This study assesses the mortality risks associated with urban heat islands (UHIs) in 85 European cities from 2015-2017. UHIs increase mortality risk during heat extremes (45% median increase), but offer protection during cold extremes (7% median decrease). The annual economic impact of UHI-induced heat-/cold-related mortality averages €192/€-314 per adult urban inhabitant, comparable to air pollution costs. Findings emphasize the need for city planning strategies that consider UHI's seasonality and social costs.

Wan Ting Katty Huang, Pierre Masselot, Elie Bou-Zeid, Simone Fatichi, Athanasios Paschalis, Ting Sun, Antonio Gasparrini, Gabriele Manoli