The Amazon is approaching a point of no return to become a savannah

Climate change and deforestation are pushing the Amazon rainforest towards a point of no return, a path that could turn it into a savannah, warns a scientific study published in the journal Nature Climate Change.

Based on observational data collected between 1991 and 2016, the researchers conclude that nearly three-quarters of the forest mass of the Amazon, which plays a crucial role in regulating the planet’s climate, has lost its ability to regenerate in the face of storms. ecosystem disturbances.

An analysis of high-resolution satellite images suggests that the areas closest to human activity, such as urban spaces or farmland, as well as areas that receive less rain from the jungle, tend to lose their resistance to changes faster.

The research is part of the European climate project TiPES, dedicated to identifying “tipping points in the earth system”.

Brake to regeneration

“We have focused on the Amazon because we believe that it is one of the parts of the climate system that can reach a point of no return.”, said Tim Lenton, a researcher at the University of Exeter (United Kingdom).

“By this we mean that an alternative state can be reached for the vegetation and the land surface in this part of South America. It could perhaps transform into something more like a savannah”, added the scientist.

The first stages in this kind of alterations consist of the forests losing their capacity to recover from regular events such as annual periods of drought, indicate the researchers, who perceive precisely these warning signs in the evolution of the Amazon forest.

“The system is losing stability. We can see these signals without the need for large changes in biomass or forest cover.”, Lenton wields.

Although during the period studied there is a loss of vegetation, partly due to deforestation, for the researcher the most worrying thing is the decline in the capacity of the forest to regenerate.

Metamorphosis in a few decades

Once the Amazon reaches a critical point of no return, the authors of the study published in “Nature Climate Change” consider that the conversion into a savannah could take place in “a few decades”.

The apparent resilience of tropical forests in the Amazon Basin increased between 1991 and 2000, but has since decreased, according to published data.

Scientists describe this process as an interaction between periods of increasing drought, lack of plant renewal and an increase in large forest fires, factors that would reduce the green mass of the area with increasing speed.

The average volume of rainfall in the Amazon has not varied sharply in recent years, despite climate change, but dry seasons are now longer and more severe, increasing pressure on ecosystems.

The scientists stress that there is still uncertainty about the time it would take to reach the tipping point that can trigger the definitive loss of forest mass and stress that this phenomenon will be seen first in areas located near human activity.

reverse the process

The verification of the danger that the South American jungle runs leads the authors of the work to defend the need to take measures to “reverse deforestation and degradation” of the tropical forest.

There is a “window of opportunity” to achieve this, argues Niklas Boers of the Technical University of Munich, but it is “extremely narrow” relative to other terrestrial habitats at risk.

“Among the elements of the climate system near a tipping point, the Amazon is undoubtedly one of the fastest (to degrade)”, adds the researcher.

“Its death will occur faster than the melting of the Greenland ice sheet. much much faster”, Emphasizes Boers.