By David L. Brown
Energy Secretary Steven Chu has stated that if we were to paint all flat roofs white it would reflect solar rays back into space and help reduce global warming. Well, maybe. Let’s take a look at what might be called the “albedo” solution.
The term “albedo” refers to the reflectivity of an object. It is most often used in astronomy to denote the percentage of the Sun’s light that is normally reflected by a particular planet or other object. For example, the Moon reflects a paltry 12 percent on average, yielding an albedo index of 0.12. Venus, the brightest planet, reflects 65 percent for an albedo of 0.65. The Earth has an albedo of 0.37. These figures are averages for the entire surface of each object, so reflectivity could vary widely from place to place. For example on the Earth solar rays will strike bright white clouds in some locations and dark volcanic rock in others.
Albedo already plays an important role in the Earth’s ability to maintain temperature levels. Snow and ice in the Arctic and Antarctic reflect a lot of heat back into space. A serious concern about the ongoing loss of Arctic Ocean sea ice is the fact that dark open water will absorb a lot of heat that would previously have reflected off of the white snow and ice. Summer ice coverage has been shrinking, causing the Arctic to warm faster than any other region on the planet. This is called a feedback effect, since the more ice melts, the warmer the area will become, causing even more melting and so on.
Sec. Chu’s proposal to paint rooftops white is presumed to cool the Earth by raising the average albedo of the planet. He also noted that roads and sidewalks should also be made “lighter colored” to enhance the effect.
Dr. Chu is a Nobel Prize winning physicist and his ideas should not be discarded out of hand. Not surprisingly, FoxNews.com contributor Steven Milloy, known for his commentary on so-called “Junk Science” (www.junkscience.com) does exactly that. “It’s past simplistic — it’s ridiculous,” FoxNews.com quotes the avowed climate-change skeptic in this article. “Imagine the glare on roads, in urban areas, imagine the UV radiation bouncing around. Snow blindness would be replaced by road blindness.”