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 cools cities, but its benefits often reach disadvantaged residents least, a growing concern as urban heat risks intensify. 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 vegetation cooling across Switzerland using process-based modeling and link estimates to geocoded census records for over seven million urban residents. 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, and over a third of Swiss municipalities combine above-average inequality with benefits favoring socioeconomically advantaged or permanently settled residents. By classifying both the magnitude and social direction of inequality across municipalities and 1-km² cells, we provide a spatial diagnostic for equitable, climate-resilient greening interventions. Our findings reveal vegetation-cooling inequality as an emergent scaling property of cities.