Growing Heat Disparities in the Contiguous United States by End of Century

Abstract

Global warming increases heat-related health risks. Historical evidence suggests disproportionate heat impacts among different regional and socioeconomic groups in the US. However, little is known about the scale of potential disparities and which sub-populations will be most exposed under various future climate scenarios. Here, we assess county-level exposure to moist heat stress from present-day to 2100 in the contiguous US using Earth System Model results from CMIP6 for five future warming scenarios coupled with their corresponding socioeconomic development pathways. Our results reveal stark spatial and sociodemographic disparities in present and future heat stress, mainly for people of color and those aged 65+. The large proportion of high-risk populations residing in the Southern US makes this region particularly vulnerable to heat stress increases, with future warming projected to further increase disparities among disadvantaged groups. Our findings underscore the need for considering sociodemographic factors when developing climate adaptation plans and prioritizing policy responses for vulnerable communities.

Keywords: Heat Index, heat stress disparity, Earth System Models, United States, climate change