Paint It White

In California, flat-roofed premises are now required to have white roofs. Photograph: Alamy

Mick Jagger and The Rolling Stones wanted us to paint it black; but, Hashem Akbari, a scientist at Lawrence Berkeley National Laboratory in California, is now calling for us all to paint it white. Why white? Why now?

Akbari’s scheme is incredibly simple. It can be done by anyone, anytime, anyplace there are surfaces to paint. All that is required is a desire to change the world, elbow grease and paint, lots of it.

His scheme is based on observations of old technologies; some so subtle and natural they have possibly gone unnoticed until now as the legitimate technologies they are.

Southern Europe and North Africa are full of whitewashed villages. Was there knowledge here we had failed to recognize?

“Turn enough of the world's black urban landscape white,” he says, “and it would reflect enough sunlight to delay global warming, and grant us some precious breathing space in the global struggle to control carbon emissions.”

Akbari is now prepared to take his campaign to the people. He plans to start his “paint the world white” campaign by uniting dozens of the world’s major cities in an effort to replace dark, heat-absorbing materials used on roads and roofs with a material that is a little more reflective.

The vast majority of people do not realize that the effect of this could be quite dramatic. Study after study has shown that buildings with white roofs stay cooler during the summer. The change reduces the way heat accumulates in built-up areas - known as the urban heat island effect - and allows people who live and work inside to switch off power-hungry air conditioning units.

Oh, those crazy Californians!! California is one beautiful state, one huge water-guzzling state – but; beautiful nonetheless. Governor Schwarzenegger seems to be quite an environmentally concerned governor. Personally, I have noticed that he has taken the environment into consideration on many occasions. I was happy to see that California passed a law in 2005 that forced warehouses and other commercial premises with flat roofs to paint them white. Hopefully, the effort can be extended. It could make a huge difference.

Together, roads and roofs are reckoned to cover more than half the available surfaces in urban areas. A mass movement to change their colour, Akbari calculates, would increase the amount of sunlight bounced off our planet by 0.03%. Wait, wait, it gets better!!

“And,” he says, “that would cool the Earth enough to cancel out the warming caused by 44bn tons of CO2 pollution. If you think that sounds like a lot, then you're right. It would wipe out the expected rise in global emissions over the next decade.”

“It won't solve the problem of climate change,” Akbari says, “but; could be a simple and effective weapon to delay its impact - just so long as people start doing it in earnest. Roofs are going to have to be changed one by one and to make that effort at a very local level, we need to have an organization in place to make it happen," he says.

Groups in several US cities, including Houston, Chicago and Salt Lake City, are on board with his plan, and he is talking to others.

The idea is a form of geo-engineering, a broad term used to cover all schemes that tackle the symptoms of climate change, namely catastrophic temperature rise, without addressing the root cause, our spiraling greenhouse gas emissions. Akbari says his plan is more workable than other geo-engineering ideas. The science is simple. Sunlight reflected from a surface does not contribute to the greenhouse effect, which drives global warming. That problem comes when dark surfaces soak up sunlight and send it back up as thermal energy, at just the right wavelength to rebound off CO2 in the sky.

I finish this up next blog.