The extreme heat we experienced during the summer just gone killed more than 50,000 people in Europe, in urban areas. This is the finding of two scientific studies published by Imperial College London and the London School of Hygiene & Tropical Medicine, whose researchers examined 854 urban areas home to approximately 40 per cent of the total population of the countries analysed — namely the twenty-seven member states of the European Union, plus the United Kingdom, Norway and Switzerland.

The worst figure in 26 years

The overall figure is the worst ever recorded since analyses of this kind began, in 2000, and the authors of the studies explain that roughly two thirds of the deaths are attributable to climate change caused by human activities, starting with the burning of fossil fuels (coal, oil and gas). This means that at least some of the deaths could have been avoided had we acted decisively and effectively to cut greenhouse gas emissions.

The analyses were carried out by cross-referencing data on the extreme temperatures reached in European cities with data on the historical relationship between heat and deaths observed between 2000 and 2026. "This methodology," the authors explain, "produces results consistent with the official statistics on excess mortality subsequently published by national health authorities."

Summer peaks of extreme heat up to +12 degrees Celsius above the 1991–2020 average

This year's summer was characterised by a succession of extraordinarily intense and prolonged heatwaves, exactly as the scientific community had predicted — the same community that warns conditions will only deteriorate in the years ahead. "Western Europe," the scientists stress, "recorded the highest thermal anomaly, with overall summer temperatures approximately 2.9 degrees Celsius above the 1991–2020 average." On certain days, the exceedance reached peaks of +12 degrees Celsius.

The studies note that the 2026 death toll far surpassed all previous records: the highest figures had previously been recorded in 2022 (around 29,000 deaths) and in 2003 (around 28,000), while last year the figure had remained around 15,000. The analyses also show that the period of highest mortality was that between 17 June and 1 July, when daily average temperatures across all cities in western Europe were consistently more than 5 degrees Celsius above the 40-year mean.

The western and southern parts of the continent, as one might expect, suffered the worst consequences in terms of deaths — but even countries where summers are normally less scorching recorded dramatic figures: in the United Kingdom, for example, the death toll stood at around 4,350.

The data for Italy, the country hardest hit by extreme heat

Looking specifically at Italy, the major cities top the death toll rankings: Milan (an estimated 2,467 deaths, 1,627 attributable to climate change), Rome (2,253, 1,558 attributable), Naples (1,845, 1,416 attributable) and Turin (720, 421 attributable). Italy's four largest cities rank first, third, fifth and eighth respectively in the European league table.

As a result, Italy as a whole records by far the highest number of deaths: 13,300, of which more than 8,700 are attributable to climate change. In second place, France counts "only" 7,200; third is Spain with 6,800.

"Yet another warning about the imperative need to abandon fossil fuels"

A further cause for concern is that those losing their lives are not only the elderly, and therefore the most vulnerable to extreme heatwaves: it is estimated that around six thousand people under the age of 65 died in urban areas due to excessively high temperatures. "These numbers are a stark reminder that our increasingly hot and extreme summers are having an ever more severe impact on public health. Behind these statistics are people who have lost their lives and families who mourn them," commented Clair Barnes, an expert in extreme weather events and climate change at Imperial College London.

"This is," she added, "yet another warning both about the imperative need to adopt targeted measures to protect those most vulnerable to extreme heat, and about the need to abandon fossil fuels in order to slow the pace of climate change and limit warming in the future."