Record heat across Europe this summer caused 50,391 deaths in 854 cities, and 32,619 of those deaths are attributed to the extra heat produced by burning coal, oil and gas, according to a study in an upcoming issue of Nature Health.
That is 71% higher than the previous deadliest summer, 2022, when the same research team counted 29,480 deaths in the same cities.
How the count was built
Researchers modelled heat-related deaths by age group in 854 European cities during repeated heat waves in June, July and August. The cities hold about 40% of Europe's population.
The authors say the true figure is higher. The count excludes a deadly heat wave in May and does not cover deaths outside those cities.
About a third of the deaths fell between 17 June and 1 July, a period when temperatures ran 5.3 C above normal. Some cities recorded temperatures 12 C warmer than their seasonal average.
Who died
More than half of the people who died were 85 or older. The heat also killed more than 800 people aged 20 to 44, a group that public health messaging often overlooks.
Italy, France, Spain and Germany recorded the highest death tolls.
A continent built for a cooler climate
Lead author Clair Barnes, a climate scientist at Imperial College London, said infrastructure in much of Western and Northern Europe was not designed for the temperatures now being recorded.
Europe is the fastest-warming continent and is about 2.5 C hotter than in pre-industrial times. Barnes said that even a small rise in the baseline shifts temperatures from uncomfortable to dangerous for people with heart, lung and kidney conditions.
Dr Jonathan Patz of the University of Wisconsin-Madison, who was not part of the research, said cities need better cooling and protection for vulnerable residents, but that adaptation alone cannot keep up. "We can't just be mopping up the mess on the floor without thinking about turning the faucet off," he said.