Climate change blamed for thousands of heat deaths across Europe this summer

An analysis of heat-related mortality across 854 European cities found that human-caused climate change was responsible for roughly 68% of an estimated 24,400 deaths during the summer, adding about 16,500 fatalities above what would be expected in an unheated climate, researchers said.

The study, produced by teams including researchers at Imperial College London and the London School of Hygiene & Tropical Medicine, reported that the United Kingdom experienced more than 1,100 heat-attributable deaths and that Italy, Spain and Germany also recorded thousands of additional fatalities linked to rising temperatures. People older than 65 accounted for about 85% of the deaths, and 41% were aged 85 or older.

Researchers said Europe endured several intense heatwaves this summer, including a particularly deadly episode from July 21–27 that struck Romania, Bulgaria, Greece and Cyprus, causing an estimated 950 heat deaths when temperatures reached as much as 6°C above the seasonal average. The capitals with the highest per-capita death rates were Rome, Athens and Bucharest, reflecting local exposure to extreme heat.

The analysis provided country-level estimates of deaths attributable to human-induced warming, finding roughly 4,597 in Italy, 2,841 in Spain, 1,477 in Germany, 1,444 in France, 1,147 in the United Kingdom and 1,064 in Romania. Smaller but non-negligible totals were reported across much of the continent, from Poland and Greece to Croatia and the Netherlands.

"It may not sound like much, but our study shows that shifts in summer heat of just a few degrees can be the difference between life and death for thousands of people," said Dr. Clair Barnes of the Centre for Environmental Policy at Imperial College London. Friederike Otto, professor in climate science at the same centre, said the fatalities would largely have been avoided if societies had not continued to burn fossil fuels over recent decades.

Researchers emphasized that most heat-related deaths occur in homes and hospitals where people with existing health conditions are pushed beyond their limits and that heat is seldom recorded on death certificates. "Heatwaves are silent killers," said Dr. Garyfallos Konstantinoudis of the Grantham Institute. He and other academics noted that despite established heat-health warning systems across Europe, the health burden from heat has remained high in recent summers.

Deaths directly linked to single incidents and individual cases were reported across the continent. Authorities in Spain and Italy documented workers and municipal employees who died during outdoor work in extreme temperatures, illustrating occupational risks. Meteorological agencies in several countries reported all-time or near-record temperatures in multiple locations, with parts of France seeing daytime maxima as much as 12°C above recent norms.

Public-health researchers and meteorologists who contributed to the analysis said adaptation measures—such as heat-health warning systems, flexible work schedules, altered school calendars, increased urban green space, access to air conditioning and improved public-health infrastructure—can reduce risk but will have limited effect unless greenhouse gas emissions are sharply reduced. "Policies to adapt to heat are important," said Dr. Malcolm Mistry of the London School of Hygiene & Tropical Medicine, "but the harsh reality is that unless we urgently reduce greenhouse gas emissions, these interventions will have a limited role in mitigating the risks of human-induced global warming."

European nations are among the fastest-warming regions globally and are expected to face increasingly hot summers if the world does not transition away from fossil fuels, the authors wrote. The study's findings add to a growing body of research quantifying how incremental increases in average temperature multiply the public-health impacts of heat extremes, especially for an ageing population.

Researchers called for both accelerated mitigation of greenhouse gas emissions and strengthened, targeted adaptation measures to protect vulnerable populations. They urged public-health authorities to ensure that heat is systematically tracked as a cause of death and that heat response plans are updated to reflect rising baseline temperatures and the heightened frequency and intensity of heatwaves.

The analysis did not make policy recommendations beyond these broad calls for emissions reductions and improved adaptation, and the authors noted that heat-related mortality remains underreported in official statistics because heat is often not listed as a direct cause on death records.