This “urban heat island” effect can raise local temperatures by two to five degrees Fahrenheit on average. Such “cool roofs” could cut temperatures by roughly 2.6 degrees Fahrenheit in California’s cities and by 3.2 degrees in cities like Washington or New York. Still, experts caution that more research is needed to figure out just how sensible this idea really is. There’s cost to consider: Are reflective roofs a more effective way to cool a city than, say, planting lots of trees? In Florida, for instance, their models found that reflective roofs had a much smaller cooling effect (about 0.7 degrees) because they caused a slight reduction in local rainfall.

Source: New York Times May 09, 2018 15:22 UTC