European heat toll hits 50,391 as warming drives two-thirds of deaths

Extreme heat across Europe this summer contributed to 50,391 excess deaths, according to a new study by researchers at Imperial College London. Of that total, 32,619 deaths were attributed specifically to the additional heat caused by burning coal, oil, and gas.

The study, set to appear in Nature Health, modeled heat-related mortality in 854 European cities during heat waves in June, July, and August. The death toll is 71 percent higher than the previous record set in 2022, when the same team counted 29,480 deaths. Authors note the figures are likely an underestimate because they exclude a deadly May heat wave and cover only cities that hold about 40 percent of Europe's population.

Italy, France, Spain, and Germany recorded the highest numbers of heat-related deaths. More than half of the victims were aged 85 or older, but the heat also killed more than 800 people between the ages of 20 and 44. Co-author Garyfallos Konstantinoudis, a biostatistician at Imperial College London, said about one-third of the deaths occurred between June 17 and July 1, when temperatures ran 5.3 degrees Celsius above normal.

Lead author Clair Barnes, a climate scientist at the same institution, said some cities experienced temperatures 12 degrees Celsius above normal. She noted that infrastructure in much of Western and Northern Europe was not designed for these conditions. Barnes added that Europe is the fastest-warming continent and is now 2.5 degrees Celsius hotter than pre-industrial levels. She described how that extra warming can tip temperatures from uncomfortable to dangerous and potentially deadly.

The team separated natural heat from climate-driven heat by running computer simulations of a world without climate change and comparing those results with actual summer deaths. Barnes said the share of heat deaths attributable to warming has risen from about 45 percent in the early 2000s to 65 percent now. Because heat deaths are often underreported on death certificates, the researchers used statistical models that account for age and each city's optimal temperature. The model produced 2,700 excess deaths for Britain in May and June, compared with 2,800 reported by the UK's health statistics agency.

Outside experts praised the methods while calling for action. Dr. Howard Frumkin, former director of the National Center for Environmental Health in the U.S., said summers are getting hotter while attribution tools are becoming more accurate, leading to higher and more reliable counts. Dr. Courtney Howard, president-elect of the Canadian Medical Association, called for investment in early-warning systems and equitable access to low-carbon cooling. Dr. Jonathan Patz of the University of Wisconsin-Madison stressed the need to address fossil fuel burning, stating society cannot keep mopping up the mess without turning off the faucet.