You read the headline correct. I agree (mostly) with this story from the LA Times: To slow global warming, install white roofs
Builders have known for decades that white roofs reflect the sun’s rays and lower the cost of air conditioning. But now scientists say they have quantified a new benefit: slowing global warming.
If the 100 biggest cities in the world installed white roofs and changed their pavement to more reflective materials — say, concrete instead of asphalt-based material — the global cooling effect would be massive, according to data released Tuesday at California’s annual Climate Change Research Conference in Sacramento.
Here is a part of Man’s effect that I have mentioned once or twice here on my blog (and should discuss more), but, discuss with people more often. It is also known as the urban island effect and urban heat sink effect. What you have is buildings and roadways that trap heat, particularly in more built up areas. This increases the average temperatures in those areas. The land is not able to cool down. Much of it is localized, but, added up, it can increase the overall climate in the lower levels of the atmosphere where humans live. Instead of a good chunk of Sunlight being reflected back in to space, it is trapped.
Interestingly, this does show that the Sun has a massive effect on the climate.
Anyhow, I have never understood the point of black roofing. One would think that a lighter color would work better, particularly in areas that tend to get warm and hot, for the home.
Globally, roofs account for 25% of the surface of most cities, and pavement accounts for about 35%. If all were switched to reflective material in 100 major urban areas, it would offset 44 metric gigatons of greenhouse gases, which have been trapping heat in the atmosphere and altering the climate on a potentially dangerous scale.
I’m not sure if I buy in to combining better reflective materials in to the greenhouse gas debate, but, using more reflective materials in roofing and paving would decrease the average temperature in built up areas. We just have to make sure we do not reflect too much. The land, and water, still need to capture a certain amount, and reflecting too much can create a little, or big, ice age.
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Teach said: Interestingly, this does show that the Sun has a massive effect on the climate.
Of course it does. Solar radiation is what power’s the climate system, but there has been no significant change in the output from the Sun that would account for the current rate of change in the climate. What this really shows is that things that trap heat (such as greenhouse gases) or reflect heat (such as cloud cover, snow & ice) can alter the earth’s temperature. In addition, there are feedback mechanisms in the climate system that can amplify the effects. For example as rising concentrations of greenhouse gases warm Earth’s climate, snow and ice begin to melt. This melting reveals darker land and water surfaces that absorb more of the Sun’s heat, causing more warming, which causes more melting – it’s a self-reinforcing cycle.
Uh-oh. Reflective material might blind the pilots in aircraft though. :-?