Amazon rainforest soaking up almost one-third less carbon in past decade

The Amazon: not the carbon sink many had thought. Photo: BrazilPhotos The Amazon: not the carbon sink many had thought. Photo: BrazilPhotos

The Amazon: not the carbon sink many had thought. Photo: BrazilPhotos

The Amazon: not the carbon sink many had thought. Photo: BrazilPhotos

The Amazon rainforest has long been a vital sink for the world’s greenhouse gases, but new research shows the amount of carbon absorbed by the Amazon’s trees has dropped by almost one-third in the past 10 years.

The study of 321 plots in parts of the Amazon found forest growth had flatlined in the past decade, and estimated the net amount of carbon dioxide absorbed by the forest had fallen 2.0 billion tonnes a year in the 1990s to 1.4 billion tonnes in the 2000s.

“The net carbon uptake of forests has significantly weakened…The whole forest is living faster – trees grow faster, die faster,” lead author Roel Brienen of the University of Leeds told Reuters.

The implications of the study’s findings are “enormous,” said Professor David Ellsworth, senior scientific advisor for the Eucalyptus Free-Air CO2 Enrichment (EucFACE) experiment in the Cumberland Plain forest.

“It is just enormous, because the land area were talking about is huge. The tropics represent an extremely large sink for carbon,” he said, adding, “carbon that they are not storing is landing in the atmosphere and results in rising atmospheric rising of Co2.”

“We rely on plants to put the skids on the increase in atmospheric Co2, because they take up that carbon. If they are taking up less carbon than we thought we’ve got to consider other options for slowing that rise in Co2 in the atmosphere.”

The scientists of the study said it was unclear if the decline would continue and if the trend applied to other tropical forests such as the Congo basin or Indonesia.

To measure the change scientists observed 200,000 trees in 321 plots across eight countries, studying any changes in height, diameter, wood density and births and deaths.

They suggested increased tree deaths, of more than a third since the mid-1980s, could be linked to severe droughts, such as in 2005.

The paper, published by Nature, HYPERLINK, acknowledged that the behaviour was at odds with expectations, underlining “how difficult it can be to predict the role of land-vegetation feedbacks in modulating global climate change.”

Professor Ellsworth said the findings are relevant for his own research in understanding how the Australian carbon sink will change into the future.

“We would want to know, does this apply to Australian rainforests or not? The authors are very clear this applies in the Amazon region of South America,” he said.

“My research would need to dovetail the information that comes out of what I’m doing, and the carbon release from the Amazon…to understand what it means in terms of atmospheric carbon dioxide and how fast it’s rising, or whether its slowing.”

Carbon dioxide is rising at a rate greater than two per cent per year, which, “if it’s your bank account is really good, but if its not then you might have pause to think,” Professor Ellsworth said.

– with Reuters

The original release of this article first appeared on the website of Wuxi Plastic Surgery Hospital.