Could White Roofs Paint Greener Future?

Painting Your Roof White Could Save Energy And Be Good Defense Against Global Warming

(CBS)  Could painting your roof white be an effective defense against global warming?

Some very important people think so.

Early Show national correspondent Hattie Kauffman put that idea to the test.

In any given city, most rooftops are black. And that's the problem. The darker the surface, the more heat it retains.

Kauffman was joined by "Bill Nye the Science Guy" on the roof of CBS Television City.

Nye used a meter to demonstrate that the lighter the surface, the better it is for the environment.

"The building doesn't get as hot, so you don't need to run the air conditioner nearly as long -- if (the roof is)white," Nye said.

A shiny example is the white-painted villages in Greece. Turns out they were ahead of their time. Energy Secretary Steven Chu says, if all rooftops and roads in the world were made white it could combat global warming.

"That would be the equivalent as if you took off all the automobiles of the world for of the world for eleven years," Chu said.

Think of it this way: Every year, you would keep 2.4 billion tons of carbon dioxide out of the atmosphere, or the emissions produced by 60 million cars. There would be even more savings if roads and parking lots were not covered in black asphalt.

"So the same needle says just 2 1/2 -- which means it's absorbing more heat, keeping the city warmer," he noted. "It's squandering billions of tons of carbon dioxide every year."

For much more information, visit "White Roofs Cool the World, Directly Offset CO2 and Delay Global Warming".

[jetranger7]

WHITE ROOFS - OK ~~ Everybody, I've got White Paint for sale,, for you to paint your roof WHITE,, I can sell you a 5-gallon bucket for say,, $700.00 and a sponge roller for say $200.00 , doesn't include shipping but another 1000.00 will cover that,,,, Geeeee Wally, said the Beaver,, this sounds like a money makin opportunity, sure am glad they printed this story, Wally, we'll have our on Roof Painting business, but I don't want to get all messy Beaver,,, maybe we can hire some ILLEGALS and pay them $2.00 a day to work on those hott roofs, while we just drive by in our Expensive Air-Conditionined SUV's and watch, sounds like a plan Wally,, glad you thought of that,,, ya, and guess what Beaver, nobody will ever hardly notice because they'll be like 5 to 20 stories up on the roof and nobody will ever see them, so we can't in trouble with customs officials,,, cool idea huh beaver --- sure is Wally- Thanks ~!!!!!

[astm-d6866]

Agree with beals1978, white roofs would not be beneficial during winter.

www.radiocarbon.eu

[doctor_know]

Perhaps, but the savings would come in summer when your house is too hot. Having a heater in your home us not useful in summer, but you still have one just for the winter, right?

[rf35]

Where I live, the temp rarely climbs above the mid-80s(F). Most houses in the area don't have AC units. In fact, not many other buildings do, either. We're more concerned about the cost of heating the homes in winter, which can get quit expensive. It would make more sense to cover our roofs in black insulating material. If someone wants to turn my roof white, they can also start paying a persentage of my heating oil bill.

[doctor_know]

Right, so don't paint your roof white. Simple. Nobody is talking about making you paint your roof white, especially considering the climate in which you live.

[sjc_1]

I flew into Las Vegas recently and noticed grey roofs on industrial buildings along with all the AC units. If those roofs were painted white, the AC units would not use as much electricity cooling a building taking in the heat of the sun.

[doctor_know]

Correct

[sjc_1]

White roofs are like proper tire pressure in that they both are simple and they both work. The right wing scoffs at these, but they DO actually work and are simple. Since they are simple many people can do this. When lots of people do this, lots of energy is saved. It is as simple as that, but some people do not want to accept it, for whatever reasons...if you can call them that.

[fcs25]

"Some very important people think so" A few hundred years ago "some " important people thought the world was flat also.Global warming is junk science just as global cooling was during the 70's.First humans were responsibile for the Earth cooling,and now they are responsibile for the warming of the Earth....make your simple minds up...which is it?

[doctor_know]

You are correct when you imply that science has progressed immensely over the past hundred years.... but I do not understand your reasoning for thinking that we should do nothing about climate. Doctors used to try to bleed illness out of sick patients. What you are saying is like having your doctor tell you you have cancer and need chemotherapy, and responding that chemotherapy is junk medicine just like bleeding was, and therefore you would like to just let yourself die of cancer!

[panton41]

A few hundred years ago "some " important people thought the world was flat also....?

It's my understanding that ancient Greek philosophers/scientists not only knew the Earth was round (from watching ships going out to sea) but also calculated the size of the Earth fairly accurately using simple geometry.

The myth that Columbus wanted to prove the Earth was round was just that, a myth. Most educated people in the world in the 15th century were well aware the world was round.

Apparently, if you can't even get that basic fact right what's to make us think anything else you said was true?

[GiveMeFreedom]

If we just grounded Al Gore's private jets, dry docked his yacht and foreced him to tear down his 20,000 plus sq ft home we would save more than painting our house roofs the racist white color.

[parisdakar]

Sorry, not 'reduction' in reflectivity, 'increase' in reflectivity OR reduction in energy trapped. Same difference.

[parisdakar]

Wait a minute:

There are 127 million households in the US,
times maybe 1500 sq feet of roof per household,
equals 190.5 billion square feet of roof,
equals 6833 sq mi of roof,
There are 3.5 million sq mi of land area in the US,
So roof area is .195 % of land area,
Now, the sun doesn't shine on our roofs all day,
not even half the day on average, but say half anyway = .5
And not all roofs are black,
but say reflectivity is cut by half (really generous) = .5

So .00195 times .5 times .5 is .00048 and change,
equals .05% reduction in reflectivity in the US
Remember we're talking globally here,
and earth's 8500 mile diameter disk is more than 56 million square miles
so redo the first part,
6833 sq mi of roof divided by 56 mil sq mi instead
equals 0.00012% of global land area is roof,
times .5, times .5= ~0.00003,

Which is a 0.003% reduction in global sun energy trapped by roofs in the US

You mean to tell me this will make a measurable difference??

That's like throwing a dime onto your roof and saying it will noticable cool your house.

I think Secretary Chu is just pulling numbers out of his butt. White roofs making any difference is a load of crap.

And can you tell it's a slow day here at work?

[doctor_know]

Your calculation misses the main point, which is that the houses we want to keep cool with A/C are precisely where the white roofs keep temperature down. There is more to it than just changing the overall reflectivity of the planet....

[sjc_1]

Fly into Phoenix or Las Vegas and see all the commercial building roofs that are dark grey. You will notice the AC units mounted on the roofs as well. If painting those roofs white would reduce the power consumption of those AC units, we should all be for that. They do and thus we should.

[parisdakar]

White roofs are better than black roofs? Gasp...Racism!

[Aldymac]

Studys by the roofing industry have shown there is only three degrees difference between a white or black asphalt roof, white highways will be blackened by rubber from tires in a very short time. What advantage would be gained? Those who do the painting or whatever, are the only ones who would benefit, think of the money they would make.

[doctor_know]

Aldymac: the benefit to an individual is small, but when talking about hundreds of millions or even billions of people, the global impact can be huge.

itsjustathought: Why are you so afraid that Obama will mandate everything? The most that is likely is a tax incentive for a white roof... so when you need to re-roof, you can get a white roof for less money, thereby helping reduce the US carbon output. Quit using scare tactics to try and shoot down good ideas!

[edivincison]

This must be a hoax issued by the energy lobbies who keep us hostages at the end of their supply networks.

The truth is that with a photovoltaic rooftop and provided you can store surplus summer energy through a private hydrogen generator, your whole family no more needs any external energy supply.

We know this kind of hoax in Switzerland where our national hero Nicolas Hayek (the "father" of the Swatch) has founded Belenos Clean Power with George Clooney on the board of directors... poor George! (Hayek already killed the hybrid car with VW's Swatchmobile... or did you naively believe it was his own baby?)

[beals1978]

The roof needs to be black in the winter to heat the building and melt the snow. This works both ways.

[doctor_know]

Two comments:

itsjustathought: You are correct that white reflects more light. But white reflects more visible light, which our atmosphere lets escape into space. What happens with black is that it absorbs visible light, heats the object, which then re-emits that energy as infrared radiation which is trapped by the atmosphere. So there is a significant warming reduction with white roofs, not to mention the fact that the house stays cooler, meaning less power wasted on AC.

beals1978: Snow is white, so I dont see having a black roof helping. Besides, heating a house is much eeasier than cooling it, especially with the wasted heat from appliances etc.

[mtoc]

roofs should do more than cover the structure. create electricity, collect rain, etc.