Satellite observations show the Amazon rainforest is nearing a tipping point where it could shift into a grassland, which could fuel climate change and imperil biodiversity, according to a study published in the journal Nature Climate Change.
Yet satellite images taken over the past several decades reveal that more than 75 percent of the rainforest is losing resilience, according to a study published Monday in the journal Nature Climate Change. The vegetation is drier and takes longer to regenerate after a disturbance. Even the most densely forested tracts struggle to bounce back.tipping point
For the past 50 million years, the Amazon has been in a wet rainforest phase. The trees themselves ensured their continued existence: Water evaporating from leaves created an endless loop of rainfall, while the dense canopy prevented sunlight from drying out the soil. The contours of the forest may have shifted somewhat in response to ice ages, wildfires and rising seas, but it was always able to return to its lush, verdant state.
Mathematician Niklas Boers, who contributed to the new paper, compared it to someone leaning back in a chair. If they don’t tilt too far, they can easily return to having all four legs on the floor. But once they pass the tipping point, the whole system comes crashing down. And it is much harder to get up again than it was to fall.
“My friend uses the idea of Wile E. Coyote running off a cliff,” Boulton said. “He looks fine, and he suddenly looks down and realizes he’s gone over the cliff.”That’s what makes this study — the first empirical assessment of instability across the entire rainforest — so valuable, he added. “If we’re showing that one of these systems is moving toward a tipping point, that might make people wake up,” Boulton said.