The Green Geek

Another Reason To Like Green Roofs

Green Roofs are a great feature for any flat roofed building; they reduce stormwater runoff, they keep buildings and cities cool, they create habitats for birds, and they’re much nicer to look at than a tar & gravel rooftop. A recent study has given us another reason to cheer for planted rooftops; they sequester a decent amount of carbon dioxide as well.

Researchers at Michigan State University studied 10 existing green roofs and planted 20 one-meter square plots. The results:

Over a two-year period, the plants on the East Lansing campus were periodically harvested. Leafy parts stored on average 168 grams of carbon per square meter, the roots and the soil respectively stored 160 and 300 grams on average. Combined, each plot had the capacity to store 375 grams of C02 per square meter.

That’s not very much, however it’s better than a regular roof which has a negative environmental impact. They state:

“Green roofs certainly don’t store the kind of carbon that a forest or productive grassland stores, but a traditional roof is essentially a wasteland — no carbon storage whatsoever.”

They calculate that if all of the roofs in Detroit were green instead of black, it would offset the Carbon Dioxide emitted by 10,000 SUVs.

Miller McCune via Treehugger.com