Research Finds California’s Subsidized Housing Units More Vulnerable to Extreme Heat

An article in Housing Policy Debate, Extreme Heat Vulnerability of Subsidized Housing Residents in California,” finds that subsidized housing in California is disproportionately located in neighborhoods that have more days with extreme heat, more heat-sensitive populations, and less infrastructure to mitigate the effects of extreme heat. The authors suggest various policy solutions to mitigate the adverse effects of high-heat neighborhoods, including increased tree canopies, urban forest initiatives, permeable pavement, and retrofitting subsidized housing with green infrastructure.

Extreme heat is the number one weather-related cause of death in the country. As temperatures rise and urbanization continues, the risk of mortality or illness due to extreme heat will grow even more pronounced. Extreme heat disproportionately affects poorer communities and communities of color, as these neighborhoods are more likely to be highly paved with limited green space. Vulnerability to extreme heat is especially pronounced for seniors, children, and individuals with pre-existing health conditions.

The researchers used historical climate data and climate modeling to identify census tracts that are predicted to have extreme heat in 2040. “High heat” tracts are ones that fall in the top 25% of predicted extreme heat days for the state. They also created an Adaptive Capacity and Sensitivity Index (ACSI) to quantify how vulnerable tracts are to extreme heat. Tracts with a high ACSI score have a greater share of heat-sensitive individuals and/or a built environment less adaptable to extreme heat. The index combines variables measuring the heat sensitivity of the population—such as the share of population under 18 or over 65—with variables measuring the adaptive capacity of the neighborhood. Adaptive capacity is indicated by the share of the population lacking central air conditioning, the share of land in the neighborhood without tree canopy, and the share of land with impervious surfaces. Other ACSI variables include the tract’s poverty rate and percent renters.

The authors assessed the relative proportion of subsidized housing in high-heat tracts, high-ASCI tracts, and “high-high” tracts (high-heat and high-ASCI). While the researchers did not find a disproportionate share of subsidized housing in high-heat tracts, they did find a disproportionate share of subsidized units in high-ASCI tracts, meaning greater vulnerability and less adaptability to extreme heat. Sixty-nine percent of public housing, 47% of LIHTC, and 42% of Housing Choice Vouchers (HCV) are located in high-ACSI tracts. Many variables used to construct the ACSI index are highly correlated with neighborhoods that contain high shares of subsidized housing, such as poverty rate and percentage of renters.

Subsidized housing is also disproportionately located in tracts that experience both extreme heat and high-ACSI indices. The researchers identified a total of 620 high-high tracts. Whereas 8% of all occupied rental homes in California are in these neighborhoods, 16% of public housing units, 14% of Low-Income Housing Tax Credit (LIHTC) units, and 10% of homes occupied by Housing Choice Voucher (HCV) holders are in such neighborhoods. The study reports that subsidized housing units are less likely to have air conditioning, which could exacerbate the effects of extreme heat on subsidized housing residents.

The authors propose various policy solutions to mitigate future impacts of extreme heat, particularly for neighborhoods that have higher proportions of sensitive populations and limited adaptive capacity. California’s Affordable Housing and Sustainable Communities Program provides subsidized housing for low-income renters and retrofits these units to make them more energy efficient and resilient; this program could serve as a model for future programming. Additionally, localities should consider proposals to expand urban forestry initiatives, limit parking spaces, install permeable pavement, and provide access to residential green infrastructure.

The article is at: