NextFin news, Climate change intensified summer heat across Europe in 2025, resulting in an estimated 16,500 additional heat-related deaths in 854 cities, according to a study published on Thursday by the London School of Hygiene & Tropical Medicine (LSHTM) and Imperial College London.
The rapid analysis found that human-driven climate change was responsible for approximately 68% of the 24,400 estimated heat deaths during June to August 2025. Average daily temperatures increased by 2.2°C due to climate change, with peaks up to 3.6°C above pre-industrial levels.
The study covered cities representing about 30% of Europe's population, indicating that the true death toll is likely higher. Heat-related deaths are often undercounted because many result from exacerbated underlying health conditions such as cardiovascular and respiratory diseases, with heat rarely recorded as a direct cause on death certificates.
Older adults were disproportionately affected, making up 85% of the estimated deaths. The study highlights the vulnerability of Europe's aging population, with the proportion of people aged over 80 projected to rise from 6% today to 15% by 2100.
Among European capitals, Rome, Athens, and Paris experienced the highest numbers of excess deaths attributable to climate change, with London also significantly affected. Italy recorded 4,597 climate change-attributable heat deaths, Spain 2,841, Germany 1,477, France 1,444, and the UK 1,147.
A particularly severe heatwave from July 21 to 27 caused nearly 1,000 deaths in Romania, Bulgaria, Greece, and Cyprus, with temperatures reaching up to 6°C above average.
The study used ERA5 temperature data and established exposure-response relationships from 1990 to 2019 to estimate excess mortality under observed conditions and a counterfactual scenario without anthropogenic warming. This approach isolates deaths attributable to human-induced climate change.
Heatwaves are described as "silent killers" because most deaths occur in homes and hospitals among people with pre-existing health conditions, and heat is rarely mentioned on death certificates. Experts warn that even small increases in temperature can mean the difference between life and death for thousands.
Urban areas are particularly at risk due to the urban heat island effect, where cities can be several degrees hotter than surrounding rural areas. Policies such as increasing urban green spaces, flexible work schedules, and improved public health infrastructure are important adaptation measures but may have limited impact without urgent greenhouse gas emission reductions.
In addition to mortality, climate change-driven extreme heat has caused massive economic losses across Europe, including damage to buildings, crops, and reduced productivity, amounting to billions of dollars, according to related studies.
Researchers emphasize that the findings underscore the urgent need for global action to reduce emissions and adapt urban environments to protect vulnerable populations from escalating heat risks.
Sources: London School of Hygiene & Tropical Medicine (2025-09-18), Euronews (2025-09-17), tovima.com (2025-09-19), Nature Climate Change (2025-09-18)
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