planted city

From Reuters:

Painting black tar roofs with a white, solar-reflective coating is a low cost, quick and tangible way to reduce the risk of power grid ‘brown-outs’, save millions of dollars in energy costs, and curb climate change. The statistics are as simple as they are staggering: A roof covered with solar-reflective white paint reflects up to 90% of sunlight as opposed to the 20% reflected by a traditional black roof. On a 90°F day, a black roof can be up to 180°F. That heat has a major impact on interior building temperature, potentially heating your room to between 115 – 125°F. A white roof stays a cool 100°F. Plus the inside of the building stays cooler than the air outdoors, around 80°F in this example, reducing cooling costs.

White roofs also reduce the “urban heat island” effect in which temperatures rise in dense urban areas because of the proliferation of heat-radiating, black tar surfaces. For example, the Urban Heat Island effect causes New York City to be about 5 degrees warmer than surrounding suburbs and accounts for 5 to 10 percent of summer electricity use.

In New York City alone, 12% of all surfaces are rooftops. It’s estimated that implementing a white roof program in 11 metropolitan cities could save the United States 7 gigawatts in energy usage. That’s the equivalent of turning off 14 power plants, and a cost savings of $750 million per year.

Recently, former President Bill Clinton wrote in Newsweek, “Every black roof in New York should be white; every roof in Chicago should be white; every roof in Little Rock should be white. Every flat tar-surface roof anywhere! In most of these places you could recover the cost of the paint and the labor in a week.” The former president regularly touts the white roofs as one of those win-win scenarios that could also help create jobs and stimulate the economy.

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If we were to coat 5 percent of rooftops per year worldwide, we would be finished by 2030. This would save the U.S. 24 billion metric tons in CO2. That happens to be exactly how the world as a whole emitted in 2010. So, in essence, this would be like turning the world off for an entire year — while also saving some money on the energy bills while doing it.

Check out the rest of the article here. You may also be interested in checking out the White Roof Project and Cool Roofs NYC; two efforts focused on “greening” New York’s rooftops. 

(Photo credit: Beyond Oil NYC)