Reflective Roofs and PavementCould Play Big Role in Combating Warming

Installing white roofs on buildings in the world’s 100 largest cities and paving roads with more reflective materials, such as concrete, could have a huge cooling effect on the planet, according to a new study. Hashem Akbari, a physicist at Lawrence Berkeley National Laboratory in California, said that widespread use of light-colored materials would reflect enough heat back into space to offset all the greenhouse gases emitted worldwide in a single year. Presenting his findings at the Climate Change Research Conference in Sacramento, Akbari said that roofs account for 25 percent of city surfaces and pavement another 35 percent. Most of these surfaces are now dark and absorb vast amounts of heat, said Akbari, whose findings will soon be published in the journal Climate Change. California has passed a law requiring that by 2009 builders install heat-reflective roofing on all new residential and commercial structures.