Extreme heat across Europe during the summer of 2026 caused an estimated 50,391 deaths, according to new research examining mortality in 854 cities. Nearly two-thirds of the deaths were attributed to additional warming caused by human activity, principally greenhouse gas emissions from burning fossil fuels.

The findings, reported on 23 October, indicate that 32,619 people died as a consequence of temperatures intensified by human-induced climate change. The estimated total represents a 71 per cent increase compared with 2022, previously the deadliest summer in the researchers’ historical dataset, when 29,480 heat-related deaths were calculated.

The research builds on a long-term assessment of heat-related mortality, published in Nature Health on 14 October, which examined the impact of rising temperatures across European cities between 2000 and 2025. The latest estimates for 2026 extend that analysis to an exceptionally severe summer marked by successive heatwaves across much of the continent.

Italy, France, Spain and Germany among worst affected

The highest estimated death tolls were recorded in Italy, France, Spain and Germany, where prolonged periods of extreme heat placed considerable pressure on vulnerable populations and public-health services.

Approximately one-third of the deaths occurred between 17 June and 1 July, when temperatures in some affected areas exceeded seasonal averages by 5.3°C.

The scale of the June heatwave had already become apparent in preliminary national mortality statistics. As EU Today reported in July, France, Belgium and the Netherlands recorded at least 3,700 excess deaths during the early stages of the summer’s extreme temperatures.

Subsequent official assessments suggested that the mortality impact was considerably greater. According to France’s national public-health agency, at least 5,764 excess deaths were recorded during the heatwave between 17 June and 2 July, followed by another 1,243 during the period from 3 to 22 July.

These national figures measure excess deaths from all causes during heatwave periods and are not directly equivalent to the temperature-attributable mortality estimates in the European study.

The researchers also cautioned that their European estimates probably understate the total mortality burden. The 854 cities included in the analysis represent approximately 40 per cent of Europe’s population, while deaths associated with an earlier heatwave in May were excluded.

Climate change responsible for almost two-thirds of deaths

Researchers used established climate-attribution methods to estimate how many deaths would have occurred under natural summer conditions and how many resulted from additional warming associated with greenhouse gas emissions.

Their calculations compared observed temperatures with computer simulations representing a climate without human-induced global warming. The difference between the two scenarios provided an estimate of mortality attributable to climate change.

Clair Barnes, a climate scientist at Imperial College London and lead author of the research, said Western and Northern European infrastructure was not designed to withstand the temperatures now being experienced.

In some European cities, temperatures during the summer reached as much as 12°C above seasonal norms.

The researchers estimated that the proportion of heat-related deaths attributable to human-induced climate change has increased from approximately 45 per cent in the early 2000s to around 65 per cent today.

The findings are consistent with the European Commission’s assessment of rising heat risks, which identifies Europe as the world’s fastest-warming continent, with temperatures increasing at approximately twice the global average rate.

Elderly Europeans account for majority of fatalities

People aged 85 and above accounted for more than half of the estimated deaths, although the research also identified more than 800 deaths among adults aged between 20 and 44.

Extreme temperatures increase the risk of cardiovascular and respiratory complications, dehydration and heatstroke. According to the World Health Organisation’s assessment of heat-related health risks, older people and those with existing medical conditions face particularly serious consequences from prolonged exposure.

The findings also reflect the impact of high overnight temperatures, which prevent buildings from cooling and reduce opportunities for physical recovery after extreme daytime heat.

EU Today previously examined how rising night-time temperatures are exposing weaknesses in European housing and public-health preparedness, particularly in densely populated urban areas.

The latest research identified Rome as having the highest cumulative heat-related death toll among European capitals between 2000 and 2025.

Belgium records separate evidence of climate-related mortality

A study published by Vrije Universiteit Brussel on 20 October provides additional evidence of the mortality impact of this summer’s temperatures.

Researchers estimated that Belgium’s June heatwave caused 1,181 heat-related deaths, of which 665, or 56 per cent, were attributable to human-induced climate change.

The study found that climate change increased temperatures during the heatwave by approximately 3.9°C and more than doubled the estimated number of heat-related deaths. Its findings have not yet undergone peer review.

Belgium’s public-health authorities separately recorded 2,018 excess deaths during and immediately after the heatwave, the highest figure associated with any Belgian heatwave since monitoring began in 2003.

European governments face growing pressure to adapt

The latest findings add to concerns about the capacity of European healthcare systems, residential buildings and urban infrastructure to withstand increasingly severe summer temperatures.

The European Commission has warned that public-health systems across many EU and European Economic Area countries remain insufficiently prepared for extreme heat.

Researchers have identified improved early-warning systems, accessible cooling facilities, better building design and targeted assistance for elderly residents as measures capable of reducing mortality.

The new estimates also demonstrate the limitations of existing mortality records. Heat frequently contributes to deaths without being identified as the immediate medical cause, requiring researchers to use statistical models to calculate its wider impact.

The estimated 50,391 deaths therefore represent modelled heat-attributable mortality rather than individually certified fatalities. Nevertheless, the results indicate that extreme temperatures are becoming an increasingly substantial public-health risk across Europe, extending beyond Mediterranean countries into regions historically less exposed to prolonged summer heat.