How white roofs could have a green impact

David A. Fahrenthold in the San Francisco Chronicle via the Washington Post: Could climate change be staved off by making the United States look like the set of "Mamma Mia!"?
That was suggested in a recent talk by Energy Secretary Steven Chu - although, because he was speaking to Nobel laureates, he did not mention the ABBA musical set in the Greek Islands. He said that global warming could be slowed by a low-tech idea that has nothing to do with coal plants or solar panels: white roofs.

Making roofs white "changes the reflectivity ... of the Earth, so the sunlight comes in, it's reflected back into space," Chu said. "This is something very simple that we can do immediately," he said later.

…But if anybody is seriously considering a global whitewash, "simple" and "immediate" are probably not words that come to mind. "I don't think that it could ever be done at a sufficient scale," said Ken Caldeira, a climate scientist at the Carnegie Institution in Stanford. "It's hard enough, in many of the cities of the world, to keep the streets swept, much less to keep the city reflective."…

White roofs on the island of Santorini in Greece, shot by zaragkito