The Lancet's 2026 Europe Cities Report, covering more than 800 cities, finds heat-related deaths rose in 98.7% of European cities. Southern cities recorded a 161% increase (132 additional deaths per 1 million) between 2015–2024 versus 1991–2000, while western cities averaged 64 extra deaths per 1 million. The study also documents a 7% rise in wildfire-smoke exposure days (2003–2023), a 111% average increase in dengue risk, and growing pollen concentrations — yet only 14% of cities meet the recommended 30% tree canopy cover.
Heat-Related Deaths Soar 161% In Southern European Cities, Lancet Report Warns
FILE PHOTO - A tourist fans herself to find relief from the intense heat in the Galleria Vittorio Emanuele. (is associated with: «Study: Heat-related deaths up by 161% in southern European cities») Duilio Piaggesi/IPA via ZUMA Press/dpa
A major analysis published in The Lancet's 2026 Europe Cities Report finds dramatic increases in climate-related health risks across European urban areas. The study examined more than 800 cities and documents sharp rises in heat-related mortality, wildfire smoke exposure, mosquito-borne disease risk and pollen concentrations — with southern and eastern cities among the hardest hit.
Key findings
Heat mortality: Cities in southern Europe recorded an additional 132 heat-related deaths per 1 million inhabitants between 2015 and 2024 — a 161% increase compared with 1991–2000. By contrast, western European cities saw an average rise of 64 additional heat-related deaths per 1 million over the same recent decade, below the continent-wide average increase of 82 per 1 million.
Wildfire smoke: Across Europe the annual number of smoke-exposure days rose by 7% between 2003 and 2023, with southern and eastern cities most affected. Increased smoke exposure heightens respiratory and cardiovascular health risks for urban populations.
Vector-borne diseases: Warming temperatures have enabled the northward and inland spread of disease-carrying mosquitoes. The risk of dengue infection increased by 111% on average across European cities when comparing 2015–2024 with 1981–2010; eastern European cities experienced the largest rise (369%). The study reports similar upward trends for Zika and chikungunya risks.
FILE PHOTO - A girl swims in the sea at Palma Nova Beach in Mallorca. (is associated with: «Study: Heat-related deaths up by 161% in southern European cities») Clara Margais/dpa
Pollen and allergies: Pollen concentrations are rising in many cities. Birch pollen intensity climbed markedly in eastern Europe (Budapest saw an average increase of 137% between 2015 and 2024), while olive pollen increased in parts of southern Europe. Western cities also recorded notable seasonal birch rises (Berlin +66%, Brussels +82% compared with 1991–2000).
Adaptation and nature-based solutions
"Cities have a central role in addressing climate change by implementing adaptation and mitigation solutions that deliver resilient and low-carbon communities, boost local economies, and improve citizens' health," the authors write.
The report highlights urban trees and green spaces as essential for reducing heat stress, improving air quality and supporting mental wellbeing. It notes the UN Economic Commission for Europe's recommended minimum canopy cover of 30% — but finds only 14% of European cities meet that threshold.
Implications: The findings underline an urgent need for coordinated city-level action: expanding tree canopy and green space, strengthening heat-health warning systems, improving air-quality controls, and scaling vector surveillance and public-health preparedness to limit the growing burden of climate-driven illnesses.
Photo credit: Clara Margais/dpa — File photo associated with the study
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