Chicago's City Hall got a green roof in 2001. The project was designed to test various concepts and methods and to test the benefits. Credit: Wikipedia Commons
From Live Science:
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 green roofing, some 12 percent of all flat roofs are green, with the German green roof industry growing 10 to 15 percent annually.
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