Green Roofs

Rooftops covered with plants — logically dubbed “green roofs” — could help fight global warming, scientists now suggest.

Green roofs are growing more popular in cities, with the number of green roofs increasing by more than 35 percent from 2007 to 2008 in the United States, representing more than 3.1 million square feet installed last year. In Germany, widely considered the leader in greenroofing, some 12 percent of all flat roofs are green, with the German green roof industry growing 10 to 15 percent annually.

“In Stuttgart in Germany, 25 percent of all roofs there are green. It’s just normal. I think we can get to that level here,” said researcher Brad Rowe at Michigan State University, an environmental scientist in East Lansing. “It’s possible to choose plants where you don’t need to water them if you’re in a place like Arizona, if you have the right cactus species, for instance.”

These roofs can reduce heating and air conditioning costs, with Department of Energy simulations projecting they can lead to a roughly 10 percent reduction in natural gas consumption and a 2 percent drop in electricity use for a typical building. Moreover, green roofs last two to three times longer than standard roofs because they are protected from ultraviolet radiation and the extreme fluctuations in temperature that cause roof membranes to deteriorate. They also retain and detain storm water, which could otherwise exacerbate flooding and erosion.

Link Below:

http://www.livescience.com/9714-green-roofs-curb-global-warming-study-finds.html