Inequality in the Availability of Residential Air Conditioning Across 115 US Metropolitan Areas
Residential air conditioning (AC) is one of the most prevalent and widely available methods of heat adaptation; it is, therefore, potentially a large determinant of heat vulnerability. In the US, many prior estimates of AC prevalence rely on large surveys at city or regional levels that are of varying temporal resolution. As a consequence, inter-urban and regional differences in AC are well-understood, but intra-urban variation in AC is more poorly characterized. We develop census tract-level estimates of residential AC prevalence in 115 US core-based statistical areas (CBSAs, ‘metropolitan areas’) to examine how AC varies within cities and how this variation correlates with other indicators of heat vulnerability. The spatial distribution of residential AC is unequal within US metropolitan areas, with census tracts in and around the urban “core” demonstrating lower relative AC prevalence than their more outlying counterparts. Further, this inequality is correlated with several indicators of social vulnerability, as well as heat exposure amplification. Our results provide further evidence that heat vulnerability is systematically unequally distributed within US cities.
Cities, home to 68% of the world’s population by 2050, are on the front lines of climate adaptation. Peak and total electricity demand are anticipated to increase worldwide as increasing extreme high temperatures amplify the demand for adaptation via space cooling. We address the critical need to understand the drivers of demand at the fine spatial and temporal scales at which urban residents make adaptation decisions. Amplification of peak and total electricity demand will be concentrated in mid-latitude, temperate cities, mostly in North America. Although tropical urban areas experience larger increases in high-temperature exposures, their less temperature-responsive electricity demand profiles result in smaller impacts. The upshot is that climate change-driven amplification of electricity demand is unlikely to keep growing as one moves from the mid-latitudes to the equator.
The frequency, severity, and duration of heat stress are expected to increase under continued climate change, highlighting the importance of residential AC as a method of adaptation, especially in urban areas where the urban heat island (UHI) effect amplifies heat exposures. The availability of AC is, therefore, a potentially large determinant of heat vulnerability that is critical to protecting human health. In the US, inter-urban differences in AC prevalence are well-understood, but how it varies within cities is comparatively less well understood. We address this need to characterize intra-urban variation in residential AC availability by constructing empirically derived probabilities of residential AC for 45,995 census tracts across 115 metropolitan areas. Our results illustrate a fundamental inequality in the intra-urban availability of residential AC across US metro areas, whereby census tracts in and around the urban “core” demonstrate lower relative rankings of AC compared to their outlying counterparts, a trend that persists regardless of locational context and regional climate. Further, we find this pattern is strongly correlated with disparities in social vulnerability and urban heat amplification, with the potential for differences along any of the three dimensions examined to manifest substantial differences in adverse health outcomes.
Using data from the American Housing Survey (AHS) and the American Community Survey (ACS), we construct census tract-level probabilities of any residential AC across a large sample of US metropolitan areas that reflect 67% of the total US population. Across regional climates and unique locational contexts, intra-urban variation in AC is unequally distributed within US metropolitan areas. Furthermore, this disparity is strongly correlated with both heat exposure amplification and social vulnerability, suggesting that differentials in AC availability further compound existing disparities in urban heat vulnerability.