'Green' roofs could counter global warming

EAST LANSING, Mich., Sept. 24 (UPI) -- A Michigan State University study has determined "green roofs" -- those covered with plants -- could help fight global warming.

The scientists, led by horticulturist Kristin Getter and Professor Brad Rowe, found replacing traditional roofing materials with green plants in an urban area with a population of about 1 million, would be equivalent to eliminating a year's worth of carbon dioxide emitted by 10,000 mid-sized sport utility vehicles and trucks.

The researchers said their study is the first of its kind to examine the ability of green roofs to sequester carbon, which may impact climate change. Getter and colleagues say scientists have known green roofs also absorb carbon dioxide, a major greenhouse gas that contributes to global warming, but nobody had measured the impact until now.

The scientists said they measured carbon levels in plant and soil samples collected from 13 green roofs in Michigan and Maryland during a two-year period. They found green roofing an urban area of about 1 million people would capture more than 55,000 tons of carbon.

The research is to be reported in the Oct. 1 issue of the journal Environmental Science & Technology.