Feel the heat? Sure you do, but not everyone in the U.S. suffers equally. During many heat waves, more non-white Americans die than white Americans. That surely has to do with the links between race and poverty—and thus not having air conditioning—in the U.S., but one team of public health researchers had another idea.
What if some people in the U.S. live in areas that are hotter than the neighbors just across town? The researchers, all from the University of California, Berkeley, decided they wanted to check if access to trees and other green cover, which keeps neighborhoods cool, is correlated with race. Having more trees and less asphalt in an area keeps reduces air conditioning bills and air pollution.
The researchers found that non-white Americans are more likely to live in census blocks that have little tree cover and more asphalt than white Americans. Blacks were the most likely to live in so-called “heat islands” in cities and suburbs, followed by Asians, then Hispanics, then whites.
This means that in the future, if global warming brings on more heat waves, non-whites could be more vulnerable than their white neighbors. To fix this, cities could plan tree-planting initiatives, the Berkeley researchers wrote in a paper they published in the journal Environmental Health Perspectives. Many major cities, including New York and Chicago, already have new-tree plans in place.
The racial effect persisted even after the researchers controlled for home ownership and poverty. (Poorer neighborhoods all over the world tend to have less tree cover than richer neighborhoods.) Controlling for population density did reduce the effect. That is, people of all races are more likely to live in heat islands if they live in highly populated, dense metropolitan areas. However, previous research has shown that in general, minorities are more likely to live in denser neighborhoods, especially in cities with a history of housing laws and culture that segregate people.
Other research groups have found the link between trees and race in individual cities. The Berkeley researchers used data from the U.S. Census Bureau and the U.S. Department of Agriculture to show that it’s true all across the U.S.
Of course, reducing the disparities in heat-related deaths in the U.S. will require more than just trees. Other researchers have found other reasons driving those racial differences, including that some non-white groups are more likely to have diabetes and heart disease, which make people more vulnerable to heat.