Environmental science finds that so-called heat islands occur when urbanized areas experience much higher temperatures than neighboring outlying areas within major metropolitan areas. In and around U.S. cities, more affluent parts of these metropolises are typically heavily covered with trees and green vegetation, while areas that have a high concentration of office buildings and dense residential areas are usually located in the downtown sections of cities, and are in and around more impoverished communities.

The inequitable consequences of these heat islands in the summer months of the year—and increasingly in the late spring and early autumn, too—are many and are growing due to climate change. Consider that in today’s exceedingly hot summer climate, intercity metropolitan temperatures can differ significantly even between neighborhoods. In many major metropolitan localities, such as Washington, DC, there is, at times, as much as a 17 degree Fahrenheit difference between inner-city temperatures and surrounding urban areas. So, one area of a major U.S. city could be enjoying a warm, 88 F day on the same day and time when another area is contending with temperatures of 105 F.

What are the inequitable consequences associated with what environmental economists refer to as “thermal inequality” due to heat islands? Varying heat levels within cities increase demand on a metropolitan area’s energy grid, often leading to power outages in less wealthy parts of those cities just when demand is highest due to the heat island effect. There are losses in labor productivity among workers in dense and less wealthy urban centers due to high heat levels. There are increased rates of hospitalizations due to seasonal heat islands. And rises in urban crime also are linked to heat islands.

Another important way that variations in temperatures within metropolitan areas affect economic outcomes relates to how heat islands shape housing demand and, ultimately, housing costs. My own forthcoming research shows the effects of increased levels of heat on rental property prices within metropolitan statistical areas, or MSAs, of the United States. My initial findings reflect that over time, as temperatures continue to increase, two trends are becoming more pronounced.

One trend points to rising rental prices in some metropolitan statistical areas. As localities within some MSAs that are habitually cooler begin to warm, this warming shifts the climate of places with traditionally harsh winters, making them shorter, less severe, and more bearable. This leads to an increase in rental housing demand as individuals begin to migrate to areas of the United States with more temperate climates.

Read the full article about heat islands by Michael Garvey at Washington Center for Equitable Growth.