Leave the white paint in the bucket. It won’t help climate change. Add solar panels instead to “green” your home.
Stop the contractors! If you were thinking about painting the roof of your house white this winter, before winter rains start, leave the paint in the bucket: Environmentalists were advocating white, just like they offer a quick fix to climate change by getting you to change to CFL lightbulbs.
But according to a new study by Mark Jacobson from Stanford, the white roof doesn’t act like an anti-warming device, keeping your house cooler in the summer. White paint, it turns out, is a big fat waste of money.
Writing in the journal Climate, Jacobson and his research student John Ten Hoeve did report that white surfaces cooled houses, but the white roof effect also reduced cloudiness, thereby allowing more of the sun’s rays to reach the ground.
“There does not seem to be a benefit from investing in white roofs,” says Jacobson. “The most important thing is to reduce emissions of the pollutants that contribute to global warming.”
Solar panels, the team reports, are better than white paint: “The better thing to do is to put a solar panel on the roof because that not only cools the house by absorbing the sunlight to make electricity. It also offsets fossil fuel generation at power plants.”
They are dead set against any other form of quick fix or geo-engineering schemes to “fix” climate change: “With all geo-engineering approaches, you are not solving the problem but masking it. There are all kinds of consequences people are not aware of, and it doesn’t solve the problem. You are still going to have all these greenhouse gases going into the air.”
The effect of heat islands whereby buildings cover natural vegetation needs to be studied more.
Photovoltaic panels helpful
How you can upgrade your house while leaving the white paint in the bucket? One way to reduce emissions while simultaneously reducing summer air conditioning demand is to install photovoltaic panels on roofs.
Such panels not only generate electricity, reducing emissions of fossil fuels from electricity-producing power plants, but they also reduce sunlight absorbed by buildings because they convert sunlight to electricity. Because photovoltaic panels do not reflect the sunlight back to the air, unlike white roofs, reflected light is not available to be absorbed again by pollutants in the air, creating heat.
“Cooling your house with white roofs at the expense of warming the planet is not a very desirable trade-off,” Jacobson said. “A warmer planet will melt the sea ice and glaciers faster, triggering feedbacks that will lead to even greater overall warming. There are more effective methods of reducing global warming.”