A new study, which analyzes satellite data on Amazonian vegetation, has revealed that the resilience of the Amazon rainforest – the ability to recover from events such as droughts or fires – has systematically declined in more than three-quarters of the ecosystem since the early 2000s.
The investigation, carried out by Chris Boulton and Tim Lentongives University of Exeter (UK) and Niklas Boersgives Technical University of Munich it’s him Potsdam Climate Impact Research Institute (Germany), illustrates the need to minimize human land use in the Amazon region and limit greenhouse gas emissions. greenhouse effect worldwide. The results are published in the journal Nature Climate Change
According to the authors, the Amazon may soon reach a inflection pointwhose crossing would trigger a regressive death of vegetation and would transform a large part of the forest into sheet. This would have important repercussions on biodiversity, global carbon storage and climate change.
It’s unclear when that tipping point might be reached, but the study says the loss of resilience is “consistent” with approaching a tipping point. “Many researchers have theorized that a tipping point could be reached, but our study provides vital empirical evidence that we are approaching that threshold,” says Boers.
“If it does, the consequences would be devastating on many levels. The world, South America and Brazil would lose an important ecosystem that provides many of their services, such as climate and water regulation, biodiversity, cultural context and food supply, to name just a few”, he warns. alex koberleresearcher of Grantham Institute for Climate Change and the Environment from Imperial College London (United Kingdom) in statements to the science media center (SMC) of the United Kingdom.
pronounced loss
Scientists analyzed 30 years of satellite data, revealing the decreased resilience since the early 2000s, with more pronounced losses in drier areas, as well as in regions located less than 200 kilometers from large farms and settlements.
“This is alarming, as the Intergovernmental Panel on Climate Change (IPCC) models project a general drying out of the Amazon region in response to anthropogenic global warming,” says Boers.
The study used several data sources, including those from the optical depth of vegetation (VOD), a measure of the total biomass of trees and other plants in a given area.
Despite climate change, average rainfall in the Amazon has not changed dramatically in recent decades. However, the dry seasons lengthened and droughts became more frequent and severe.
The VOD measurements from the study suggest that the overall biomass has declined slightly, but the loss of resilience is much more pronounced. The researchers emphasize this distinction between resilience and the average “state” of the rainforest.
“The rainforest may look more or less the same, but it may be losing resilience, slowing down recovery from a major event like a drought,” explains Lenton, director of the Global Systems Institute of Exeter (United Kingdom).
“Previous studies based on computer simulations have indicated that much of the Amazon may be in decline before showing a strong change in the middle state. Our observational analysis now shows that destabilization appears to be already underway in many areas,” warns Boulton.
The rainforest may look more or less the same, but it may be losing resilience, causing it to recover more slowly from a major event like a drought.
the time to act
“Our new analysis of empirical data provides additional evidence for concerns about the resilience of forests, especially in the near future,” says Lenton. “This confirms that it is necessary to strongly limit logging, but also to limit global greenhouse gas emissions, to safeguard the amazon”.
“Passing this tipping point would make it even more difficult to reach our global net emissions target, due to the loss of the ‘free service’ provided by the Amazon carbon sink, which currently removes some of our emissions,” he says. Chantelle Burtonscientist of Hadley Meteorological Center (UK) speaking to SMC.
However, it seems that There is still time take action: “Our study shows that the Amazon is approaching a tipping point, but also that it is likely not yet crossed,” concludes Boers.
Reference:
“Pronounced loss of resilience of the Amazon rainforest since the early 2000s”. Nature Climate Change. 2022