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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.'"
Makes me wonder why roofs and not pavement. There's a lot of roads and parking lots around the world. Seems like there's more surface area of those than roofs.
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and make all the birds blind. we had a man in the neighborhood who had a white roof and it was filled with dead birds. birds fly towards white objects for some reason as if it's the sky, and splatter to death.
Wasn't there a study a year or two ago, which was loudly trumpeted by NPR, CNN, MSNBC, etc, that concluded that manmade global warming (or "climate change") was already a sure thing, and it was way past too late for us to do anything about it now.
So, uh... What happened to that? Was that fake, or is this guy ignorant? Or do climate-change types believe stuff whenever it's convenient for them?
If white roofs are good, maybe we can put down aluminum foil and that will be even better.
Now all we need is white tar...
Welcome to the Panopticon. Used to be a prison, now it's your home.
I wonder if he calculated the amount of green house gas and other pollution would be created by manufacturing all this new paint. If they were you make roofing tiles and shingles white, what would the pollution cost from people throwing out their old roofs to bring in new white ones? Same with roads. My favorite roof solution, and something I plan on working on this summer or next summer is to turn my garage roof in to a natural garden by placing a protective tar paper over the shingles, a couple of inches of dirt and then grass or moss seeds. I'll let nature reclaim my man-made structure. Inch for inch, it would be just like grass growing on the ground, except not.
Amazing, isn't it? Two to three degrees in temperature reduction in a major city just by resurfacing, repainting, and planting trees. Yeah, sure, it's not sexy. But the cost savings ... staggering. Add in the health benefits of reducing smog, plus the reduction of human misery from over-heated citys, and you wonder why we haven't done this years ago.
I know this is going to sound like a self-serving political statement from a hardcore Democrat -- but well done, President Obama. You picked a scientist to run an agency. You gave him a mission to better humanity through reducing carbon emissions and energy consumption. You gave him a platform where he would be heard. Well done indeed.
Paint roofs white? With the efficiency increases in photo-electric technology, why not put solar panels on every roof? Not only would we reduce the amount of heat being re-radiated back into the atmosphere but, if done on a global scale, we'd eliminate one of the primary reasons for climate change in the first place : the burning of fossil fuels. And before you respond with "but it will cost too much and generate more CO2 than it eliminates" let me give you one word : Bootstrapping. That's right -- Use the power from the existing global infrastructure for solar energy capture to build more global infrastructure for solar energy capture; That way, you would generate a minimal amount of greenhouse gases in the manufacture of new solar panels while at the same time creating a self-sustaining positive feedback loop wherein the more energy we can capture, the more energy capture infrastructure we can build, resulting in our ability to capture more energy.
I didn't RTFA but the summary sounds retarded.
jdb2
and sea levels, but not for the pH balance of the oceans, which are acidifying as they absorb additional carbon from the atmosphere.
I remember reading about green roofs (growing plants etc on the roof of buildings) and the effect it had on temperatures when done in urban environments:
Reduce heating (by adding mass and thermal resistance value) and cooling (by evaporative cooling) loads on a building â" especially if it is glassed in so as to act as a terrarium and passive solar heat reservoir â" a concentration of green roofs in an urban area can even reduce the city's average temperatures during the summer.
The Fairmont Hotel, here in Vancouver BC does this, growing herbs for the hotel kitchens.
This brilliant "idea" fails to take into consideration the fact that in the winter, sunlight falling on a roof does add to the heat inside the house. If the roof were a light color, that heat would have to be replaced by burning some sort of fuel. So unless you're in a location that never needs heat, the idea doesn't work.
Personally I don't believe there is such a thing as anthropomorphic climate change, but if I did, I would still keep my roof a dark color.
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Yep. I have often speculated on using the road heat and vibrations to generate power.
I believe it is nothing more then an engineering problem at this point.
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The colour of a surface effects immision equally to absorption (this is a fundimental of physics, if it didn't it would violate time/parity symmetry), therefore when your building is net loosing energy (ie when you are trying to keep it warm by heating it) it looses less energy, and when it is net gaining energy ...OK the exact nature of the relationship in terms of net loss/gain is only true for a specific wavelengh but the general point stands: less absorbant surfaces are also less emissive.
Although this change the earth's albedo noticeably, it doesn't deal with the problem, and leaves some nasty side-effects, such as:
1. Acidification of oceans. If atmospheric CO2 doesn't decrease, neither does CO2 dissolved in oceans. This means coral still dies etc etc.
2. Rising sea levels. In fact, it makes it worse. Because the albedo is only change in temperate and tropical zones (there are no roofs or roads at the poles) and because the greenhouse effect continues unabated, the temperature at the poles continues to increase even though the temperature at the equator drops. Cue melting ice-cap apocalypse etc etc.
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How does that work? I would expect that the color of the roof would be irrelevant if it was buried under a blanket of white, insulating snow - no sunshine would hit it.
All you need is a little crack of black and you'll start melting. One of my favorite methods of asphalt-driveway shoveling when there's only 4-8 inches of snow: Drive out to the road, packing down some snow, then shovel two lines right next to the wheel-trenches. If the temperature is at least 20F, then the whole driveway melts and evaporates in one sunny afternoon. If it's 10-20F, then at least in a few days there is considerably less snow, but you'll have some ice (which is easy to scrape to the side).
Someone needs to tell that caller about the difference between optical light and infrared light. I wonder if he has ever tried to boil coffee with a flashlight.
Just because you are paranoid does not mean that no-one is out to get you.
Hey, I love trees. They're green, provide shade, and help increase the property value in a city. What's not to love about them?
If you're referencing the situation in LA, I'd say that was a good question. Utility and maintenance companies hate them because they add work and cost. Homeowners can be generally stupid, so most opt for the bare landscaping with an palm tree here or there.
Amazing, isn't it? Endless miles of concrete in a city where the heat is pervasive, smog is a given, and air-conditioning is a must, and no one thinks to plant a few trees.
I'm an Alaskan (and I apologize for Palin), and so as one of those people in a cold place, I can say you _want_ snow on your roof. Snow traps heat in, because snow is a great insulator. Snow is good. And we don't get enough insolation in the winter to pick up much heating from that, anyhow. But in the summer, you have to cool your place (it gets into the high 80s here in Fairbanks) because of how much light is constantly bombarding your home. The other day, it was 95 inside my poorly designed home.
I appreciate that this guy is a really smart physicist, thus I'm sure he's got the math right on the effect of changing the albedo of structures.
However, I seriously question the environmental economics of this. It seems that this needs a very well-scoped Cost Benefit Analysis.
We are talking about replacing or altering a vast surface area of global structures. This alone has a massive environmental impact - even just in the trucks needed to transport materials alone. Not to mention the retooling of factories, mining or manufacturing new materials and disposing of waste products, as well as disposing of the old surfaces and excess stock of the same. Not to mention also that shifting to whiter concrete roads, for example, will significantly increase noise pollution, and may result in the need for more salt/grit use in Winter (a serious environmental impact), as well as a higher risk of accidents from glare, reduced ability to see ice patches, etc.
Obviously this would take generations to complete, even in the US with a huge amount of money and resources at its disposal, even if there was a massive construction program that started right now.
It would take far, far longer in countries like India or China. It may never happen in Africa, or take many centuries. Surely the time taken for the deferred benefit of making these changes to kick in, would barely offset the significant short-run environmental impact of making those changes long-run, if at all. The carbon issues are far greater in developing countries, they cannot afford to make these changes, some developing countries are vast in geographic size and population, with a large number of structures. They carbon impact will increase, while not being able to afford to offset it by utilizing this method. For it to work fully and effectively the world world's structures need to be painted white. There really aren't that many in the US compared with other nations.
The environmental costs listed above are probably only the tip of the iceberg, just off the top of my head without thinking too hard. With a fully-scoped Cost Benefit Analysis there will be many, many additional costs to those listed here. He's really only examined the benefit. I do not believe the benefit exceeds the cost in this case.
Surely there is a quicker, better way to achieve the same benefit.
And which direction is this "climate change" thing heading again? In the sixties they scared us with global warming of catastrophic consequences. In the seventies they scared us with catastrophic global cooling. Then they again started with the warming. At which point of the brain-mincing propaganda cycle are we currently? I'm sorry, I'm not following the news recently, and this new "climate change" terminology doesn't help, either.
This is already common practice in many tropical locations with flat roofs (as seen in TFA in the video). The problem is keeping them clean -- mildew grows pretty fast in warm moist climates. Biennial cleaning is necessary at a *bare minimum*, and even then the roof will still be largely covered by the time it's due for cleaning.
In temperate climates, you won't have as much of a net gain because you'll be losing natural heating during the winter.
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Anyone in the US who thinks the earth needs to be cooler needs to sleep outside for a year. If you still have the same opinion a year later, give me a call.
So do both parties enjoy plutocratic embraces? Sure. But it's largely different groups of plutocrats, and quite often their bread is buttered on different sides.
The analogy I like to use is that of the offensive and defensive lines of an American football team. People who get all partisan about the Democrats vs the Republicans are like people who've missed the point of the game entirely, and instead of recognizing the game for what it is, insist that the offensive line of one team is "their team" and spend all their energy cheering for it while running down the defence of the same team, blissfully unaware that there is a whole 'nother contest going on.
It looks ludicrous to anyone who understands what the game is actually about, to see people insisting, "but they're different people!" as if they weren't essentially the same kind of people, all on the same team, all headed in the same direction (toward more powerful government.)
I understand that if you look closely enough at them you'll see differences, but if you don't think the differences between Them and Us are far larger than the difference between Them and Them, you've been blinded by the dazzle and the hype.
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There are much better stuff than white paint for reflecting the sun light.
There are retro-reflectors, which send the sun back into space, while white paint sends most of it to the ground and clouds.
My system can even turn off the reflection, to cool off at night. It is a sun driven air conditioner, or heater, and cheap as well
http://kim.oyhus.no/SunValve/
Kim0
It may be good for increasing the reflectivity of road surfaces, but production of cement emits a LOT of greenhouse gases.