Source from Anthropocene Magazine
Heat is the deadliest weather. Between 1986 and 2015 an average of 130 people per year died from excess heat in the United States, about one-fifth of all natural hazard deaths.
And heat waves are expected to become more frequent and severe with climate change. In Chicago, a 1995 heat wave that was responsible for 700 deaths was unprecedented in 123 years of temperature records. But if high greenhouse gas emissions continue, such conditions are expected to occur every other year by mid-century and three times a year by 2100. Even in a low-emissions scenario, a heat wave of similar intensity is likely to occur twice a decade by the 2050s.
City planners are increasingly interested in green roofs to provide relief from urban heat. Green roofs can insulate buildings, reduce electricity consumption, provide shade and green space, and cut air pollution. In 2008, the Chicago Climate Action Plan set a goal of having 6,000 green roofs installed throughout the city by 2020.
But where should green roofs go in order to maximize their benefits?
A team of researchers from Notre Dame University tackled this question in a paper published September 6 in Environmental Research Letters. They found that while green roofs are often installed on top of City Hall or in other high profile locations, low income neighborhoods stand to gain the most significant benefits. “Thus, efforts to mitigate heat impacts, such as implementation of green roofs, offer solutions to environmental justice issues as well,” the researchers write.
They used computer models to determine how much green roofs could ease the heat in different parts of the city. This depends on factors such as the size and shape of buildings, and local weather patterns like the proximity of cooling breezes from Lake Michigan.
“To determine green roof locations that successfully reduce heat stressors on vulnerable populations, it is critical not only to identify where green roofs can lower the temperatures most, but also to identify populations that are disproportionately affected by high temperatures,” the researchers write.