'Green' roofs may help put lid on global warming

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"Green" roofs, such as the one above, could fight climate change, scientists report. Credit: Wikimedia Commons

"Green" roofs, those increasingly popular urban rooftops covered with plants, could help fight global warming, scientists in Michigan are reporting.

The scientists found that replacing traditional roofing materials in an urban area the size of Detroit, with a population of about one-million, with green would be equivalent to eliminating a year's worth of carbon dioxide emitted by 10,000 mid-sized SUVs and trucks. Their study, the first of its kind to examine the ability of green roofs to sequester carbon which may impact climate change, is scheduled for the Oct. 1 issue of ACS' Environmental Science & Technology.

Kristin Getter and colleagues point out in the new study that green roofs are multi-functional. They reduce heating and air conditioning costs, for instance, and retain and detain stormwater. Researchers knew that 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 measured carbon levels in plant and soil samples collected from 13 green roofs in Michigan and Maryland over a two-year period. They found that green roofing an urban area of about one million people would capture more than 55,000 tons of carbon, the scientists say. That's an amount "similar to removing more than 10,000 mid-sized SUV or trucks off the road a year," the article notes.

More information: "Carbon Sequestration Potential of Extensive Green Roofs", Environmental Science & Technology, DOI: 10.1021/es901539x

Source: American Chemical Society (news : web)

   

• defunctdiety - Sep 23, 2009
  • Rank: 4 / 5 (5)
  I love the idea of green roofs, I'm all for bringing more nature into everyday city life, however as any engineer or architect knows, water is a building's worst enemy. And one of your primary concerns as such is getting as much water off of your structure as quickly as possible, green roofs by default purposely keep water on your structure, if not introduce water onto it beyond what would naturally be there through precipitation, not to mention the plants will by their very nature exploit and worsen any weaknesses in their never ending search for new ground. Do they really contribute to sustainability? Doubtful.
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• Velanarris - Sep 24, 2009
  • Rank: 5 / 5 (1)
  I'm a fan of green roofs as well. It cools the city, combats urban sprawl, insulates heat in the winter and helps reduce the amount of masonry damage caused by rainfall.
  
  Question is, what is the water impact?
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