How to Slow Warming: Paint Everything White

[FireNexus]

http://www.miller-mccune.com/science_en ... green-1117

Science & Environment
Is White the New Green?

Three California energy experts make a convincing — and sincere — case that painting roofs white in the hot parts of the planet could offset the greenhouse gas woes caused by the world's cars

By: Sam Kornell | April 03, 2009 | 08:00 AM (PDT) | comment 4 Comments


It has long been known that white-roofed buildings, like this one in Andalusia in Spain, stay cooler in hot weather. Three energy experts make the case that painting white the roofs and pavement in the hot parts of the planet could offset the greenhouse gJosep Altarriba

In early January, Hashem Akbari sent federal officials a rather improbable sounding proposal. An Iranian-born nuclear engineer who, for the last three decades, has worked as a scientist at the Lawrence Berkeley National Laboratory, Akbari would like to see $3 billion of the economic stimulus package directed toward painting white or a light color as many of the nation's roofs, and as much of its pavement, as possible — all with the goal of directing more solar radiation into space.

Akbari, along with Surabi Menon, another LBNL scientist, and Arthur Rosenfeld, a former LBNL scientist and now a California Energy Commission board member, claim that painting urban surfaces in warm parts of the world white or a light color could offset the carbon emissions of all 600 million of the world's cars for 18 to 20 years — at a savings equivalent to at least $1 trillion worth of CO2 reductions.

This is not a hoax: Akbari, Menon and Rosenfeld are three of the country's leading experts in their field, and their study published in the journal Climatic Change is backed by years of carefully calculated data.

It has long been known that white-roofed buildings stay cooler in hot weather. Blinding confirmation of this can be found in the streets of Andalusia in Spain, or the Greek Islands.

It turns out that they cool the air outside of their walls, too. On a typical summer day, Los Angeles is 5 degrees warmer than surrounding areas, and studies have consistently shown that by far the largest factor in this discrepancy is the absorption of solar heat by dark roofs and pavement — a phenomenon known as the "urban heat island" effect.

In 1985, Akbari and his colleagues began attempting to quantify how much "cool" roofs and pavement might improve urban air quality (hotter weather equals dirtier air), while cutting down on the need for air-conditioning. Then, five years ago, it occurred to them that cooling urban areas might also mitigate climate change.

As the greenhouse effect intensifies, one of the most dangerous consequences is a decrease in the earth's albedo — the degree to which it reflects solar radiation. Antarctic ice, for example, acts like a giant mirror, reflecting the heat of the sun back into space; as the ice melts, the earth absorbs more heat, leading to more global warming — a self-perpetuating process scientists call a feedback loop.

The idea of "geo-engineering" the world to make it bounce more of the sun's heat back into space has been around for years, but until Akbari and his colleagues decided to look into it, no one had attempted to quantify how much atmospheric cooling might be achieved by, as it were, painting the town white.

In 2004, they began running the numbers, and when they finished they were incredulous.

"When we did the calculations, initially we couldn't believe the results," Akbari said. "So we re-checked the numbers in different ways." Again, he said, the results were unambiguous: Every 100 square feet of roof area turned from a dark color to white is equivalent to offsetting the emission of one ton of heat-trapping, atmospheric CO2.

To get an idea of what this means, consider that in a single year, the average American is responsible for about 20 tons of CO2 emissions. Per capita, Americans have the largest carbon footprint of any nationality in the world, and all of the activities that make this so — driving our cars, using our electrical appliances, buying consumer products — adds up to the equivalent, atmospherically speaking, of 2,000 square feet of white roof.

In all, Akbari, Menon and Rosenfeld estimate that permanently retrofitting roofs and pavement in tropical and temperate regions of the world would offset 44 gigatons of CO2 emissions. It takes about a year and a half for the entire world to cook up 44 gigatons of CO2.

The scale of such mitigation, in proportion to its cost, is unrivaled among technology-based climate solutions. "This is not trivial a number," said Stephen Schneider, the co-director of Stanford's Center for Environmental Science and Policy, and the editor of Climatic Change.

Schneider emphasized that the plan would offset, not eliminate, the necessity of reducing carbon emissions, but he said that as singular greenhouse mitigation strategies come, the LBNL study is elegant, simple and profoundly cheap.

It's also well timed. Akbari pointed out that by his and his colleagues' calculations, the plan could save Americans $2 billion annually in unspent air conditioning, even after taking into account the increased need for heating in winter. Moreover, he argued, it dovetails with the president's economic and environmental goals.

The Obama administration has made it clear that it wants a substantial portion of the stimulus package to go toward creating a greener economy, but that desire has to be balanced against the imperative to immediately circulate cash and create jobs. Painting or resurfacing roofs or pavement, Akbari said, would nicely fulfill both objectives. The technology exists and is readily available, and since a substantial portion of the country's home and commercial real-estate owners are going to need to re-roof at some point in the near future anyway, it's about as shovel-ready as any proposal currently on the table.

Akbari has thus far not heard back from the government, but he's holding out hope that his funding proposal will be folded into the energy-efficiency provision of the stimulus package.

"I don't see why it shouldn't be," he said. "It will be lucrative for the government and for business owners, and it will create jobs and offset carbon emissions."

However, he noted that the attraction of urban cooling is unlikely to fade anytime in the foreseeable future — indeed, with 70 percent of the world's population projected to live in cities by 2040, it should only increase. He makes a convincing case.

As Schneider said, "It's a clever idea that has no obvious side effects and gives us good bang for our buck."

White paint is an eyesore, and it'll require a decent amount of upkeep to make sure things stay white, but all in all this is an interesting idea. Anybody smarter than me see obvious holes it?

[Ilya Muromets]

I somehow doubt that will really make a dent in regulating the planet's temperature. I mean, the overall area of even several big cities' worth of roofs and pavement doesn't seem to be a significant amount of reflective area to me. That, and painting pavement reflective white is a bad idea unless you wanna end up blinding drivers and pedestrians during the daytime.

[PeZook]

It doesn't need to be reflective white, just a light color, which will still reflect an order of magnitude more energy than dark asphalt.

The sheer elegant brilliance of the idea is stunning.

To get an idea of what this means, consider that in a single year, the average American is responsible for about 20 tons of CO2 emissions. Per capita, Americans have the largest carbon footprint of any nationality in the world, and all of the activities that make this so — driving our cars, using our electrical appliances, buying consumer products — adds up to the equivalent, atmospherically speaking, of 2,000 square feet of white roof.

In all, Akbari, Menon and Rosenfeld estimate that permanently retrofitting roofs and pavement in tropical and temperate regions of the world would offset 44 gigatons of CO2 emissions. It takes about a year and a half for the entire world to cook up 44 gigatons of CO2.

I wonder if they included the CO2 cost of paint production and upkeep, but come on: 2000 square feet to offset carbon emission of a single person? My home has about 450-500, which means a full one quarter of my emissions can be offset by this, if their calculations are accurate. A truly stunning amount, for a miniscule amount of work.

In fact, I think I will start negotiating with my wife to do exactly that

[Shroom Man 777]

Our roof is white, or sort of a creamish color. That good enough?

I do like the notion, and the simple elegance, of painting it all white. I live in a goddamn humid and hot tropical shithole and I really hate it when things are designed without any attention to reducing the goddamn heat. Like buildings with shit window layouts that don't correspond to the wind currents, or goddamn useless windows that can't open to let us BREATHE, or black paint that just ABSORBS the thermal radiation. Like my sister, how when we ride her black car, we have to crank up the AC because it gets all hot inside. And morons wearing black clothes in day despite the heat. Bleh. Fuck em.

The only downside though is that when you're outside, with all the buildings and roads painted white, all the radiation will be reflected back at you and you'll end up being cooked - just like in the beach! But at least staying inside the white buildings will be totally literally cool.

Hate the goddamn weather. I have to shower three times a day...

[Oskuro]

The idea is neat, unless it is used as an excuse not to reduce CO2 emissions, or worse yet, to increase them since they are being offset by the roofs of Whiteopia.

[Alferd Packer]

I somehow doubt that will really make a dent in regulating the planet's temperature. I mean, the overall area of even several big cities' worth of roofs and pavement doesn't seem to be a significant amount of reflective area to me. That, and painting pavement reflective white is a bad idea unless you wanna end up blinding drivers and pedestrians during the daytime.

It would be no worse than being outside on a sunny winter day when the ground is snow-covered; just wear sunglasses. Though, I guess if you live a place that doesn't get snow, it might take some getting used to.

[Tolya]

The problem of combating global warming is not lack of ideas, but rather the incentive of putting them to work. I mean, c'mon, this may be a good idea, but who actually thinks that any significant portion of the planet's population will change colors of their residences? Or which governments would pave the roads with asphalt in a light color?

I appreciate the work of scientists, I really do. But at the same time Im pissed off that everyone treats these sort of news as tuesday evening entertainment. "LOL boffins strange shit".

Im currently engaged in the topic of european union funding. The idea is brilliant: EU gives us (Poland) money for projects that will contribute to the modernization of infrastructure, help develop new technologies, make people more technologically-oriented.

For example, you have a few towns in the underdeveloped, eastern part of Poland. Several kilometers from the nearest city, with huge unemployment, lack of perspectives etc. Your average redneck lives there. Now, technically, the president of a gmina (the smallest form of administrative division in Poland) can apply for EU funding and literally give his people internet for free for a couple of years, bearing only about 15% of actual costs (85% is refunded by the EU). But you need to be a bloody expert just to fill the bloody forms, not to mention doing budget analysis, feasibility studies, the lot. You need a consulting agency to do that for you, which is not really bad if your project is worth many millions of euros. But if you want to run a small EU funded internet operator in a rural area, costs of applying for funds may a big portion of the amount of cash you will receive them.

THAT is bloody beaurocracy.

[Gil Hamilton]

It's not a bad idea in theory. By painting enough surfaces white, you'll increase the albedo of the planet and it should cool. More to the point, a cooler building draws less power in airconditioning, and the less energy used, the less energy related pollution. This is an aspect of a whole; building a better, more efficient human civilization. Personally, I'd just as soon panel the roofs of places that get alot of sun with organic photovoltaic cell/panel/sheets and make the house simply be less of a burden on the grid (hell, you can run an AC with that power), but this is good too.

I just wonder where they are going to get that much titanium dioxide.

[Solauren]

Uh, interesting idea. And probably effective too.

If we end up moving, I should try and convince my wife to let me paint the roof white / off-white to see if that does anything.

Of course, that could lower the temperature of the house during the winter, and increase heating requirements.

[Twoyboy]

I just wonder where they are going to get that much titanium dioxide.

There's a massive surplus of it right now. And of cheap labour. If someone's going to act on this, now's the time to do it.

In a few years the tables will turn and it'll be FUCKING expensive.

[Gil Hamilton]

There's a massive surplus of it right now. And of cheap labour. If someone's going to act on this, now's the time to do it.

In a few years the tables will turn and it'll be FUCKING expensive.

Heh, I'd love to see the environmental impact statement on "We are going to cover the tops of every house in Los Angeles with titanium(IV)dioxide."

But you are right. I didn't know there was a vast surprus of it, even if it is somewhat cheap, so it would be a good idea to get on this if we are going to do it.

[TithonusSyndrome]

Of course, that could lower the temperature of the house during the winter, and increase heating requirements.

Maybe something more akin to seasonal roof tarps would work better in places where the climate gets colder, like here in Canada?

[Gil Hamilton]

Of course, that could lower the temperature of the house during the winter, and increase heating requirements.

It shouldn't increase the heating requirements significantly. Most heat loss from a house is thermal and incidental sunlight lost from a reflect roof won't cool your house significantly, I'd imagine, so long as your insulation is good.

[Solauren]

Of course, that could lower the temperature of the house during the winter, and increase heating requirements.

Maybe something more akin to seasonal roof tarps would work better in places where the climate gets colder, like here in Canada?

That's a pretty good idea actually.

Unfortunately, it would require multiple tarps if solar panels were to be installed on the roof. Either that, or cutting a hole in the tarp and taping it down. Either way is workable.

Thanks TS

[Gil Hamilton]

That's a pretty good idea actually.

Unfortunately, it would require multiple tarps if solar panels were to be installed on the roof. Either that, or cutting a hole in the tarp and taping it down. Either way is workable.

Thanks TS

Depends. If the solar panels are the ones that work on the near-UV, which is the general direction of solar technology, you wouldn't need to remove the tarps at all, depending on what they are made of. Heck, the solar panels would continue to work with several inches of snow on top.

[XaLEv]

This reminds me of something I was wondering about as a way of keeping a house cooler, which was to cover the roof in some sort of retroreflective material. That way, the light will still be reflected, but it will mostly be reflected back at the sun specifically, instead of in all directions.

[Turin]

This idea has been reflected in the various green-building standards here in the US for a number of years. The LEED standard (which has some serious flaws, but that's irrelevant for this discussion) grants a point for using a white roof. As others have mentioned, it's not just the albedo reflecting the sun back for its own sake, but the reduction in cooling loads.

Of course in new construction you get better results if you can pair the white roof with appropriately placed trees. The roof reflects the higher summer sun, and you use deciduous trees to block the sides of the building (and the roof, partially) which absorbs that energy and fixes carbon with it. In the winter the leaves fall off the trees and that low winter sun can hit the building and warm it up.

[Kon_El]

painting pavement reflective white is a bad idea unless you wanna end up blinding drivers and pedestrians during the daytime.

This it the only problem that jumps out at me. Houses could still be a good idea. Wouldn't mind seeing the math they were talking about.

[Solauren]

That's a pretty good idea actually.

Unfortunately, it would require multiple tarps if solar panels were to be installed on the roof. Either that, or cutting a hole in the tarp and taping it down. Either way is workable.

Thanks TS

Depends. If the solar panels are the ones that work on the near-UV, which is the general direction of solar technology, you wouldn't need to remove the tarps at all, depending on what they are made of. Heck, the solar panels would continue to work with several inches of snow on top.

Well, obviously, if I didn't need to cut the tarps, I wouldn't.

[whackadoodle]

Actually, there is already a term for this idea, coined by Gregory Benford: Albedo Chic.

[aimless]

With the issue of white streets being horrible on the eyes, wonder if they did studies with something like light gray.

Though come to think of it the whitewashed wonderland requiring everyone to wear sunglasses in the city could be a neat little bit in a sci-fi future setting.

[Einhander Sn0m4n]

painting pavement reflective white is a bad idea unless you wanna end up blinding drivers and pedestrians during the daytime.

This it the only problem that jumps out at me. Houses could still be a good idea. Wouldn't mind seeing the math they were talking about.

The other problem is the roof-shingle industry. Don't ask me why they have such a hardon for the color black, but they do, and they have money. That means lobbying Congress, possibly to the point of even outlawing any light color at all on roofs (or possibly even any part of a building). Before you start going at me, I direct your attention to the Digital Millennium Copyright Act and the USA PATRIOT Act. Never underestimate the power of money and stupidity when added copiously to large groups. This goes doubly so for Congress.

[aimless]

The other problem is the roof-shingle industry. Don't ask me why they have such a hardon for the color black, but they do, and they have money. That means lobbying Congress, possibly to the point of even outlawing any light color at all on roofs (or possibly even any part of a building). Before you start going at me, I direct your attention to the Digital Millennium Copyright Act and the USA PATRIOT Act. Never underestimate the power of money and stupidity when added copiously to large groups. This goes doubly so for Congress.

Are you sure they really love black that much? Would they really have an issue with people painting over their shingles (or does it not work like that?). Plus lightly colored shingles are already made, the shingle industry would probably be very gung ho for anything that involved making people buy millions of new, lightly colored shingles from them.

Hrm here's a shingle that has the energy reflectivity of white without actually being white. http://www.allbusiness.com/energy-utili ... 837-1.html

[Sea Skimmer]

The other problem is the roof-shingle industry. Don't ask me why they have such a hardon for the color black, but they do, and they have money.

Yeah, bitch about a whole industry you know nothing about, good job. Most shingle is black because most shingle today is asphalt based. You'd have to go to extra trouble to make it anything but black. People might start being willing to pay for that if they realized how much it could save them on an AC bill. Don’t blame the guys making the shit for making it cheap, which is what people want right now. You might as well complain about people making all the roads black in the first place too.

[fgalkin]

painting pavement reflective white is a bad idea unless you wanna end up blinding drivers and pedestrians during the daytime.

This it the only problem that jumps out at me. Houses could still be a good idea. Wouldn't mind seeing the math they were talking about.

The other problem is the roof-shingle industry. Don't ask me why they have such a hardon for the color black, but they do, and they have money. That means lobbying Congress, possibly to the point of even outlawing any light color at all on roofs (or possibly even any part of a building). Before you start going at me, I direct your attention to the Digital Millennium Copyright Act and the USA PATRIOT Act. Never underestimate the power of money and stupidity when added copiously to large groups. This goes doubly so for Congress.

Yes, of course, that must be it. They will do it because they're Evil Corporatists, and the random namedrop of two widely criticized laws (which you have probably never actually read in full) fully supports this. All because most roof shingles are black, and the Evil Corporatists will do in their power to keep it that way. Because they're Evil Corporatists and that is what they do.

Einy, I like you and all, but do something like that again and I'll send it to Testing. Capiche?

Have a very nice day.
-fgalkin