"Unfortunately there's no law (yet) in California that requires reflective surfaces on city streets or sidewalks."

Sorry, that is just a dumb idea. If you've ever lived in a place that sees a lot of snow you'd know that's a dumb idea, white roads are very hard on the eyes on a sunny day in a northern city in the winter, I can't imagine what it would be like in LA in the summer. Your carbon offset would probably be more than eclipsed by the number of cars that needed replacing after accidents brought on by poor visibility.

Not to mention, lots of dead people from silly legislation doesn't help a party stay in power.

Wouldn't it be awfully difficult to see, if the roads and sidewalks were reflective? But the roof idea's been around for awhile, I remember seeing an article about it over ten years ago...

Global warming bullshit is so far and gone away and over it's not even funny.

I think the better idea is to put non-reflective roof structures in place that take advantage of all that heat/light we're getting from the sun. The point of this "finding" is that by sending the energy back into space, our planet won't get too hot as quickly. But if we could use the energy to run our buildings' heating and lighting systems, or even just to supplement them, that's a FAR greater gain.

Reflective paint on roofs is a good idea for short-term and cheap, but we can do tons better.

On roads, parking lots, whatever, no. Maybe there could be a slightly lighter shade encouraged, but as someone who used to drive a lot, I know I really want the roads fairly dark and non-reflective.

That's so you the bright reflective things, like other cars and people and stuff, really stand out against the background of the road.

See, you want those things to stand out so as to make it less likely that inattentive drivers will HIT THEM with their speeding automobiles.

Just to clarify that bit.

White or reflected pavement, really really bad idea. Drivers and pedestrians need to see clearly. Imagine night time, all those headlights reflected off pavement, what a nightmare!

Black cars are the hottest on hot days because the color absorbs the heat.

Yes, but Black Cars Look Better in the Shade.

A better use, even from the AGW-believer viewpoint, for that vast acreage of residential roof space would be solar cells. The cost may still be in trust-fund tinkerer terrain, but it's coming down rapidly.

If you want to engineer climate, a stronger approach would be to "paint the Earth white" by finding ways to increase cloud cover. Clouds, by raising the albedo (reflectivity) of the planet, cool it off.

For covering the desert sands with solar collectors.

if part of the Sonoran desert were covered with 40 square miles of solar collectors, I seriously doubt that the environmental impact would compare with that created by the city of Phoenix.

And if you get 10 miles outside the city limits, believe me, the desert does not seem to care very much about Phoenix at all.

They shade that black roof in the summer and drop their leaves to allow solar heat in the winter.

I don't see how this would make a difference. White and black differ in how fast they absorb heat, not in how much heat they absorb. Black heats up faster, but also cools down faster. White takes forever to heat up but also takes forever to cool down. The reason a black car "feels" hot is that it is willing to give up its heat faster (to your hand in this case). At equilibrium, both come to the same temperature.

The LBL guys are smart. It must be a different reason if it works.

Pure black absorbs all photons, heats up, and passes the energy on to the environment. Pure white reflects all photons. In general, blacker means more absorption.

For a given temperature, a black surface radiates more heat than a white one. That might be what you are thinking of, but it is not what matters.

1. Aren't there fossil fuel savings for those of us with dark roofs who live in the north where it's cold for much of the year? That is, if dark roofs absorb heat, doesn't that help us keep our homes warm?

2. The questions about the comparative safety of dark vs. light roads is interesting. I am not sure the angry posters who are so sure that white roads will cause accidents are right -- is there data showing that DRY (non-iced) roads up north in the winter are more dangerous on sunny days than dark dry roads in the summer? More data & perhaps a more comprehensive model to analyze the data are required, don't you think? Also, since black roads absorb the sun, it may take less energy to clear & de-ice them (or not -- I just don't know) -- is this factor considered?

The bottom line is that not every place has a climate like California's -- in fact, California has more than one kind of climate within it -- so does the model on which the proposed legislation is based take a variety of climates into account?

Like refugees. I would support that.

A lot of roads in Florida are nearly white, because they're made of coral conglomerate. I've never noticed a problem with visibility while driving on them.

without a doubt, the white coral roads are noticeably cooler than black hardtop.

If painting the roofs white in the ten largest uban areas would counter the effects of the CO2 we wouldn't need this crazy complex economy-hobbling guilt-addressing self-flaggelating crabon offset program and then where would that leave those who are about to turn carbon offset programs into major investments? So, obviously that won't work. You see, just because there is a simple solution doesn't mean the solution would work particularly if those who are currently in the forefront of creating the complex solution have their soup bowls firmly affixed to the complex plan they've rigged up and are looking forward to getting even with their ideological adversaries.