Unequal scaling of urban vegetation cooling across sociodemographic groups

Yuyang Chang , Gabriele Manoli, Alby D. Rocha, Jonas Schwaab, Maarten J. van Strien, Dominic Andreas Martin, Ronita Bardhan, Jaboury Ghazoul, Fritz Kleinschroth

Urban vegetation mitigates heat in cities, but its benefits often reach disadvantaged residents least, an inequality of growing concern as climate change intensifies urban heat. Whether residence-based cooling exposure and its inequality scale systematically with population size and density, as infrastructural and socioeconomic attributes do, remains unclear. Here, we simulate process-based vegetation cooling and quantify residential exposure across radii using seven million geocoded census records covering urban Switzerland. Mean cooling per resident decreases in denser and more populous areas, with steeper declines among socioeconomically disadvantaged residents and temporary-permit holders. Cooling inequality rises with population size and density. An equity typology combining inequality magnitude and social direction identifies priority municipalities and 1-km² cells, with over a third of municipalities classified as high-inequality and pro-advantaged for both socioeconomic position and residence status. Our findings reveal that both vegetation-cooling inequality and the social stratification of cooling are emergent scaling properties of cities.