Summer heat killed a record 50,000 people in Europe’s cities — including 4,354 in the UK

Extreme heat killed a record 50,000 people in Europe’s cities this summer, according to new research, with scientists attributing two in every three of those deaths to climate change.

The study estimated that the extra heat caused by greenhouse gas pollution cut short about 32,000 lives in urban areas between June and August. The researchers, who modelled deaths across 854 cities using long-established links between temperature and mortality, said the toll was the worst they had recorded.

Relentless heatwaves killed nearly twice as many people as in either of the next two deadliest summers, the study found.

In the UK, scientists estimated that 4,354 people died because of the heat.

‘Staggering’ numbers

“In some sense, the absolute numbers of the heat-related deaths estimated across the 854 urban areas are indeed staggering,” said Malcolm Mistry, a climate and health scientist at the London School of Hygiene & Tropical Medicine and a co-author of the study. “But perhaps what is even more alarming is the proportion of these deaths that we attribute to anthropogenic climate change.”

The share of heat deaths linked to human-caused warming has risen from about 40% at the start of the century to 65% this summer, the researchers said.

Katie White, the UK’s climate transition minister, said: “These shocking figures represent thousands of families who have lost a loved one this summer due to the climate crisis.”

Where the heat hit hardest

People died from the heat at the highest rates in Malta, Italy and Hungary. The largest total numbers of deaths were in Italy, France, Spain, Germany and the UK, reflecting the size of their populations.

Naples was the worst-affected city on the continent, with 815 deaths per million people, based on the study’s age-adjusted estimates.

Mario Guarino, an emergency doctor at the Ospedale CTO in the north of Naples, said his department saw a 15% rise in emergency visits during the hottest weeks. The defining feature of the summer, he said, was the way heat worsened complex health problems, with loneliness and poverty making matters worse.

“We took in a terminal cancer patient who lived in a hot attic simply because his family couldn’t find a company to install air conditioning during the summer,” he said. He described an elderly man with dementia who was left alone when his carer returned to Ukraine to say goodbye to her son, who had been called up to fight. Emergency services found the man lying on the floor one night with a fractured pelvis, trying to call a neighbour.

“The real epidemic these days is loneliness,” Dr Guarino said. “Many elderly people are left alone during the summer, abandoned by their families, and due to their low income, they can’t afford air conditioning or, if they do have it, avoid turning it on because of the cost of electricity.”

Who died

People over the age of 85 made up almost half of the deaths. Younger adults were not immune, however: an estimated 833 people aged between 20 and 44 also died because of the heat.

Hot days push vulnerable bodies into overdrive, straining the heart and lungs, while warm nights stop them from recovering. Because death certificates rarely record heat as a contributing factor, such as when high temperatures push a stroke patient or someone with lung cancer beyond their limits, many families never learn that the weather played a part in their relative’s death.

The cities studied are home to about 40% of Europe’s population, and the researchers said their figures could not simply be scaled up to give a full death toll including towns and villages.

A record summer

The EU’s Copernicus climate monitoring service announced this month that western Europe had experienced its hottest summer on record, with more than half the continent exposed to “very strong” heat stress that felt hotter than 38C. Slightly less extreme temperatures in eastern Europe brought the continent-wide average to its third-highest level.

Europe has warmed about twice as fast as the global average. While cold still kills more people than heat, scientists expect rising temperatures to claim more lives than they save, because heat deaths are projected to rise faster than cold deaths fall.

Questions over the method

The study combined known relationships between heat and mortality with temperature records for 2026 to produce rapid estimates. Its country totals differ from those calculated by national public health agencies using their own methods.

David García-García, a researcher at the mortality monitoring system of the Carlos III health institute in Madrid, who was not involved, called the work a “valuable contribution” that allowed comparisons across the continent. “However, it is important to bear in mind that these are estimates based on observed temperatures and epidemiological models, which do not incorporate actual data on deaths occurring in the summer of 2026,” he said.

Doctors have urged governments to cut fossil fuel use, the main driver of rising temperatures, while strengthening health services, planting more greenery in cities and expanding access to cooling. They also stress simple measures: drinking water, staying in the shade and checking on elderly or vulnerable neighbours and relatives, so that help can arrive before a crisis becomes a tragedy.