LAUSR

A growing literature documents the effects of heat on premature mortality and other adverse health outcomes. Urban heat islands (UHI) can exacerbate climate change impacts by amplifying heat exposure in the day and inhibiting the body's ability to recover at night. The UHI effect varies not only across but within cities. This intra-city variation raises potential environmental justice issues. We combine remote sensing with census data to examine the relationship between distributions of both UHI and income at the neighborhood scale for 25 cities around the world. While we determine a negative relationship between vegetation and UHI and positive relationship between built-up area and UHI, we do not find clear trends between albedo or shortwave surface reflectivity within urban areas and UHI. We find that UHI tends to be less equally distributed than income. In most cases, the impact of this inequity falls most heavily on poorer neighborhoods. Our findings suggest that policymakers should design UHI reduction strategies with explicit considerations for mitigating its impacts on the most socioeconomically vulnerable populations that may not be well-equipped to adapt to climate change. Since the strongest contributor of intra-urban UHI variability among the physical characteristics considered is a neighborhood's vegetation density , increasing green space in lower income neighborhoods is one strategy urban policymakers can adopt to ameliorate some of UHI's inequitable burden on economically disadvantaged neighborhoods.