don’t paint your roof white

The land covered by urban areas more than doubled between 1992 and 2005, to about 0.128% of Earth’s surface, Mark Z. Jacobson and John E. Ten Hoeve of Stanford University report in the Journal of Climate. A worldwide conversion to white roofs, they found, could actually warm the Earth slightly due a complex domino effect.

Although white surfaces are cooler, the increased sunlight they reflect back into the atmosphere by can increase absorption of light by dark pollutants such as black carbon, which increases heating.
The Guardian, 27 Oct 2011
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