Urban sprawl has many negative consequences. Now another has been added to the list; researchers have found that the most sprawling US cities have 2.6 times the risk of deadly extreme heat events than those with the least sprawl. This relationship, which the researchers say has not been documented before, holds regardless of the population, location, or rate of growth of an urban area. Reduced vegetation and increased pavement and other dark surfaces in peripheral developed areas are among the prime suspects in the heat increases.
The study was published online June 23, 2010, in the journal Environmental Health Perspectives.
- "Urban Form and Extreme Heat Events: Are Sprawling Cities More Vulnerable to Climate Change than Compact Cities?"  Brian Stone et al.
The study covers 53 US urban areas that had available data for sprawl and heat events from 1956-2005, providing an easy way to cover this topic for those audiences. In addition, you can apply the same principle to some degree to other cities that have some form of sprawl and temperature data. For instance, the National Climatic Data Center has developed a heat stress index for 187 cities, and the sprawl index used by the researchers is available for 83 urban areas. Even without some of this data, there are issues to report, since the urban areas with the least sprawl still had an average of one additional extreme heat day every decade.