Friday, April 4, 2008

how much is deforestation causing climate change?

i read an interesting article about how solar rays and correlated low cloud cover are not the cause of climate change, at least according to the latest study.

and an idea struck me. if lower atmosphere clouds (or the lack thereof) cause global warming, then the source of these clouds is pretty important. more than anything else, forests create clouds. sure, oceans and lakes create clouds along the coastlines, but virtually every molecule of water in the atmosphere more than about 100 miles inland has passed through a plant since it last saw the ocean.

this was my most important take away from my brief environmental science studies in university: if you cut down the fist 100 miles of the amazon rain forest, the rest would slowly dry up an die.

so, if forest create clouds, enhance evaporation, reduce heat absorption (vs bare ground), could they not be an important factor in determining the global temperature? how could they not be?

to re-enforce this idea, we could look at global forest cover over the last few centuries and how it correlates with global temperatures or create a model to examine impacts, which is what a few scientists did at the university of Kansas a few years ago. they found that tropical forests had a significant cooling effect, while temperate forests had a net warming effect, but that the impact was comparatively small at around 2 degrees C over the next 100 years.

i was kinda hoping i wouldn't find a paper on the subject. kinda bursts my bubble, really.

interestingly, the blurb doesn't specifically mention clouds, or the CO2 released by changing from forest to grassland, and, since it was done 3 years ago, couldn't have included cloud-causing bacteria considerations. instead, it focused only on heat reflectivity and moisture influence of ground covers.

so there.

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