Scientists warn! Climate change could kill millions in Europe by 2099

A major study published in Nature Medicine has issued a stark warning for Europe’s future. Led by the London School of Hygiene & Tropical Medicine (LSHTM), the research projects that over 2.3 million additional deaths could occur across European cities by 2099 due to rising temperatures driven by climate change. Covering data from 854 urban areas in 30 countries, the study emphasizes that while cold-related deaths may decline, the overwhelming surge in heat-related mortality will far outweigh any benefits. The findings highlight the urgent need for decisive carbon reduction and climate action.


Mediterranean and central Europe face the greatest risk
The study identifies southern and central Europe as the hardest-hit regions, particularly Mediterranean cities such as Barcelona, Rome, Naples, and Athens. These areas already experience frequent heatwaves, and their ageing populations, dense urbanisation, and high baseline temperatures make them especially vulnerable. By century’s end, Barcelona alone could record more than 246,000 climate-linked deaths. The Balkans and Central European cities are also projected to see dramatic spikes in heat-related fatalities.


Northern Europe: A temporary reprieve
Some northern countries, including Sweden, Finland, and Ireland, may initially experience declines in mortality due to fewer cold-related deaths. However, the benefit is only short-lived. As heat extremes intensify in the late century, even traditionally cooler regions such as Helsinki and Stockholm are projected to shift toward net increases in heat-related mortality.


Why adaptation alone isn’t enough
Researchers stress that adaptation measures like greening cities, improving insulation, and expanding access to air conditioning can help reduce risks. However, even under optimistic adaptation scenarios, the projected death toll remains substantial. The study concludes that without aggressive reductions in greenhouse gas emissions, public health interventions will be insufficient to protect millions of lives.


A stark reminder of climate urgency
Professor Antonio Gasparrini, senior author and head of the Environment & Health Modelling Lab at LSHTM, emphasized that the findings debunk the misconception that global warming could yield “beneficial” reductions in mortality. Instead, the study demonstrates a net increase of about 50% in climate-related deaths by 2099 under current emissions trajectories. Up to 70% of these fatalities, however, could be prevented with immediate and decisive climate action.

This research echoes previous warnings linking recent deadly heatwaves in Europe to climate change. In June 2025 alone, over 2,300 deaths were attributed to extreme heat. The Nature Medicine findings underscore that unless emissions are drastically cut, Europe faces a staggering and avoidable death toll, highlighting climate change as not only an environmental threat but one of the century’s most urgent public health challenges.