Painting Rooftops White Would Slow Global Warming
Study: If we painted every rooftop in 100 major cities white, it would offset the entire planet’s carbon dioxide emissions for one year. That’s nearly 44 metric gigatons.
It makes sense. We all know white reflects heat (that’s why we wear white shirts and dresses on hot days), and we even knew that painting rooftops white lessens the need for air conditioning. But until now, we didn’t know that changing dark-colored surfaces to white would help fight against global warming.
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The news broke yesterday at California’s Climate Change Research Conference. Hashem Akbari, attending the conference from the Lawrence Berkeley National Laboratory, announced that replacing dark shingles on an average-sized household rooftop with a lighter color would offset 10 metric tons of carbon dioxide—comparable to taking two mid-sized cars off the road for a year.
Speaking of roadways, they’re part of the problem too. Because of its cheap nature, most roads are paved with black asphalt instead of light grey concrete, which causes roads to absorb an inordinate amount of heat. Repaving roads with lighter-colored materials would have a similar impact to painting rooftops.
California already mandates that newly-built large buildings have light-colored rooftops, but the law was intended to decrease air conditioning costs. Akbari hopes to enlist the United Nations in an effort to convince major cities to make their roadways and rooftops more pale.
Read a full summary of the report here.
Photo Credit: Robert Whitlock on Flickr under Creative Commons license.
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@Adam Williams - “Why take the chance?”
Many of the proposed changes that experts, governments, and lobbyists argue for are too extreme when we consider that the certainty of doom due to anthropogenic global warming is not certain at all or very clear.
I find it odd that we, as humans, are fallible only until it comes to the much touted and vaulted climate models that we have created. Climate models cannot yet accurately predict (using the scientific definition of prediction) what the Earth’s climate will be like in the future.
At this point we must take the chance and study our planet further until a deeper understanding is reached.
This might make an impact in places that use nothing but air conditioning, but anywhere that has to HEAT a building would use far more electricity to keep it warm than it does to keep it cool. For places like North Dakota, this is a BAD IDEA. We’ll take all the heat absorption we can get.
Chopping down trees in the north will increase the earth’s albedo by allowing the sun’s rays to be reflected by snow cover.
Gentlemen, Start Your Chain Saws!
This is splendid idea. What will it do to my heating bill and gas consumption in the winter?
David from Canada (at the end of an extraordinarily short and cool summer)
If 99% of astrophysicists told you that an asteroid was on a collision course with earth and was going to kill millions of people and change the climate, and 1% said it was going to miss the earth, would you take the chance the 1% was right? And if the one thing you could do that might have some chance to save the earth was to paint your roof white, would you say no?
Global warming theory might be wrong. By the time we all are absolutely sure one way or another it will be too late to affect it. Are you willing to take that chance?
“Global COOLING” - “change you can believe in…”
Oh my god. This is seriously reaching. You global warming freaks are clearly on your last lap. Paint roofs white? That is silly. It will do absolutely NOTHING to REDUCE carbon emissions. Last I checked a sedentary roof doesn’t PRODUCE a single molecule of co2. Yes, it will reflect sunlight. But what good is reflecting sunlight back into a haze of co2? How much co2 is produced when you make a gallon of paint? I’m sure its plenty. And it takes a lot of paint to cover and entire roof. This is clearly desperation. I love the idea of reducing carbon emissions, it can’t hurt. But this is such a bad idea, I’ll poop on it.
The summary illustrates a huge flaw in the analysis. A comparison is made to greenhouses where the glass is whitewashed in order to keep the greenhouse cool. Clearly by whitewashing our rooftops and roads (OK, just making them more grey) we can reduce global heating significantly. Except that the analogy is faulty. You don’t whitewash the floor of the greenhouse, you whitewash the GLASS. In our analogy of “Carbon Dioxide creates a greenhouse around the earth” we would have to paint the atmosphere and prevent the solar radiation from ever reaching the surface.
If the technique is going to have a cooling effect on the atmosphere (as opposed to simply reducing the amount of energy used for AC) then you need to talk about the fact that the light reflected is primarily in the visible range, which passes through the atmosphere where as when it is absorbed, it is re-radiated out in the IR band, which is primarily absorbed by CO2 (I think that’s right, I forgot most of this a long time ago). This is NOT the same mechanism as employed by greenhouses (which is effectively shading).
Maybe a good solution for areas with severe weather changes from season-to-season would be a double-sided plate/cover to put on top of the roof. Then you could flip it over from white to black when it starts getting cold.
This whole “human” induced global warming is ridiculous to begin with. But now to suggest painting rooftops? The earth is always changing and that means the climate too!! Things have always gone extinct and things have always adapted. This global warming is just another cycle of the earth. Yes, I’m sure we can contribute to it, but we are not the main cause. Painting rooftops is not going to SOLVE anything.