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« Frog’s Eye to Frog’s Brain, Part IV | John C. Yoo Should Be Disbarred »

Could White Roofs Really Buy Us Time on Global Warming?

I have to give the idea some credit simply because it is being repeated by US Energy Secretary Steven Chu.  This is a smart guy, I am happy to see him in the mix trying to determine energy policy.  Maybe in the long run it is the kind of simple adjustment in infrastructure that makes for a sustainable world. I don’t know.

clipped from www.washingtonpost.com

Energy Secretary Pitches Low-Tech Idea to Reflect Solar Energy Back Into Space

White Rooftops May Help Slow Warming

Making roofs white “changes the reflectivity . . . of the Earth, so the sunlight comes in, it’s reflected back into space,” Chu said. “This is something very simple that we can do immediately,” he said later.
White roofs work because of the physics of sunlight. Dark roofs absorb and hold more than 80 percent of solar energy, while white ones can reflect 75 percent of it away. That makes a white-roofed building cooler and cheaper to air-condition.Because of that energy savings, California has since 2005 required most flat-roofed buildings to have white tops, and Walmart has installed them on about 75 percent of its U.S. stores. In January, the District will require new flat roofs on commercial buildings to be covered in vegetation or a reflective material.The idea does not treat the root cause of climate change, which is heat-trapping pollution such as carbon dioxide and methane. But white roofs do help with the primary symptom: heat. The light they reflect escapes through the polluted atmosphere like a BB through a greenhouse.
“We may have to figure out a way to artificially cool the planet while the atmosphere is still super-saturated with greenhouse gases,” said Mike Tidwell of the Chesapeake Climate Action Network. This could be it, he said, “because the planet, it’s a closed system, it’s an absolutely closed system, except for one thing: sunlight.”

A spokeswoman for Chu said the Energy Department is exploring ways to encourage more white roofs on private and public buildings. (For now, Google Maps shows that Chu’s own headquarters is a light beige on top.) She also noted that some homeowners who purchased a “cool” roof would be eligible for an expanded tax credit intended for “weatherizing” homes.

And then there is the look of the thing.

To get all the benefits of a white roof, plain old white paint will not do. Instead, the roofs should be covered in a reflective coating, or a specially made membrane (Details about cool-roof products approved by the Environmental Protection Agency can be found at http://www.energystar.gov/index.cfm?c=roof_prods.pr_roof_products).

  blog it

This entry was posted on June 14, 2009 at 9:47 am and is filed under News, Connect the Dots, Small Foot Print, Global Warming. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response or trackback from your own site.

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