Compound urban heat risk revealed by co-location of social vulnerability and elevated temperatures in London, UK: A spatial analysis

Heatwaves are worsening globally under climate change, with significant impacts on human health. Cities are at increased risk due to the urban heat island effect, and vulnerable populations are more likely to experience morbidity and mortality from extreme heat. Improved modelling of social vulnerability is needed in urban areas to better plan for worsening heatwaves and their public health impacts. This study performs Principal Component Analysis (PCA) on fifteen heat-health vulnerability indicators for the borough of Hackney in London, UK and develops a Heat Vulnerability Index (HVI) to rank relative social vulnerability within the borough. Air temperature during the peak of the 2022 UK heatwave is then modeled for the study area to represent the hazard of extreme heat. Social vulnerability to extreme heat is found to vary spatially within Hackney and there are clusters of statistically significant high and low vulnerability scores present. Areas scoring highly on the HVI were significantly associated with higher temperatures during the 2022 UK heatwave, highlighting a positive association between social vulnerability and the hazard intensity of extreme heat. This heat vulnerability map can be used by urban planners and emergency managers to target heat-health interventions to those most at-risk during a heatwave. • A Heat Vulnerability Index is developed for a borough of London, UK using PCA. • Clusters of high vulnerability are revealed, particularly closer to central London. • More vulnerable areas experienced higher temperatures in the 2022 heatwave. • Methods are reproducible using open-source, neighborhood-level data. • Findings provide guidance for targeted urban planning and heatwave adaptation.