More than 50,000 people are estimated to have died due to extreme heat across 854 European urban areas in 30 European countries this past summer.

According to the study Heat-related urban mortality attributable to human-induced climate change in Europe in summer 2026, published in Nature Health, approximately two-thirds of those deaths can be attributed to human-caused climate change, primarily driven by the burning of fossil fuels.

Dr. Clair Barnes, extreme weather and climate change researcher at the Centre for Environmental Policy at Imperial College London, said in a press release, “I think we can be quite confident in stating that the summer of 2026 is likely to have been the worst on record for heat-related mortality across much of Europe.” The research also involved scientists from several institutions, notably the London School of Hygiene & Tropical Medicine.

The researchers used temperature records and historical data that looked at the relationship between heat and mortality to estimate the number of heat-related deaths between 2000 and 2026. Their models found that 2026 had the highest estimated number of heat-related deaths since 2000, surpassing the previous peaks of approximately 29,000 deaths in 2022 and 28,000 in 2003.

Western Europe experienced the highest heat anomaly with temperatures for the summer as a whole about 2.9°C above the 1991-2020 average, though some days exceeded it by as much as 12°C. 

To put it into perspective, according to the Copernicus Climate Change Service (C3S), the European climate agency, the average summer temperature in Western Europe as a whole, between 1991 and 2020, was 19.15°C, compared with 21.69°C in 2026, an increase of 2.54°C.

The same effects were felt in Canada. The Canadian Climate Institute reported that Canada is warming twice as fast as the global average and in 2025, the country experienced 12 extreme heat events, most likely due to climate change. As for deaths, a study published in 2024, Estimating the heat-related mortality and morbidity burden in the province of Quebec, Canada, found that heat contributes to approximately 470 deaths each summer in Quebec.

The health impacts

Extreme heat can cause heat stress when the body can’t get rid of internally generated heat fast enough due to high temperatures, humidity and low wind, according to the World Health Organization (WHO). This stresses the body. It also worsens underlying medical conditions such as respiratory and cardiovascular disease, diabetes, dementia and mental health disorders.

Older adults are particularly vulnerable. In the 2026 European study, researchers estimated that 22,502 heat-related deaths occurred among people aged 85 and older, accounting for nearly 45% of the total. However, an estimated 6,000 people under age 65 also died from heat-related causes, including 833 people aged 20 to 44.

Earlier in the century, climate change was estimated to account for about 40% of heat-related deaths, compared with approximately two-thirds in 2026.

Economic and Insurance impacts

Apart from the health impacts, climate change is affecting economics and insurance. The Canadian Climate Institute’s The Health Costs of Climate Change report found that heat-related productivity losses in Canada’s manufacturing sector could reach $1-2 billion annually by 2050.

In a written exchange with the Insurance Portal, Jason Alleyne, FCIA, chair of the Canadian Institute of Actuaries’ Climate Strategy Committee, says, “The effects of extreme heat events on mortality are currently being studied in the actuarial academic community. Insurers are currently focused on the effects of extreme weather on property and casualty insurance claims, and the economic impact of transitioning to a lower-carbon or net zero environment.”

The researchers have called for targeted measures to protect vulnerable populations including reducing reliance on fossil fuels, more green spaces and improvements to health-care facilities that may not be equipped to withstand prolonged heat.