/ 16 January 2009

New weapon in climate war is brilliant white roofs

Should we paint the world white to tackle the impact of global warming? Hashem Akbari, a scientist at Lawrence Berkeley National Lab in California thinks so, and is launching a worldwide campaign to brighten up our cities. Turn enough rooftops and roads a whiter shade of pale, he says, and enough extra sunlight will be bounced back into space to cool the planet.

It won’t solve the problem of climate change. Like other geoengineering schemes, such as mirrors in space and dumping iron in the ocean, it counteracts the symptoms of global warming — the warming — without addressing the carbon emissions at the root of the problem. Akbari is careful to say that emission curbs are also needed, but that making urban areas more reflective could buy us some time.

It’s not just about millions of people heading out with a ladder and a brush, though that could certainly help.

Akbari wants communities, local authorities and householders to think about using more reflective materials when they perform routine maintenance or repairs. That way it wouldn’t cost any more — and such switches could even make money. If cash from carbon offsets can be channelled into changing to cleaner lightbulbs and cooking stoves, then why not into making shinier cities?

Akbari isn’t the only scientist looking at changes in reflectivity. Experts have talked of shinier fields of crops, such as barley, soy and wheat, while others have suggested we could cover the deserts in plastic sheets, scrubbed clean by robots. Space scientists have even considered painting the moon to make it less reflective, so more of the sun’s energy seeps into the lunar soil where it could be tapped by astronauts.

Are lighter rooftops and roads the way to go?

California already makes all flat roofs white to cool its cities. Should other places follow its lead? Would you want to live in a house with a white roof? Or should we forget about such schemes and focus on what really matters — getting our carbon footprints down? – guardian.co.uk