More than 50,000 people are estimated to have died from heat in European cities during the summer of 2026, making it the region’s deadliest summer in 26 years, according to a new analysis. About two-thirds of the deaths have been attributed to human-induced climate change driven by fossil fuel pollution.

The findings, reported by CNN, estimate that 50,391 heat-related deaths occurred across 854 cities in 30 European countries between June and August. More than 32,600 of those deaths were estimated to be attributable to climate change. The cities covered by the analysis account for about 40 percent of the population of the countries studied.

The findings were published in two peer-reviewed papers in the journal Nature Health.

“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,” Clair Barnes, an author of the reports and an extreme weather and climate change researcher at Imperial College London, told CNN.

The analysis comes weeks before international leaders gather in Turkey for the annual United Nations climate talks and days after a UN report warned that the world had lost its chance of limiting global warming to 1.5 degrees Celsius above pre-industrial levels.

“We’re well off-track to limit the worst consequences of climate change, and governments need to realize that without faster action and coordination, things will only get worse,” Barnes said.

Europe is the world’s fastest-warming continent, and extreme heat is already becoming increasingly dangerous. Unprecedented temperatures scorched the continent from late May until the end of August, with western Europe recording its hottest summer on record.

Temperatures in western Europe averaged 2.9 degrees Celsius (5.2 degrees Fahrenheit) above the 1991-2020 average. On individual days, temperatures in some countries were more than 12 degrees Celsius (21.6 degrees Fahrenheit) above normal.

To estimate the death toll, researchers compared temperatures recorded in 854 cities with those expected in a hypothetical world without climate change. They then applied established research on the relationship between high temperatures and daily deaths to estimate heat-related mortality over the three summer months.

The figures are modelled estimates rather than a count of deaths officially recorded as heat-related. However, researchers said the method has previously produced estimates broadly consistent with those later reported by national health authorities.

Southern and western Europe experienced the worst impacts, but cooler northern regions, including the United Kingdom, also recorded thousands of estimated heat-related deaths.

People aged 85 and older had the highest death rates. However, the toll extended to younger age groups, with more than 800 people aged between 20 and 44 estimated to have died from heat-related causes. Thousands of people under 65 were also estimated to have died.

The findings suggest that the contribution of climate change to heat-related mortality has grown substantially. Earlier this century, fossil fuel pollution was responsible for about 40 percent of heat-related deaths, compared with around two-thirds today.

Raquel Nunes, an associate professor of health and environment at the University of Warwick who was not involved in the research, said the findings added to growing evidence of the dangers of extreme heat.

She said heat is often described as a “silent killer” because its effects are not always immediately visible.

Nunes also highlighted the number of younger people estimated to have died, saying the toll among people under 65 was particularly concerning.

The estimates should nevertheless be treated with caution, according to Lasse Vestergaard, chief physician at the European Mortality Monitoring Network, known as EuroMOMO. He said the calculations involved several uncertainties and assumptions, although the overall estimates were broadly in line with figures reported by the monitoring network during the summer.

The findings were released as scientists warned that the health consequences of extreme heat would worsen without more decisive action to reduce emissions.

“Until we kick the fossil fuel habit, we will continue to see increasingly hot and dangerous summers,” Barnes said.

“These numbers are a stark reminder that our hotter, more extreme summers are having an increasingly severe impact on public health,” she added. “Behind these statistics are real people whose lives were lost and real families who grieve for them.”