Monday, June 29, 2009

White Roofs

I saw a newspaper article the other day about the idea of “white roofs”. The premise was that if all our roofs, at least in the warmer parts of the world, were white in color, then those roofs would reflect back more sunlight, stop global warming and keep our cities cooler in the summer.

The idea sounds too good to be true, so I started tracing it back and pretty quickly you find that the theory comes from an article entitled “Global cooling: increasing world-wide urban albedos to offset CO2” by Hashen Akbari, Surabi Menon and Arthur Rosenfeld. It first was published (online, where you can still find it at in Climate Change last November.

I have to admit I missed the article when it first came out. I also have to admit that I didn’t understand much of it when I did read it.

But a couple of statements caught my attention. First, the energy savings every year in the United States by switching to “cool roofs and pavement” would be worth about $1 billion. Second, the reduction in global warming is equivalent to savings in the emission of greenhouse gases that would otherwise cost about $1,100 billion worldwide. That seems like pretty good money just for a change of color.

Of course the idea of painting something white to keep it cooler isn’t exactly new. In Spain, the pueblos blancos have been resisting the hot, dry climate of Andalucia for the last 1,000 years. That’s enough history to make me think the idea might just work. It also looks pretty good.

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