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An interesting idea in reducing global warming has been suggested by a reader of New Scientist magazine. Mike Follows Willenhall from England points out that if the roofs of all of the buildings on Earth were painted white, the amount of sunlight reflected back into space may be increased, which could reduce global temperatures by an average of 1 degree Celsius. This would almost exactly cancel out the global warming that has taken place since the start of the industrial revolution.

From the article:

The Earth has an albedo of 0.29, meaning that it reflects 29 per cent of the sunlight that falls upon it. With an albedo of 0.1, towns absorb more sunlight than the global average. Painting all roofs white could nudge the Earth’s albedo from 0.29 towards 0.30.

There are risks in tampering with Earth’s climate in this way… but it’s an interesting idea, worthy of further study. As a side benefit, this could also reduce air conditioning costs in warmer climates, since white-topped buildings would reflect away more heat. On that note, perhaps dark shingles that lighten in color as temperature rises would be a good compromise… they would absorb needed heat in the winter, and reflect unwanted heat in the summer. How about it, science?

New Scientist article