Europe hottest summer deaths surged to more than 50,000 in cities, according to new modeling that links the record heat to a sharp rise in mortality across the continent.
Scientists say this past summer was the hottest Europe has ever recorded. Five intense heat waves since May drove temperatures to levels far above normal, with the season averaging about 5.2 degrees Fahrenheit, or 2.9 degrees Celsius, above the 1991 to 2020 baseline.
On some days, readings were close to 22 degrees F, or 12 degrees C, over the norm. Researchers modeled the effects across 854 urban areas covering about 40 percent of the population, and their 2026 analysis found this summer was by a large margin the deadliest on record.
“We’re seeing significantly higher modeled deaths,” said Clair Barnes, an extreme weather researcher at Imperial College London. Previous peaks were in 2022 and 2003, with about 29,000 and 28,000 excess deaths, respectively.
Scientists attribute the trend to climate change making extreme heat more likely, more frequent, and longer lasting. Even small temperature increases can sharply raise health risks, Barnes said.
She and colleagues estimated about two-thirds of the 50,000 deaths identified in their modeling, which Nature Health is set to publish next week, were driven by human-caused warming.
“Any one of those heat waves would have been deadly, but we’ve had five,” Barnes said, noting that most years might see one or two. “It’s not just summer. It’s been turbocharged by climate change and now it’s dangerous.”
The approach for attributing heat deaths to climate change is standard, said Kai Chen, faculty director of the Yale Center on Climate Change and Health, who was not involved. Researchers compare temperatures and associated mortality in a world with climate change to a counterfactual without it, then report the difference.
“This tells people that climate change is not a distant threat anymore,” Chen said, adding that the speed of the analysis provides critical information in near real time.
From June 17 to July 1, daily average temperatures across Europe ran more than 9 degrees F, or 5 degrees C, above the 30-year average. Schools shut down, public transit networks halted service, wildfires flared, and preparedness plans were tested.
Even the Tour de France faced disruptions. Southern and western Europe saw the worst impacts.
Italy recorded the highest modeled excess deaths at 13,303, followed by France with 7,268. Chen noted Europeans are particularly vulnerable because air conditioning is less common than in the United States, where studies show the technology can more than halve fatalities.
Older adults face the greatest peril, since heat can worsen underlying conditions. The latest modeling reflected that pattern, with all but roughly 6,000 of the excess deaths occurring among people 65 and older.
“People don’t realize how dangerous extreme heat can be,” Barnes said. “It’s really important to bring home those risks.”
Europe hottest summer deaths highlight urgent readiness
The World Health Organization called 2026 a “dress rehearsal” for what is ahead. Barnes said analyses like this can raise awareness about preparing for extreme heat while underscoring the need to cut climate pollution.
The modeling could also be run on forecast temperatures to help authorities plan before heat arrives, she noted. Barnes aims to expand the work to other regions, particularly historically marginalized areas such as Africa, where people often feel the effects of extreme heat but may not link them to climate change.
Data gaps could limit that effort in some places, she said. Comparable data largely exist for the United States, where Chen and others are working to implement similar analyses.
The World Health Organization called 2026 a “dress rehearsal” for what is ahead. “That will be very important for the U.S. conversation too,” Chen said. “It can raise awareness and motivate policy action.”
Researchers compare temperatures and associated mortality in a world with climate change to a counterfactual without it, then report the difference, a method also used in a report on how heat pumps and the grid can work in sync.
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