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Painting The World's Roofs White Could Slow Climate Change
Hugh Pickens writes "Dr. Steven Chu, the Nobel prize-winning physicist appointed by President Obama as Energy Secretary, wants to paint the world white. Chu said at the opening of the St James's Palace Nobel Laureate Symposium that by lightening paved surfaces and roofs to the color of cement, it would be possible to cut carbon emissions by as much as taking all the world's cars off the roads for 11 years. Pale surfaces reflect up to 80 percent of the sunlight that falls on them, compared with about 20 percent for dark ones, which is why roofs and walls in hot countries are often whitewashed." (Continues, below.)
"An increase in pale surfaces would help to contain climate change both by reflecting more solar radiation into space and by reducing the amount of energy needed to keep buildings cool by air-conditioning. Since 2005 California has required all flat roofs on commercial buildings to be white and Georgia and Florida give incentives to owners who install white or light-colored roofs. Put another way, boosting how much urban rooftops reflect would be a one-time carbon-offset equivalent to preventing 44 billion tons of CO2 from entering the atmosphere. 'For the first time, we're equating the value of reflective roof surfaces and CO2 reduction,' says Dr. Hashem Akbari. 'This does not make the problem of global warming go away. But we can buy ourselves some time.'"
Unfortunately, producing the massive amounts of white paint needed to paint all these surfaces and maintain them produces about as much CO2 as was saved by starting this excellent project.
To Terminate, or not to Terminate, that's the question - SCSIROB
Personally, I wouldn't want to drive on a surface that bright; I'd be squinting even with my sunglasses on!
If you've driven on an interstate in the mid-west, chances are you've driven on cement. It really isn't any worse than asphalt.
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Maybe there's some legitimate debate over how reversible it is, independently of whether or not it's happening.
No, that was accurate - the climate is changing all the time, and humans have caused various changes to accelerate in ways that are detrimental to the survival of our species (growth of deserts, loss of farmland, etc.)
What this is proposing, is a way to mitigate some of the detrimental changes.
That aside, why the snark? I understand that people of course have personal investment in their enviroment (it's where we live, after all), but for someone proposing a simple change like this that could have multiple beneficial results for our species, I'm not sure why you feel so threatened.
Also, where is all this paint coming from? What are the environmental and economic impacts of making all of this paint?
That's nice for the hot countries. What about cold countries? Maybe we like having black roofs and roads to melt the snow faster if there's a little opening?
There might be some safety issues with making road surfaces reflect more light. . .things that come to mind:
* Increased road glare on sunny days - good sun glasses could largely deal with this, but if you don't happen to have a pair of sunglasses, you might be having a pretty hard time seeing on very bright days.
* Night driving: harder to see the painted lines and reflectors embedded in the concrete (I'm not sure if this would really be much of a problem or not, but maybe could be)
* Winter driving - In the winter, I'm sure that black pavement absorbing sunlight has some beneficial effect in the form of melting ice off the road sooner than light-colored pavement would. Lighter colored road surfaces might lead to ice lasting longer, or requiring more salt to be put on the roads by road crews.
Although this would reduce the amount of energy used for cooling, heating costs would go up. For most people, it takes far more energy to heat a house than cool it. It takes 1200 KWh to cool a house in a temperate climate for a year, but it takes 12000 KWh to heat one . It is more useful to look for ways to heat a house more efficiently than cool it.
Well, even if we can't reverse the process, there are other good reasons to lower our energy consumption.
Energy isn't free; by polluting less, you often spend less in the long run... It's not only good for the planet, it's good for the economy in general.
Both shouldn't be seen as incompatible things.
Or we could put solar panels on roofs and convert the sunlight, that would ordinarily be
converted to heat, into electricity which I am sure we could find a use for.
You're worried about nighttime light pollution from white roofs reflecting more sunlight? (I doubt moonlight would be significant enough to be a factor.)
uhh, in the winter your roof is covered by snow anyways, so the color your roof is not going to make any difference. And for states/countries where it doesn't snow in the winter, you probably also don't need 12000KWh to heat them up.
-- the cake is a lie
In the winter, a dark, hot roof doesn't heat a house very effectively (heat rising and all that- plus there's less incident solar energy).
In the summer, there's a lots of solar energy hitting your roof; and a hot roof leads to a hot attic, which retards flow of heat/hot air in the house (heat rising and all that).
So, a light-colored roof has a much more profound impact on cooling than on heating.
A metal roof will help both heating and cooling- and snow slides off them- but they are not cheap!
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Is it likely to be reversble if it isn't happening?
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Asphalt has it's issues in cold climates.
Up here in Toronto, highways are concrete (yes concrete) with an asphalt layer on top.
Every summer the asphalt has to be repaired, leading to our two seasons.
Winter, and Road Repair.
Things may be similar in the midwest but I am only speculating.
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"I don't want to get too technical on this black paint versus white paint and reflection of heat and so forth because it misses the point."
He always says something like that and what it really means is "I don't want to get too technical on this [Inser topic] becasue there are no technical aspects to my argument that are true.
Fight it on the rights issue, but don't fight it on a science issue when you do not understand the science.
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I know this is going to sound like a self-serving political statement from a hardcore Democrat -- but well done, President Obama.
My cynicism knows no bounds, which gives me to think what the Democratic response to this might have been if a Bush Administration official had proposed it. I'm betting something to the tune of, "Oh those damned Republicans they want to use band-aid technological fixes so they can go on driving their SUVs over baby polar bears for another ten years!"
I think this is a good idea, and if Chu can make it happen (again, colour me cynical) it'll be a good thing, particularly because of the reduced energy demand aspect, which will help with the whole peak oil deal.
But I can't help thinking about how mindless partisans (not necessarily you) would have reacted if the Offence rather than the Defence had suggested this (both parties are ultimately on the same team, of course, representing the plutocrats united against the people.)
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What you have to understand is that there's climate change, and the movement to save the environment. Then, there's "global warming" and the movement to sell you yet more products that can "save the environment!!" (despite the fact that selling unnecessary products and not living simply enough is the main cause of damage)
Wouldn't it be better to simply plant grass instead? Ignoring the problem of having to reinforce roofs that is...
And far LESS expensive in the long term.
There is a tipping point to the cement argument which is why you don't see it in truly cold locations like Canada. Cement roads have a longer lifespan than asphalt and it works out to be cheaper in some locations. In other locations ,due frost, the ground moves too much to see the return on investment. In Canada where there is heavy frost every winter a cement road would still be required to be repaired every year but at a much greater cost due to the cracks caused by frost. This is why you see more cement roads in the southern states and less in the northern. Asphalt's lower cost to install and repair makes it a better fit in colder areas. Neither is a perfect solution but each serves it's purpose in it's place. The perfect solution, as always, is to give us our flying cars.
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Rush Limbaugh does sound like a doofus when he tries to talk about science, but he is no racist. He consistently agrees with Dr King's ideal of judging people by the content of their character, not the color of their skin. Rush agrees with and supports people who agree with his political viewpoint regardless of skin color, and opposes those who disagree in like kind. A man who had a problem with black people would not let Dr Walter Williams guest host his show so often, would not interview Justice Clarence Thomas on his program, etc. It saddens me that politics has become so polarized that it is considered normal for people who never listen to Rush Limbaugh to "know" that he is a racist, plus get modded funny based on that smear.
They can scrape & repave large sections of a highway in a weekend if using asphalt, compared to weeks for cement. Of course, if they're doing cement it usually means they're tearing up the whole road and rebuilding it from the bottom up. Also, when the top layer of cement wears out, they often throw a layer of asphalt over it to extend the road's life a few more years.
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The idea has some merit, but Chu is yapping his face off about Global Warming in order to make sure his buddies get more dumptruckfulls of money to further "study" and "quantify" exactly how much this might help.
So the idea has merit, but anybody that tries to study it is just in it for the money?