Color line, reflected in green: The racial/ethnic distribution of heat risk-related land cover in relation to residential segregation

Objective: To examine the distribution of heat risk-related land cover (HRRLC) characteristics across racial/ethnic groups in relation to residential segregation.

Methods: Block group-level tree canopy and impervious surface estimates were derived from the 2001 National Land Cover Dataset for densely populated urban areas of the United States and Puerto Rico, and linked to demographic characteristics from the 2000 Census. HRRLC was characterized as living in a block group with no tree canopy and at least half the ground covered by impervious surface (roofs, driveways, sidewalks, roads). Residential segregation was characterized for metropolitan areas in the United States and Puerto Rico using the multigroup dissimilarity index.

Results: After adjusting for ecoregion and precipitation, and holding segregation level constant, non-Hispanic Blacks were 52% more likely (95% confidence interval (CI): 37% to 69%), non-Hispanic Asians 32% more likely (95% CI: 18% to 47%), and Hispanics 21% more likely (95% CI: 8% to 35%) to live in HRRLC conditions compared to non-Hispanic Whites. Within each racial/ethnic group, HRRLC conditions increased with increasing degrees of metropolitan area-level segregation. Further adjustment for home ownership and poverty did not substantially alter these results, but adjustment for population density and metropolitan area population largely explained the segregation effects.

Conclusions: Land cover was strongly associated with segregation within each racial/ethnic group, which may be partially explained by the concentration of racial/ethnic minorities into densely populated neighborhoods within larger, more segregated cities. In anticipation of greater frequency and duration of extreme heat events, climate change adaptation strategies, such as planting trees in urban areas, should explicitly incorporate an environmental justice framework that addresses racial/ethnic disparities in HRRLC.