Science News Review

White Roofs to Mitigate Global Warming?

Jun 15 at 9:09pm by Aileen

The Washington Post reported on a recent talk by Energy Secretary Steven Chu that white rooftops may help slow global warming by reflecting sunlight instead of absorbing it. Perhaps even better, white roofs cut energy consumption for cooling by an almost equal percentage.

Climate scientists say the reflective properties of white are so much greater than gray, black, green or any other color, that simply by putting white roofs on enough buildings and houses we could buy the time we need to make other necessary changes to combat global warming. In fact, the energy savings alone on air conditioning caused the state of California to begin requiring that most new flat-roofed buildings have reflective roofs, and retail giant Walmart has installed them on 75% of its stores in the United States. Even Washington, D.C. has gone so far as to require than new flat roofs be covered either in vegetation or have reflective roofs for the energy savings alone.

The Environmental Protection Agency offers good information and cost analysis for reflective roofing products on its Energy Star website with multiple links to manufacturers, resources and data.

Secretary Chu emphasized in his speech that the Lawrence Berkeley National Laboratory conducted research demonstrating that if just 63% of the roofs in 100 large cities and tropical/temperate areas worldwide were white, the effect would provide the same climate benefits as taking all the cars in the world off the road for a full decade. That’s considerable, and definitely worth the effort.