Record European Summer Heat Linked to More Than 50,000 Deaths, Study Finds

Extreme heat across Europe this summer contributed to the deaths of more than 50,000 people, and nearly two-thirds of those deaths can be blamed on human-caused climate change, according to a new study.

Researchers modelled heat-related deaths by age group in 854 European cities through repeated heat waves in June, July and August. They estimated that 50,391 people died because of warmer temperatures, including 32,619 who died because of the added heat from burning coal, oil and gas. The findings are set to appear in an upcoming issue of Nature Health.

The toll is 71 per cent higher than that of the previous deadliest summer, 2022, when the same team counted 29,480 deaths. The authors say this year's figures are likely an underestimate. They leave out a deadly heat wave in May and cover only the 854 cities, which hold about 40 per cent of Europe's population. Italy, France, Spain and Germany recorded the highest death tolls.

About one-third of the deaths came between June 17 and July 1, when temperatures ran 5.3 C above normal, said co-author Garyfallos Konstantinoudis, a biostatistician at Imperial College London. More than half of the victims were 85 or older, but the heat also killed more than 800 people aged 20 to 44.

Lead author Clair Barnes, a climate scientist at Imperial College London, said some cities saw temperatures 12 C above normal this summer. "Much of Western and Northern Europe, our infrastructure is just not designed to cope with the sort of temperatures that we are seeing now because of the effects of human-caused warming," she said. Europe is the fastest-warming continent and is now 2.5 C hotter than in pre-industrial times, she added. That extra warming, she said, can tip temperatures "from uncomfortable to dangerous and potentially deadly."

To separate natural heat from climate-driven heat, the team ran computer simulations of a world without climate change and compared them with this summer's actual deaths. The gap represents the effect of global warming. Barnes said the share of heat deaths attributable to warming has risen from about 45 per cent in the early 2000s to 65 per cent now.

Because heat deaths are underreported and often not recorded on death certificates, the researchers relied on statistical modelling that accounts for age and for each city's optimal temperature, the point at which the fewest deaths occur. They checked the results against government estimates, which mostly matched. For the May and June heat waves in Britain, the model produced 2,700 excess deaths, while the United Kingdom's health statistics agency reported 2,800. Several outside experts called the methods state-of-the-art.

Dr. Howard Frumkin, former director of the National Center for Environmental Health in the U.S., who was not involved in the study, said summers are getting hotter while the tools for attributing deaths to heat are becoming more accurate. Together, he said, the trends produce higher and more reliable counts.

Outside experts said adaptation must go hand in hand with cutting emissions. Dr. Courtney Howard, president-elect of the Canadian Medical Association, called for investment in early-warning systems, equitable access to low-carbon cooling and neighborhood buddy systems for people most at risk. Dr. Jonathan Patz of the University of Wisconsin-Madison said society cannot keep "mopping up the mess on the floor without thinking about turning the faucet off," and stressed the need to address fossil fuel burning.