The overlapping crises of extreme heat and Covid-19 “severely stretched” an already overwhelmed healthcare system in the UK with “deadly consequences”, a new study finds.
The research, published in Nature Climate Change, estimates the number of heat- and cold-related deaths in England and Wales before and during the Covid-19 pandemic.
The study finds that pressure on the health system during heatwaves was as much as three times higher for the pandemic years than it was in the previous decade. The authors find a similar result during cold periods.
The number of heat-related deaths “shifted higher” in the Covid-19 years, the study says, suggesting that Covid “may have impacted temperature-related mortality during extreme weather events”.
The authors warn that “if health services are already operating at capacity because of one crisis, the additional health burden from another crisis can break the system entirely, endangering the lives of many people”.
One expert not involved in the study tells Carbon Brief that any future pandemic is likely to be a “syndemic”, where its impacts intertwine with those of a changing climate.
And as similar groups tend to be most vulnerable to both major disease outbreaks and extreme weather, anticipating and preparing for the co-occurrence of such events “would be lifesaving”, the study authors conclude.
Heat, cold and Covid
Extreme weather events and pandemics are among the most serious risks facing the UK, according to the UK National Risk Register. Since 2020, both have claimed thousands of lives in the UK.
Between the UK’s first documented Covid-19 case on 30 January 2020 and the end of 2022, around 190,000 people in England and Wales died of the virus, according to death certificates.
Over this two-year study period, the UK has also seen extreme hot and cold temperatures – from the coldest UK temperature in more than 20 years during February 2021 to the country’s first recorded instance of 40C heat in July 2022.
To assess the link between temperature and mortality, the authors produced “epidemiological models” that analyse exposure to different temperatures and human mortality in different regions of the UK.
Dr Eunice Lo is a research fellow in climate change and health at the University of Bristol and lead author on the study. She tells Carbon Brief that “heatstroke and heat exhaustion can occur quite rapidly” and that, in her models, “we expect the mortality outcome to be within three days of exposure to heat”. In contrast, it takes longer for cold snaps to cause mortality, she adds.
The plot below illustrates the example of London. The lowest point on the curve – indicated by a “relative risk” level of one – shows the optimum temperature, when people are at lowest risk of physiological harm from temperature extremes.
If the temperature rises above (red) or falls below (blue) the optimum temperature, the risk of temperature-related mortality increases. This is indicated by a relative risk level greater than one.
Cumulative relative risk of death in London for the overall population, using data from 1981-2022. Source: Lo et al (2024).
The authors developed a series of models for locations across England and Wales. The study estimates that, over the study period, almost 8,500 excess deaths were attributable to high temperatures and more than 125,000 deaths to cold.
The study points out that cold-related deaths are more common in the UK as “most days of the year are considered moderately cold”. As the planet continues to warm, heat-related deaths are expected to rise, while cold-related deaths will likely fall.
Lo tells Carbon Brief that factors including age and socioeconomic status also affect temperature-related mortality, but these were not included in the model.
Extreme temperatures
The chart below, from the study, shows a timeseries of daily deaths attributable to heat (red), cold (blue) and Covid-19 (purple) in England and Wales over the study period. The black line shows deaths in the UK from all causes. The right-hand section of the chart focuses on the July 2022 heatwave, when daily heat-related mortality peaked at 580 deaths – higher than at any time of over the previous decade.
Annual “all-cause mortality” in England and Wales was higher during the pandemic than it was in the preceding decade, as Covid-19 drove up mortality rates, the study finds.
The authors note that cold-related mortality “dominated” heat-related mortality in all months other than July, August and September – adding that spikes in cold-related mortality often coincided with spikes in deaths due to Covid.
There are a range of reasons for this. For example, low humidity in winter allows droplets containing the virus to spread further. And peoples’ immune systems are weaker in the winter due to a lack of vitamin D, making them more vulnerable to the virus.
The study also notes that, over the whole study period, “cumulative temperature-related deaths exceeded cumulative Covid-19 deaths by 8% in south-west England”. And while total temperature-related deaths did not exceed those from Covid in other regions, they did amount to 58% (East Midlands) to 75% (London) of Covid-19 deaths by the end of 2022.
The approach used in the study assumes that deaths caused by Covid-19 and temperature extremes are independent of each other. In other words, individuals are assumed to die either due to Covid or as a result of extreme temperature exposure, but not a combination of the two.
Nonetheless, the findings suggest that Covid “may have impacted temperature-related mortality during extreme weather events”, the study says. For example, “heat-related mortality shifted higher in the Covid-19 years”, compared to extreme events that were not affected by the disease, the authors note.
At the same time, “extreme heat may have exacerbated Covid-19 mortality”, the authors note, pointing out that on 19 July 2022 – the day that 40C heat was recorded – Covid caused 91 more deaths than the daily average over 10-25 July.
The results “highlight the complex interplay between extreme temperatures and the Covid-19 pandemic, as well as its implications on population health and health services capacity”, the study says.
Mapped
The study maps out Covid- and temperature-related deaths to see how they vary regionally.
The authors select 70 heatwave days and 70 cold days from the 30 January 2020 to 31 December 2022 study period. They then calculate regional mortality rates due to Covid, heat and cold during these days.
The maps below show the ratio of temperature-related deaths to Covid-driven deaths over the full study period (left), heatwave period (middle) and cold period (right). Numbers below zero, shown in grey, indicate that Covid-related deaths are higher than temperature-related deaths. Numbers above zero, shown in blue and purple, indicate that temperature-related deaths are higher.
During heatwaves, heat-related deaths far exceed deaths due to Covid-19 in almost all the regions studied. The study finds that the ratio of temperature to Covid-related deaths was highest in London at 2.7, where temperatures tend to be higher.
(This is likely due, in part, to the urban heat island effect – in which a combination of factors, such as buildings, reduced vegetation and high domestic energy use, cause urban areas to become hotter than more rural regions.)
This finding shows that “that even during the Covid-19 pandemic, heatwaves posed a serious threat to public health”, the study says.
Meanwhile, during cold snaps – when both cold-related mortality and deaths due to Covid spiked – Covid-related mortality was higher. The ratio ranges from 0.4 in east of England to 0.8 in south-west England.
The authors suggest that this is mainly due to “large surges in Covid-19 mortality following the first emergence of the coronavirus and the domination of the Alpha variant, both of which occurred in winter”.
The authors then performed the same heatwave and cold snap calculations for the decade preceding the pandemic, to provide a 2010-19 pre-Covid baseline.
The maps below show the ratio of average annual deaths per 100,000 people during the Covid study period to that during the preceding decade, during heatwaves (left) and cold snaps (right). Lighter green indicates that mortality rates in the Covid and pre-Covid periods were similar, while darker colours indicate that deaths during the Covid study period were higher.
The authors find that during pre-Covid heatwave days, heat-related deaths ranged from six to 14 people per 100,000. They add that during the Covid-19 study period, deaths due to heat and Covid-19 together range from 19 to 24 deaths per 100,000 people.
The authors assume that mortality broadly links to regional demand on health services. As such, they estimate that demand on regional health services was between 1.6 (London) and 3.2 (north-west England) times higher during the pandemic than in the previous decade.
By carrying out the same analysis, the authors find that during cold snaps, demand on health services was between 2.0 (south-west England) and 3.4 (east of England) times higher during Covid than in the previous decade.
The paper highlights “the deadly consequences of an already overwhelmed NHS severely stretched to function through the compound crises of extreme weather and Covid-19”, the authors say, adding:
“If health services are already operating at capacity because of one crisis, the additional health burden from another crisis can break the system entirely, endangering the lives of many people.”
Dr Kristina Dahl is senior climate scientist at the Union of Concerned Scientists. In 2020, she was a co-author on a comment paper in Nature Climate Change on the compound risks of climate change and the Covid pandemic.
Dahl tells Carbon Brief that the results of this study highlight the need for “amplified public messaging to increase awareness of temperature-related risks”, for “stronger policies and protections around extreme weather”, and to “more adequately prepare public health systems for the co-occurrence of hazards”.
Co-occurring hazards
Despite the study treating temperature- and Covid-related deaths as independent, Lo tells Carbon Brief that “there is certainly a two-way interaction” between the two.
She explains that “a lot of vulnerabilities to temperatures and Covid-10 are shared”, noting that elderly people and those with pre-existing conditions are vulnerable to both extreme temperatures and viruses. This means that one could exacerbate the other, she warns.
She adds that many measures taken to reduce the spread of Covid may have contributed to a rise in temperature-related death. For example, closing social spaces, such as swimming pools and air-conditioned buildings, meant that many people “didn’t have as much of an escape” from the high temperatures in their homes, she says.
Dr Colin Carlson is an assistant research professor at Georgetown University’s centre for global health, science and security and another co-author on the Nature Climate Change comment paper.
Carlson, who studies the relationship between global climate change, biodiversity loss and emerging infectious diseases, tells Carbon Brief that “for the last two decades, we’ve been operating in a very limited framework with how we think about climate change and infectious disease”.
He adds that “going forward, every pandemic will probably be a ‘syndemic’ with a few climate change-related components”.
Lo notes that while this study focuses on the relationship between Covid-19 and extreme temperatures, it speaks to a larger point about the link between climate-related extremes and other hazards, as co-occurring crises can threaten healthcare and other key systems.
Similarly, Dahl warns:
“As climate-related extremes become more frequent, the likelihood that they will intersect with other crises – whether related to public health, social or political unrest, or other environmental problems – will increase.”
The post Dual impact of extreme heat and Covid-19 had ‘deadly consequences’ for UK appeared first on Carbon Brief.
Dual impact of extreme heat and Covid-19 had ‘deadly consequences’ for UK
Four Ugandan farmers filed a case with London’s High Court on Tuesday, aiming to stop the East African Crude Oil Pipeline (EACOP) from starting to operate by asking the court to apply Uganda’s laws against the project’s UK-registered company.
The controversial 1,443-kilometre (897-mile) pipeline, majority-owned by French energy company TotalEnergies, aims to carry crude from Ugandan fields for export through neighbouring Tanzania. About 80% has been built so far, according to its developers.
The pipeline’s first oil exports are expected as soon as October, according to its developers, and the campaign group Avaaz, which is backing the farmers’ crowdfunded lawsuit, called it “one final chance to stop one of the worst oil pipelines on the planet”.
The claim, filed by London law firm Leigh Day, argues that EACOP Ltd’s role in developing and operating the pipeline breaches Ugandan laws that protect citizens’ right to a clean and healthy environment.
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Ugandan farmers use British court to try to stop East Africa oil pipeline
The farmers and their lawyers will argue that a UK-based entity linked to the East African Crude Oil Pipeline has breached Ugandan law and construction should halt -
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Oil and gas giant TotalEnergies has been given six months by a court to publish a more robust climate plan -
Uganda cites contentious IEA fossil fuel scenario backed by Trump administration
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One of the claimants, Racheal Tugume, told a press conference she had been displaced from her land due to the pipeline’s construction, which she said had damaged local rivers, wildlife and ecosystems that communities depend on for their livelihoods just as erratic weather linked to climate change takes an increasing toll.
“I am very happy that there are people in countries like the UK who are listening to us, who are behind us and who have come to support us,” Tugume said, adding that she hoped the case would bring justice to communities affected by the pipeline.
Ugandan law in UK court
While the pipeline is a joint venture led by TotalEnergies, with smaller stakes owned by Ugandan, Tanzanian and Chinese national oil firms, it is operated by EACOP Ltd, a company registered to an office in London’s Canary Wharf financial district.
EACOP Ltd did not respond to a request for comment.
The claim appears to be the first attempt to have Uganda’s climate and environmental protections enforced in a foreign court, partly reflecting concerns over whether cases challenging the multibillion-dollar pipeline would get a fair trial in Uganda.
Ugandans living near new oil pipeline let down by compensation programmes
Concerns about access to a fair hearing are among the issues the court will consider when deciding if it should take on the case, said Matthew Renshaw, partner at Leigh Day.
Renshaw said that precedents including the Nigerian oil pollution case against Shell have shown that claims against British-registered companies for harms overseas can be successfully fought in UK courts.
“We are proud to represent the four brave principled individuals,” Renshaw said.
Constitutional protections
The pipeline project has already been subject to repeated lawsuits in several countries, none of which have succeeded. A climate lawsuit filed in Uganda more than a decade ago by a group of young people has yet to conclude. Another at the East African Court of Justice, brought by campaign groups against Uganda and Tanzania, was rejected on procedural grounds last November.
A separate ongoing lawsuit in TotalEnergies’ home country of France – a refiled version of an earlier failed claim – cannot stop EACOP going ahead, but it does seek damages from TotalEnergies for affected communities.
With the newly launched case, Leigh Day’s legal adviser Marc Willers said the claim draws on specific Ugandan laws in a bid to stop EACOP’s operations.
Uganda may see lower oil revenues than expected as costs rise and demand falls
These include the Ugandan constitution, a 2019 environmental law and the National Climate Change Act 2021, which gives Ugandans the right to bring a case before a court in circumstances where anyone or any entity threatens the country’s ability to mitigate climate change.
Stopping a “carbon bomb”
The pipeline, which will link Uganda’s Lake Albert oil fields to Africa’s east coast in Tanzania, has already displaced thousands of people and cuts through the Lake Victoria basin, one of East Africa’s major freshwater systems and a critical water source for around 40 million people.
According to the BankTrack non-profit, when the pipeline is at peak production, it will carry 216,000 barrels of crude oil per day and release over 33 million tonnes of carbon emissions each year. Over its full lifetime of 25 years, it is estimated to release about 379 million tonnes of greenhouse gas emissions across its value chain including construction, refining and product use.
A May 2026 report from Earth Insight also warns that the pipeline and related infrastructure could affect 158 wetlands in Uganda, 11 rivers, 44 protected areas and seven key biodiversity areas while disrupting about 2,000 square km of protected wildlife habitats.
This is why the primary focus of the UK court case is to stop the operation of the pipeline in its tracks, Leigh Day’s Willers said, calling it a “carbon bomb” that would worsen the world’s climate crisis.
Long wait for first hearing
While the purpose of the case is to stop the pipeline from launching operations, Renshaw said it could take about 12 months before the case gets a first hearing and about 18 months before it goes to trial.
Billions unlocked as Green Climate Fund agrees to spend more and save less
The farmers are, however, seeking an injunction to stop EACOP Ltd from proceeding with operations. In the event that shipments begin, the lawsuit will still seek to stop the pipeline from then on, Renshaw said.
“We will be doing what we can to expedite matters but it is possible that EACOP will have started operating the pipeline before the claim is heard. If that is the case, the claim would intend to halt operations from that point. For example, the pipeline may operate for just one year rather than 30-plus, resulting in far less harm,” he said.
The post Ugandan farmers launch UK court case against East African oil pipeline appeared first on Climate Home News.
Ugandan farmers launch UK court case against East African oil pipeline
Climate Change
Cited 7 July 2026: ‘Impossible’ heat | Global ocean record | Climate change and the ozone hole
Welcome to Cited, your essential guide to new climate research.
In the news
‘HEAT ALERT’: At least 25 people died as a “heat dome” smothered the eastern half of the US, reported the Guardian, with more than 20 states under “stifling temperatures more than 100F (38C)”. More than 140 million people were under heat alerts, the outlet said, with dead bodies found in “homes with no air conditioning, outside their residences, on the street and in parked cars”. Analysis by World Weather Attribution (WWA) found that the combined heat and humidity would have been “virtually impossible” without human-caused warming, reported the New York Times.
‘MORTALITY WILL RISE FURTHER’: Meanwhile, extreme heat continued to hit Europe, with Le Monde reporting on temperatures of 40C in France, Portugal and Spain again this past weekend, alongside “devastating” wildfires. Public Health France doubled its preliminary estimate of the “excess deaths” from the extreme heat in late June, from 1,000 to more than 2,000, according to the Guardian. The higher figure was still “probably an underestimate”, the agency said. Analysis published by Carbon Brief put the figure at 2,700 heat-related deaths. A WWA attribution study, covered by Carbon Brief, found that Europe’s June heatwave would have been “virtually impossible” even 50 years ago.
‘BOOST TO GLOBAL TEMPERATURES’: The UN World Meteorological Organization (WMO) “raised its forecast for the rapid emergence of a strong El Niño in the coming months, warning that the phenomenon is likely to drive global temperatures higher”, reported Reuters. A WMO scientist told the newswire that “El Niño conditions have emerged in the equatorial Pacific and there is a remarkable agreement between forecast models that this will be a strong El Niño”.
Research picks
Extremes
- The annual season when “intense” tropical cyclones occur has lengthened by 10-14 days per decade across the world since the 1980s | Nature Communications
- There is an “increasing” and “overlooked” global threat from glacial outburst floods from small lakes | Nature Sustainability
- Female smallholder farmers in sub-Saharan Africa experience crops losses 2-2.5 times greater than male smallholders in periods of extreme heat | Nature Sustainability
Policy
- The summaries for policymakers in Intergovernmental Panel on Climate Change (IPCC) mitigation reports over 2001-22 “have not yet become more solution-oriented while abiding by their policy-neutrality principle” | npj Climate Action
- Two-thirds of countries address inequality in their national pledges under the Paris Agreement – particularly in “countries with lower levels of human development and greater income inequality” | Climate and Development
- To “future proof” the Paris Agreement’s “well-below 2C” limit, it should be interpreted as a median “peak warming” of 1.6-1.8C, rather than a 66-90% chance of staying below 2C | Nature Climate Change
Land sink
- From 2001 to 2015, northern Eurasia absorbed about 0.47bn tonnes of carbon each year – around one-third of the total global land carbon sink | Global Biogeochemical Cycles
- Model simulations of potential land-use carbon emissions out to 2100 show that “deforestation and forest regrowth dominate variability” of emissions, with policy timing and ambition “exerting strong control” | Nature Communications
- Tropical forests are facing an increase in areas that exceed critical temperatures where their “photosynthetic system breaks down” | Proceedings of the National Academy of Sciences
Captured
On 21 June, global average sea surface temperature (SST) reached a record high for the day of the year, according to the Copernicus Climate Change Service (C3S). Daily SST for the global ocean, excluding polar regions, reached 20.86C on 21 June, exceeding the 20.83C reached on the same day in both 2023 and 2024, the C3S said. Global SST has remained at record levels for every day since. The conditions “could indicate the beginning of a new phase, leading, once more, to uncharted territory”, said C3S director Carlo Buontempo.
56 hours and 30 hours
The amount of time that the average lifespan of tropical cyclones in the north-east and north-west Pacific has shortened, respectively, over 1982-2024, according to a study in npj Climate and Atmospheric Science. This shorter lifespan “compresses the time available for weather forecasting and disaster preparedness”, the authors said.
Spotlight
The ozone hole and climate change
As a new “thought experiment” asks whether the hole in the ozone layer could, theoretically, have been identified decades before it was discovered, Carbon Brief explores the interactions between climate change and the ozone hole.
It is now more than 40 years since the discovery of the hole in the ozone layer over Antarctica, detailed in the journal Nature in 1985.
A study more than a decade earlier had predicted that chlorine-based substances – such as chlorofluorocarbons (CFCs) – could lead to the destruction of ozone in the stratosphere.
So, in theory, how early could the ozone hole have been detected?
New research, published in the Proceedings of the National Academy of Sciences, explored this very question.
Study co-author Prof Susan Solomon from the Massachusetts Institute of Technology is a leading atmospheric scientist. In the late 1980s, Solomon and colleagues identified the mechanism behind how CFCs were causing ozone depletion.
The new study is a “thought experiment”, Solomon told Carbon Brief, asking when scientists could have discovered the ozone hole had they had access to modern satellite observations.
“We found that depletion could have been detected as early as 1957 in the tropical upper stratosphere, where natural variability is especially small,” explained Solomon.
This would have been before the use of CFCs became widespread, Solomon added. Instead, early ozone depletion was caused by carbon tetrachloride, a chemical used as a cleaning agent, as well as in fire extinguishers and for producing refrigerants.
For many decades, the ozone hole and global warming have often been confused by the public and the media, Solomon explained:
“It’s common to imagine that because ozone is so important at shielding us from the UV [ultraviolet] light that causes skin cancer, then having less ozone must mean the Earth would warm up.”
For example, in a 1995 editorial, the Los Angeles Times congratulated the Nobel prize-winning chemists who identified the threat of CFCs to the ozone layer. The newspaper noted that these processes “threaten calamitous global warming by damaging the Earth’s protective layer of ozone”.
However, said Solomon, “the Earth is warmed much more by visible light – UV doesn’t really contribute, so ozone depletion doesn’t cause significant warming”.
Regional impacts
The depletion of ozone actually has a very small cooling effect at the Earth’s surface. But this is more than outweighed by the warming impact of CFCs and other ozone-depleting substances.
This warming impact means that efforts to reverse ozone depletion have had a beneficial impact on the climate.
The Montreal Protocol, a 1987 international agreement to phase out CFCs, “has played – and is playing – a very substantial role in safeguarding climate too”, said Solomon:
“It turns out that the CFCs and their replacement gases HCFCs [hydrochlorofluorocarbons] are strong greenhouse gases, so phasing out their production has not only avoided a lot of ozone depletion that would otherwise have occurred, it also had a big influence on global warming.”
HCFCs were considered as “transitional substitutes” for CFCs – they still damaged ozone, but to a lesser extent – until ozone-safe alternatives were commercially available.
Hydrofluorocarbons (HFCs), which are not ozone depleting, began to be used widely in the 1990s. However, HFCs are also potent greenhouse gases. HFCs and similar replacements are now being phased out under the 2016 Kigali Amendment to the Montreal Protocol.
While the ozone hole itself has only a very small impact on global temperatures, it does have a clear impact on the regional climate over Antarctica.
Prof David Thompson from Colorado State University, working with colleagues including Solomon, has published research demonstrating that “changes in southern-hemisphere winds linked to the stratospheric ozone losses extend all the way down to the ground in some seasons”, explained Solomon.
This has “reduc[ed] warming that would have occurred in interior Antarctica and enhanc[ed] warming in the Antarctic Peninsula region”, she said.
The knock-on impacts include “wind changes [that] actually extend beyond Antarctica to the mid-latitudes of the southern hemisphere, where they even affect rainfall”, she added.
Preprints to watch
Carbon Brief’s pick of new papers under review
- The drying impact over Africa from using stratospheric aerosol injections to stabilise global temperatures would only be minimised “when combined with a strong decarbonisation effort” | Earth System Dynamics
- The El Niño-Southern Oscillation and Indian Ocean Dipole could “shape” the playing conditions at the Rugby World Cup 2027 in Australia | Journal of Southern Hemisphere Earth Systems Science
- A “strong” weakening of the Atlantic Meridional Overturning Circulation (AMOC) would “profoundly alter the climate-carbon cycle system”, underscoring the “importance of explicitly accounting for AMOC risks in long-term climate assessments” | Earth System Dynamics
Noticeboard
- 6 July-25 September: Registration open for experts to review the first-order draft of the Intergovernmental Panel on Climate Change’s Working Group I report
- 7-15 July: UN High-level Political Forum on Sustainable Development, New York
- 19 July: Application deadline for a postdoctoral scholar in transdisciplinary climate research at Penn State University, US | Salary: unknown
- 22 July: Application deadline for PhD project on “climate change impacts on the Antarctic coastal ocean carbon sink” at the University of East Anglia, UK
- 26 July: Application deadline for PhD projects on “AI for land-atmosphere feedbacks during hydroclimatic extremes” at the Helmholtz School for Integrated Data Science in Environmental & Life Sciences, Germany
- 29 July: Application deadline for an assistant professor in Earth and environmental geosciences (palaeoclimatology) at Colgate University, US | Salary: $97,500-101,500
- 31 July: Application deadline for PhD project on Arctic Ocean methane oxidation at Stockholm University, Sweden
Cited is researched and written by Cecilia Keating, Robert McSweeney, Ayesha Tandon, Daisy Dunne and Dr Giuliana Viglione.
Please send tips, feedback and upcoming climate research to cited@carbonbrief.org
This is an online version of Carbon Brief’s fortnightly Cited email newsletter. Subscribe for free here.
The post Cited 7 July 2026: ‘Impossible’ heat | Global ocean record | Climate change and the ozone hole appeared first on Carbon Brief.
Cited 7 July 2026: ‘Impossible’ heat | Global ocean record | Climate change and the ozone hole
In June 2026, a record-breaking heatwave swept across Europe, with France among the first and hardest hit countries.
In a new analysis, we estimate that the extreme conditions caused more than 2,700 heat-related deaths in France.
We also show how France’s extreme temperatures in June exceeded projections from climate models.
Our findings illustrate the human toll of extreme weather as the world warms.
We also highlight the challenges in projecting the magnitude of future heatwaves and their impacts on people.
Outpacing projections
For most of this century, Europe has seen summer heat extremes that outpace projections from climate models.
Several different factors likely explain this trend, including reductions in planet-cooling aerosols as nations have cleaned up their air pollution, as well as changes in atmospheric circulation patterns, which models struggle to represent.
In June 2026, daily high temperatures averaged across France reached 36.9C, shattering the previous June record set in 2022 by 2.4C.
[For more on the impacts and coverage of Europe’s June heatwave, see Carbon Brief’s explainer.]
The rise in observed temperatures in France has outpaced projections made by climate models, with June maximum temperatures more in line with what was expected for the 2070s.
This is illustrated in the figure below, which shows how France’s average maximum daily high temperature for June recorded in 2026 (black line) compares to climate model projections (blue and orange lines).
Counting the death toll of climate change
The downstream impacts of these extreme temperatures are lethal.
Scientists are able to estimate the death toll of high temperatures in many locations, depending on the availability of mortality and climate data.
There are several ways to do this.
One option is to examine death certificates to see which deaths have been directly recorded by physicians as related to heat. However, there is strong evidence that this method significantly undercounts heat-related deaths, as most death certificates do not consider environmental factors such as heat when diagnosing the cause of death.
Alternatively, it is possible to calculate the rate of total (“all-cause”) mortality in a given time period relative to previous time periods – for example, by comparing the total number of deaths in June 2026 compared to the average of previous Junes. This “excess deaths” figure can be used as an estimate of the deaths from a heat wave.
Using this approach, Public Health France attributed around 2,000 deaths in France to the extreme heat in the week of 22-28 June.
Finally, scientists can use long-term data on overall mortality and correlate changes in mortality with changes in temperature to understand the statistical relationship between the two.
Research published in Proceedings of the National Academy of Sciences in 2025 that used this third approach found that mortality rates in France increase rapidly in cold or hot conditions as daily maximum temperatures depart further from approximately 20C.
This pattern of a U-shaped response of mortality to temperature – shown in the figure below – is very consistent across time periods and regions around the world.
To calculate the death toll of the June 2026 heatwave in France, we compared observed temperatures over 12-29 June to their baseline average over 1980-2025.
The difference between these two temperatures helps us understand how many more people died than they would have in the absence of such extreme conditions.
Over 12-29 June, we found that France has experienced around 2,700 heat-related deaths above the average baseline. Day-to-day heat-related mortality rates rose from less than 100 to almost 300 on the hottest days of 24 and 25 June.
This is shown in the graph below, which illustrates the cumulative total heat-related deaths seen in France over the two-and-a-half week period. The inset shows how heat-related deaths fluctuated on a day-to-day basis during this time.
Recent analysis by World Weather Attribution has already shown that human-caused climate change increased the frequency and intensity of the June heat wave across Europe.
Meanwhile, previous research has shown there is substantial evidence that heat-related mortality in Europe has already been elevated by greenhouse gas emissions.
As a result, we can be confident that at least some of the more than 2,700 deaths already seen in France are directly due to the burning of fossil fuels.
Calculating climate risk
In April, the UN-led body responsible for coordinating the work of climate modelling centres – the Coupled Modelling Intercomparison Project (CMIP) – unveiled a set of seven new emissions scenarios.
These are designed to replace the previous scenarios that have been used by scientists to understand how the climate might change in the future. They will feed into the upcoming seven assessment report (AR7) of the Intergovernmental Panel on Climate Change (IPCC).
The range of future emissions in the new CMIP scenarios is smaller, with scenarios of very high or very low emissions no longer on the table.
The retirement of the very-high emissions scenario – known as “RCP8.5” – led to certain commentators in the media and in politics, including US president Donald Trump, arguing that the risks of climate change had been “overstated”.
[For more on false and misleading claims around the new emissions scenarios, see Carbon Brief’s factcheck.]
Our analysis of June’s heat-related deaths in France suggests that, even if the most severe emissions pathways are no longer needed, climate impacts are taking a heavy toll on society.
Moreover, the temperatures seen in France show that climate models continue to underpredict the magnitude of heatwaves for a particular level of global warming.
This is because greenhouse gas emissions are only a first step in estimating the impacts of climate change.
The second step is converting emissions to changes in the climate at both the global and local levels – or hazards. This includes heatwaves, flash floods and droughts.
The third step is to determine how changes in the hazards will affect local populations. This can be determined by calculating people’s exposure and vulnerability to hazards.
Substantial uncertainty persists at every stage of this sequence.
For example, scientists do not know exactly how the global climate will react to ever-rising greenhouse gas emissions – nor the extent to which global temperature increases will drive local climate hazards. We also do not know how climate change at a local level impacts human health outcomes.
Managing the future of heat risk
Almost all heat-related deaths are preventable.
Adaptation options, such as air conditioning, heat action plans and social support for isolated people, will be crucial as the climate moves away from the typical conditions that people are used to.
Our previous research showed that France made a lot of progress reducing heat-related mortality after the deadly 2003 summer heatwave by taking many of these actions.
Adaptation can reduce deaths, but it cannot eliminate the risk created by continued warming.
Without a move away from fossil fuels, future heatwaves will keep testing the limits of public health systems and more people will die.
The post Guest post: France’s June heatwave caused more than 2,700 heat-related deaths appeared first on Carbon Brief.
Guest post: France’s June heatwave caused more than 2,700 heat-related deaths
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Greenhouse Gases2 years ago嘉宾来稿：满足中国增长的用电需求 光伏加储能“比新建煤电更实惠”
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Climate Change2 years ago嘉宾来稿：满足中国增长的用电需求 光伏加储能“比新建煤电更实惠”
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Renewable Energy9 months agoSending Progressive Philanthropist George Soros to Prison?
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Climate Change2 years ago
Bill Discounting Climate Change in Florida’s Energy Policy Awaits DeSantis’ Approval
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Carbon Footprint2 years agoUS SEC’s Climate Disclosure Rules Spur Renewed Interest in Carbon Credits
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Greenhouse Gases12 months ago
嘉宾来稿：探究火山喷发如何影响气候预测