Heat and the City: How urban agglomerations devise adaptation measures to protect human health

Over the last few years, climate change has intensified heat effects across broad swaths globally. In 2024, for the first time, global temperatures remained at least 1.5°C above the pre-industrial average for one year. In 2025, persistent heat caused record-setting European heatwaves, which have been recurrent since 2022. The spatial distribution of such effects clearly includes areas where human life is concentrated: cities, megacities, and urban agglomerations at large, rendering cities dangerously hotter and necessitating urgent, specific adaptation measures. We examine the increasing trend in summer temperatures in cities, a key driver of environmental and health issues, to identify the major risks posed by extreme heat, particularly for vulnerable communities. We also evaluate how well current measures across cities worldwide address this growing, ubiquitous issue, with a focus on European cities.

We analyse and compare specific measures and strategies used across cities worldwide to address rising urban heat. We review real-world examples from 2023 and 2024 to examine how cities (such as those in the C40 alliance) are coping with extreme temperatures, employing solutions ranging from urban greening to early warning systems, from water management strategies to population sheltering. We find that, while some cities have made considerable progress in enhancing their heat resilience, a pressing need remains for more refined measures to address urban heat effectively and strategically protect human health. Metropolitan areas across Europe and expanding megacities worldwide thus need comprehensive strategies and shared best practices to manage summer heatwaves and adapt to the impacts of a changing climate that poses novel, compounded hazards to human health.

We argue that public urban spaces are central to climate adaptation in cities because they are highly vulnerable to extreme heat. However, those very spaces can also be pivotal for implementing innovative solutions to improve citizens' well-being. We thus underscore the urgency for cities to adopt adaptive strategies to cope with rising temperatures, given the foreseeable trajectory of heatwaves through time. In analysing the pressing global urban heat challenge, we urge policymakers and urban planners to prioritise sustainable and effective interventions demanded by populations across the complex spectrum of contemporary societies and the compounded hazards that these face.