50,391 Europeans died during the hottest summer on record

50,391 people died in European cities this summer because of extreme heat, according to a new study published in Nature Health. The researchers found that 32,619 of those deaths were directly linked to additional warming caused by the burning of coal, oil, and gas.

The team modeled heat-related mortality by age group across 854 European cities during the heat waves in June, July, and August. These figures mark a 71% increase over the previous record set in 2022, when the same research group counted 29,480 deaths. The authors note that the current total is likely an underestimate because it excludes a deadly heat wave in May and covers only the 854 cities, which hold about 40% of Europe's population.

Italy, France, Spain, and Germany recorded the highest death tolls. Garyfallos Konstantinoudis, a biostatistician at Imperial College London and co-author of the study, stated that about one-third of the deaths occurred between June 17 and July 1. During that two-week period, temperatures ran 5.3 degrees Celsius above normal. More than half of the victims were aged 85 or older, but the heat also claimed the lives of more than 800 people between the ages of 20 and 44.

Clair Barnes, the lead author and a climate scientist at Imperial College London, said some cities experienced temperatures 12 degrees Celsius above normal this summer. She explained that much of Western and Northern European infrastructure was not designed to handle the current temperature range. Barnes added that Europe is the fastest-warming continent, now 2.5 degrees Celsius hotter than pre-industrial times. She described this extra warming as the factor that can tip temperatures from uncomfortable to dangerous and potentially deadly.

To isolate the effect of climate change, the team ran computer simulations of a world without human-caused warming and compared those models to this summer's actual death counts. The difference represented the mortality attributable to global warming. Barnes noted that the share of heat deaths linked to warming has risen from approximately 45% in the early 2000s to 65% today.

Heat deaths are frequently underreported and rarely listed on death certificates. To account for this, the researchers used statistical models that factor in age and each city's optimal temperature, which is the point where the fewest deaths occur. They validated these results against government estimates. For the heat waves in Britain in May and June, the model calculated 2,700 excess deaths, while the United Kingdom's health statistics agency reported 2,800. Several outside experts described the methodology as state-of-the-art.

Dr. Howard Frumkin, former director of the National Center for Environmental Health in the U.S., was not involved in the study. He observed that summers are growing hotter while the tools for attributing deaths to heat are becoming more accurate. He stated that these two trends together produce higher and more reliable counts.

Outside experts emphasized that adaptation measures must accompany efforts to cut 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 those most at risk. Dr. Jonathan Patz of the University of Wisconsin-Madison argued that society cannot continue to clean up the consequences without stopping the source of the problem. He stressed the need to address fossil fuel burning directly.