In cities across the United States, roofs that are covered with plants, otherwise known as "green roofs" are gaining popularity.
The number of "green roofs" increased by 35% across the United States between 2007 and 2008, according to the LiveScience article.
"Green roofs" are most popular in Germany, with 12% of all roofs being "green".
Green roofs and CO2
Scientists at Michigan State University measured carbon levels in plant and soil samples collected from 13 green roofs in Michigan and Maryland over a two-year period.
The researchers found that replacing traditional roofing materials with green roofs in an urban area the size of Detroit, with a population of about one million, would capture more than 55,000 tons of carbon. That is roughly similar to eliminating a year's worth of carbon dioxide emitted by 10,000 mid-sized SUVs and trucks, according to LiveScience.
Other benefits of "green roofs"
--Reduce heating and cooling costs of buildings. 10% reduction in natural gas consumption and 2% drop in electricity use in a typical building.
--Retain and detain storm water.
--Attract birds and wildlife, which may be good or bad, depending on the species.
--Absorb noise and pollution.
--"Green roofs" also last 2 to 3 times longer than standard roofs because they are protected from ultraviolet radiation and the extreme fluctuations in temperature that cause roof membranes to deteriorate.
Brad Rowe, and environmental scientist at Michigan State University believes that the U.S. Government does not need to mandate the roofs in the future, but instead provide incentives for them, similar to policies of other countries.
"Green roofs are more expensive, but only initially. Over time, they're cheaper once you consider their benefits energy-wise. It takes about 11 to 14 years to break even", according to Rowe. (article courtesy of AccuWeather.com) http://global-warming.accuweather.com/2009/10/green_roofs_slowly_gaining_pop_1.html
