The Amazon rainforest may be nearing a tipping point of rainforest dieback —the point where rainforest will turn to savannah — with signs of resilience loss being found in over 75% of its area since the early 2000s, according to observational evidence presented in Nature Climate Change.
Tropical forests such as the Amazon play a critical role in climate regulation. Climate change and human-induced activities such as deforestation, however, have been putting increasing pressure on the Amazon rainforest in recent decades.
Using satellite remote sensing data, Chris Boulton and colleagues determine changes in the resilience —the ability of an ecosystem system to recover from a disturbance — of the Amazon rainforest between 1991 and 2016. The team combine this information with data on forest cover as a measure of the mean state of the ecosystem, as well as climate data. Analyses reveal that 75% of the Amazon has been losing resilience since the early 2000s, indicating that the forest may be approaching a critical transition. Loss of resilience is most prominent in areas that are closer to human activity, as well as in those that receive less rainfall. Importantly, loss of resilience does not coincide with a loss in the forest cover, implying that the forest could be nearing a tipping point without showing changes in its mean state.
The authors conclude that these findings are important as they provide observational evidence that drier conditions and deforestation are likely pushing the Amazon towards a critical threshold.
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