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Deforestation May Be At Root of Brazil Drought

The frame of a car is revealed by the receding water line in the Atibainha dam, part of the Cantareira System that provides water to the Sao Paulo metropolitan area, in Nazare Paulista, Brazil. The sky rivers are generated by the forest acting as a massive pump, according to research that has shown the jungle’s uniform humidity consistently lowers atmospheric pressure in the Amazon basin. That allows it to draw moist air currents from the Atlantic Ocean much farther inland than areas that don’t have forests. Those currents travel west across the continent until they hit the Andes mountains, where they pivot and carry rains south to Buenos Aires and east to Sao Paulo.

Deforestation May Be At Root of Brazil Drought


The cutting of trees, scientists say, is hindering the immense jungle's ability to absorb carbon from the air — and to pull enough water through tree roots to supply gigantic "sky rivers" that move more moisture than the Amazon river itself. More than two-thirds of the rain in southeastern Brazil, home to 40 percent of its population, comes from these sky rivers, studies estimate. When they dry up, drought follows, scientists believe.

It's not just Brazil but South America as a whole for which these rivers in the sky play a pivotal meteorological role, according to a recent study by a top Brazilian climate scientist, Antonio Nobre of the government's Center for Earth System Science.