New Study: Paint Your Roof White, Save the Planet

A recent study by Lawrence Berkeley Laboratory scientists has revealed a simple, low-tech way that anyone can use to help cool the planet and reverse global warming: painting your roof white.  Everyone knows that white reflects heat, resulting in a cooling effect.  But, these scientists have put a number on it: according to Hashem Akbari, a physicist at the Lawrence Berkeley lab, the average 1,000-square-foot roof could offset 10 metric tons of carbon dioxide.

From Machinist:

According to his data, roofs constitute 20 to 25 percent of urban surfaces, while pavement is about 40 percent. Therefore, if all of those surfaces were switched to a reflective material (or color) in the 100 largest urban areas in America, his calculations show, this would offset 44 metric gigatons of carbon dioxide. That’s more than all countries emit in a single year. Further, that’s worth about $1.1 trillion at current carbon trading rates.

Obviously, this is a rather large undertaking, but legislation requiring white on the roofs of buildings is one easy way to make sure that these effects are felt. As the Los Angeles Times reports, flat commercial buildings in California must have white roofs — a rule that’s been around since 2005. However, a new state law says sloped roofs on residential and commercial structures when constructed new or being retrofitted must have reflective coloring. This new rule takes effect in July 2009.

It makes sense.  There are an awful lot of dark-colored roofs out there absorbing heat – why not use this low-tech solution to reflect it instead? Obviously, this isn’t going to fix all of our problems, but it’s a step that a lot of people can take to help.

Read the Lawrence Berkeley Laboratory’s press release to get all the details on the study.

Link [Machinist]
Photo credit: Flickr user Robert Whitlock

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