If you're planning a new data center or renovating one, a reflective white roof should be a part of your planning.

In a recent speech, Energy Secretary Steven Chu suggested that global warming could be slowed by reflective white roofs. Dark roofs absorb more than 80% of solar energy, while white roofs can reflect up to 75% of solar energy away. A Washington Post article expands on Secretary Chu's speech, and on some of the legal requirements:

Because of that energy savings, California has since 2005 required most flat-roofed buildings to have white tops, and Walmart has installed them on about 75 percent of its U.S. stores. In January, the District [of Columbia] will require new flat roofs on commercial buildings to be covered in vegetation or a reflective material.

How many roofs need to be white, and how much effect will it have? According to Secretary Chu's research (he's a Nobel laureate after all), if 63 percent of the roofs in 100 temperate-climate cities worldwide were painted reflective white, it would provide the same climate benefits as taking the world's cars off the roads for 10 years. Yes, that's all the cars in the world, for 10 years.

White paint alone is not enough to do it, and white roofs can be expensive. There are critics to the idea as well, but the carbon benefits do seem very significant. Perhaps it's time a white reflective roof should become part of every new data center's plans?