SEP 15

Yeah, old story.
I told many many times to many many people to paint roads in white (with black stripes).

Just add up all the black road surfaces on the earth and you get something mindblasting area of a sun collector. What do you think all those heat is gone? Into the air. Making even higher need for super efficientless air-conditioners turning more power into heat.
Nice loop, yeah.

Will solar-voltaic cells work to use this energy? Black, passive solar collectors, re-use stored heat at night-time, net effect? Can we use black swimming pools to collect and store this heat, then use Stirling type engines to make electricity? Net effect? Is ther a market for a metal roof super reflective white paint for thei purpose? My tin roof is silver, net effect? Please do another article on this fantastic subject. Thank you!

It would be better with rooftop solar panels because then powerplants take no more space. Is a good idea, especially for southern california where it is warmer much more of the year. The farther north you get the lesser the effect would be, say alaska for an extreme example you wouldn't want white because it would use more energy than the heat you get from black.

"It would be better with rooftop solar panels because then powerplants take no more space."

Better, maybe. More expensive, perhaps prohibitively so? Without question. Paint the roof white first, worry about expensive energy-capture needs second. Anybody with a bucket of whitewash or paint, both cheap and easily available, could paint a roof white in a few hours. Don't make this any more complicated than it needs to be.

I'm a little bit suspicious about that global warming quote. Mostly because global warming is global (duh), whereas the the heat-island effect in urban areas is a microclimate. They occur by completely different mechanisms, and I'd be surprised if the albedo shift in urbanized areas could have such dramatic impacts on a larger level.

The two effects likely stack, however, so maybe the implication is that if we eliminate the existing local heating, it will help to alleviate the global climate effects in those areas?

Crazy! I think this is pretty cool, but I'm also curious about the benefit for an area like Minnesota, where the summers can have extremely hot periods and winters extremely cold ones - would the money saved in the summer have to go straight into heating the place in the winter? Or is it just too dang cold at -20 degrees (farenheit) to get any heat from the sun on your roof no matter what?

Yes but if the roofs were white in winter the heat would have to be turned up. Air conditioning uses less energy than heating, because with AC the temp is brought down only 20-30 degrees, while in winter the interior temp has to be brought up 50-70 or more degrees. Why is AC always vilified more than heating?

Wouldn't concrete roads emit more CO2 in their production than they would offset in reflection? Also, what kind of paint is being used, how is it being made. I think that any large retrofit that will at best be carbon neutral is likely to cost more through its very mobilization.

Instead of using paint, couldn't large sheets of white material, just be laid over the roof of homes and such? And that way it's adjustable for both winter and summer, because if sunlight is deflected in the winter, you just get a problem of not gaining as much heat in the winter.

Wow, way to think only of people living in sunny Cali. You may or may not have heard about this, but several billion people live in other places. Places that may not offer scorching temperatures year round. Places, even, where no one wants or needs A/C during the summer.

Please, hit yourself with a cluebat.

Androo, just think about where the extra heat is gone? Even if it is in heat island mode? Where the heat is gone? It must be in-house somewhere. Somewhere on earth.

Two years ago we put a foam roof with a white elastomeric top skin on top of our house, to replace the decades-old tarpaper-and-gravel. It transformed our home, lowering peak temperature on scorching days by more than 10 degrees, and saving significant winter heating costs. What's more, should it ever leak, it keeps problem localized, and holes are easily and permanently repaired with a small can of urethane foam.

If we turned roads and roofs white instead of black, wouldn't we run into the same problem that you get on pleasant winter days? I guess instead of black on the roads, we'd just have it under our eyes...

Isn't your roof in the winter insulated by snow cover? This would be great in the midwest where a white roof would combat the searing summers and would not matter at all in the winter.

Some roofers on a construction job I was working on, were showing me the white elastomer made by Firestone. Comes in different thicknesses, and different time guarantees. You can Google their website. I brought some scraps home and did my porch roof. The stuff is so bright up on the roof on a sunny day sun glasses are a requirement. You have to dry the glue with a heat gun. Works on RV's too.

We installed a spray on foam roof over three joined downtown buildings, about 13,000 s.f. total. On top of that we but the elastomeric white paint. We have 3 heaters we don't even use any more in the winter, and the 5 a/c units on the roof have a much cooler place to work. The amount of savings is HUGE!

I think it's a great idea to paint roofs white, and i'm all for offsetting the effects of global warming however painting the roads white would not be a good idea. If the roads were white, light would reflect into the driver's eyes and thus create more accidents.

ABOUT 3 YEARS AGO I PAINTED MY SHINGLES WHITE AND THE HEAT REFLECTED OFF LEAVING MY ATTIC COOLER. MERRY CHRISTMAS MIKE

I agree with Emily above, white roofs are a great idea, but I think the roads would best be left alone. Not only would white roads cause light to reflect in the driver's eyes, but it would not be near as visible in snow. White roads would also be difficult to keep white, its easy to forget that our roads have endless amounts of dust like dirt and debris.

Even better - vegetate roofs. You'll get more albedo like white roofs but also evaporative cooling, insulation, rainwater attenuation and wildlife habitat/or food

Well John, I dont think the author of this article meant stark white roads, rather a lighter color... There already in use, if you look at some suburban streets, They're all made out of a grayish light brown concrete, in alternating slabs... These streets need fewer maintenance than their asphalt counterparts and keep the neighbor hoods a lot cleaner, smoother, and cooler. Plus, reflection is no issue. I believe if this initiative was made and we stuck to it, we could save our planet...!

This whole premise seems wrong. Black roads absorb energy in the daytime and return it back to the atmosphere every night. White roads would simply return the heat back during the day for the same net effect on the atmosphere. To assume that the heat is radiated out to space is stupid. The reason we are able to survive on this planet is due to the atmosphere's ability to retain the heat that we receive from the sun. I went to that "study" link and it is a bunch of hogwash. Furthermore, to make the statement that this simple "solution" will "save the planet" is complete BS. First it would cost many trillions of dollars to change all those roads to concrete, and it deserves some serious scientific study first. We should look for some more practical solutions before wasting time on this stupid simplistic proposal.

The question of white roofing material is one I have studied some. I have a torch on roof and chose the lightest colour available. a very light grey. I did some tests where created three panels. On one I used conventional tar and gravel, 2, the light coloured Torch-on, and a third with the light material painted white using a white insulating paint called Ceramic Insulcoat. The panels were exposed to the sun and I measured the back side of the panels at different times of the day. The difference was dramatic. In one case the backside of the black panel measured 64C, while the white painted panel measured only 26C. Same angle, same thickness of panel, all the variables had been eliminated. Enough to convince me and I live in a temperate zone (Vancouver Island, Canada)

energy comes from the sun some 93 million miles away. the energy from the sun is split roughly half half between heat and visible light.

this energy falls on the planet's surface and atmosphere. the heat is absorbed mainly by water vapour, the carbon dioxide molecule and the other greenhouse gasses. thanks to the greenhouse gasses life on earth flourishes, without these gasses life would be much tougher (colder).

when heat hits the surface it warms the surface and emits heat back into the atmosphere heating it up. when heat hits the atmosphere it heats it up too.

when visible light hits the atmosphere some of it gets reflected back by things like white clouds and some gasses. when some visible light hits the surface some of it gets reflected back into space unchanged and so sails back into space without heating the atmosphere to any appreciable level - for example snow covered regions will be colder because visible light energy gets reflected back into space without heating the atmosphere. the whiteness of the snow fields reflects visible light energy back into space.

the visible light that gets absorbed by the surface heats it and this heat is then radiated from the surface and so heats the atmosphere as carbon dioxide and water vapour absorb heat (not visible light). areas where light is readily absorbed will be scorching this is why solar hot water heating does so well it absorbs most of the energy of the sun to heat water.

white paint imitates the snow fields by reflecting visible light energy and reflecting this light energy back into space unchanged and importantly by this energy remaining unchanged it doesn't get absorbed by greenhouse gasses and hence heat the atmosphere creating problems such as over heating. remember it is only heat/ infra red that is absorbed by the atmospehere in all practical terms NOT visible light. white roofs will reflect a significant amount of the suns energy back into space without heating the atmosphere.

the properties of white paint mean that visible frequencies do not get turned into heat by absorption and the world gets cooler, we create a snowfield effect to turn the tide of global warming.

get painting

The reason we don't paint or make roads out of anything white is because of driver safety. White roads reflect light sure, right into the eyes of drivers, and thats dangerous and can lead to many more accidents. Asphalt is the material that lasts the longest and can endure wear and pressure over such a long time. You make a road out of anything else and you'll kill yourself with the man power and money it takes to resurface it every few years. You guys have GOT to realize theres a reason for EVERYTHING we do.

This article does not give white roof enough credit.

I live in Arizona. My roof is a standard roof like any typical roof needing replacement every 15 to 30 years. But, with a thin white foam and the bright wight paint on top of that I don't have to worry about the 15 to 30 year replacement any more. It is all sealed up. My summer electric bill was cut in half. I have the guy clean and repaint once every five or six years for about $600 (I saved that much on the first year's power bills)

Anyone living in a hot climate who does not do this either has money to burn or they are just plain stupid.

As for white roads...white would not be so good, due to the blinding safety issue, but why not line roads with beautiful trees to provide shade. Last I heard, the leaves of the trees absorb the sunlight and carbon dioxide turning them into energy rich hydrocarbon fuel, wood. Sure wood burns but why not go back to using wood for furniture and so many other products in stead of plastics which need much energy for their manufacture processes.

jons on the money

roads probably wouldn't be a good candidate for white paint. you could if you really wanted to make the white lines thicker i suppose and make them of the very good reflective type as found in the UK.

not all roads are jet black though even driving around my area you can find asphalt that isn't jet black , it is a lighter shade, even this would be better than jet black.

a white roof on the otherhand will not dazzle anyone except birds, clouds and airline pilots who can't be bothered to wear sunglasses.

vast tracts of the planet could be utilised right now to act against global warming anywhere,right now.

the main thing is to start telling people via the net or your friends. the quicker we start painting the better. global cooling could be acted upon by anyone who wanted to pick up a paintbrush, you don't need any major training other than a willingness to understand what paint to buy and how to prepare the surface.

in the housing estates of australia as you drive along by them or amongst them it is still common to see dark roofs. on a "quiet" day you can hear the hum of airconditioning. airconditioning that is turned on because people's houses have become a magnet for heat - no wonder their house is like a griddle for beef burgers!!

the main thing is that this simple information is spread so that anyone with goodwill can act upon this information and save the planet.

The amount of glare on white roads would present far too much of a hazard to bother with, especially in some climates, after a while it would soon be rendered grey/black with other residues.

Nowhere in the article does the author suggest white roads. He simply suggests the lighter concrete that is already widely in use as opposed to black asphalt.

This info is dead solid right on. Well done.

In the UK we tend not to have flat roofs. They are usually slate and they last hundreds of years, adding paint would only visually and chemically pollute the environment. The light would be reflected not into space but onto neighbours, so no thanks.

One of the reasons this has not been done comes down to pure and simple economics. The materials that have been used and are not eco friendly, are used because they are the least expensive alternative. America lives and embodies the capitalistic idea(s) of making and accumulating as much as you can.
Speaking of green ideas though-- why is it only some brands of pop/wine/ beer/sparkling water that have a deposit still! With the explosion of bottled water and other drinks in plastic bottles where is the deposit for those containers???? so that people recylce instead of trashing them.

even painting your shed roof white would do something. remember you in in effect creating an artificial snow field. a city with white roofs would be a lot cooler in summer. some people like sittig in their own private furnace in the dead of summer, there nothing you can do but smile at them and whilst saving money.

you can lead a horse to water....

Global Warming is a pseudoscientific myth.
Go and check how the supposedly IPCC scientific consensus is a political construction, how very few scientists created very controversial and limited projections, revised them in the last years to became less and less catastrophic, and still they don't match the actual data. Meanwhile a propaganda machine has greatly exaggerated the fears, and the planet is ironically not warming since the nineties, and cooling since 2007.
Also, this painting the roofs is too limited to have an effect. I spend very little, near zero, in air conditioning, and A LOT in heating the house, so by painting the roof black I could save money (=methane, i.e. energy with attached pollution). And I live south of the 45°. Imagine the nordic regions.

Nights are cooler than days because of night radiation. Almost all heat gained by day is lost by night. It is a dynamic balance. A black surface is a better radiator than white, it takes up more heat but also radiates more. The 24 hour net gain of a black surface is equal to that of a white surface. So your roof should be white by day and black by night.

Not all of the places in the world can sustain a whiter superior surface to help reflect sun rays back to space.
However in those place that can't stand white on your roof. Just plant a garden up there.
Read up on the effects of having grass growing on your roof.

About the air-conditioning...
That's just for some people. I don't have air conditioning. A have a small fan that has a resistance to heat up my feet and that is it, and that's only when i fail to properly dress myself.

With the right costume you wouldn't need more heating. Just better prepared housing and better clothing.

Wonderful idea, but I think I would tear my eyes out if that actually happened. I'm extremely sensitive to light and seeing bright Florida sunlight reflecting off just about anything is wont to give me a migraine from hell. What would those like me do in that case, then?

I really like the look of the white roof better but what happens when it rains too much and eventually it's starts chipping like crazy. Something tells me you're better off with the black roof since you will not have to touch it up as often.

It's hilarious and saddening to read the immense number of idiotic trolls that frequent these comments. Grow up, will ya? Or gain a few IQ points.

Anyway, this was actually a suggestion on aol no less just a few days ago. As long as we emphasize that warm climates (ie, basically anyone south of the mason dixon line) use it and NOT the colder climates... it would do a world of wonder in reducing energy bills at a very very tiny cost. Ditto with low-e windows as well. Only in warm climates. During the winter you want that heat to come in.

To address a few things I've seen in other commenters posts: Black roads absorb the heat and basically anywhere from right next to the road up about 30 feet (or higher, probably) is much warmer than the actual air temperature. Band practice has taught me that hands on. Anyway, any buildings near blacktop are immensely affected by their parking lots because of the much higher temperatures hovering above it.

Using paper is a bad idea because there's a wonderful thing called: RAIN. Wouldn't work. We could just manufacture light colored roof tiles to begin with. That would certainly help too.

I did this on several roofs and found out from the manufacturer of the crap elastometric white roof coating people have been suckered into using for this that it rots the roof much faster than if you did not use it! It only belongs on rubber roofs NOT ASPHALT OR SHINGLE ROOFS!

I dont agree much with this article; heres why:

FIRST
"I know, tar is black, and that's what most roofs are sealed with, but I really can't imagine a much dumber decision."

Yes, tar is used on rooftops but gravel is spread evenly over the tar making the roof a lighter color. The gravel helps shield the tar from UV rays giving it a longer life. So the gravel itself is instrumental in preventing the absorption of heat by the tar membrane. On other roofing systems a black roof membrane is usually covered even with reflective paint.


SECOND
"Sure, it's great in the winter, when the roof becomes a giant solar heat collector. "

In winter the roof doesnt absorb as much heat. Especially in geographical locations where it snows. The reason largely being the snow itself.
See, when snow falls rooftops get covered with snow. We all know that snow is white. So the heat is reflected back. Under the roof membrane insulation keeps heat from escaping the building through the roof.


I think the best idea would be to place solar panels on top of roofs. If every one had at least one panel on the roof, we could produce so much "free" energy, lowering the green house gases.

black bodies will heat up faster than white and their mass will hotter.

black bodies will radiate better of an night but they will be hotter than white bodies during the day

either way the atmosphere still gets hotter with black roofs and black bodies.

white paint rteduces the amount of heat energy being absorbed by the atmosphere

This article is fantastic and I am already thinking about how to convince the whole neighborhood to switch.

To all those in doubt of white roofs (I will ignore the other blatant idiocy posted) it's completely based on the concept of albedo.
Albedo is the concept of reflecting back light from the sun. Snow albedos reflect a majority of light, but due to greenhouse gases, snow on both ends of the poles is melting.
Without albedos we will quite literally cook ourselves alive.

For those complaining about winter time and getting heat: get your attics well insulated! Snow and ice will form on roofs creating a perfect insulation, animals sleep under snow during the winter to keep warm (same goes for igloos and quinchees!) If your roof isn't forming snow then your roof is letting out heat.

Mother nature knows best, let's help her do her job.

I'm just happy to see these kinds of discussions taking place. People, local governments are doing it. And in America, great.
Of course, as long as it saves a buck, that motivation is still there, the almighty dollar.
But it's still great to see, Bravo.