Examining thermal inequities: Land surface temperature, social vulnerability, and historical redlining in San Antonio, TX

Abstract

Rising urban temperatures significantly impact human health, with their effects varying across socio-economic groups. With a focus on San Antonio, Texas, during its notably intense summer heat in 2023, this research explores the intricate relationship between urban heat and social vulnerability. Through the analysis of Land Surface Temperature (LST) data from Landsat 8 data, captured during three exceptionally hot days, a positive correlation between LST and the Social Vulnerability Index (SVI) was revealed. This relationship shows that areas with higher SVI, indicative of greater vulnerability, consistently experience higher LSTs. The study further investigated two distinct census tracts: one in a previously redlined area with a high SVI and another in a ‘A-best’ HOLC area with a low SVI. The comparative study between these two tracts revealed significant Normalized Difference Vegetation Index (NDVI) and subsequent thermal variances. It was found that the tract in the historically redlined area consistently experiences higher minimum and mean LST, indicating how past housing policies continue to impact present-day environmental and social conditions. Findings reveal the critical connection between urban heat and social vulnerability, contributing to a broader understanding of the interplay between historical and social factors in shaping thermal inequities in a historically redlined city.