White Roofs Cool Cities More Than Trees Cities are hot spots.
Their paved surfaces and dark rooftops absorb energy from the
sun, which creates localized areas of high temperatures.
Expanded out from the building scale to the city scale, these
hot roofs and blacktops collectively create a blanket of
retained warmth in a city, raising temperatures an annual
average of about 2 to 5 degrees Fahrenheit. It’s a phenomenon
known as the urban heat island effect, and it can have huge
impacts on energy use and even health in the warm months. It’s
like wearing a city-sized sweater on a hot day in July. As
cities become focused on reducing energy use and costs, this
inherent increase in temperature is seen as an important, if
largely amorphous, target. Combating the urban heat island
effect has become, in a catch-phrasey sort of way, an official
imperative in cities across the county and all over the world.
There are various approaches to fighting the problem, but the
primary methods are to plant more trees and make roof