To Slow Global Warming, Install White Roofs

If you ask an architect or a civil engineer regarding cost-efficient roofs, they will normally tell you to paint it white. Obviously for two reasons - white colored roofs will reflect heat, meaning lesser chances of using the air conditioning unit, and it's cheaper to paint it white (since you only need one color unlike other colors, which needs white as a primer or initial color before applying it). But scientist today found one more benefit - slowing global warming.

According to a data released during the Fifth Annual California Climate Change Research Conference, if the 100 biggest cities installed white roofs and change their pavements from asphalt-based materials to reflective materials, the global cooling effect will be massive.

Since 2005, the Golden State has required all flat commercial infrastructures to have white roofs. Next year, new and retrofitted residential and commercial establishments, whether flat or sloped roofs, will have to install heat reflecting materials in compliance of the energy-efficient building code. But still, there are no provisions or legislation pertaining to heat-absorbing asphalt pavements, which is a cheap byproduct of oil refining.

According to Hashem Akbari, a physicist with the Lawrence Berkeley National Laboratory, a 1,000 square-foot roof - the average size of an American home - offset 10 metric tons of planet-heating carbon dioxide emissions in the atmosphere of dark-colored shingles or coatings are replaced with white material.

According to recent statistics, Globally - roofs account for 25% of the surface of most cities, and pavements account for 35%. Considering these data, if all major urban cities shifted to these kind of materials, an estimated 44 metric gigatons will offset the production of greenhouse gasses, which have been trapping heat in the atmosphere and altering the climate for a potentially dangerous scale.

That is more than all the countries emit in a year. Installing these heat-reflective materials will induce cooler atmospheres thus offsetting 10 years of emission growth even without slashing industrial pollution.

"I call it a win-win" Akbari said. "First, a cooler environment not only conserves energy but induce comfort. Second, cooling a city by a few degrees dramatically reduces smog. And third, is offsetting global warming."