The Amazon rainforest—the world’s largest rainforest, covering more than three million square miles—has been under threat from deforestation and exploitation for decades. But scientists now think that the damage done to the forest could be fundamental. A new study looks at how quickly the largest ecosystems in the world could be lost after they reach critical tipping points. The larger the ecosystem, they found, the faster it can change. And the Amazon could reach that tipping point and disappear within 50 years.
“We scoured the world for data of what we call regime shifts—any data where an ecosystem had changed from one state to another state,” says Simon Willcock, a senior lecturer at Bangor University in Wales and one of the authors of the new study. Those changes included, for example, lakes turning into oxygen-depleted dead zones, the bleaching of coral reefs, and African grasslands turning to desert. “We use that [data] to make a relationship between the time these collapses took and the size of these ecosystems. Then from that, if you give me any ecosystem size, I can then tell you how long it will take to collapse,” he says.
When an ecosystem is degraded over time, it will eventually reach a tipping point where massive change becomes inevitable. Willcock compares it to a boulder reaching the top of a hill. It’s hard, he says, to identify when a tipping point occurs. In the Amazon, as deforestation makes the region less humid and reduces rainfall, and as climate change makes the forest hotter, the forest is likely to begin to die back and turn into a savannah. Around 10 million species live in the rainforest; right now, the forest also absorbs around two billion tons of CO2 each year, making it vital for fighting climate change. There’s growing evidence, the study says, that the Amazon could reach the tipping point as early as 2021—and perhaps it already has. “Potentially, we could have already crossed it,” Willcock says. “Tipping points are really hard to identify before the event.”
After it reaches the point of no return, the Amazon rainforest could disappear within 50 years, within the lifetime of people alive now. Other large ecosystems could also disappear quickly: the coral reefs in the Caribbean, for example, might disappear within 15 years after reaching a tipping point.
The speed of collapse makes it even more important to quickly address climate change and take other steps to protect ecosystems such as ending deforestation in corporate supply chains. “We need to use ecosystems more sustainably,” says Willcock. “When an ecosystem does show signs of damage, for example, the recent Amazon fires, then we need to react very quickly and in a united way. We can’t spend decades negotiating things about climate agreements between countries. It will be far too slow. We need to effectively get our act together and sustainably manage our ecosystems. And we need to do this a lot faster than we have been.”