Interesting piece in yesterday's New York Times about the link between deforestation and drought. Especially tropical deforestation. A mature tree in Amazonian rainforest transpires about 1,000 liters of water a day; the entire Amazonian Basin sends up about 20 billion tons of water a day into the atmostphere. The atmosphere over Amazonia carries more water than the Amazon River – which itself contains about one fifth of all the freshwater on the planet.
According to the article:
"One way forests may move water is known as biotic pumping. As water transpires into the atmosphere above the forest, the theory holds, it creates a low-pressure system that sucks in air surrounding it, eventually and continually pumping moisture inland from the ocean.Cutting down forests degrades these low-pressure systems, essentially turning off the pump. Large-scale deforestation is thus believed to be a major contributor to the extreme drought in Brazil".
and
"Forest represent a kind of ecological infrastructure that helps maintain comfortable living conditions on the plante, whether by taking up and holding carbon dioxide, cleaning water through their roots, preventing floods by stabilizing soil – or, in this case, regulating climate".
Lots of reasons to stop cutting down tropical forests. And, really, how many soybeans and hamburger patties do we need?