Bradford Plumer defends Energy Secretary Steven Chu for suggesting that we paint our roofs white to slow climate change:

[J]ust refitting the 30 billion or so square feet of commercial roof space in the United States would be the equivalent of taking roughly 75 million cars off the road for a year. And, as a bonus, buildings with white roofs tend to stay 30 percent cooler than their black-topped counterparts during the summer, which curtails energy use. Obviously this wouldn't stop global warming, but on the list of pain-free measures that would make a fair bit of inroads on the problem, this has to rank very high up there.