Monday, June 29, 2009

Offsetting Greenhouse Gases

feature photo

It has long been known that white-roofed buildings, like this one in Andalusia in Spain, stay cooler in hot weather. Three energy experts make the case that painting white the roofs and pavement in the hot parts of the planet could offset the greenhouse gases. Josep Altarriba

Sam Kornell wants to know, "Is White the New Green?"
Three California energy experts make a convincing — and sincere — case that painting roofs white in the hot parts of the planet could offset the greenhouse gas woes caused by the world's cars.

In early January, Hashem Akbari sent federal officials a rather improbable sounding proposal. An Iranian-born nuclear engineer who, for the last three decades, has worked as a scientist at the Lawrence Berkeley National Laboratory, Akbari would like to see $3 billion of the economic stimulus package directed toward painting white or a light color as many of the nation's roofs, and as much of its pavement, as possible — all with the goal of directing more solar radiation into space.

Akbari, along with Surabi Menon, another LBNL scientist, and Arthur Rosenfeld, a former LBNL scientist and now a California Energy Commission board member, claim that painting urban surfaces in warm parts of the world white or a light color could offset the carbon emissions of all 600 million of the world's cars for 18 to 20 years — at a savings equivalent to at least $1 trillion worth of CO2 reductions.

This is not a hoax: Akbari, Menon and Rosenfeld are three of the country's leading experts in their field, and their study published in the journal Climatic Change is backed by years of carefully calculated data.

It has long been known that white-roofed buildings stay cooler in hot weather. Blinding confirmation of this can be found in the streets of Andalusia in Spain, or the Greek Islands.

It turns out that they cool the air outside of their walls, too. On a typical summer day, Los Angeles is 5 degrees warmer than surrounding areas, and studies have consistently shown that by far the largest factor in this discrepancy is the absorption of solar heat by dark roofs and pavement — a phenomenon known as the "urban heat island" effect.[...]

The Obama administration has made it clear that it wants a substantial portion of the stimulus package to go toward creating a greener economy, but that desire has to be balanced against the imperative to immediately circulate cash and create jobs. Painting or resurfacing roofs or pavement, Akbari said, would nicely fulfill both objectives. The technology exists and is readily available, and since a substantial portion of the country's home and commercial real-estate owners are going to need to re-roof at some point in the near future anyway, it's about as shovel-ready as any proposal currently on the table.

Akbari has thus far not heard back from the government, but he's holding out hope that his funding proposal will be folded into the energy-efficiency provision of the stimulus package.

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