfire/wildfire-climate-connection">drying that can lead to wildfires</a>.</p>
<h2>So, what can we do about it?</h2>
<p>Not every kind of bad weather is <a href="https://theconversation.com/extreme-heat-waves-in-a-warming-world-dont-just-break-records-they-shatter-them-164919">associated with burning carbon</a>. There’s scant evidence that hailstorms or tornadoes or blizzards are on the increase, for example. But if summer 2023 shows us anything, it’s that the extremes that are caused by fossil fuels are uncomfortable at best and often dangerous.</p>
<p>Without drastic emission cuts, the direct cost of flooding has been projected to rise to <a href="https://doi.org/10.1088/1748-9326/aacc76">more than US$14 trillion per year</a> by the end of the century and sea-level rise to <a href="https://news.cornell.edu/stories/2017/06/rising-seas-could-result-2-billion-refugees-2100">produce billions of refugees</a>. By one estimate, unmitigated climate change could reduce per capita income by nearly a quarter by the end of the century globally and even <a href="https://doi.org/10.1038/nature15725">more in the Global South</a> if future adaptation is similar to what it’s been in the past. The potential social and political consequences of economic collapse on such a scale are incalculable. </p>
<p>Fortunately, it’s quite clear how to stop making the problem worse: Re-engineer the world economy so that it no longer runs on carbon combustion. This is a big ask, for sure, but there are affordable alternatives. </p>
<p>Clean energy is <a href="https://www.utilitydive.com/news/renewables-cheaper-energy-than-99-percent-of-us-coal-plants-just-energy-transition/642393/">already cheaper than old-fashioned combustion</a> in most of the world. <a href="https://about.bnef.com/blog/cost-of-clean-energy-technologies-drop-as-expensive-debt-offset-by-cooling-commodity-prices/">Solar and wind power</a> are now about half the price of coal- and gas-fired power. New methods for transmitting and storing power and balancing supply and demand to eliminate the need for fossil fuel electricity generation are coming online around the world. </p>
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<p>In 2022, taxpayers spent about $7 trillion <a href="https://www.imf.org/en/Publications/WP/Issues/2023/08/22/IMF-Fossil-Fuel-Subsidies-Data-2023-Update-537281">subsidizing oil and gas purchases and paying for damage they caused</a>. All that money can go to better uses. For example, the International Energy Agency has estimated the world would need to spend about <a href="https://www.iea.org/reports/world-energy-outlook-2022">$4 trillion a year by 2030</a> on clean energy to cut global emissions to <a href="https://www.un.org/en/climatechange/net-zero-coalition">net zero by midcentury</a>, considered necessary to keep global warming in check. </p>
<p>Just as the summer of 2023 was among the hottest in thousands of years, 2024 will likely be hotter still. <a href="https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml">El Niño is strengthening</a>, and this weather phenomenon has a history of heating up the planet. We will probably look back at recent years as among the coolest of the 21st century.</p>
<p><em>This article was updated Sept. 15, 2023, with NOAA and NASA also confirming summer 2023 the hottest on record.</em></p><img src="https://counter.theconversation.com/content/213021/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Scott Denning has received research funding from the US National Science Foundation, the US National Aeronautical and Space Administration, the US Department of Energy, and the National Oceanic and Atmospheric Administration. He serves on the Board of Trustees for the GEOS Institute, a nonprofit company that advises communities on adaptation to our changing climate. </span></em></p>There’s nothing normal about the blast furnace heat much of the world has been experiencing, as an atmospheric scientist explains.Scott Denning, Professor of Atmospheric Science, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2125642023-09-06T09:47:53Z2023-09-06T09:47:53ZFrom fatal allergies to heart attacks and malaria – the devastating health effects of global warming in Africa<p>The winds that whip the towns of the Eastern Cape in South Africa have the power to generate energy. But on a dry, hot day, those winds can gather up embers and dump them into tinder dry savannah and forest, destroying crops, fodder and homes, and taking lives. </p>
<p>Wild fires create their own weather systems, generating fire storms with devastating effects. </p>
<p>Global warming will increase the number of days of shimmering heat, creating the ideal conditions for fire. In the past months, southern Europe and North Africa have experienced record-breaking temperatures and fierce fires, and the terrible effects of both on human lives, habitat and environment. The southern hemisphere is next.</p>
<p>But heat, not fire, is the <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)01860-2/fulltext">major cause of death worldwide</a>. The extremes in Europe and the US augur future changes globally. Countries throughout southern Africa, parts of east Africa and Madagascar are all projected to face rapidly <a href="https://www.un.org/africarenewal/magazine/december-2018-march-2019/global-warming-severe-consequences-africa">increasing temperatures</a> to the end of this century. </p>
<p>I am an anthropologist and public health academic, working both in Australia and South Africa. Both countries are recurrently affected by the <a href="https://www.weather.gov/mhx/ensowhat">El Niño–Southern Oscillation</a> and resultant sea rise, with floods, drought and higher temperature in its wake. Global warming and El Niño combined suggest that the years ahead will result in increasing, devastating impacts. </p>
<h2>Heat, air quality and health</h2>
<p>As is clear from reports from multilateral agencies such as the <a href="https://www.ipcc.ch/report/ar6/wg2/">Intergovernmental Panel on Climate Change</a> and national bodies such as the <a href="https://health2016.globalchange.gov/downloads">US Global Change Research Program</a>, high temperatures can be <a href="https://www.who.int/news-room/fact-sheets/detail/the-top-10-causes-of-death">fatal</a>, and vast populations worldwide are vulnerable.</p>
<p>High <a href="https://www.who.int/news-room/fact-sheets/detail/climate-change-heat-and-health">temperatures</a> cause heat stroke, heat exhaustion, heart attacks, strokes and other cardiovascular disease.</p>
<p>South Africa will experience more heat waves, so more heat-related deaths are likely. People in informal settlements, and badly maintained and crowded buildings, are especially vulnerable to heat stress. </p>
<p>Cities are also hot spots. Heat absorbed by roads and buildings results in the urban <a href="https://www.sciencedirect.com/topics/engineering/urban-heat-island-effect">“heat island effect”</a>, while increased use of energy for cooling adds to greenhouse gas emissions. </p>
<h2>Less food, lower nutrition</h2>
<p>On the continent food security is directly threatened by extreme events, but also more broadly by climate change and global warming. In<a href="https://jamba.org.za/index.php/JAMBA/article/view/562"> South Africa</a>, drought recurrently affects subsistence agriculture, livestock and commercial crops. This has already stimulated interest in <a href="https://www.frontiersin.org/articles/10.3389/fsufs.2021.692185/full">local coping strategies</a> faced with food insecurity.</p>
<p>The impact of drought on food and nutrition will be felt by the most vulnerable, including infants, small children and pregnant women and those who already live on or below the poverty line.</p>
<p>Large numbers of people across the continent live as subsistence farmers, and in the absence of food or water we are likely to see increased migration and humanitarian crises. </p>
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Read more:
<a href="https://theconversation.com/climate-change-will-force-up-to-113m-people-to-relocate-within-africa-by-2050-new-report-193633">Climate change will force up to 113m people to relocate within Africa by 2050 - new report</a>
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<p>In South Africa, too, a large proportion of the population relies on <a href="https://www.statssa.gov.za/?p=1447">subsistence farming or other small-scale farming.</a> Crop failure and drought, combined with increased food costs associated with disruptions to global food resources, will affect every one of us. </p>
<h2>Every drop counts</h2>
<p>Drought and water shortages add to these risk factors. Humans require adequate hydration to survive, and the combination of increasing temperatures and water shortages heightens the risk of organ failure and death.</p>
<p>In addition, dependence on poor quality and contaminated water has an impact on household and personal hygiene, and intestinal infections. </p>
<p><em>Vibrio cholerae</em> – the bacteria that cause cholera – is present in waterways in both high and lower income countries, and infection can be mild. But increased concentrations of the bacteria without rapid intervention to prevent severe dehydration can be lethal. The sharp increase in cholera and other <a href="https://www.ncbi.nlm.nih.gov/books/NBK2302/#:%7E:text=Diarrheal%20diseases%20remain%20one%20of,to%20four%20years%20of%20age.">diarrhoeal diseases</a> worldwide is associated with rising temperatures and drought. </p>
<h2>Neglected diseases</h2>
<p>Other viral and bacterial infectious diseases, especially prevalent in Africa, are also likely to increase with global warming. Bundled together as <a href="https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0000332">“neglected diseases of poverty”</a>, these include both parasitic and viral vector borne diseases such as Rift Valley fever, malaria, filariasis, schistosomiasis, dengue fever, chikungunya and <a href="https://www.sciencedirect.com/science/article/pii/S266727822100081X?via%3Dihub">influenza</a> as well as arboviruses such as different influenza pathogens. </p>
<p>The ways in which climate change will affect different vector borne disease will vary. Sluggish and stagnant waterways and polluted water sources are one risk factor. </p>
<p>There is growing evidence of <a href="https://www.lowyinstitute.org/the-interpreter/what-climate-change-means-mosquito-borne-diseases">mosquito migration </a>to higher altitudes, infecting people who have not been exposed before. </p>
<p>At the same time, there is growing evidence of vector behavioural change and resistance to insecticides in some settings, including the <a href="https://www.nature.com/articles/s41598-020-71187-4">Ifakara</a> region of Tanzania.</p>
<h2>So where does this leave us?</h2>
<p>When the Intergovernmental Panel on Climate Change was established in 1988, we had a choice to interrupt climate change and slow global warming. </p>
<p>Globalisation, national politics and global capitalism have meant we have failed, and 35 years on we face an inevitable crisis. </p>
<p>This does not mean there is nothing we can do to halt the destruction of planetary life. </p>
<p>It does require that we urgently and radically change how we provide and use energy, how we live, and how we <a href="https://www.weforum.org/agenda/2022/10/3-key-fronts-africa-climate-change/">change living conditions</a> for those who are, by the circumstances of their everyday lives, most at risk of the lethal effects of global warming.</p><img src="https://counter.theconversation.com/content/212564/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lenore Manderson 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’s future looks catastrophic if we don’t act now on climate change.Lenore Manderson, Distinguished Professor, Public Health and Medical Anthropology, University of the WitwatersrandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2124102023-08-28T21:11:10Z2023-08-28T21:11:10ZHurricane Idalia intensifies over extremely warm Gulf waters, on track for Florida landfall as a dangerous major hurricane<p><em>Forecasters expected Hurricane Idalia to intensify into a <a href="https://www.nhc.noaa.gov">major hurricane</a> as it headed over exceptionally warm waters in the Gulf of Mexico, on track for landfall in Florida on Wednesday, Aug. 30, 2023. <a href="https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/093743.shtml?radii#contents">Hurricane warnings</a> were posted along a wide stretch of Florida’s Gulf coast, from near Sarasota to the Panhandle, including Tampa Bay.</em></p>
<p><em>Hurricane scientist <a href="https://scholar.google.com/citations?user=rkIN19EAAAAJ&hl=en">Haiyan Jiang</a> of Florida International University explains how two conflicting forces – <a href="https://climatereanalyzer.org/clim/sst_daily/">record-high ocean heat</a> and wind shear, the latter influenced by El Niño – were determining Idalia’s future, and how they have made the 2023 hurricane season overall <a href="https://www.noaa.gov/news-release/noaa-forecasters-increase-atlantic-hurricane-season-prediction-to-above-normal">difficult to forecast</a>.</em></p>
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<h2>What role is ocean temperature playing in Idalia’s forecast?</h2>
<p>Forecasters are watching several factors, but the biggest is the very high <a href="https://www.ospo.noaa.gov/data/sst/contour/gulfmex.cf.gif">sea surface temperature</a> in the Gulf of Mexico. The Gulf is typically warm in late August, and we <a href="https://www.nhc.noaa.gov/climo/">often see hurricanes</a> this time of year. But this summer, the sea surface temperature has been extremely high, with record temperatures <a href="https://climatereanalyzer.org/clim/sst_daily/">far above average</a>.</p>
<p>Near Cuba, sea surface temperatures were close to <a href="https://www.ospo.noaa.gov/data/sst/contour/gulfmex.cf.gif">86 degrees Fahrenheit</a> (30 degrees Celsius) as Idalia passed by the island on Monday. As the storm moves north, it will pass over sea surface temperatures that are even warmer. By Wednesday morning, the storm is forecast to be over waters that are <a href="https://www.ospo.noaa.gov/data/sst/contour/gulfmex.cf.gif">around 88 F (31 C)</a> at the surface. That is very, very high.</p>
<p>The heat isn’t just at the surface – the ocean heat extends deep into the upper ocean layer, or the thermocline, which is roughly 150 feet (50 meters) to 500 feet (150 meters) deep.</p>
<p>That <a href="https://www.climate.gov/news-features/understanding-climate/climate-change-ocean-heat-content">accumulated heat</a> provides fuel for the storm.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/545099/original/file-20230828-123419-9k4txk.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map shows dark red areas with the deepest ocean heat in the Caribbean and stretching up into the Gulf of Mexico." src="https://images.theconversation.com/files/545099/original/file-20230828-123419-9k4txk.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/545099/original/file-20230828-123419-9k4txk.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/545099/original/file-20230828-123419-9k4txk.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/545099/original/file-20230828-123419-9k4txk.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/545099/original/file-20230828-123419-9k4txk.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/545099/original/file-20230828-123419-9k4txk.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/545099/original/file-20230828-123419-9k4txk.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Oceanic Heat Content measures how deep warm water goes, showing the depth from the sea surface to the 26 C (78.8 F) isotherm. Idalia’s forecast path, from west of Cuba on Aug. 28, 2023, toward the Florida Panhandle, follows some of the deepest heat.</span>
<span class="attribution"><a class="source" href="https://coastwatch.noaa.gov/cwn/products/oceanic-heat-content-mixed-layer-depth-and-depths-20degc-and-26degc-isotherms.html">NOAA Coast Watch</a></span>
</figcaption>
</figure>
<p>As the ocean temperature increases, the amount of water vapor available to the storm also increases. Physics show that <a href="https://theconversation.com/2022s-us-climate-disasters-from-storms-and-floods-to-heat-waves-and-droughts-196713">warmer air can hold more water vapor</a>. With more heat and water vapor in the atmosphere, clouds heat up and the storm can rotate faster. It can also bring more intense rainfall.</p>
<h2>Can wind shear weaken the hurricane?</h2>
<p>A few things will weaken a hurricane. One is if the storm encounters cold water. Without warm water as a fuel source, the hurricane can no longer strengthen. In this case, however, the Gulf is exceptionally warm.</p>
<p>Wind shear is another important factor. Wind shear is a difference in wind speed and direction at different heights in a storm. Strong <a href="https://theconversation.com/atlantic-hurricane-season-2023-el-nino-and-extreme-atlantic-ocean-heat-are-about-to-clash-204670">wind shear can tear apart</a> a tropical storm. That’s common in the Atlantic basin during El Niño years like 2023. The question everyone has been asking this year is whether the wind shear will be strong enough to counter the extreme heat, and that doesn’t appear to be happening with Idalia.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1696245604974768580"}"></div></p>
<p>The wind shear was around 16 knots on Monday morning. The <a href="https://www.nhc.noaa.gov/archive/2023/IDALIA.shtml?">moderate wind shear</a> along Idalia’s path wasn’t expected to be strong enough to tear the hurricane apart – it’s still going to rapidly intensify because of the heat.</p>
<p>That wind shear is still beneficial for people in the storm’s path. Without it, a hurricane over water this warm could grow into a catastrophic Category 4 or 5 hurricane. Right now, Idalia is <a href="https://www.nhc.noaa.gov/text/refresh/MIATCPAT5+shtml/291153.shtml">forecast to be a Category 3</a> or close to it, which is still dangerous.</p>
<h2>Does climate change play a role in hurricane intensification?</h2>
<p>Long term, research shows Atlantic hurricane intensity has an <a href="https://doi.org/10.1029/2006GL028836">increasing trend as the climate warms</a>.</p>
<p>If you just look at wind speed, the average intensity of storms across all six major ocean basins isn’t increasing. But rainfall intensity is a different story.</p>
<p>My research shows that over the past 20 years, tropical cyclone-induced rainfall has <a href="https://doi.org/10.1038/s41467-021-25685-2">increased by about 1.3% per year</a> on average across the world’s basins and by even more in the Atlantic, about 1.6% per year. We linked the increase in rainfall intensity to increasing sea surface temperature and water vapor. Other researchers have <a href="https://doi.org/10.1038/s41467-021-22304-y">found the same thing</a>.</p>
<p>Each ocean basin is very different, and there are several reasons that the Atlantic may be seeing more intensification. One is that the Gulf is very warm, making it a source of strong hurricanes. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/545101/original/file-20230828-170871-41k57r.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A chart shows average global sea surface temperatures over time. 2023 is far above all other years, and 2022 was also high." src="https://images.theconversation.com/files/545101/original/file-20230828-170871-41k57r.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/545101/original/file-20230828-170871-41k57r.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=382&fit=crop&dpr=1 600w, https://images.theconversation.com/files/545101/original/file-20230828-170871-41k57r.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=382&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/545101/original/file-20230828-170871-41k57r.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=382&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/545101/original/file-20230828-170871-41k57r.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=480&fit=crop&dpr=1 754w, https://images.theconversation.com/files/545101/original/file-20230828-170871-41k57r.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=480&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/545101/original/file-20230828-170871-41k57r.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=480&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Global ocean temperatures, including in the Atlantic, have been well above previous years. The middle dotted line shows the average.</span>
<span class="attribution"><a class="source" href="https://climatereanalyzer.org/clim/sst_daily/">Climate Reanalyzer/Climate Change Institute/University of Maine</a></span>
</figcaption>
</figure>
<p>More intense rainfall can mean greater flooding potential, as large parts of Florida saw during <a href="https://www.nesdis.noaa.gov/news/hurricane-ians-path-of-destruction">Hurricane Ian in 2022</a>. Even if wind speed isn’t increasing in every basin, the damage can be higher because intense rainfall could also come from a storm’s rain bands, not just from the eyewall.</p>
<p>Florida residents need to be aware of that risk as they prepare for Idalia.</p>
<p><em>This article, originally published Aug. 28, 2023, was updated with Idalia strengthening into a hurricane.</em></p><img src="https://counter.theconversation.com/content/212410/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Haiyan Jiang receives funding from NSF, NOAA, and NASA. </span></em></p>A hurricane scientist explains the conflict between 2023’s abnormally high ocean heat and the storm-disrupting wind shear accompanying El Niño.Haiyan Jiang, Professor of Earth and Environment, Florida International UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2110292023-08-23T20:09:51Z2023-08-23T20:09:51ZGreenhouse gases are changing air flow over the Pacific Ocean – raising Australia’s risks of extreme weather<figure><img src="https://images.theconversation.com/files/543865/original/file-20230822-15-u5fe58.jpg?ixlib=rb-1.1.0&rect=64%2C16%2C5327%2C3573&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/clouds-gather-over-seascape-near-new-1339682141">Shutterstock</a></span></figcaption></figure><p>After a <a href="https://theconversation.com/la-nina-3-years-in-a-row-a-climate-scientist-on-what-flood-weary-australians-can-expect-this-summer-190542">rare three-year La Niña event</a> brought heavy rain and flooding to eastern Australia in 2020-22, we’re now bracing for the heat and drought of El Niño at the opposite end of the spectrum. </p>
<p>But while the World Meteorological Organisation <a href="https://public.wmo.int/en/media/press-release/world-meteorological-organization-declares-onset-of-el-ni%C3%B1o-conditions">has declared</a> an El Niño event is underway, Australia’s Bureau of Meteorology is <a href="http://www.bom.gov.au/climate/enso/outlook/">yet to make a similar declaration</a>. Instead, the Bureau remains on “El Niño alert”. </p>
<p>The reason for this discrepancy is what’s called the <a href="https://climateextremes.org.au/what-is-the-pacific-walker-circulation/">Pacific Walker Circulation</a>. The pattern and strength of air flows over the Pacific Ocean, combined with sea surface temperatures, determines whether Australia experiences El Niño or La Niña events.</p>
<p>In our new research, published today in the journal <a href="https://doi.org/10.1038/s41586-023-06447-0">Nature</a>, we asked whether the buildup of greenhouse gases in the atmosphere had affected the Walker Circulation. We found the overall strength hasn’t changed yet, but instead, the year-to-year behaviour is different.</p>
<p>Switching between El Niño and La Niña conditions has slowed over the industrial era. That means in the future we could see more of these multi-year La Niña or El Niño type events. So we need to prepare for greater risks of floods, drought and fire. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/ydMP4kG3SXs?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">What is the Pacific Walker Circulation? An explainer.</span></figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/la-nina-is-finishing-an-extremely-unusual-three-year-cycle-heres-how-it-affected-weather-around-the-world-196561">La Niña is finishing an extremely unusual three-year cycle – here's how it affected weather around the world</a>
</strong>
</em>
</p>
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<h2>An ocean-atmosphere climate system</h2>
<p>La Niña and its counterpart El Niño are the two extremes of the El Niño Southern Oscillation — a coupled ocean-atmosphere system that plays a major role in global climate variability.</p>
<p>The Walker Circulation is the atmospheric part. Air rises over <a href="https://geoscienceletters.springeropen.com/articles/10.1186/s40562-016-0054-3">the Indo-Pacific Warm Pool</a> (a region of the ocean that stays warm year-round) and flows eastward high in the atmosphere. Then it sinks back to the surface over the eastern equatorial Pacific and flows back to the west along the surface, forming the Pacific trade winds. In short, it loops in an east-west direction across the equatorial Pacific Ocean.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-where-does-wind-actually-come-from-198404">Curious Kids: where does wind actually come from?</a>
</strong>
</em>
</p>
<hr>
<p>But the Walker Circulation doesn’t always flow with the same intensity — sometimes it is stronger, and sometimes it is weaker. </p>
<p>Periods of stronger or weaker Walker Circulation have <a href="https://climateextremes.org.au/what-is-the-pacific-walker-circulation/">major impacts on Australian climate</a>. A stronger Walker Circulation means stronger-than-average trade winds, and generally La Niña-like ocean conditions. This often brings wetter weather to eastern Australia. </p>
<p>On the flip side, a weaker Walker Circulation brings weaker-than-average trade winds, and El Niño-like ocean conditions. A weak Walker Circulation is often associated with drier weather across northern and eastern Australia. </p>
<p>So far, the Walker Circulation is what’s missing from the current El Niño event developing in the Pacific Ocean: it has not weakened enough for the Bureau to declare an El Niño event. </p>
<figure class="align-center ">
<img alt="Animated GIF illustrating the Pacific Walker Circulation" src="https://images.theconversation.com/files/543868/original/file-20230822-15-hqqzna.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543868/original/file-20230822-15-hqqzna.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543868/original/file-20230822-15-hqqzna.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543868/original/file-20230822-15-hqqzna.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543868/original/file-20230822-15-hqqzna.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543868/original/file-20230822-15-hqqzna.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543868/original/file-20230822-15-hqqzna.gif?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">In the Pacific Walker Circulation, warm air rises above the western Pacific Ocean, cools down and sinks over the east of the Pacific Ocean, circling back and continuing an important atmospheric cycle for the entire planet.</span>
<span class="attribution"><a class="source" href="https://climateextremes.org.au/what-is-the-pacific-walker-circulation/">The ARC Centre of Excellence for Climate Extremes via Canva.com</a></span>
</figcaption>
</figure>
<h2>What’s happening to the Walker Circulation?</h2>
<p>The Walker Circulation is a <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018RG000596">major influence</a> on weather and climate in many places around the world, not just Australia.</p>
<p>A stronger-than-usual Walker Circulation even contributed to the “<a href="https://www.nature.com/articles/nclimate2106">global warming slowdown</a>” of the early 2000s. This is because a stronger Walker Circulation is often associated with slightly cooler global temperature. </p>
<p>So we need to know how it is going to behave in the future. To do that, we first need to know if — and if so, how — the Walker Circulation’s behaviour has changed due to human activities. And to do that, we need information about how the Walker Circulation behaved <em>before</em> humans started affecting the climate system. </p>
<p>We reconstructed Walker Circulation variability over the past millennium. We used global data from ice cores, trees, lakes, corals and caves to build a picture of how the Walker Circulation changed over time.</p>
<p>We found that on average, there has not yet been any industrial-era change in the strength of the Walker Circulation. This was surprising, because <a href="https://climateextremes.org.au/climate-modelling/">computer simulations of Earth’s climate</a> generally suggest global warming will <a href="https://www.nature.com/articles/nature04744">ultimately cause a weaker</a>, or more El Niño-like, Walker Circulation. </p>
<p>There are a few possible reasons for this. One is that <a href="https://www.nature.com/articles/s41558-021-01101-x">a buildup of fine particles in the air</a>, such as smoke or industrial pollution, may be driving a stronger Walker Circulation, hence “cancelling out” the weakening effect of global warming.</p>
<p>Another is there may have been <em>some</em> weakening, but so far it is too small to be detectable among the Walker Circulation’s large year-to-year variability. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/smoke-from-the-black-summer-fires-could-have-made-the-triple-la-nina-more-likely-205292">Smoke from the Black Summer fires could have made the triple La Niña more likely</a>
</strong>
</em>
</p>
<hr>
<p>Our research also does not rule out the possibility that with future increases in global temperature, the Walker Circulation will indeed weaken, in a trend to more El Niño-like conditions. In that scenario, Australians might expect <a href="https://climateextremes.org.au/understanding-australias-rainfall/">decreased rainfall in the north and east</a>, as well as warmer temperatures across the continent, and <a href="http://www.bom.gov.au/climate/updates/articles/a008-el-nino-and-australia.shtml">less snow in the Australian Alps</a>. </p>
<p>Even though the average strength of the Walker Circulation has not changed in the industrial era, there has been a subtle change in the length of time taken for the Walker Circulation to switch from one state to the next. </p>
<p>The Walker Circulation now switches more <em>slowly</em> between weak and strong phases, and we suspect this is influenced by climate change. This has potentially important implications for climate extremes, as El Niño and La Niña conditions could hang around for longer. </p>
<p>Our research also found that major explosive volcanic eruptions — at least as big as the 1982 eruption of El Chichón — can trigger an El Niño-like weakening of the Walker Circulation one to three years after the eruption. Unfortunately, volcanic eruptions remain <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018JB016974">extremely difficult</a> to predict, so this doesn’t help our long-term climate predictions.</p>
<h2>What is the message for Australians?</h2>
<p>In terms of predicting how the Walker Circulation will change in the future, we can now focus attention on the particular climate models whose outputs <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GL100011">most closely match</a> what we discovered from our reconstruction.</p>
<p>That is, models that show no industrial-era weakening trend. This approach might help us get more accurate predictions of future Walker Circulation change. </p>
<p>The other thing we can do is to be prepared for more consecutive-year El Niño and La Niña events, and the sustained wet or dry spells they could bring to Australia.</p>
<p>And if there is a major volcanic eruption? Be prepared for a couple of years of weak Walker Circulation, and the warm, dry weather that can bring. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/new-study-helps-solve-a-30-year-old-puzzle-how-is-climate-change-affecting-el-nino-and-la-nina-205128">New study helps solve a 30-year-old puzzle: how is climate change affecting El Niño and La Niña?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/211029/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Georgina Falster receives funding from the Australian Research Council Centre of Excellence for Climate Extremes. This research was funded by the US National Science Foundation.</span></em></p>It’s not just ocean temperatures that determine whether we have El Niño or La Niña. Air circulation also plays a role, and it’s changing in unexpected ways.Georgina Falster, Postdoctoral Fellow, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2118692023-08-18T21:50:54Z2023-08-18T21:50:54ZTropical Storm Hilary pounds Southern California with heavy rain, flash flooding<figure><img src="https://images.theconversation.com/files/543534/original/file-20230818-19-oy7ob6.jpg?ixlib=rb-1.1.0&rect=975%2C10%2C2274%2C1368&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Hurricane Hilary was a powerful Category 4 storm as it headed for Baja California on Aug. 18, 2023.</span> <span class="attribution"><a class="source" href="https://www.star.nesdis.noaa.gov/goes/">NOAA NESDIS</a></span></figcaption></figure><p><em>Tropical Storm Hilary <a href="https://apnews.com/article/hilary-tropical-storm-flooding-california-mexico-f89aeddeb62d55c935699ac81ca85f1d">made landfall</a> on Mexico’s Baja peninsula, and its damaging wind and heavy rainfall moved <a href="https://www.nhc.noaa.gov/text/WTUS86-KLOX.shtml">into Southern California</a> on <a href="https://www.nhc.noaa.gov/refresh/graphics_ep4+shtml/204813.shtml?cone#contents">Aug. 20, 2023</a>. For the <a href="https://twitter.com/NWSSanDiego/status/1692564593132933367">first time ever</a>, the National Hurricane Center had <a href="https://www.nhc.noaa.gov/archive/2023/ep09/ep092023.public.011.shtml?">issued a tropical storm watch</a> for large parts of Southern California. Forecasters warned of a “<a href="https://www.nhc.noaa.gov/archive/2023/ep09/ep092023.discus.014.shtml?">potentially historic</a> amount of rainfall,” and the governors of <a href="https://www.gov.ca.gov/2023/08/19/governor-newsom-proclaims-state-of-emergency-as-hurricane-hilary-approaches-california/">California</a> and <a href="https://carsonnow.org/story/08/20/2023/governor-lombardo-declares-state-emergency-across-nevada-due-hurricane-hilary">Nevada</a> declared states of emergency.</em></p>
<p><em>Hurricane scientist <a href="https://scholar.google.com/citations?user=5uEy_XoAAAAJ&hl=en">Nick Grondin</a> explained ahead of landfall why <a href="https://www.nhc.noaa.gov/archive/2023/HILARY.shtml?">the storm</a>, with help from El Niño and a heat dome over much of the country, could bring <a href="https://www.nhc.noaa.gov/archive/2023/ep09/ep092023.public.011.shtml?">flash flooding</a>, wind damage and mudslides to the region.</em></p>
<h2>How rare are tropical storms in the Southwest?</h2>
<p>California had only one confirmed tropical storm landfall in the past. It was in September 1939 and called <a href="https://www.sandiegouniontribune.com/news/150-years/sd-me-150-years-september-26-htmlstory.html">the Long Beach Tropical Storm</a>. It caused <a href="https://www.aoml.noaa.gov/hrd/Landsea/chenowethlandsea.pdf">about US$2 million dollars</a> in damage in the Los Angeles area – that would be about $44 million today. A <a href="https://doi.org/10.1175/BAMS-85-11-1689">hurricane in 1858</a> came close but didn’t make landfall, though its winds did significant damage to San Diego.</p>
<p>What the Southwest does see fairly regularly are the remnants of tropical cyclones, storms that continue on after a tropical cyclone loses its surface circulation. These remnant storms are <a href="https://doi.org/10.1175/2010MWR3389.1">more common</a> in the region than people might think. </p>
<p>Just last year, <a href="https://www.nhc.noaa.gov/data/tcr/EP122022_Kay.pdf">Hurricane Kay</a> took a similar track to the one Hurricane Hilary is on and brought significant rainfall to Southern California and Arizona. Famously, <a href="https://www.wpc.ncep.noaa.gov/tropical/rain/nora1997.html">Hurricane Nora in 1997</a> made landfall in Mexico’s Baja California and kept moving north, bringing tropical storm-force winds to California and widespread flooding that caused <a href="https://www.weather.gov/media/hazstat/sum97.pdf">hundreds of millions of dollars in damage</a>, particularly to fruit trees <a href="https://www.weather.gov/media/hazstat/sum97.pdf">and agriculture</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/543551/original/file-20230819-19-dbyiqs.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map shows rainfall forecast across much of Southern California and into Arizona and Nevada." src="https://images.theconversation.com/files/543551/original/file-20230819-19-dbyiqs.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543551/original/file-20230819-19-dbyiqs.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=482&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543551/original/file-20230819-19-dbyiqs.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=482&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543551/original/file-20230819-19-dbyiqs.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=482&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543551/original/file-20230819-19-dbyiqs.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=605&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543551/original/file-20230819-19-dbyiqs.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=605&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543551/original/file-20230819-19-dbyiqs.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=605&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 National Hurricane Center’s three-day rainfall forecast issued Aug. 19, 2023, shows rainfall totals that are well above what some areas typically receive in a year.</span>
<span class="attribution"><a class="source" href="https://www.nhc.noaa.gov/refresh/graphics_ep4+shtml/175024.shtml?rainqpf#contents">National Hurricane Center</a></span>
</figcaption>
</figure>
<p>A study led by atmospheric scientist <a href="https://scholar.google.com.au/citations?user=rHHmqXgAAAAJ&hl=en">Elizabeth Ritchie</a> in 2011 found that, on average, <a href="https://doi.org/10.1175/2010MWR3389.1">about 3.1 remnant systems</a> from tropical cyclones affected the U.S. Southwest each year from 1992 to 2005. That’s a short record, but it gives you an idea of the frequency.</p>
<p>Typically, the remnants of tropical cyclones don’t go beyond California, Nevada and Arizona, <a href="https://www.wpc.ncep.noaa.gov/tropical/rain/tcrainfall.html">though it wouldn’t be unprecedented</a>. In this case, forecasters expect the effects to extend far north. The National Hurricane Center on Aug. 18 projected at least a <a href="https://www.nhc.noaa.gov/refresh/graphics_ep4+shtml/175024.shtml?ero#contents">moderate risk of flooding</a> across large parts of Southern California, southern Nevada and far-western Arizona, and a high risk of flooding for regions east of San Diego.</p>
<h2>What’s making this storm so unusual?</h2>
<p>One influence is the <a href="https://theconversation.com/el-nino-is-back-thats-good-news-or-bad-news-depending-on-where-you-live-205974">El Niño climate pattern</a> this year, which is showing signs of strengthening in the Pacific. Another, which might be less intuitive, is the <a href="https://www.washingtonpost.com/weather/2023/08/17/heat-wave-texas-excessive-heat-warning/">heat dome over much of the U.S.</a></p>
<p>During El Niño, the tropical Pacific is warmer than normal, and both the eastern and central Pacific tend to be more active with storms, as we saw in 2015 and 1997. Generally, hurricanes need <a href="https://oceanexplorer.noaa.gov/facts/hurricanes.html">at least 80 degrees</a> Fahrenheit (27 degrees Celsius) to maintain their intensity. Normally, the waters off Southern California <a href="https://www.ncei.noaa.gov/access/coastal-water-temperature-guide/spac.html">are much cooler</a>. But with the high initial intensity of Hurricane Hilary over warm water to the south, and the fact that the storm is moving fast, forecasters think it might be able to survive the cooler water.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1691594717115335132"}"></div></p>
<p>The influence of the heat dome is interesting. Meteorology researcher <a href="https://scholar.google.com/citations?user=16yNCisAAAAJ&hl=en">Kimberly Wood</a> published a fantastic thread on X, formerly known as Twitter, describing the <a href="https://twitter.com/DrKimWood/status/1691956790144155962">large-scale pattern around similar storms</a> that have affected the southwestern United States. A common thread with these storms is the presence of a ridge, or high-pressure system, in the central U.S. When you have a high-pressure system like the heat dome covering much of the country, air is pushed down and warms significantly. Air around this ridge is moving clockwise. Meanwhile, a low-pressure system is over the Pacific Ocean with winds rotating counterclockwise. The result is that these <a href="https://twitter.com/WeatherProf/status/1691594717115335132">winds are likely to accelerate Hilary northward</a> into California.</p>
<p>Despite the rarity of tropical cyclones reaching California, numerical weather prediction models since the storm’s formation have generally shown Hilary likely to accelerate along the west coast of Baja California and push into Southern California.</p>
<h2>What are the risks?</h2>
<p>The threat of tropical storm-force winds led the National Hurricane Center to issue its <a href="https://twitter.com/NWSSanDiego/status/1692564593132933367">first-ever tropical storm watch</a> for Southern California on Aug. 18. However, water is almost always the primary concern with tropical storms. In California, that can mean flash flooding from extreme rainfall enhanced by mountains.</p>
<p>When a tropical storm plows up on a mountain, that can lead to more lifting, more condensation aloft and more rainfall than might otherwise be expected. It happened with <a href="https://www.nhc.noaa.gov/data/tcr/EP142018_Lane.pdf">Hurricane Lane in Hawaii</a> in 2018 and can also happen in other tropical cyclone-prone locations with significant orographic, or mountain, effects, such as the west coast of Mexico.</p>
<p>That can mean dangerous flash flooding from the runoff. It can also have a secondary hazard – mudslides, <a href="https://twitter.com/CAL_FIRE/status/1692596995330814311">including in areas recovering from wildfires</a>.</p>
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<p>In dry areas, heavy downpours can also trigger flash flooding. Forecasts showed Death Valley likely to get <a href="https://twitter.com/Climatologist49/status/1692550601677390298">more rain from the storm</a> than <a href="https://www.nps.gov/deva/planyourvisit/weather.htm">its average</a> for an entire year. Death Valley National Park warned of <a href="https://www.nps.gov/deva/planyourvisit/conditions.htm">flash flooding through Aug. 22</a> and closed its visitor centers and campgrounds. </p>
<p>Keep in mind this is still an evolving situation. Forecasts can change, and all it takes is one band of rain setting up in the right spot to cause significant flooding. Those in the path of Hilary should refer to their local weather offices for additional information. This would include local <a href="http://www.hurricanes.gov">National Weather Service</a> offices in the United States and <a href="https://smn.conagua.gob.mx/es/">Servicio Meteorológico Nacional</a> in Mexico.</p>
<p><em>This article, originally published Aug. 18, 2023, was updated with Tropical Storm Hilary making landfall.</em></p><img src="https://counter.theconversation.com/content/211869/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nicholas Grondin 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>Forecasters warned of ‘potentially historic rainfall’ and ‘dangerous to locally catastrophic flooding.’ A hurricane scientist explains what El Niño, a heat dome and mountains have to do with the risk.Nicholas Grondin, Assistant Professor of Environmental Studies, University of TampaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2106932023-08-01T00:22:59Z2023-08-01T00:22:59ZWhy is Australia having such a warm winter? A climate expert explains<figure><img src="https://images.theconversation.com/files/540096/original/file-20230731-17-nj0u87.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6669%2C3138&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>If you’ve been out and about the past few days, you may have noticed Australia is experiencing an unseasonably warm winter. It’s been t-shirt weather across many parts of the country’s east, including Sydney where <a href="https://www.theguardian.com/environment/2023/jun/08/australia-ski-season-no-snow-skiing-snowboarding-resorts-closed-warm-weather">temperatures topped 25°C</a> on Sunday.</p>
<p>Meanwhile, at high altitudes, the cover at some snowfields remains <a href="https://twitter.com/Cam_Walker/status/1685525535521402880">lacklustre</a>, even after warm conditions forced <a href="https://www.abc.net.au/news/2023-06-09/nsw-resorts-postpone-ski-snowboarding-kings-birthday-lack-snow/102456510">a delay</a> to the start of the traditional ski season.</p>
<p>All this comes after the world experienced its hottest month since reliable records began. July brought <a href="https://qz.com/hottest-days-month-ever-recorded-july-2023-1850685494">an incredible 21 of the warmest 30 days</a> ever recorded – prompting the United Nations to declare a new era of “<a href="https://www.theguardian.com/science/2023/jul/27/scientists-july-world-hottest-month-record-climate-temperatures">global boiling</a>”. </p>
<p>So what’s going on with the weather in Australia? Should we just enjoy the pleasant conditions, or is it a troubling sign of what’s to come under climate change? </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1685525535521402880"}"></div></p>
<h2>The nice weather, explained</h2>
<p>Australia’s unseasonably warm conditions are the result of both natural drivers of our weather and continued global warming.</p>
<p>Since early July, warmer and drier conditions have dominated, due to a high pressure system sitting stubbornly over Australia at the moment. The clear conditions are leading to warmer daytime conditions. </p>
<p>For example, daytime temperatures in Canberra in July – historically known for its cold winters – were <a href="https://www.9news.com.au/national/canberra-on-track-for-warmest-july-max-temps-on-record/1d0b9683-7dda-4cc0-b6a6-1e32bfa51407">the warmest on record</a>, despite frequent frosty mornings. Sydney has just experienced its <a href="https://www.theguardian.com/australia-news/2023/jul/31/australia-weather-august-warmth-heat-winds-tasmania#:%7E:text=Sydney%27s%2023.5C%20was%20enough,Hill%20goes%20back%20to%201858.">warmest July</a> on record, too.</p>
<p>The high pressure has caused the air over the continent’s interior to warm. When cold fronts move across the south of Australia they push this warm air ahead of them, bringing warm and windy conditions to southern coastal areas. This is similar to the weather pattern we see in summer when cities such as Adelaide and Melbourne experience their hottest days.</p>
<p>On Thursday, an approaching cold front is forecast to lift temperatures ahead of it to about 23°C in Adelaide, 20°C in Melbourne and 18°C in Hobart. These are very warm temperatures in these locations for early August.</p>
<p>And what about the oceans? Around Australia, oceans are a bit cooler than average in some places including <a href="http://www.bom.gov.au/products/IDYOC053.Global.SSTAnomaly.shtml">to the northwest of the continent</a>. </p>
<p>But as the image below shows, ocean temperatures are currently above normal in many places around the world, including the west Indian Ocean and the central and eastern tropical Pacific. This indicates a developing El Niño and positive Indian Ocean Dipole – two natural climate drivers that affect Australia’s weather patterns.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/540054/original/file-20230730-191965-434fnd.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/540054/original/file-20230730-191965-434fnd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/540054/original/file-20230730-191965-434fnd.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=364&fit=crop&dpr=1 600w, https://images.theconversation.com/files/540054/original/file-20230730-191965-434fnd.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=364&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/540054/original/file-20230730-191965-434fnd.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=364&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/540054/original/file-20230730-191965-434fnd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=458&fit=crop&dpr=1 754w, https://images.theconversation.com/files/540054/original/file-20230730-191965-434fnd.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=458&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/540054/original/file-20230730-191965-434fnd.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=458&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Across most of the world’s oceans, temperatures remain well above normal.</span>
<span class="attribution"><span class="source">National Oceanic and Atmospheric Administration</span></span>
</figcaption>
</figure>
<p>This difference in ocean temperatures reduces the amount of atmospheric moisture over southern and eastern Australia. It also makes low pressure systems weaker and less frequent, reducing rainfall over the region.</p>
<p>Over the coming months, warm and dry weather is expected to continue. For the rest of winter and spring, it’s expected to be <a href="http://www.bom.gov.au/climate/outlooks/#/rainfall/summary">drier than normal</a> in the southwest of Western Australia and much of the east of the continent. And the whole of Australia is predicted to be <a href="http://www.bom.gov.au/climate/outlooks/#/temperature/summary">warmer than normal</a> during this period. Of course, this doesn’t rule out occasional cool, wet spells.</p>
<p>So is climate change a factor here? Yes. Australia’s land areas have <a href="https://www.ipcc.ch/report/ar6/wg1/downloads/factsheets/IPCC_AR6_WGI_Regional_Fact_Sheet_Australasia.pdf">already warmed by 1.4°C</a> since pre-industrial times. This is the result of humans burning fossil fuels and releasing greenhouse gases.</p>
<p>The record winter warmth is part of a <a href="https://theconversation.com/australias-record-breaking-winter-warmth-linked-to-climate-change-83304">long-term upward trend</a> in Australian winter temperatures. </p>
<p>As I’ve written <a href="https://theconversation.com/australias-record-breaking-winter-warmth-linked-to-climate-change-83304">previously</a>, there has been at least a 60-fold increase in the likelihood of a very warm winter that can be attributed to human-caused climate change. </p>
<p>And we’re likely to see more record warm winters as the planet continues to warm.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/global-warming-to-bring-record-hot-year-by-2028-probably-our-first-above-1-5-c-limit-205758">Global warming to bring record hot year by 2028 – probably our first above 1.5°C limit</a>
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<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1684861967922765824"}"></div></p>
<h2>Looking north</h2>
<p>Of course, Australia’s spell of warm weather seems harmless compared to the Northern Hemisphere’s weird and wild summer. </p>
<p>There, simultaneous extreme heatwaves have struck all four continents in recent weeks. Ocean temperatures are well <a href="https://www.washingtonpost.com/weather/2023/07/28/ocean-temperature-maps-heat-records/">above previous record highs</a> for this time of year. Last week, <a href="https://edition.cnn.com/2023/07/25/weather/canadian-wildfire-us-air-pollution/index.html">1,000 wildfires burned</a> in Canada alone.</p>
<p>The planet’s warmest average temperatures typically happen in July. That’s because the Northern Hemisphere’s large land masses heat up more quickly than the oceans, in response to the high amounts of radiation from the sun. Still, the heat of the last few weeks has been unprecedented.</p>
<p>The heatwaves are <a href="https://theconversation.com/a-climate-expert-explains-the-northern-hemispheres-weird-wild-summer-and-what-it-means-for-australia-209862">linked to</a> high-pressure weather systems that are “blocking” or deflecting oncoming low-pressure systems (and associated clouds and rain). On top of this, human-caused global warming is greatly increasing the chance of record-breaking extreme heat events and concurrent heatwaves across many regions.</p>
<p>Worryingly, a <a href="https://www.worldweatherattribution.org/extreme-heat-in-north-america-europe-and-china-in-july-2023-made-much-more-likely-by-climate-change/">rapid analysis</a> by international experts suggests the extreme heat should not be viewed as unusual, given the effects of climate change. For example, it says China’s recent <a href="https://www.smh.com.au/world/asia/china-logs-52-2-celsius-as-extreme-weather-rewrites-records-20230718-p5dp1v.html">record-breaking heatwave</a> should now be expected about once in every five years, on average. </p>
<p>Not all extreme weather events can be attributed to human-caused climate change. But the study found climate change significantly contributed to the recent heatwaves in China, North America and Europe.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1684185665322332163"}"></div></p>
<h2>A sign of what’s to come</h2>
<p>The Northern Hemisphere’s heatwaves are very alarming. But Australia’s temperatures are also unusually high for winter – and this is also cause for concern.</p>
<p>Warm winters in Australia can negatively affect some parts of the economy, including the ski industry. It also disrupts flora and fauna and increases the chance of “<a href="https://theconversation.com/flash-droughts-can-dry-out-soil-in-weeks-new-research-shows-what-they-look-like-in-australia-161286">flash droughts</a>” – where drier-than-normal conditions turn into severe drought in the space of weeks. </p>
<p>The warm, dry conditions may also lead to an <a href="https://www.theguardian.com/cities/2018/aug/15/sydneys-bushfire-season-starts-in-winter-we-may-have-to-rethink-how-we-live">earlier start</a> to the fire season in Australia’s southeast. </p>
<p>So while we may appreciate warm winter weather, we mustn’t forget what’s driving it – and how urgently we need to stabilise Earth’s climate by slashing greenhouse gas emissions.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/two-trillion-tonnes-of-greenhouse-gases-25-billion-nukes-of-heat-are-we-pushing-earth-out-of-the-goldilocks-zone-202619">Two trillion tonnes of greenhouse gases, 25 billion nukes of heat: are we pushing Earth out of the Goldilocks zone?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/210693/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew King receives funding from the National Environmental Science Program. </span></em></p>What’s going on with the weather in Australia? It’s partly the result of natural drivers of our weather – and partly due to global warming.Andrew King, Senior Lecturer in Climate Science, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2099752023-07-27T12:24:47Z2023-07-27T12:24:47ZGlobal temperatures are off the charts for a reason: 4 factors driving 2023’s extreme heat and climate disasters<figure><img src="https://images.theconversation.com/files/539635/original/file-20230726-25-xefux.jpg?ixlib=rb-1.1.0&rect=0%2C36%2C4119%2C2891&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">2023's weather has been extreme in many ways.</span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/GermanyDailyLifeWeather/5bb903448a224f9ab42c325eddffade8/photo">AP Photo/Michael Probst</a></span></figcaption></figure><p>Between the <a href="https://theconversation.com/summer-2023-was-the-hottest-on-record-yes-its-climate-change-but-dont-call-it-the-new-normal-213021">record-breaking global heat</a> and <a href="https://theconversation.com/as-extreme-downpours-trigger-flooding-around-the-world-scientists-take-a-closer-look-a-global-warmings-role-213724">extreme downpours</a>, it’s hard to ignore that something unusual is going on with the weather in 2023.</p>
<p>People have been quick to blame climate change – and they’re right: <a href="https://www.ipcc.ch/2021/08/09/ar6-wg1-20210809-pr/">human-caused global warming</a> plays <a href="https://nca2018.globalchange.gov/chapter/appendix-5/">the biggest role</a>. The weekslong heat wave that started in June 2023 in Texas, the U.S. Southwest and Mexico would have been <a href="https://www.worldweatherattribution.org/extreme-heat-in-north-america-europe-and-china-in-july-2023-made-much-more-likely-by-climate-change/">virtually impossible without it</a>, one study found.</p>
<p>However, the extremes this year are sharper than anthropogenic global warming alone would be expected to cause. September temperatures were <a href="https://climate.copernicus.eu/copernicus-september-2023-unprecedented-temperature-anomalies">far above any previous September</a>, and around 3.1 degrees Fahrenheit (1.75 degrees Celsius) above the preindustrial average, according to the European Union’s earth observation program.</p>
<p>July was Earth’s <a href="https://climate.copernicus.eu/july-2023-global-air-and-ocean-temperatures-reach-new-record-highs">hottest month on record</a>, also <a href="https://www.noaa.gov/news/record-shattering-earth-had-its-hottest-july-in-174-years">by a large margin</a>, with average global temperatures more than half a degree Fahrenheit (a third of a degree Celsius) above the previous record, set just a few years earlier in 2019.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/552407/original/file-20231005-27-dz512e.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Bar char shows temperature anomalies compared to the 1991-2020 average." src="https://images.theconversation.com/files/552407/original/file-20231005-27-dz512e.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552407/original/file-20231005-27-dz512e.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=388&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552407/original/file-20231005-27-dz512e.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=388&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552407/original/file-20231005-27-dz512e.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=388&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552407/original/file-20231005-27-dz512e.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=488&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552407/original/file-20231005-27-dz512e.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=488&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552407/original/file-20231005-27-dz512e.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=488&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">September 2023’s temperatures were far above past Septembers.</span>
<span class="attribution"><a class="source" href="https://climate.copernicus.eu/copernicus-september-2023-unprecedented-temperature-anomalies">Copernicus</a></span>
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</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/552435/original/file-20231006-28-9oo854.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A bar chart shows rising average global temperatures since 1940, with July 2023 well above the next warmest year." src="https://images.theconversation.com/files/552435/original/file-20231006-28-9oo854.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552435/original/file-20231006-28-9oo854.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=388&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552435/original/file-20231006-28-9oo854.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=388&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552435/original/file-20231006-28-9oo854.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=388&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552435/original/file-20231006-28-9oo854.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=488&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552435/original/file-20231006-28-9oo854.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=488&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552435/original/file-20231006-28-9oo854.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=488&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">July 2023 was the hottest month on record and well above past Julys.</span>
<span class="attribution"><a class="source" href="https://climate.copernicus.eu/july-2023-global-air-and-ocean-temperatures-reach-new-record-highs">Copernicus Climate Change Service</a></span>
</figcaption>
</figure>
<p>Human activities have been increasing temperatures at an <a href="https://theconversation.com/five-climate-change-science-misconceptions-debunked-122570">average of about 0.2 F (0.1 C) per decade</a>. But this year, three additional natural factors are also helping drive up global temperatures and fuel disasters: El Niño, solar fluctuations and a massive underwater volcanic eruption.</p>
<p>Unfortunately, these factors are combining in a way that is exacerbating global warming. Still worse, we can expect unusually high temperatures to continue, which means even more extreme weather in the near future.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/539673/original/file-20230726-21-c7byq9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An illustrated chart showing global warming has a much greater influence on temperature" src="https://images.theconversation.com/files/539673/original/file-20230726-21-c7byq9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/539673/original/file-20230726-21-c7byq9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=470&fit=crop&dpr=1 600w, https://images.theconversation.com/files/539673/original/file-20230726-21-c7byq9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=470&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/539673/original/file-20230726-21-c7byq9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=470&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/539673/original/file-20230726-21-c7byq9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=591&fit=crop&dpr=1 754w, https://images.theconversation.com/files/539673/original/file-20230726-21-c7byq9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=591&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/539673/original/file-20230726-21-c7byq9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=591&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An illustration by the author shows the typical relative impact on temperature rise driven by human activities compared with natural forces. El Niño/La Niña and solar energy cycles fluctuate. The Hunga Tonga-Hunga Ha’apai volcano’s underwater eruption exacerbated global warming.</span>
<span class="attribution"><span class="source">Michael Wysession</span></span>
</figcaption>
</figure>
<h2>How El Niño is involved</h2>
<p>El Niño is a climate phenomenon that occurs every few years when surface water in the tropical Pacific reverses direction and heats up. That warms the atmosphere above, <a href="https://www.climate.gov/news-features/blogs/enso/what-el-ni%C3%B1o%E2%80%93southern-oscillation-enso-nutshell">which influences temperatures and weather patterns around the globe</a>.</p>
<p>Essentially, the atmosphere borrows heat out of the Pacific, and global temperatures increase slightly. This happened in 2016, the time of the <a href="https://www.climate.gov/media/14880">last strong El Niño</a>. Global temperatures increased by about 0.25 F (0.14 C) on average, making <a href="https://www.climate.gov/media/10685">2016 the warmest year on record</a>. A weak El Niño also occurred in 2019-2020, contributing to 2020 becoming the world’s second-warmest year.</p>
<p>El Niño’s opposite, La Niña, involves cooler-than-usual Pacific currents flowing westward, absorbing heat out of the atmosphere, <a href="https://www.climate.gov/news-features/blogs/where-does-global-warming-go-during-la-ni%C3%B1a-0">which cools the globe</a>. The world just came out of three straight years of La Niña, meaning we’re experiencing an even greater temperature swing.</p>
<figure class="align-center ">
<img alt="Charts show the reversing of El Nino and La Nina ever 5-7 years or so and how each El Nino peak corresponds with higher temperatures." src="https://images.theconversation.com/files/539655/original/file-20230726-19-q9sqyp.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/539655/original/file-20230726-19-q9sqyp.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=373&fit=crop&dpr=1 600w, https://images.theconversation.com/files/539655/original/file-20230726-19-q9sqyp.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=373&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/539655/original/file-20230726-19-q9sqyp.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=373&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/539655/original/file-20230726-19-q9sqyp.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=469&fit=crop&dpr=1 754w, https://images.theconversation.com/files/539655/original/file-20230726-19-q9sqyp.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=469&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/539655/original/file-20230726-19-q9sqyp.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=469&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Comparing global temperatures (top chart) with El Niño and La Niña events.</span>
<span class="attribution"><a class="source" href="https://www.swpc.noaa.gov/products/solar-cycle-progression">NOAA Space Weather Prediction Center</a></span>
</figcaption>
</figure>
<p>Based on increasing Pacific sea surface temperatures in mid-2023, climate modeling now suggests <a href="https://www.climate.gov/news-features/blogs/july-2023-el-ni%C3%B1o-update-learning-steps">a 90% chance</a> that Earth is headed toward its first strong El Niño since 2016.</p>
<p>Combined with the steady human-induced warming, Earth may soon again be breaking its annual temperature records. June 2023 was the <a href="https://public.wmo.int/en/media/news/preliminary-data-shows-hottest-week-record-unprecedented-sea-surface-temperatures-and">hottest in modern record</a>. July saw global records for the hottest days and a large number of regional records, including an incomprehensible heat index of <a href="https://www.washingtonpost.com/weather/2023/07/18/extreme-heat-record-limits-human-survival/">152 F (67 C) in Iran</a>.</p>
<h2>Solar fluctuations</h2>
<p>The Sun may seem to shine at a constant rate, but it is a seething, churning ball of plasma whose radiating energy changes over many different time scales.</p>
<p>The Sun is slowly heating up and in half a billion years will boil away Earth’s oceans. On human time scales, however, the Sun’s energy output varies only slightly, <a href="https://climate.nasa.gov/climate_resources/189/graphic-temperature-vs-solar-activity/">about 1 part in 1,000</a>, over a repeating <a href="https://www.swpc.noaa.gov/products/solar-cycle-progression">11-year cycle</a>. The peaks of this cycle are too small for us to notice at a daily level, but they affect Earth’s climate systems.</p>
<p>Rapid convection within the Sun both generates a strong magnetic field aligned with its spin axis and causes this field to fully flip and reverse every 11 years. This is what causes the 11-year cycle in emitted solar radiation.</p>
<figure class="align-center ">
<img alt="A chart shows regular waves of increasing and decreasing sunspot activity. The current cycle is above what was forecast but not near previous highs." src="https://images.theconversation.com/files/539621/original/file-20230726-25-6phzl4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/539621/original/file-20230726-25-6phzl4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=445&fit=crop&dpr=1 600w, https://images.theconversation.com/files/539621/original/file-20230726-25-6phzl4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=445&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/539621/original/file-20230726-25-6phzl4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=445&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/539621/original/file-20230726-25-6phzl4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=559&fit=crop&dpr=1 754w, https://images.theconversation.com/files/539621/original/file-20230726-25-6phzl4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=559&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/539621/original/file-20230726-25-6phzl4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=559&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Sunspot activity is considered a proxy for the Sun’s energy output. The last 11-year solar cycle was unusually weak. The current cycle isn’t yet at its maximum.</span>
<span class="attribution"><a class="source" href="https://www.swpc.noaa.gov/products/solar-cycle-progression">NOAA Space Weather Prediction Center</a></span>
</figcaption>
</figure>
<p>Earth’s temperature increase during a solar maximum, compared with average solar output, is only about <a href="https://www.climate.gov/news-features/understanding-climate/climate-change-incoming-sunlight">0.09 F (0.05 C)</a>, roughly a third of a large El Niño. The opposite happens during a solar minimum. However, unlike the variable and unpredictable El Niño changes, the 11-year solar cycle is comparatively regular, consistent and predictable.</p>
<p>The last solar cycle hit its <a href="https://www.swpc.noaa.gov/products/solar-cycle-progression">minimum in 2020</a>, reducing the effect of the modest 2020 El Niño. The current solar cycle has already <a href="https://www.swpc.noaa.gov/products/solar-cycle-progression">surpassed the peak</a> of the relatively weak previous cycle (which was in 2014) and will peak in 2025, with the Sun’s energy output increasing until then.</p>
<h2>A massive volcanic eruption</h2>
<p>Volcanic eruptions can also significantly affect global climates. They usually do this by <a href="https://scied.ucar.edu/learning-zone/how-climate-works/how-volcanoes-influence-climate">lowering global temperatures</a> when erupted sulfate aerosols shield and block a portion of incoming sunlight – but not always.</p>
<p>In an unusual twist, the largest volcanic eruption of the 21st century so far, the 2022 eruption of Tonga’s <a href="https://www.nature.com/articles/s43247-022-00618-z">Hunga Tonga-Hunga Ha’apai</a>, is having a <a href="https://eos.org/articles/tonga-eruption-may-temporarily-push-earth-closer-to-1-5c-of-warming">warming and not cooling effect</a>.</p>
<figure class="align-center ">
<img alt="An animated GIF shows the eruption from under water sending a large cloud of water vapor into the sky." src="https://images.theconversation.com/files/538885/original/file-20230724-16-8u9xkn.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/538885/original/file-20230724-16-8u9xkn.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/538885/original/file-20230724-16-8u9xkn.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/538885/original/file-20230724-16-8u9xkn.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/538885/original/file-20230724-16-8u9xkn.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/538885/original/file-20230724-16-8u9xkn.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/538885/original/file-20230724-16-8u9xkn.gif?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">The Hunga Tonga-Hunga Ha’apai volcano’s eruption was enormous, but underwater. It hurled large amounts of water vapor into the atmosphere.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/feature/jpl/tonga-eruption-blasted-unprecedented-amount-of-water-into-stratosphere">NASA Earth Observatory image by Joshua Stevens using GOES imagery courtesy of NOAA and NESDIS</a></span>
</figcaption>
</figure>
<p>The eruption released an unusually small amount of cooling sulfate aerosols but an enormous amount of water vapor. The molten magma exploded underwater, vaporizing a huge volume of ocean water that erupted like a geyser high into the atmosphere.</p>
<p>Water vapor is a powerful greenhouse gas, and the eruption may end up warming Earth’s surface <a href="https://doi.org/10.1038/s41558-022-01568-2">by about 0.06 F (0.035 C)</a>, according to one estimate. Unlike the cooling sulfate aerosols, which are actually tiny droplets of sulfuric acid that fall out of the atmosphere within one to two years, water vapor is a gas that can stay in the atmosphere for many years. The warming impact of the Tonga volcano is expected to last for at least five years.</p>
<h2>Underlying it all: Global warming</h2>
<p>All of this comes on top of anthropogenic, or human-caused, global warming.</p>
<p>Humans have <a href="https://www.carbonbrief.org/analysis-why-scientists-think-100-of-global-warming-is-due-to-humans/">raised global average temperatures</a> by about 2 F (1.1 C) since 1900 by releasing large volumes of greenhouse gases, particularly carbon dioxide, into the atmosphere. The amount of carbon dioxide in the atmosphere is up 50%, primarily from the combustion of fossil fuels in vehicles and power plants. The warming from greenhouse gases is actually greater than 2 F (1.1 C), but it has been masked by other human factors that have a cooling effect, <a href="https://climate.nasa.gov/explore/ask-nasa-climate/3271/aerosols-small-particles-with-big-climate-effects/">such as air pollution</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/552419/original/file-20231005-23-d3niz1.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A line chart shows sea surface temperatures by year since 1981.The 2023 line is far above the others." src="https://images.theconversation.com/files/552419/original/file-20231005-23-d3niz1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552419/original/file-20231005-23-d3niz1.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=382&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552419/original/file-20231005-23-d3niz1.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=382&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552419/original/file-20231005-23-d3niz1.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=382&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552419/original/file-20231005-23-d3niz1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=480&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552419/original/file-20231005-23-d3niz1.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=480&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552419/original/file-20231005-23-d3niz1.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=480&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sea surface temperatures in 2023 (bold black line) have been far above any temperature seen since satellite records began in the 1970s.</span>
<span class="attribution"><a class="source" href="https://climatereanalyzer.org/clim/sst_daily/">University of Maine Climate Change Institute</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>If human impacts were the only factors, each successive year would set a new record as the hottest year ever, but that doesn’t happen. The year 2016 was <a href="https://www.climate.gov/media/15021">the warmest</a> in part because temperatures were boosted by the last large El Niño.</p>
<h2>What does this mean for the future?</h2>
<p>The next couple of years could be very rough.</p>
<p>If a strong El Niño develops over the coming months <a href="https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml">as forecasters expect</a>, combined with the solar maximum and the effects of the Hunga Tonga-Hunga Ha’apai eruption, Earth’s temperatures will likely continue to soar. </p>
<p>As temperatures continue to increase, <a href="https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM.pdf">weather events get more extreme</a>. The excess heat can mean more <a href="https://doi.org/10.1038/s43247-022-00524-4">heat waves</a>, <a href="https://doi.org/10.1088/1748-9326/aa5835">forest fires</a>, <a href="https://apnews.com/article/flooding-rainfall-climate-change-warming-atmosphere-d207e68ba3374bdc2df3d36e97a84a1b">flash floods</a> and other <a href="https://www.carbonbrief.org/mapped-how-climate-change-affects-extreme-weather-around-the-world/">extreme events</a>, climate models show.</p>
<figure class="align-center ">
<img alt="A person carries a sandbag on their shoulder while walking through shin-high water past businesses in the rain. A fire hydrant is almost submerged in the flood water." src="https://images.theconversation.com/files/552424/original/file-20231005-23-obpabh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552424/original/file-20231005-23-obpabh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552424/original/file-20231005-23-obpabh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552424/original/file-20231005-23-obpabh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552424/original/file-20231005-23-obpabh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552424/original/file-20231005-23-obpabh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552424/original/file-20231005-23-obpabh.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">A heavy downpour flooded streets across the New York City region, shutting down subways, schools and businesses on Sept. 29, 2023.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/b8ec0f2c55e64a6995ad055d8fe5fa4a?ext=true">AP Photo/Jake Offenhartz</a></span>
</figcaption>
</figure>
<p>In January 2023, scientists wrote that Earth’s temperature had a <a href="https://doi.org/10.1038/s41558-022-01568-2">greater than 50% chance</a> of reaching 2.7 F (1.5 C) above preindustrial era temperatures by the year 2028, at least temporarily, increasing the risk of triggering <a href="https://www.oecd.org/environment/climate-tipping-points-abc5a69e-en.htm">climate tipping points</a> with even greater human impacts. Because of the unfortunate timing of several parts of the climate system, it seems the odds are not in our favor.</p>
<p><em>This article, originally published July 27, 2023, has been updated with September’s record heat.</em></p><img src="https://counter.theconversation.com/content/209975/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Wysession 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 bad news: Extreme heat is probably going to stick around for a couple of more years.Michael Wysession, Professor of Earth, Environmental, and Planetary Sciences, Arts & Sciences at Washington University in St. LouisLicensed as Creative Commons – attribution, no derivatives.