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White roofs could help warming cities

By Juliet Eilperin

Painting the roofs of city buildings white could help cool urban areas and combat climate change worldwide, according to a new study led by scientists at the National Center for Atmospheric Research.

While researchers have floated the idea of using white roofs to reflect heat from the sun for years, the study slated for publication in Geophysical Research Letters represents the first computer modeling study that simulates the global impacts of this approach on urban areas.

But the paper's authors warn some obstacles remain in terms of actually using white roofs to counteract warmer temperatures.

"Our research demonstrates that white roofs, at least in theory, can be an effective method for reducing urban heat," says NCAR scientist Keith Oleson, the study's lead author. "It remains to be seen if it's actually feasible for cities to paint their roofs white, but the idea certainly warrants further investigation... It's not as simple as just painting roofs white and cooling off a city."

The modeling suggests that if all roofs in the world's urban areas were entirely painted white, it would cool the world's cities by an average of about 0.7 degrees Fahrenheit. In the real world this would be hard to achieve, however, since dust and weathering over time would slightly darken the roofs' color, and opening such as air vents would not be able to be painted white.

For a photo of how workers are painting roofs white in D.C., click here.


Juliet Eilperin

 |  January 28, 2010; 2:58 PM ET Save & Share:  Send E-mail   Facebook   Twitter   Digg   Yahoo Buzz   StumbleUpon   Technorati  
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