Climate change could result in over 2,3 million additional temperature-related deaths in Europe by the end of century
In all climate scenarios examined, the increase in mortality due to heat exceeds any reduction in cold-related deaths. The study highlights the urgency of cutting carbon emissions, the primary driver of climate change, and developing strategies for cities to adapt to rising temperatures

Beach in Barcelona. / Istock
. A new study, led by the London School of Hygiene & Tropical Medicine and with the participation of the Doñana Biological Station - CSIC estimates that changes to the climate could directly result in over 2,3 million additional temperature-related deaths in Europe by 2099 if urgent action is not taken to cut carbon emissions. However, up to 70% of these deaths could be prevented if rapid action is taken.
The analyses shows that climate change will likely result in a significant rise in deaths from heat across Europe, substantially surpassing any decrease in cold-related deaths. This trend persists across climate change scenarios and even under high adaptation to heat, reinforcing the need for aggressive mitigation policies.
The study suggests that even if enormous efforts were made to adapt cities to changing temperatures this would not be enough to balance increased health risks due to exposure to heat, especially in the most vulnerable areas such as the Mediterranean region, Central Europe, and the Balkans. Only swift cuts to carbon emissions that keep temperatures down were shown to reduce the number of extreme heat deaths
Pierre Masselot, lead author at the EHM-Lab at the London School of Hygiene & Tropical Medicine (LSHTM), said: “Our results stress the urgent need to aggressively pursue both climate change mitigation and adaptation to increased heat. This is especially critical in the Mediterranean area where, if nothing is done, consequences could be dire. But, by following a more sustainable pathway, we could avoid millions of deaths before the end of the century.”
The Mediterranean region, one of the most vulnerable
To conduct the study, the researchers use risk functions of temperature in 854 European cities, accounting for local and age-specific adaptation and acclimatisation. These are combined with projections of temperatures, population, and death rates to estimate expected temperature-related death tolls that can be attributed specifically to changing temperatures. The researchers considered a range of climate and epidemiological simulations to assess the uncertainty associated with the estimates, under scenarios defined for the IPCC sixth assessment report. The researchers additionally computed death tolls for scenarios in which the risk of mortality related to heat is reduced.
Due to their larger populations the highest numbers of temperature-related deaths are projected in the most populous Mediterranean cities, but many smaller cities in Malta, Spain and Italy are also likely to be badly affected with high temperature-related death rates.
‘Spain's significant vulnerability is primarily due to the high rates of warming projected for the western Mediterranean region,’ explains Veronika Huber, a researcher at the Doñana Biological Station - CSIC and co-author of the paper. ‘In the most pessimistic scenario analyzed, average temperatures in some Spanish cities are expected to rise by more than 5 degrees above current levels, while the anticipated warming in northern Europe is around 3 degrees’
Barcelona, Madrid and Valencia, in the top ten with the most deaths expected
According to the modelling study, in the worst-case scenario, three Spanish cities -Barcelona, Madrid, and Valencia- are among the ten European cities expected to experience the highest number of temperature-related deaths by the end of the century. Barcelona ranks first, with an estimated additional death toll of more than 246,000. Madrid is estimated to have almost 130,000 additional deaths and Valencia around 67,500.
Another vulnerable country is Italy, which has four cities on this list: Rome and Naples, with around 147,000 additional deaths each, Milan with 110,000 and Genoa with 36,000. The list is completed by Athens (around 87,000 deaths) and Bucharest (around 47,000).
Away from the Mediterranean region, impacts are expected to be less severe, with other European capitals such as Paris (13,515) projected to see a smaller, but still significant, increase in cumulative cold and heat deaths. On the other hand, most cities in the British Isles and Scandinavian countries could see a net decrease in deaths, one being London (-27,455). This lower death toll would however be massively outweighed by the increases in the rest of Europe, resulting in 2.3 million additional deaths across the whole of Europe.
Climate change mitigation and adaptation in cities
Increasing green spaces in cities and planting more trees are essential measures to help prevent at least some of the heat-related deaths in a warmer world. "There are numerous studies showing that green spaces reduce the so-called urban heat island effect," explains researcher Huber. "In addition to lowering the ambient temperature in cities, trees and urban parks offer other health benefits. They provide spaces for social interaction and stress relief”
However, these measures are not enough. According to Huber: ‘Our study shows that the adaptation rates required to prevent an increase in extreme temperature-related mortality are difficult to achieve under an intense warming scenario. For this reason, the continuation of ambitious policies to reduce fossil fuel use is crucial for protecting the health of Europe's population’
In the current geopolitical context, climate policies tend to prioritise adaptation over mitigation. Professor Antonio Gasparrini, senior author of the article and lead of the EHM-Lab at the London School of Hygiene & Tropical Medicine (LSHTM), said: “This study provides compelling evidence that the steep rise in heat-related deaths will far exceed any drop related to cold, resulting in a net increase in mortality across Europe. These results debunk proposed theories of ‘beneficial’ effects of climate change, often proposed in opposition to vital mitigation policies that should be implemented as soon as possible.”
Adaptation scenarios devised in this research inform on the degree of risk reduction needed but remain abstract and do not inform on specific action to be taken. Additionally, this research focuses on daily mean temperature and does not account for specific weather events that could modify the estimated death toll such as extreme night time temperatures and humidity conditions.
Los escenarios de adaptación concebidos en esta investigación informan sobre el grado de reducción del riesgo necesario, pero siguen siendo abstractos y no informan sobre las medidas concretas que deben tomarse. Además, esta investigación se centra en la temperatura media diaria y no tiene en cuenta fenómenos meteorológicos específicos que podrían modificar el número estimado de víctimas mortales, como las temperaturas nocturnas extremas y las condiciones de humedad.
Reference
Masselot, Pierre et al. Estimating future heat-related and cold-related mortality under climate change, demographic and adaptation scenarios in 854 European cities. Nature Medicine. https://www.nature.com/articles/s41591-024-03452-2