The Amazon rainforest seems to be approaching a tipping point

More than three-quarters of the Amazon rainforest have been losing resilience since early 2000, and the rainforest now shows characteristic signs of approaching a tipping point. That is the conclusion of an analysis of vegetation satellite data by Chris Boulton and Tim Lenton from the Exeter University, UK, and Niklas Boers, Technical University of Munich and Potsdam Institute for Climate Impact Research (PIK), Germany. The findings, published today in Nature Climate Change, illustrate the need to minimize human land use in the Amazon region and limit greenhouse gas emissions globally. The study is part of the TiPES project on Tipping Points in the Earth System, administered by the University of Copenhagen, Denmark and PIK.

The Amazon rainforest represents more than half of the world’s tropical rainforest and is home to unparalleled biodiversity. The rainforest plays an important role as a carbon sink in the Earth’s climate system.

Pronounced loss

In the study, an analysis of 30 years of satellite data revealed loss of resilience since the early 2000s, with more pronounced losses in drier areas as well as in regions within approximately 200 kilometres from human land use, such as large farms and settlements.

This means the forest is at risk of dieback with profound implications for biodiversity, carbon storage and climate change at a global scale, conclude the authors of the paper, Pronounced loss of Amazon rainforest resilience since the early 2000s, published in Nature Climate Change.

The analysis also revealed that the loss of resilience has brought the forest closer to a tipping point, where it risks undergoing an abrupt transition to a much drier habitat. Such a warning signal for tipping was found in the form of critical slowing down.

Critical slowing down is typical behaviour of a system that can be in more than one state and is approaching the point where an abrupt transition between states would occur. Essentially, critical slowing down reflects a weakening of the restoring forces that bring the system back to its equilibrium after perturbations.

Time to act

If the Amazon rainforest or parts of it experience such abrupt transitions, the forest is suspected to become a savanna-like habitat. However, there seems to be still time to act.

”Our study shows that the Amazon is approaching a tipping point, but also that it has likely not yet crossed it,” says Niklas Boers, PIK Potsdam.

The latest climate model simulations, however, reveal future rainfall declines in the Amazon due to climate change. And the results published in Nature Climate Change show that this is particularly bad news for the Amazon, as drying will amplify the resilience loss further in the near future.

The TiPES project is an EU Horizon 2020 interdisciplinary climate science project on tipping points in the Earth system. 18 partner institutions work together in more than 10 countries. TiPES is coordinated and led by The Niels Bohr Institute at the University of Copenhagen, Denmark and the Potsdam Institute for Climate Impact Research, Germany. The TiPES project has received funding from the European Horizon 2020 research and innovation program, grant agreement number 820970.