Forest fires in the Amazon

Amazon forest fires in October 2023

Gustavo Basso/NurPhoto via Getty Images

Large swathes of the Amazon rainforest are threatened by the combined effects of drought, heat and deforestation, which could push some ecosystems past a tipping point. But the possibility of widespread destruction is uncertain.

“The forest as a whole is very resilient, and that’s why we still have a window to work,” says Marina Hirota at the Federal University of Santa Catarina in Brazil.

Researchers have warned for decades that rising temperatures and deforestation could occur. Push Amazon past a tipping point. Further runaway feedback leads to a rapid transition from forest to savanna. Drought and heat Driven by the ongoing El Nino And with climate change, warming has sounded the alarm again.

But climate and environmental models that represent the enormous complexity of the Amazon disagree on when and where such a tipping point might occur.

To understand which areas of the Amazon are most at risk, Hirota and his colleagues looked at satellite data to predict how several different ecosystem stresses might change in the coming decades. These included temperature during the dry season, risk of drought and risk of fire and deforestation.

They found that 10 percent of the Amazon basin is at risk of being exposed to at least two of these strains by 2050, and therefore has a high potential for transition to degraded forest or savanna-like ecosystems. About 47 percent of the basin is predicted to be exposed to at least one strain – meaning it is at risk.

“Some forests are going to be lost because of the ongoing changes, but there are things we can do to avoid going to 47 percent,” Hirota says. She explains that most of the forest is inland. Protected areas And local area, which are associated with lower rates of deforestation. Brazil also has a high rate of deforestation. President Luiz Inacio Lula da Silva’s administration fell.although they have Other parts increased of Amazon.

Dominic Sprinklin The University of Leeds in the UK says the study is a robust survey of the various threats Amazon faces. However, he says this does not address the differences between the models presenting a potential tipping point.

For example, models suggest that some of the negative effects of warming may be offset by increased concentrations of atmospheric CO2, which should promote plant growth. But other factors, such as nutrient and water availability, vary widely across the basin and affect the strength of this effect, creating considerable uncertainty for modeling the Amazon’s future.

“For such an important ecosystem, it’s a pretty scary place,” he says.

The nature
DOI: https://doi.org/10.1038/s41586-023-06970-0