Climate crisis: A tipping point in the Amazon rainforest looms | amazon rainforest

The data suggests that the Amazon is approaching a tipping point, after which the rainforests will be lost with “profound” repercussions for global climate and biodiversity.

Computer models previously indicated the possibility of a mass death in the Amazon, but the new analysis is based on real-world satellite observations over the past three decades.

The new statistical analysis shows that more than 75% of the virgin forest has lost stability since the early 2000s, meaning it takes longer to recover after drought and wildfire.

The greatest loss of stability occurs in areas near farms, roads, urban areas and in areas that are becoming drier, suggesting that forest destruction and global warming are to blame. The scientists concluded that these factors “may have already pushed the Amazon to near the critical threshold of rainforest death.”

The study does not make it possible to predict when the tipping point will be reached. But the researchers caution that by the time the tipping point can be detected, it will be too late to stop it.

Once released, the rainforest will turn into grassland over a period of a few decades at most, releasing massive amounts of carbon and accelerating global warming even further.

Turning points on a planetary scale are among climate scientists’ greatest concerns, as they are irreversible on human time scales. In 2021, the same statistical technique was revealed Warning Signs of a Gulf Stream Collapse and other major currents in the Atlantic Ocean, with “almost complete loss of stability during the last century”.

Closing these currents would have devastating consequences worldwide, disrupting monsoon rains and endangering the Antarctic ice sheets.

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Another recent study showed that a large portion of The Greenland Ice Sheet is on the Brink of a Tipping Pointwhich could lead to a sea level rise of 7 meters over time.

“Many researchers have theorized that a tipping point could be reached in the Amazon, but our study provides vital experimental evidence that we are approaching that limit,” said Professor Niklas Pors, of the Technical University of Munich, Germany.

“Seeing such a loss of flexibility in the notes is troubling. amazon rainforest It stores huge amounts of carbon that can be released in case of partial death.”

The edge of the ice sheet in northern Kangerlussuaq, Greenland.
The edge of the ice sheet in northern Kangerlussuaq, Greenland. Photograph: Hannibal Hanschke/Reuters

Scientists said Amazon’s death had “profound effects on a global scale”. “The Amazon is certainly one of the fastest transformation of these elements in the climate system,” Boyers added.

search, Published in Nature Climate Changeexamined satellite data on the amount of vegetation in more than 6,000 retinal cells across the pristine Amazon from 1991 to 2016.

They found that in the past 20 years, areas affected by drought or fire have taken longer to recover than before. This is a major sign of increased instability as it shows recovery processes are weakening.

The drier areas of the forest lost more stability than the wetter areas. “This is concerning, as is the IPCC [Intergovernmental Panel on Climate Change] Models predict a blanket drying of the Amazon in response to global warming.”

The areas closest to human destruction of the forest are also becoming more disturbed. Trees are crucial to rain production, so cutting them down to prepare the ground for them beef And the soybean production It creates a vicious cycle of drier conditions and more tree loss.

Another study in 2021, based on data from hundreds of small flights, showed that The Amazon now emits more carbon dioxide than it absorbsMostly because of fires.

But Bowers said the data suggest the tipping point has not yet been crossed: “So there is hope.” “It supports efforts to reverse deforestation and degradation of the Amazon to bring it back some resilience in the face of ongoing climate change,” said Professor Tim Linton of the University of Exeter, UK, who is a co-author of the study.

Chris Jones, from the UK Met Office’s Hadley Centre, who is not part of the study team, said: “This research adds compelling evidence that climate change is now a threat, and that these severe and irreversible effects can become a reality. We have a window Narrow opportunities for urgent action.

“The worrying result [of the study] Fits in with other recent research on increasing tree mortality, increasing fires, and reducing regional carbon sinks. Last week’s IPCC report estimated that the risks of large-scale, individual events, such as the death of Amazon, are now closer than ever.”

Bernardo Flores, from the Federal University of Santa Catarina in Brazil, said: “The study shows that although the forest may look good, with its natural structure and biodiversity, the internal processes are actually changing, silently, reducing the long-term viability of the system. The approach used is interesting because it reveals early warning signals for these changes.”

Flores research revealed that The savannah was expanding in the heart of the Amazon due to forest fires.

The government of Brazilian President Jair Bolsonaro has come under fire for it Encourage more deforestationThat rose 22% in the year through November, the highest level since 2006.

“It’s really complicated to say what will be first: to reach the tipping point by [loss of stability] The natural vegetation regime, or just the access of bulldozers to the forest.”

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