Extensive slash-and-burn cultivation could push the Amazon rainforests towards a tipping point beyond which they will be much less resilient to environmental stresses such as climate change.
This stark assessment was made by an international team of scientists who analyzed high-resolution satellite imagery data and concluded that over the past two decades, about three-quarters of Amazon forests have lost their ability to withstand the stress, including droughts and forests.
“It is worrying to see such a loss of resilience in the observations,” said Niklas Boers, a scientist at the Potsdam Institute for Climate Impact Research and the Technical University of Munich. Together with researchers from the University of Exeter in the UK, Boers and his colleagues published their findings in a study.
“The Amazon rainforest is home to a large amount of biodiversity, strongly influences rainfall throughout South America through its massive evapotranspiration, and stores huge amounts of carbon that could be released as greenhouse gases in the event of a storm. regressive or even partial death, in turn. contributing to greater global warming,” says Boers. “This is why the rainforest is of global importance.”
Other research teams have come to similar conclusions about the Amazon in recent years, but many of those conclusions were based on computer models. Boers and his colleagues relied on observational data to find signs of changes in forest resilience over the past few decades.
The Amazon is changing
To assess the data, they used stability indicators previously applied to the Greenland Ice Sheet, among other regions affected by climate change.
“These statistical indicators aim to predict a system’s approach to abrupt change by identifying a critical slowdown in the system’s dynamics, such as its response to climate variability,” the researchers explain in a statement.
“Analysis of two satellite datasets, representing forest biomass and greenness, revealed the critical slowdown. This critical slowdown can be seen as a weakening of the restoring forces that usually return the system to equilibrium after disturbances.
Needless to say, their findings are sobering.
“We see a continued decline in rainforest resilience since the early 2000s, but we cannot say when a potential transition from rainforest to savanna might occur. By the time it’s observable, it’s probably too late to stop it,” says Boers.
Alarmingly, in many parts of the Amazon, the destabilization of local forests appears to be well advanced. Once climate change begins to feel its impacts even more strongly in these and other regions over the next few decades, forests and their ecosystems will likely succumb without being able to recover.
However, we can still give these beleaguered forests a chance, the scientists point out. “Strongly limiting logging, but also limiting global greenhouse gas emissions, is necessary to protect the Amazon,” says Tim Lenton, director of the Global Systems Institute.
By Daniel T. Cross. Articles in English