Climate change caused 16,500 deaths in European cities in Summer 2025
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16,500 out of 24,400 heat-related deaths in European cities could be directly attributed to climate change.
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Tourists use umbrellas to shelter from the heat as they line up for a tour of the Forum in Rome, on Tuesday, July 22, 2025. (AP Photo/Gregorio Borgia)
An estimated 16,500 deaths in European cities during the summer of 2025 were attributed to rising temperatures caused by climate change, according to a new rapid analysis by UK-based scientists. The study used climate models and historical mortality data to estimate the impact of higher temperatures linked to human-driven global warming, even before official figures are released.
Researchers from Imperial College London and the London School of Hygiene & Tropical Medicine applied peer-reviewed modeling methods to analyze temperature increases across 854 European cities between June and August.
They found that climate change made temperatures an average of 2.2°C hotter in these urban areas compared to a world without human-induced warming.
This temperature spike resulted in an estimated 24,400 excess deaths, of which nearly 70%, or about 16,500, were linked directly to climate change.
The model used
The methodology mirrors previous peer-reviewed studies, using historical data to project how extreme heat affects mortality rates. While real-time death certificates often cite direct health conditions such as cardiovascular or respiratory failure, these are frequently triggered or worsened by extreme heat, especially among older adults.
Though the study’s figures are estimates, the researchers assert they offer a realistic preview of the official death toll, which will be released months later. "It's impossible to get real-time statistics right now," said co-author Friederike Otto, adding the results are "in the right ballpark."
Rome registered the highest number of estimated climate-related deaths at 835, followed by Athens with 630 and Paris with 409. It's also worth noting that the study used data from cities with populations above 50,000, which constitute roughly 30% of the population of Europe.
Europe’s broader heat-health crisis
According to the World Health Organization, Europe accounts for 36% of global heat-related fatalities, with approximately 175,000 deaths annually. In 2025 alone, the summer months proved devastating, particularly for the elderly and those with pre-existing health conditions. Women were also more affected than men, with adjusted data showing 56% higher mortality among females.
The summer of 2025 marks the fourth-hottest on record in Europe, continuing a deadly trend. Previous years saw similarly alarming figures, with more than 61,000 deaths in 2022 and over 47,000 in 2023 due to extreme heat.
A rapid attribution study earlier in the season focused on a 10-day heatwave from June 23 to July 2, estimating that climate change tripled the number of deaths in that period. Cities like Milan, Barcelona, and London also faced significant death tolls.
Urgent calls for adaptation
Experts emphasize that heatwaves are often overlooked as they claim lives quietly in homes and hospitals, earning them the moniker "silent killers." The continued rise in heat-related mortality underscores the urgent need for climate adaptation policies and reduced fossil fuel emissions.
“An increase in heatwave temperature of just 2-4°C can be the difference between life and death for thousands of people,” said co-author Garyfallos Konstantinoudis.
Without robust intervention, researchers warn, the toll from extreme heat in Europe is set to climb even higher in the years to come.
