Extreme temperature caused by unchecked climate change could claim 2.3 million lives in Europe by 2100, a new study warns.
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Extreme heat resulting from climate change will become a growing threat in Europe over the next 75 years, new research reports. Without substantial mitigation and adaptation efforts, an additional 2.3 million lives could be lost to extreme-temperature-related causes by the end of the century, with the effects of rising heat outpacing any potential decline in cold-related deaths.
This dire projection comes from a team of researchers led by Pierre Masselot, a statistician and environmental epidemiologist at the London School of Hygiene & Tropical Medicine. Their analysis, published in Nature Medicine, examined climate projections and estimated future temperature-related mortality in 854 European cities with populations greater than 50,000 across 30 countries. The researchers used advanced climate simulations to project daily temperatures for each city and combined the results with statistical data on annual temperature-related deaths in each area.
The worst-case scenario projects that the net death burden from climate change will rise by 50 percent, to about 215,000 deaths per year.
A 2023 study also led by Masselot found that between the years 2000 and 2019, about 143,817 deaths in these cities were attributable to extreme temperatures each year. The new study considered various warming scenarios and revealed that without substantial reductions in greenhouse gas emissions, extreme-temperature-related deaths are expected to rise. The worst-case scenario — characterized by a lack of substantial emissions reductions and minimal adaptation — projects that the net death burden from climate change will rise by 50 percent, to about 215,000 deaths per year, by the end of the century. This scenario would result in the aforementioned 2.3 million additional deaths by 2100.
Masselot noted that the consistency of the trend across all scenarios was surprising. “The takeaway is that if cities warm as much as it is projected in the worst-case scenario, it will be very difficult to adapt,” he said.
Mitigation Versus Adaptation
The study investigated the potential effects of adaptation strategies designed to protect people from heat, such as using air-conditioning and developing cooling centers. But their results found that deaths would rise even if significant adaptation efforts were implemented.
“In [the] absence of mitigation,” Masselot said, “the adaptation to heat would need to be massive to counterbalance this trend.”
Mitigation efforts would mostly take the form of reducing greenhouse gas emissions: Masselot said that up to 70 percent of these extra deaths could be averted by limiting the global average temperature increase to 2 degrees Celsius (35.6 degrees Fahrenheit) by the end of the century through reduced emissions in line with the Paris Agreement. However, recent research suggests that Earth is on track to exceed this limit.
Mediterranean Exposure
Currently, extreme cold causes 10 times more deaths than heat in Europe. However, Masselot explained that though milder winters might mean some northern countries see a reduction in overall temperature-related deaths, the increase in heat-related deaths across the continent will far outweigh this localized effect. The team identified Mediterranean regions — including eastern Spain, southern France, Italy, and Malta — as particularly vulnerable.
The Mediterranean region is more affected because it is a climate change hot spot where temperatures are increasing faster than the global average. “We had a taste of this in 2022 and 2023 when massive heat waves occurred in the region,” Masselot said.
The study also considered expected demographic changes in the European Union. For instance, the population of adults aged 80 and above is projected to increase 2.5-fold between 2024 and 2100. Factors such as age are important given older adults’ increased vulnerability to heat.
Large cities suffer from the so-called heat island effect, in which city centers can be 4 to 5 degrees Celsius (39.2-41 degrees Fahrenheit) warmer than their surroundings, thanks to a combination of pollution, high insolation (exposure to the sun’s rays), and heat-absorbing materials such as asphalt and concrete. This effect makes large Mediterranean cities particularly vulnerable.
“We need to address both climate change and air pollution, and we can do it through the same means: the decarbonization of our economy and our transport system.”
Mark Nieuwenhuijsen, an expert in air pollution and urban planning at the Barcelona Institute for Global Health who was not involved with the research, said scientists shouldn’t ignore adaptation strategies: “We could easily reduce the temperatures if we replace a lot of the asphalt with more green space.”
Particularly in more polluted cities, air pollution also plays a role by exacerbating the deadly effects of heat. Nieuwenhuijsen highlighted the importance of reducing air pollution, both to reduce heat-related deaths and to reduce heat itself, because carbon dioxide emissions drive temperature increases. Air pollution causes 300,000 deaths every year in the European Union, far more than heat or cold, and the solutions to both temperature- and pollution-related mortality go hand in hand. “We need to address both climate change and air pollution, and we can do it through the same means: the decarbonization of our economy and our transport system,” Nieuwenhuijsen said. “This is the positive message, but we can’t wait.”
Masselot noted that the next step is understanding how to build up resilience to heat, which will be necessary even with immediate mitigation efforts. “That means understanding what makes some cities more resilient to heat than others,” he said. “What are the specific characteristics of these cities that we can use to act upon later and can inform policy?”
This story by Javier Barbuzano was originally published by Eos Magazine and is part of Covering Climate Now, a global journalism collaboration strengthening coverage of the climate story.
