Narrowing urban heat disparities alongside faster greening in low-income neighborhoods across cities in the United States

Urban heat disproportionately burdens socioeconomically vulnerable communities, yet how these disparities change over time remains poorly understood. Here we show that heat disparities between low- and high-income neighborhoods generally narrowed across 55 major cities in the United States from 1986 to 2020, although substantial inequities persisted. This narrowing coincided with faster environmental improvements in disadvantaged neighborhoods, particularly greater increases in greenness. Disparity trajectories varied across climate zones, with temperate and cold cities showing narrowing heat gaps, whereas arid cities more often showed persistent or widening gaps. At the city level, environmental disparities followed diverse pathways depending on changes in both overall environmental conditions and the distribution of change between income groups. Changes in greenness disparities were more strongly associated with changes in heat disparities than were changes in cooling efficiency. These findings highlight the dynamic nature of urban environmental inequality and the importance of equitable greening in urban climate adaptation. This study finds that heat disparities between high- and low-income neighborhoods narrowed across 55 U.S. cities from 1986 to 2020, alongside faster greening in disadvantaged neighborhoods, although substantial inequalities persisted.