Urban Heat Islands

The nature of large cities, with their buildings, roadways, parking lots, and high densities of other impervious surfaces, lends itself to hotter temperatures. Data from a number of large cities around the world show that these areas are indeed a few to many degrees warmer than surrounding natural environments. Not only do these “urban heat islands” (UHIs) pose a threat of heat-related illness, particularly to vulnerable populations, but hotter conditions in urban areas can also lead to worsening air quality. Urban heat islands also carry with them environmental justice implications, as studies in several cities have shown that trees and other natural sources of shade are often lacking in poorer parts of cities. In this unit, you’ll evaluate three ways that cities can attempt to mitigate UHI impacts: planting green roofs, initiating a “cool” roofs program, and revegetating areas to provide additional cooling from shade. Your chosen course of action should consider costs vs. benefits and ensure that those most at risk are central to the solution.