By 2050, Half of the Amazon Rainforest May be Reaching a Climate Tipping Point

Large parts of the Amazon rainforest are threatened by the combined effects of drought, heat and deforestation, and some ecosystems may be pushed past tipping points. But the likelihood of a larger collapse remains uncertain.

“Forests as a whole are very resilient, so we still have room to act,” he says. Marina Hirota at the Federal University of Santa Catarina, Brazil.

Researchers have warned for decades that rising temperatures and deforestation could push the Amazon past a tipping point, leading to runaway feedbacks that could lead to a rapid transition from forest to savannah. The drought and heat caused by the ongoing El Niño phenomenon, as well as the warming temperatures caused by climate change, are once again on the rise.

But climate and ecological models that describe the Amazon's highly complex structure disagree on when and where such a tipping point would occur.

To understand which regions of the Amazon are most at risk, Hirota and his colleagues looked at satellite data to see how several different ecosystem stressors might change in the coming decades. evaluated. These include dry season temperatures, exposure to drought, and the risk of fire and deforestation.

They estimate that 10 percent of the Amazon basin is at risk of being exposed to at least two of these stressors by 2050 and is therefore likely to transition to degraded forest- or savanna-like ecosystems. I discovered that. 47% of this watershed is predicted to be exposed to at least one stressor, meaning it is also exposed to some hazard.

“Due to ongoing changes, we will lose some forest, but there are things we can do to prevent it from reaching 47%,” Hirota says. She said the majority of forests that are not exposed to stressors are located within protected areas; indigenous territory, which is associated with low deforestation rates. Brazil's deforestation rate also fell sharply under President Luiz Inacio Lula da Silva's administration. Increased in other areas as well Amazon's.

dominique spracklen Researchers from the University of Leeds in the UK say the study is a powerful investigation into the range of threats facing the Amazon. But he says the discrepancies between models predicting potential tipping points remain unresolved.

For example, models predict that some of the negative effects of warming could be offset by increased concentrations of CO2 in the atmosphere, which could boost plant growth. . However, other factors such as nutrients and water availability vary widely across the basin and influence the strength of this impact, creating considerable uncertainty in modeling the future of the Amazon. .

“It's a very scary place for such an important ecosystem,” he says.