Heat Mortality: 50,391 Dead Across European Cities This Summer

Europe's warmest summer on record coincided with 50,391 heat-related deaths across 854 cities, a study by Imperial College London researchers found.

Researchers modelled deaths by age group across June, July and August in cities that hold about 40 percent of Europe's population. They estimated that 32,619 of the deaths were tied to added heat from coal, oil and gas burning. The work is slated for an upcoming issue of Nature Health.

The count ran 71 percent above the 29,480 deaths the same team recorded in 2022, the previous deadliest summer. Italy, France, Spain and Germany logged the highest totals. Roughly a third of the deaths fell between June 17 and July 1, when temperatures averaged 5.3 C above normal. More than half the victims were 85 or older, and more than 800 were aged 20 to 44.

Co-author Garyfallos Konstantinoudis, a biostatistician at Imperial College London, said the figures likely understate the toll. The analysis excludes a deadly May heat wave and covers only the 854 cities studied. Lead author Clair Barnes, a climate scientist at the same institution, said some cities ran 12 C above normal this summer. She said Europe is now 2.5 C hotter than in pre-industrial times, adding that such temperatures can tip conditions "from uncomfortable to dangerous and potentially deadly."

To split natural heat from warming-driven heat, the team ran simulations of a world without climate change and compared them with observed 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. The model produced 2,700 excess deaths for Britain's May and June heat waves; the UK health statistics agency reported 2,800. Dr. Howard Frumkin, former director of the U.S. National Center for Environmental Health, said he was not involved in the study and called the methods state-of-the-art. Dr. Howard Frumkin said summers are getting hotter while tools for attributing deaths to heat are becoming more accurate.

Dr. Courtney Howard, president-elect of the Canadian Medical Association, called for investment in early-warning systems, low-carbon cooling access 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.