The Amazon rainforest is no longer a carbon sink

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Although the Amazon ecosystems are very diverse, the rainforest of the southeastern Amazon is no longer a terrestrial carbon sink. Deforestation, fires, and rapid local warming have reduced or eliminated its ability to release carbon dioxide. If the vast tropical forests that have absorbed them have reached saturation, this suggests worrying implications for future global warming.

Cause of climate changes and more deforestation, much of the Amazon Basin now emits CO2 instead of absorbing it, a major transformation for this crucial ecosystem in limitation Heating, according to a study published Wednesday.

Based on hundreds of samplesair collected at various altitudes over the past decade, a study published in review Nature shows that the particularly southeastern part of the Amazon went from carbon sink source CO2,, gas responsible for global warming. Over the last fifty years, plants and soils have been absorbed by more than a quarter shows CO2, even when those emissions increased by 50%.

So, if Amazon – in which half lives tropical forests particularly effective in absorbing this carbon and storing 450 billion tons of CO2 in his trees and its soils -, became a constant source of C02, resolving the climate crisis would become even more difficult.

According to the study, several factors are responsible for this development. ” Deforestation and forest degradation reduce the Amazon’s ability to act as a carbon sink “, Write authors.

And always the same litany: deforestation, arson, intensive agriculture

Among the causes of this degradation, forests burned to make room for breeding andAgriculture. Climate change is also a key factor: temperatures during season drying operations increased by almost 3 ° C compared to pre-industrial times, almost three times higher than the world average. A combination of all these factors ” calls into question the ability of tropical forests to separate large ones volumes CO2 derived from fossil fuels”, Notes Scott Denning of the University of Colorado, in a comment also posted in Nature.

Deforestation and forest degradation reduce the Amazon’s ability to act as a carbon sink

This question has long worried scientists, but satellite data so far they have not provided a complete answer, especially because clouds above the region. To circumvent the problem, a Brazilian research team collected 600 CO samples2 and from carbon monoxide between 2010 and 2018 at altitudes up to 4.5 km above the ground. According to their findings, the northwestern part of the Amazon is in equilibrium, absorbing so much CO2 which broadcasts inatmosphere. But the east, especially in the dry season, is becoming a net source.

Another recent study, using a different methodology, concluded that Brazilian Amazon released almost 20% CO between 2010 and 2019.2 more than it broadcast. With melting from ice caps, thawing eternal frost or the disappearance of coral reefs, the fall of the Amazon rainforest are among “Power points” identified by scientists as key elements whose significant modification could lead the climate system to dramatic and inevitable change.

Brazil: The Amazon rainforest now emits more CO2 than it absorbed in 10 years!

ETX Study article, published May 4, 2021

The remark is here: over the last decade, the Amazon rainforest has been shedding more carbon than it is absorbing, causing global warming and human activities. But also, in terms of deforestation, which increased sharply in 2019, degradation of forested areas along the edges is another important parameter as well as deforestation, which greatly contributes to the weakening of the Brazilian Amazon rainforest.

The Amazon forest The Brazilian, a victim of climate change and human activities, has released more carbon over the past ten years than it has absorbed, a big and unprecedented change, according to a study released this week. No noise, one of ” lungs “From a planet that absorbs between 25 and 30% of the greenhouse gases emitted by humans, climate change would be much worse. But for several years now, scientists have been worried about shortness of breath tropical forests, and they are afraid that they will play their role less and less well. carbon sink. And the concern comes especially from the Amazon rainforest, which accounts for half of the planet’s tropical forests.

The study was published Thursday in Climate change in nature international team, looks at the Brazilian Amazon, which represents 60% of this primary forest, and the situation is bleak. Between 2010 and 2019, this forest lost biomass: carbon losses in the Brazilian Amazon are approximately 18% higher than gains, according to press release of the French Research Institute for Agriculture, Food and the Environment (Inrae).

The Amazon rainforest, our last rampart, could overturn

This is the first time we have figures showing that we have switched and that the Brazilian Amazon is broadcasting “The carbon network,” one of the authors, Jean-Pierre Wigneron, a researcher at INRAE, told AFP. a priori, ” other countries make up for the losses of the Brazilian Amazon ” and so “ the whole Amazon hasn’t switched yet, but it could do so soon He continues.

So far, forests, especially tropical forests, have protected us by helping combat global warming, but our last bulwark, the Amazon, is in the process of being overturned. », Warns the researcher. The study also highlights an unrecognized but major responsibility for forest “degradation”. Unlike deforestation causing the wooded area to disappear, the degradation ends everything that can damage it without completely destroying it: weakened trees on the edge of forested areas, selective felling, small fires, obtaining trees associated with drought. Less affected easily noticeable than flattened large areas.

Using the index of emitted vegetation satellite observations microwave, allowing probing the whole stratum vegetation, not just the top eaves, the study of these forest degradations recorded 73% carbon losses, compared to 27% due to deforestation, however large.

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