A recent scientific analysis has estimated that around 2,300 people died from heat-related causes across 12 major European cities during the severe heatwave that ended last week. The study, published on Wednesday, highlights the growing health impacts of climate change-driven extreme weather.
The analysis focused on the 10-day period ending July 2, during which large parts of Western Europe endured intense heat, with temperatures exceeding 40°C (104°F) in Spain and wildfires erupting in France.
A man cools off at a fountain at Retiro park during a heatwave, in Madrid, Spain, July 1, 2025. REUTERS/Juan Medina
Climate Change Linked to Majority of Deaths
Researchers from Imperial College London and the London School of Hygiene and Tropical Medicine estimate that 1,500 of the 2,300 deaths were directly attributable to climate change, which they say significantly amplified the severity of the heatwave
“Climate change has made it significantly hotter than it would have been, which in turn makes it a lot more dangerous,” said Dr. Ben Clarke, lead researcher at Imperial College London.
The cities examined include Barcelona, Madrid, London, and Milan, where scientists found climate change increased heatwave temperatures by up to 4°C, raising the health risks especially for vulnerable populations.
A fiaker (Viennese horse carriage driver) cools his horses with water during a heat wave in Vienna, Austria, July 2, 2025. REUTERS/Lisa Leutner
Rapid Analysis Based on Historical Data
The research team used established epidemiological models and historical mortality data to estimate the toll. Their methodology aimed to provide a timely estimate, as many heat-related deaths go unreported or are not included in official statistics.
The estimated deaths include those where heat was the underlying cause, or where it exacerbated existing medical conditions, such as cardiovascular or respiratory illness.
A resident at the house for elderly persons, La Maison de Chatelet, sits next to a fan, as a heatwave hits Europe, in Chatelet, Belgium July 1, 2025. REUTERS/Yves Herman
Record Temperatures and Growing Risks
According to the EU’s Copernicus Climate Change Service, June 2025 was the third-hottest on record globally, following record Junes in 2023 and 2024. Western Europe experienced its warmest June ever, with widespread exposure to “very strong heat stress”, defined as conditions feeling like 38°C or more.“In a warming world, heatwaves are likely to become more frequent, more intense and impact more people across Europe,” said Samantha Burgess, strategic lead for climate at Copernicus.
Calls for Greater Heat Preparedness
The findings echo warnings from 2023 research, which suggested that up to 61,000 people died in European heatwaves in 2022, raising serious concerns about inadequate heat preparedness across the continent.
The increasing intensity of heatwaves is linked to the accumulation of greenhouse gases, primarily from fossil fuel combustion, which has raised Earth’s average temperature over time. As a result, each new heatwave is more likely to break previous records and cause more harm.
