Fight Global Warming with Green… Oops White Roofs

The headline can’t get any sillier than this, but history has proven that most of the amazing and most utilized innovations have been deemed stupid in the beginning. They were written off even before they were tried. Here is another one now.

Mom sense says – wear white shirts in summer to feel cool. Builders vouch for the fact that lighter color walls and roofs keep the air-conditioning costs low. Now it is the turn of environmentalists, scientist and global warming activists to go green with white. The latest green idea that is rocking the White house, tropical nations, Internet, and bloggers alike is to paint your roofs white.

An unbelievable scientific fact states that if 100 of the major urban cities switched to white roofs and pavements, it would offset 44 metric giga-tons of greenhouse gases, which have been trapping heat in the atmosphere and altering the climate on a potentially dangerous scale, since globally, roofs account for 25% of the surface of most cities, and pavement accounts for about 35%.

Now should that make us think, smile, roll our eyes, or just have a good laugh and toss it out of the window?

Not yet! According to TreeHugger, the Earth can reflect 29% of sunlight falling on it – also referred and measured as 0.29 albedo. With an albedo of 0.1, towns and cities absorb more sunlight than the global average. Painting all roofs white could nudge the Earth’s albedo from 0.29 towards 0.30, which could lead to 1 degree drop in global temperature. And this one degree drop almost cancels the global warming that has taken place since the industrial revolution.

How does painting your roof white help fight global warming?

• We all have learnt in school that light colors reflect and dark colors absorb. A dark roof absorbs light. This light heats up the roof. This heat in turn is radiated around into the atmosphere in form of infra-red rays. These infra-red rays are absorbed by the atmospheric gases and are re-emitted in form of infra-red light. This phenomenon plays a role in the increase in atmospheric temperatures and is linked to the Greenhouse Effect. Since atmospheric gases do not absorb too much visible light, these reflected light rays travel through the atmosphere and reach outer space. It does make sense to increase the amount of reflective surface to cause the light rays to travel through the atmosphere.
• The heated roof also radiates the heat energy into the building. This causes the internal temperature of the building to increase. We use air conditioners, coolers and fans to keep the room/ building cool. The higher the temperature, more energy is required to keep it cool. By painting the roof white or by installing light colored tiles, the sunrays are reflected back and the heat is not fully absorbed by the building.
• Therefore, paint your roof white or tiled in white in order to increase the amount of light reflected off your roof. If all houses and buildings in the world followed this practice, a lot of light would be reflected back, instead of being absorbed by the Earth.

Sounds like science fiction and far-fetched but it may be one of the most practical and easiest solutions to implement. If you have been thinking of solar power backups and CFLs, it might be a great idea to add a splash of white on the top and then compare your energy bills.

White Roofs and the Obama Connection

If you are still not convinced that white roofs help combat global warming effect, heavy endorsement for painting roofs white comes from no other than the Secretary of US Energy, of the Obama administration and a Noble Laureate in Physics – Steven Chu. In an interview Chu said, “If you look at all the buildings and make all the roofs white, and if you make the pavement a more concrete-type of color than a black-type of color, and you do this uniformly … It’s the equivalent of reducing the carbon emissions due to all the cars in the world by 11 years.”

And if you still have questions, we should be on the same page. It is normal to have knee-jerk reactions to radical and practical ideas. It is normal to question the validity of a new thought wave and to analyse if it really makes sense. A lot of questions ranging from what happens if too much light is reflected back into space, the use of toxic paints, aesthetics, to driving problems are being discussed.

I came across this thought-provoking and hilarious debate  (read comments) on this topic on the Telegraph Website where the reader’s reactions ranged from extreme ridicule to sombre acceptance.

We are pleasantly surprised and amused for sure. But any little step towards stabilizing the global temperatures means saving many forms of life on earth and many delicate ecosystems whose worth is incalculable.

Before you write off this idea, give it a serious thought. For it is time for basic simple solutions to combat the grave problems we and our future generations face.