YES-27-G-11: Beyond Cooling: Climate-Robust Urban Environments for Heat-Health Protection in the UK

Britain is entering a heat regime for which its cities were not designed. Across Europe, extreme heat stress is now 2.5 times more frequent than in the 1970s [1]; compound hot-day/hot-night events have risen by 73%, and 15-30 day sequences are 3.4 times more common. In the UK, the Climate Change Committee projects the risk of extreme heat in homes and offices to be four times higher in the 2050s and attributes over 3,000 excess deaths to England’s 2022 heatwaves [2]. Yet urban heat adaptation is still commonly judged by outdoor air temperature or land-surface temperature (LST), although human heat stress depends jointly on temperature, humidity, wind and radiation [1]. Housing, behaviour and vulnerability further shape the consequences of the same thermal environment. Green/blue space, surface cover, built form and ventilation can modify these components in competing ways [3,4].

This project asks: when does a cooler urban environment become a safer one, and for whom? We hypothesise that protection emerges from interactions between green/blue infrastructure, built form, ventilation and moisture, while benefits are also shaped by housing, mobility, behaviour and vulnerability.

The project will reconstruct heat stress across UK cities by integrating meteorological data with Earth observation, land-cover and urban-environment information. It will compare temperature and LST with physiologically relevant indices such as UTCI or WBGT, examining how vegetation, blue space, built form and ventilation shape daytime exposure and night-time recovery. High-resolution environmental characterisation may use building data, street-view imagery, image segmentation and GeoAI to capture fine-scale shade, greenery and urban morphology. Indoor and night-time heat will also be considered, where housing may limit physiological recovery.

Crucially, the project will move beyond residential exposure by examining where people spend time and how they move through cities. Where available, GPS traces and travel-survey diaries will be linked to fine-scale heat surfaces to estimate time-weighted exposure along routes and at activity locations. Network analysis will identify heat-intensive routes and cooler alternatives, while agent-based or activity-based simulation can test how changes in travel timing, destination or route choice alter population exposure under different heat conditions.

The project will then test whether environmental and physiological heat stress translate into meaningful differences in health risk. Longitudinal cohort data, with UK Biobank as a leading option, will link exposure histories with health outcomes. Interpretable epidemiological models, including distributed-lag non-linear models, survival models and stratified or interaction analyses, will compare temperature with physiological heat-stress indices, quantify delayed and cumulative effects, and identify susceptible groups. Analyses will span acute responses, repeated exposure over successive summers and longer-term changes in chronic disease risk and vulnerability. Where data permit, repeated heat exposure will also be related to changes in physical activity, mobility, time outdoors and cooling practices. Together, these analyses will distinguish environments that simply appear cooler from those that provide sustained protection across people, places and stages of life.

Finally, UK climate projections will stress-test urban environments under future warming. Scenario modelling will examine whether green/blue infrastructure and other interventions remain effective under warmer, drier or more humid conditions, and whether strategies that reduce temperature also reduce physiological heat stress and health risk once housing, mobility and behaviour are considered. The project will identify where environments and interventions retain, lose or gain protective value, moving climate-health research towards rigorous evaluation of adaptation effectiveness and maladaptation [5].

References

[1] Emerton, Rebecca, et al. “Global heat stress intensification and its expanding footprint on the human population.” Nature Climate Change (2026): 1-8.

[2] Climate Change Committee. A Well-Adapted UK. 2026. URL: https://www.theccc.org.uk/publication/a-well-adapted-uk/

[3] Lee, Siwoo, et al. “Global patterns of urban heat shaped by climate and morphology.” Nature Communications (2026).

[4] Borah, Angana, et al. “Dense canopies reverse the cooling effect of urban greening in humid cities.” Nature Communications (2026).

[5] Yu, Pei, et al. “Climate change, environmental extremes, and human health.” Innovation Medicine (2026).