|MadSci Network: Environment|
What a great question! It shows that you are really thinking about how the physical world works. The short answer would be 'Yes' the roads add heat. But the longer answer is more complicated. (You knew that it would be! hahaha!) OK, so the roads are black and we're thinking that the dark surface will absorb more sunlight energy, heating up the surface. This definitely happens and there is some research which directly relates ... you can start with an article from NASA: http://www.nasa.gov/centers/goddard/news/topstory/2004/0801uhigreen.html which has shown that the heat absorbed by roads and other urban surfaces has a direct effect on the climate of the city area, including influencing the growth of plants for a fair distance around the city. On a world wide scale, the impact of roads, per se, would be pretty minimal, I think. Only because, although there are lots of roads and especially in cities they take a lot of space, they are not large compared to the whole surface of the earth. I'm thinking that this would actually make a terrific Science Fair project. You could calculate the area of roads vs the whole area of say, the state of Texas. Then, measure the heat of roads vs bare ground vs covered ground, and calculate how much extra heat that meant in the state? You could even compare different kinds of road surfaces, say cement vs asphalt vs gravel or different kinds of asphalt surfaces, rough or smooth.... There's no telling when you might come up with a really important finding from this kind of simple research. Remember the Australian guys who found out about Global Dimming, like in the recent NOVA tv program: http://www.pbs.org/wgbh/nova/transcripts/3310_sun.html by noticing a little change in the amount of water evaporated from some pans.... This is definitely worth some more investment of time to work out your own answer to your interesting question. Good luck Dr. Matt McConeghy
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