Lucia Wiggers
Williams College
Project completed Spring 2021

Rosa Kirk-Davidoff
Williams College
Project completed Spring 2021

Abstract

The impacts of green space (or lack thereof) on the surface temperature of cities have long been studied through the Urban Heat Island effect. However, the extent to which the historic discriminatory housing policy of redlining influences the temperatures of different neighborhoods in the same city is still being revealed. Here, we investigate how Home Owners’ Loan Corporation (HOLC) maps correspond to land surface temperatures through the uneven distribution of tree canopy and impervious surfaces in New York’s Capital District. Using HOLC maps for Albany, Troy, and Schenectady, we calculated percent tree cover and imperviousness for each of the map’s graded blocks and calculated the land surface temperature for each block using Landsat 8 imagery. Our results showed that neighborhoods rated “hazardous” were generally hotter, more impervious, and less tree-covered than those rated “best” in Albany and Schenectady, but not in Troy. The difference between blocks rated “hazardous” and blocks rated “best” was +2.67°C in Albany, +4.18° in Schenectady, and -1.18° in Troy. Discriminatory housing policies can influence to what extent minority communities with lower resources are exposed to urban heat, and these communities should be identified to help them become more resilient to the environmental, physiological, and social impacts of climate change in the future.

KEYWORDS: Redlining, Home Owners’ Loan Corporation (HOLC), New York, Housing Policy, Heat, Temperature