Imperial Team Links 50,391 Summer Deaths to European Heat

A study due for publication in Nature Health counts 50,391 heat-related deaths across Europe this summer.

Researchers at Imperial College London modelled the effects of repeated heat waves in 854 cities during June, July and August. Their estimate assigns 32,619 of the deaths to warming caused by coal, oil and gas. Italy, France, Spain and Germany recorded the largest numbers. The team has not published city-by-city figures.

The count marks a 71 percent jump from the prior deadliest summer, 2022, when the same researchers calculated 29,480 deaths. The authors say this summer's total is likely low. Their analysis leaves out a heat wave in May, and it covers cities holding about 40 percent of Europe's population.

About one-third of the deaths fell between June 17 and July 1, when temperatures averaged 5.3 C above normal, co-author Garyfallos Konstantinoudis said. He is a biostatistician at Imperial College London. More than half of those who died were 85 or older. The heat also killed more than 800 people aged 20 to 44. Some cities recorded temperatures 12 C above normal, lead author Clair Barnes said. Barnes, a climate scientist at Imperial College London, said Europe is now 2.5 C warmer than in pre-industrial times. "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.

To isolate warming's role, the team simulated a world without climate change and compared the two runs. The gap between them yields 32,619 deaths attributed to warming. Barnes said the share of heat deaths tied to warming has climbed from roughly 45 percent in the early 2000s to 65 percent now.

Heat deaths often go unrecorded on death certificates, so the researchers modelled counts by age group and by each city's optimal temperature, the point at which fewest deaths occur. They compared results with government figures. For May and June heat waves in Britain, the model produced 2,700 excess deaths; the UK health statistics agency reported 2,800. Several outside experts called the methods state-of-the-art.

Dr. Howard Frumkin, former director of the U.S. National Center for Environmental Health, was not involved in the study. He said hotter summers and more accurate attribution methods together yield higher and more reliable counts. Dr. Courtney Howard, president-elect of the Canadian Medical Association, called for investment in early-warning systems, low-carbon cooling and neighborhood buddy systems. 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."

The findings are set to appear in an upcoming issue of Nature Health.