The South American monsoon, which determines the climate of much of the continent, is being pushed towards a “critical destabilisation point”, according to a new study that links regional rainfall to Amazon deforestation and global heating. Via the Guardian:
The authors of the report said they found their results “shocking” and urged policymakers to act with urgency to forestall a tipping point, which could result in up to 30% less rainfall, a dieback of the forest and a dire impact on food production.
Urgency, you say? I’m sure they’ll get right on it, now that they know the facts!
The study, published on Wednesday in Science Advances, examines how forest degradation and monsoon circulation are interlinked.
Using past observations and computer modelling, it finds that the Amazon and the South American monsoon are “one coupled system”, in which the evapotranspiration by the tropical rainforest recycles moisture from the Atlantic Ocean so that it can move south across the continent.
Human degradation of the Amazon – by land clearance, fire, logging and mining – is pushing that system towards a tipping point, after which drier conditions would be expected to cause an abrupt “regime shift” in the rainforest, which would be unable to sustain itself and transport moisture.
[…] The researchers on the Amazon-monsoon paper saw several precursors of the tipping point, including falling rainfall in many areas, the steady lengthening of the Amazon dry season, reduced soil moisture and the increasing frequency and intensity of droughts. There have been three statistically one-in-100-year droughts in the space of a single decade.“It is shocking to see these signs of destabilisation,” said the lead author, Nils Bochow, of the University of Tromsø and the Potsdam Institute of Climate Impact Research. “But we shouldn’t lose hope. We can still act. We need stricter rules regarding the rainforest.”
I keep thinking of all those disaster movies where a lone scientist is trying to warn of catastrophe. Guess I’ll go watch “Don’t Look Up” now.
