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Green Wombat often highlights high tech when it comes to tackling global warming and energy independence. But a new study from the University of California’s Lawrence Berkeley National Laboratory shows that simply installing white roofs on homes and commercial buildings – to reflect the sun’s rays rather than absorb them – can reduce air-conditioning costs by 20% and could save $1 billion a year in energy outlays in the United States.

Switch to cool sidewalks and roads and the savings rise to $2 billion annually, according to the study by scientists Hashem Akbari and Surabi Menon and California Energy Commissioner Art Rosenfeld to be published in the journal Climate Change.

The scientists calculated that a global white roofs and roads effort would offset 44 billion metric tons of greenhouse gas emissions, or more than a year’s worth of carbon, and help stablize future C02 emission increases.

“The 44 Gt CO2-equivalent offset potential for cool roofs and cool pavements would counteract
the effect of the growth in CO2-equivalent emission rates for 11 years,” according to the authors.

Such emission reductions, of course, can be securitized into tradable carbon credits, which the study estimates would be worth $1.1 trillion. Regulated carbon market exist in places like Europe but securities based on cool roofs have not yet been created.

A global cool roofs agreement could avoid the pitfalls of Kyoto-style accords, the scientists note.  “Installing cool roofs and cool pavements in cities worldwide does not need delicate negotiations between nations in terms of curbing each country’s CO2 emission rates.”

It’s one of those low-tech, commonsense solutions to both energy use and global warming – one used for thousands of years in the regions like the Mediterranean; those picturesque villages overlooking the sea are white-washed for a reason.

In California, commercial buildings with flat roofs have been required to cool it since 2005. But one of the biggest hurdles in the U.S. to doing the white thing may be homeowner associations that dictate everything from the color of your mailbox to where you place your rubbish bin. The vast majority of homes in California either have standard black shingle roofs or Spanish-style red tiles. A proposal to paint those roofs white will likely incite architectural outrage.

But there’s another, albeit much more expensive solution, to hot roofs: Cover them with solar panels.

photo: California Energy Commission

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