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The Ultimate Whitewash for L.A.?


According to an environmental report in today's Guardian U.K., Los Angeles may go green by painting its roofs and roads white. The article features U.C. Berkeley scientist Hashem Akbari, whose mission is to reduce "urban heat islands" by painting rooftops, parking lots and roads with reflective paint that would bounce back the sun's light, instead of letting it get absorbed.

Above: Palm Springs bakes.
Photo: Alamy/Guardian UK


Since 2005, California has required flat-topped warehouses to

paint their roofs white. Akbari calculates that by covering the earth's

urban surfaces and roads -- which account for 2.4 percent of the

planet's dry land -- we could bounce back about .03 of the sun's rays.

That would be enough to noticeably slow the upward temperature climb in an age of global

warming.

One objection that has been raised in the past is the desirability of having white-surfaced roads that shimmer and streets

of houses with glaring roofs. Akbari notes, however, that merely moving

from near-black asphalt to gray will increase the reflection of

sunlight and that there are materials that can be used in darker paints

that will reflect more infrared light that is currently being bounced

back.

"Computer simulations of Los Angeles," the article

notes, "show that resurfacing about two-thirds of roads and rooftops

with reflective surfaces, as well as planting more trees, could cool

the city by 2-3C. That would reduce LA smog as much as a total ban on

cars and lorries, and cooler roofs could also save a fortune in

electricity bills."