Story at a glance

  • The Amazon rainforest is perilously close to what top scientists are calling a “tipping point” that would cause huge sections to die back, shriveling into a drier savanna-like ecosystem.
  • Accelerating global warming and deforestation are the main forces pushing the rainforest towards the destructive threshold, which would cause the release of billions of tons of planet-warming carbon dioxide.
  • The experts call for Brazil and the rest of the world to band together in halting deforestation in the Amazon and restore what has already been lost.

Deforestation and climate change are pushing the Amazon towards a dangerous “tipping point,” warn two renowned experts. 

The scientists say continued loss of the planet’s largest rainforest will turn vast swaths into savanna — a plain with coarse grass and sparse tree growth — a transformation that would release billions of tons of planet-warming carbon dioxide and ravage wildlife, the Washington Post reports.

“The precious Amazon is teetering on the edge of functional destruction and, with it, so are we,” Thomas Lovejoy and Carlos Nobre, who have each studied the Amazon for decades, wrote in an editorial in the journal Science Advances. “Today, we stand exactly in a moment of destiny: The tipping point is here, it is now.” 

The possibility of such a tipping point in the Amazon has long been theorized but the pair decided to sound the alarm as accelerating deforestation conspired with warmer temperatures and fire to send the ecosystem careening towards thresholds once predicted to be farther off.  

To date, 17 percent of the entire Amazon has been destroyed — a figure that increases to nearly 20 percent for the Brazilian Amazon. 

The scientists say it’s primarily the loss of so many trees that is driving the ecosystem toward the destructive tipping point. 

With each chunk of forest that is slashed and burned, the Amazon gets drier. This is because the trees help sustain the Amazon’s supremely wet climate, forming an integral link between rainfall and cloud formation. 

When raindrops soak the soil, tree roots soak up huge quantities of rainwater. The trees use a portion of that water to sustain themselves but wind up releasing roughly three-quarters back into the air as water vapor — recycling the water back into moisture-laden clouds. 

If the Amazon loses too many trees, it will no longer have enough rainfall to remain a rainforest and wither into a savanna, releasing hundreds of billions of tons of carbon dioxide into the atmosphere. 

The release of all that carbon will also fuel the transformation by accelerating climate change induced warming, making the Amazon hotter and drier and lowering the amount of deforestation required to push the rainforest beyond the tipping point. 

Without climate change, the proverbial edge of the cliff lies at 40 percent deforestation, but with the additional drying caused by warming and fires, the tipping point crashes perilously close to current levels of deforestation — as low as 20 to 25 percent.

Despite the current Brazilian government’s laissez faire attitude towards protecting the environment, the researchers say there is significant public support in Brazil and in other countries around the world for conserving what remains of the Amazon.  

“A tipping point is a way to talk about a moment of system shift or system change,” Lovejoy told the Post. “In this case, it’s not going to be instantaneous, and that’s good news. It allows you to do something about it.”

Published on Dec 21, 2019