NYT: Decades of extraction have left the South American rainforest at a “tipping point.”

The Amazon has long served as a vast carbon sink, even as vegetation pumped oxygen into the atmosphere to the point it was called the “lungs of the Earth.”

But vast deforestation, despite calls to save the Amazon that originated decades ago, portends profound changes in the ecology of the huge, increasingly fragmented forest that lies mainly within Brazil.

“Just in the past half-century, 17 percent of the Amazon — an area larger than Texas — has been converted to croplands or cattle pasture. Less forest means less recycled rain, less vapor to cool the air, less of a canopy to shield against sunlight,” according to a report from Alex Cuadros.

“In one study, a team led by the researcher Paulo Brando intentionally set a series of fires in swaths of forest abutted by an inactive soy plantation. After a second burn, coincidentally during a drought year, one plot lost nearly a third of its canopy cover, and African grasses — imported species commonly used in cattle pasture — moved in.”