Replacing traditional roofing with “green” plant-covered roofs could, in an urban area the size of Detroit, reduce energy use and capture carbon each year on a scale equal to removing 10,000 mid-sized SUVs or trucks from the highways.

A study by researchers from Michigan State University in East Lansing found that, in addition to reducing heating and air conditioning costs, the green roofs can absorb and store enough carbon dioxide to play a role in lessening the amount of greenhouse gases in the atmosphere.  In two studies, one involving 12 green roofs in Michigan and Maryland and the other involving 20 garden plots on a single roof in Michigan, the scientists found that the plants on the roofs - primarily shallow-rooting Sedum species that included flowers, ground cover, and shrubs - sequestered significant amounts of carbon dioxide.

In addition to the carbon savings that result from lower demand for heating and cooling, the researcher said, the green roofs “represent a small but significant potential for sequestering carbon in urban environments.” The study will appear in the October issue of the journal Environmental Science & Technology.

Jim Dawson reports for Inside Science News Service.