White roofs can slow global warming?

If the 100 biggest cities in the world installed white roofs and changed their pavement to more reflective materials -- say, concrete instead of asphalt-based material -- the global cooling effect would be massive, according to data released Tuesday at California's annual Climate Change Research Conference in Sacramento. Globally, roofs account for 25% of the surface of most cities, and pavement accounts for about 35%. If all were switched to reflective material in 100 major urban areas, it would offset 44 metric gigatons of greenhouse gases, which have been trapping heat in the atmosphere and altering the climate on a potentially dangerous scale. That is more than all the countries on Earth emit in a single year. And, with global climate negotiators focused on limiting a rapid increase in emissions, installing cool roofs and pavements would offset more than 10 years of emissions growth, even without slashing industrial pollution. Source: Los Angeles Times, 9/9/08.