Scientists promote 'global cooling' plan

SACRAMENTO, Sept. 10 (UPI) -- U.S. scientists say they've found a way to determine how much carbon dioxide can be offset by expanding the reflectivity of such urban surfaces as rooftops.

"White roofs can cut a building's energy use by 20 percent and save consumers money," said California Energy Commissioner Art Rosenfeld. He said the potential U.S. energy savings are in excess of $1 billion annually.

Rosenfeld and Lawrence Berkeley National Laboratory scientists Hashem Akbari and Surabi Menon created a formula to quantify the effects of white roofs in populated settings in terms of CO2 offset.

The researchers estimate replacing non-reflective, dark roofing materials with white ones on an average 1,000-square-foot would result in an equivalent carbon dioxide offset of 10 metric tons annually.

Since 2005, commercial buildings with flat roofs in California have been required to have white roofs. Beginning next year, residential sloped roofs and retrofit constructions in California will be required to have "cool-colored" roofs that reflect a higher fraction of the sun's rays than current roofing materials of the same color.

The research is to be published in the journal Climate Change.