March 7, 2022

expert reaction to research on Amazon tipping points

A study, published in Nature Climate Change, has looked at Amazon rainforest tipping points.

Dr Minerva Singh, Research Fellow at the Centre for Environmental Policy at Imperial College London, said:

“The Amazon plays an important role in regulating the global climatic cycle. Reaching a tipping point would have a destabilising impact on vital ecosystem functions such as carbon sequestration. In 2021, scientists indicated that Amazon is now emitting more carbon than it absorbs. A significant proportion of these emissions are caused by fires used to clear the forests for agricultural plantations. As extreme weather events become more common and drought severity increases, extreme fires could become more common in the region.” 

Dr Jo House, Reader in Environmental Science and Policy at the Cabot Institute for the Environment, University of Bristol, said:

“This study provides critical evidence of the dire risks of rainforest loss and degradation due to manmade climate change and land use. Given the recent declarations on the importance of rainforests at COP26 in Glasgow (by 141 countries), this reemphasizes the urgency for policy makers and the public to protect and restore this globally important ecosystem before it is too late.”

Dr Alex Koberle, Advance Research Fellow at the Grantham Institute – Climate Change and the Environment at Imperial College London, said:

“The results reported in this abstract are very much in line with previous indications that, unfortunately, the Amazon is indeed close to a tipping point. Should it cross this tipping point, the consequences would be devastating on many levels. The world, South America and Brazil would lose an important ecosystem that provides many ecosystem services including climate and water regulation, biodiversity, cultural context, food provision, just to name a few.

“Ironically, while the agricultural sector is one of the main beneficiaries of these services, it is also the main driver of deforestation that is an important contributor to this loss of resilience of the Amazon biome. Worrisome variations in rainfall patterns in southern Brazil have also been linked to deforestation. The regional changes in climate patterns caused by deforestation exacerbate the impacts of global climate change.

“The rainfed agriculture that makes Brazil the largest exporter of agricultural commodities is at risk of losing its main source of water: the flying rivers that recycle water for thousands of kilometres from the primary source on the coast. Another important paper published recently indicated climatic limits to Brazilian agriculture already manifesting themselves.”

Dr Chantelle Burton, Senior Climate Scientist at the Met Office Hadley Centre, said:

“I think this is a really important study, using robust statistical methods and observational data to assess the resilience of the Amazon rainforest over the recent past. There has been a lot of research in this area of potential Amazon dieback in the last two decades, with large uncertainty in model projections. There has been a question mark over how the Amazon rainforest will stand up to the multi-faceted challenges of climate change, land-use change and fires, and justifiable concern about the loss of a forest of global importance for its biodiversity, its huge store of carbon, its role in regulating the water cycle and climate, and all of the natural habitat and ecosystem services that it provides.

“What this study does is offer some observational-based evidence for what is already happening to this significant carbon sink, and shows that human land-use and changes to weather and climate patterns are already driving an important change in the system. Passing a tipping point of this kind would make it even more difficult to achieve our goal of Net Zero emissions globally because of the loss of the “free service” provided by the Amazon carbon sink which currently removes some of our emissions.”

Dr Bonnie Waring, Senior Lecturer, Grantham Institute – Climate Change and Environment, Imperial College London, said:

“The Amazon is critical to our planet’s future, both as a harbour for biodiversity and as a carbon storehouse that protects the climate. These latest findings are consistent with the accumulating evidence that the twin pressures of climate change and human exploitation of tropical forests are endangering the world’s largest rainforest, which is home to 1 out of every 10 species known to science.”

Prof Richard Allan, Professor of Climate Science, University of Reading, said:

“The Amazon is a custodian of biodiversity and possesses a vital ability to pull in carbon dioxide from the atmosphere, so it is clearly concerning that its health is deteriorating as human-caused deforestation and climate change metes out increasingly potent and harmful impacts on the ecosystem.

“This study provides a comprehensive and rigorous assessment of the durability of the Amazon.  It reaches the tantalising conclusion that much of the Amazon is showing signs that it may be approaching a tipping point towards irreversible decline; but because multiple satellite sensors are used to infer the ‘lushness’ of the vegetation, we need to be sure those data records are showing accurate trends.

“In any case it is undeniable that human activities are waging a war of attrition from multiple sides against the natural world, though thankfully in this case the solutions are known: to cease deforestation while rapidly and massively cutting greenhouse gas emissions.”

Pronounced loss of Amazon rainforest resilience since the early 2000s’ by Chris A. Boulton et al. was published in Nature Climate Change at 4pm UK TIME on Monday 7 March 2022.

https://doi.org/10.1038/s41558-022-01287-8

Declared interests

None received.