Heat linked to 50,391 deaths in European cities, study finds

Heat is now a measurable cause of death. Research led by the London School of Hygiene & Tropical Medicine and Imperial College London estimates 50,391 heat-related deaths across 854 urban areas in 27 EU countries, the UK, Norway and Switzerland in summer 2026. It is the highest figure in 26 years, 71% above 2022.

What happened

The study, published in Nature Health on 23 October, combines temperature records with heat–mortality relationships observed in 232 cities between 2000 and 2019. The authors estimate 50,391 deaths (95% empirical confidence interval 46,026–53,878), 71% more than the 29,480 in 2022 and above the 28,462 in 2003.

Almost two-thirds of those deaths are attributed to human-induced climate change. To calculate this, researchers compared observed temperatures with those of a hypothetical world without warming, in a context of roughly 1.4°C of global heating. Nearly a third of the deaths occurred between 17 June and 1 July, when daily mean temperatures were more than 5°C above the 1991–2020 average. In western Europe, the average anomaly was about 2.9°C.

The UK recorded around 4,500 deaths across 135 urban areas, and about 6,000 of the study's estimated deaths were among people under 65. Older people remained the most affected group. A companion study covering the summers of 2000 to 2025 in the same cities estimates more than 430,000 heat deaths over the period and finds that the share attributable to climate change rose from around 40% in 2000 to more than two-thirds in 2025.

“This summer has been another dramatic reminder that climate change is everybody's problem. It is not just hot regions that are suffering anymore – some parts of Western and Northern Europe are now experiencing extreme heat and historically high health burden,” said Pierre Masselot, assistant professor at LSHTM and co-author. Clair Barnes, a researcher at Imperial College and lead author, stressed the need to “rapidly transition away from fossil fuels” and to roll out “targeted interventions to protect those who are most vulnerable”.

The map: who emits, not who suffers

The map colours countries by their CO₂ emissions per person in 2024, the latest series from Our World in Data based on the Global Carbon Project. It does not measure temperatures or deaths: it shows the scale of annual territorial emissions, an indicator of the pressure each economy puts on the climate.

In Europe, the differences are marked. Belgium records 7.3 tonnes per person; Poland, 7.1; Germany, 6.8; Italy, 5.1; Spain, 4.6; the UK, 4.5; France, 4.0; Switzerland, 3.6; and Portugal, 3.4. Malta, at 3.2, is among the lowest values on the continent. These are 2024 figures and do not include emissions imported in goods made abroad.

Comparing the map with the study helps avoid a simplistic reading. The research places the highest temperatures and estimated mortality rates in southern and western Europe. Poland (7.1), one of the highest per-capita emitters in the EU, lies outside those areas; Italy (5.1) is part of southern Europe. The map does not rank suffering: it ranks the production of emissions.

Nor is the relationship mechanical between countries. Per-capita emissions depend on the energy mix, industry, transport and the size of the economy. A country can cut its territorial emissions and still have a high footprint if it consumes goods produced elsewhere. And a country with low emissions can be especially vulnerable to heat because of its climate, demography or housing quality.

How to read the map

The unit is tonnes of CO₂ per person per year. Lighter shades mean lower emissions and darker shades higher emissions. Click a country to open a card with the value and the year; the map uses 2024 for most of the 170 countries represented. Zoom out and the flat map turns into a 3D globe you can rotate; the 2D/3D button returns to the flat view. The scale is global: countries with very small populations or emissions-intensive industries can appear at the extremes, and year-to-year differences can be large. It is not a measure of historical responsibility or climate effort.

What the map does not say

The map does not say how many people die from heat, or where. Mortality depends on the age of the population, housing, the urban heat-island effect, green space, air conditioning, the health system, outdoor work and baseline mortality. The study itself warns that it does not capture heterogeneity within cities or factors such as housing and socioeconomic status, and that its figures are modelled estimates, not official counts.

Nor does it say which countries are responsible for warming. A single year's per-capita emissions are not the same as cumulative emissions since the industrial revolution, which explain much of the rise in temperature. And they do not measure the consumption footprint: a country can import carbon-intensive goods and report lower territorial emissions.

What comes next

The authors call for two responses in parallel: cutting emissions and adapting cities. The measures they cite include heat-health warning systems, better homes and healthcare facilities, and urban planning with more shade and green space. The next political date is COP31, to be held in Antalya, Türkiye, from 9 to 20 November 2026, with the leaders' summit scheduled for 11 and 12 November. The full studies are available in Nature Health.

The estimates are modelled rather than based on death certificates, so they do not replace official records. That difference matters: 50,391 is not a closed count but an approximation the authors consider likely to be conservative, because it excludes May and rural areas.