The Amazon forest, at the turn, enters a road of no return

The problems facing nature are increasing. The changes are approaching a critical point. Much of the Amazon rainforest, a crucial climate regulator and precious reserve of biodiversity, could pass a "tipping point" by 2050 due to drought, fires and deforestation, a study warns. "Between 10% and 47%" of the Amazon's surface will be exposed to cumulative disturbances likely to trigger unexpected ecosystem transitions and worsen regional climate changes", estimates the study published in the journal Nature by an international group of approximately 20 researchers. Under pressure "warmer temperatures", "extreme droughts", "deforestation" and "erosion", almost half of Amazonia would thus reach a "breaking point" or "a tipping point", driving the forests into a vicious circle that would synonymous with a potential collapse of ecosystems. To reach this conclusion, Bernardo Flores and his colleagues analyzed five critical factors: climate warming, annual rainfall, the intensity of rainfall seasonality, the duration of the dry season and deforestation. The Amazon is home to "10% of the planet's biodiversity ", stores "an amount of carbon equivalent to 15-20 years of emissions" of humanity and produces a "net cooling effect that contributes to the stabilization of our planet's climate", recalled the authors of the study. The study identified three trajectories of the permanent evolution of the Amazon forest: it could become, in some places, a degraded forest - with fewer species, more lianas and more bamboo -, an open forest - with smaller trees surrounded by invasive grasses - or a form of savannah. From its status as holder of "carbon sinks", the Amazon runs the risk of becoming "an emitting source", scientists fear. "We may be closer to this tipping point than we thought in the past," said the study's lead author, Bernardo Flores, from the University of Santa Catarina in the Brazilian city of Florianopolis. The study highlighted three possible solutions: global reduction of greenhouse gas emissions, stopping deforestation and restoring degraded territories. The researchers relied on paleontological archives (covering a period of about 65 million years), climate models and observational data obtained since the 1980s, such as satellite observations of the spread of forest fires, the area covered by trees and deforestation. Their findings complement those of the World Weather Attribution network, which estimated in January 2024 that climate change has made the devastating drought that hit the Amazon in 2023 30 times more likely.