More than 50,000 people are estimated to have died in European cities as a result of the intense heatwaves that swept across the continent this summer, making 2026 the deadliest year on record for heat-related mortality in the region, according to a new scientific analysis.

Around two-thirds of the deaths, more than 32,600, are directly attributable to climate change, driven by pollution from fossil fuels. The findings were published in two peer-reviewed studies in the scientific 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,” said Clair Barnes, one of the studies’ authors and a researcher specialising in extreme weather and climate change at Imperial College London.

The stark death toll has emerged just weeks before world leaders gather in Turkey for the annual United Nations climate summit, and days after a UN report warned that the opportunity to limit global warming to 1.5C above pre-industrial levels has now been lost.

“We’re well off track to limit the worst consequences of climate change, and governments need to realise that without faster action and coordination, things are going to get worse,” Barnes warned.

Europe is warming faster than any other continent

Europe is the fastest-warming continent on the planet, while extreme heat, the deadliest form of extreme weather, is becoming increasingly difficult to endure.

Between late May and the end of August 2026, exceptionally high temperatures affected large parts of the continent. Western Europe experienced its hottest summer on record, with temperatures approximately 2.9C above the 1991 to 2020 average.

On individual days, however, the anomalies were considerably more pronounced, with temperatures in some countries exceeding seasonal norms by more than 12C.

How scientists calculated the 50,391 deaths

To estimate the death toll, researchers compared temperatures recorded during the summer across 854 cities in 30 European countries with those that would have been expected in a world without climate change.

They then applied peer-reviewed scientific research examining the relationship between high temperatures and daily mortality to estimate heat-related deaths between early June and late August.

According to the researchers, this methodology has previously produced mortality estimates that broadly align with figures subsequently published by national health authorities.

The analysis identified 50,391 estimated heat-related deaths across the cities studied, which account for approximately 40% of the combined population of the countries included in the research.

Researchers found that this was the highest death toll in 26 years, significantly exceeding the numbers recorded during the major European heatwaves of 2003 and 2022.

Thousands of deaths even in cooler northern European countries

Southern and western Europe were the worst-affected regions, but even traditionally cooler parts of northern Europe, including the United Kingdom, recorded thousands of deaths.

The highest mortality rates were observed among people aged 85 and over. Nevertheless, extreme heat can affect people of all ages.

According to the findings, more than 800 people aged between 20 and 44 died from heat-related causes.

The report concluded that this summer was “probably the most dangerously hot summer Europe has experienced to date”.

Climate change now accounts for two-thirds of heat-related deaths

Scientists also found that climate change is playing an increasingly significant role in heat-related mortality.

At the beginning of the century, fossil fuel pollution was estimated to account for approximately 40% of heat-related deaths. That proportion has now risen to around two-thirds.

Raquel Nunes, associate professor of environmental health at the University of Warwick, who was not involved in the research, said the findings added to the growing body of scientific evidence demonstrating just how deadly extreme heat can be.

Heat is often described as a “silent killer”, she explained, because its effects are not always immediately visible.

One of the most troubling findings, according to Nunes, was the substantial death toll among younger age groups, with thousands of people under the age of 65 estimated to have lost their lives.

Experts urge caution over mortality estimates

Lasse Vestergaard, chief medical officer at the European Mortality Monitoring Network (EuroMOMO), cautioned that mortality estimates derived from statistical models should be interpreted carefully because they involve several uncertainties and assumptions.

Nevertheless, he acknowledged that the researchers’ estimates were broadly consistent with the mortality data published by EuroMOMO during the summer.

‘Summers will become deadlier as long as we depend on fossil fuels’

Barnes warned that unless dependence on fossil fuels is reduced, Europe will continue to experience increasingly hot and dangerous summers, with potentially even higher death tolls in the years ahead.

“Until we move away from our dependence on fossil fuels, we will continue to see hotter and more dangerous summers,” she said, warning that even deadlier summer seasons could lie ahead.

“These figures are a stark reminder that increasingly hot and extreme summers are taking a growing toll on public health. Behind these statistics are real people who have lost their lives and real families grieving their loss.”