How close is the Amazon rainforest to unstoppable aridification?

Scott Stark, a researcher with the Tropical Forest Ecology Laboratory at Michigan State University, said that’s one of the most important scientific questions of our time. It needs a good answer because the Amazon stores a lot of carbon that would otherwise end up in the atmosphere as carbon dioxide, warming the planet. 

“The Amazon also helps cool the Earth by maintaining a cloudy wet atmosphere over the South American continent,” Stark said.

University of Arizona ecologist Scott Saleska said a recent research paper helps answer the question, suggesting that deforestation of from 20 to 40 percent of the Amazon could push the ecosystem over the brink toward permanent aridification.

“This is not something that is out there in the future. It is already happening now, and it will get worse with more climate change and deforestation,” Saleska said. “We may be at or approaching the threshold already and we don’t want to do this experiment to find out for sure!” The threshold, he said, depends not just on deforestation but on the degree of climate change. 

“Warming brings us closer to a tipping point all by itself,” he said. “The more warming we have the less deforestation is needed, and vice versa.”

The NASA Earth Observatory maintains detailed information of Amazon deforestation, including links to new research. 

Bob Berwyn

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