Can't Afford Solar? Paint It White

| Tue Sep. 16, 2008 9:26 PM EDT

B9a_agra700.jpg Your roof, that is. A new study calculates that installing white roofs in the world's cities could offset 1.5 years of manmade carbon emissions, reports AAAS.

Light-colored roofs cool the planet in two ways. They reflect radiation back into space. And they keep your house cooler so you use less air conditioning.

Researchers from Lawrence Berkeley National Laboratory and the state of California estimated the global number of roofs and asphalt surfaces in cities and conservatively estimated they comprise 1 percent of Earth's surface. They then found that using light-colored concrete, or applying white glazes to buildings, could increase the reflectivity of urban surfaces by 10 percent, effectively negating 44 gigatons of CO2. In comparison, halting deforestation of tropical forests would eliminate about 7 gigatons of emissions.

Total global annual emissions from fossil fuels are currently running at about 28 gigatons.

The new snow: paint.

Julia Whitty is Mother Jones' environmental correspondent, lecturer, and 2008 winner of the Kiriyama Prize and the John Burroughs Medal Award.