Climate and health: major European cities are adapting too slowly

The health effects of climate change are progressing faster than adaptation policies in major European cities. This is the main finding of a study published in The Lancet Countdown Europe, which analyzes for the first time 28 climate- and health-related indicators in 850 cities.

This research assesses, in particular, the exposure of urban populations to extreme heat, fires, pollen, and conditions that promote the transmission of certain infectious diseases. It also examines the responses implemented by local authorities in terms of urban planning, greening, mobility, and prevention.

Health risks that are progressing unevenly

The researchers highlight significant geographical disparities. "The study sheds light on regional disparities in how these cities are affected by and respond to health risks related to climate change," explains Professor Cathryn Tonne, co-lead of the Lancet Countdown Europe.

Cities in southern Europe appear particularly vulnerable to extreme heat. Mortality attributed to them increased by nearly 161% between the periods 1991-2000 and 2015-2024. The risk of forest fires also increased by 7% between 2003 and 2023.

In the east of the continent, climatic conditions favorable to dengue transmission jumped by 369% between 1982-2010 and 2015-2024. Pollen concentrations, meanwhile, more than doubled in cities in southern and eastern Europe over the period studied.

This trend exposes millions of people to increasing health risks, as Europe warms up about twice as fast as the global average.

Greening helps to reduce urban heat

European cities are not remaining inactive. Scientists have identified more than 1.500 adaptation and mitigation measures: early warning systems, development of green spaces, increased tree cover, flood protection, and transformation of mobility.

In 88% of the 533 European cities with more than 100.000 inhabitants studied, urban surface heat decreased between 2014 and 2019. The average decrease reached 0,7°C, with cities that had developed their green spaces the most registering the most significant reductions.

The authors, however, urge caution in interpreting this relationship: the observed association between the increase in green spaces and the reduction of urban heat is not, on its own, sufficient to establish a causal link.

Urban planning and building at the heart of adaptation

Researchers believe that adapting cities requires a combination of approaches. They recommend, in particular, increasing tree cover, reducing soil sealing, and using building materials that absorb less heat.

These guidelines directly concern local authorities, developers, architects, project owners, and building professionals. They imply a greater integration of summer comfort and the health protection of residents into building design, the renovation of existing buildings, and the development of public spaces.

Transforming transportation is another priority. Developing walking, cycling, and public transportation can help reduce greenhouse gas emissions and air pollution, while also promoting physical activity.

The authors also call for strengthening early warning systems and better integrating them with local adaptation plans. These systems should make it possible to anticipate episodes of extreme heat and improve the protection of the most vulnerable populations.

Financial and technical resources are still insufficient.

Despite the initiatives identified, the study concludes that action remains too slow. Researchers point to significant financial and technical obstacles, as well as insufficient political commitment.

“Much remains to be done,” they warn. Cathryn Tonne finds it “surprising” that most of the necessary solutions are already well known but still rarely implemented.

The study does, however, have several limitations. The data, primarily collected at the municipal level, may mask significant disparities between neighborhoods within the same city. Furthermore, some effects could not be assessed, notably the cost of climate change to healthcare systems.

The researchers ultimately call for a simultaneous approach to urban adaptation and greenhouse gas emission reductions. "Every fraction of a degree of warming due to climate change makes protecting health more difficult, both now and in the future," emphasizes Cathryn Tonne.