Amazon ‘megadrought’ could intensify climate change

• January 23, 2013
Satellite images of the 2005 Amazon drought, Creative Commons: NASA/JPL-Caltech/GSFC, 2005

Satellite images of the 2005 Amazon drought: NASA/JPL-Caltech/GSFC, 2005

Previously thought to be a once-in-a-century occurrence, the Amazon rainforest is now dealing with the consequences of two extreme drought events in five years.  Scientists are calling the conditions a “megadrought,” referring to both the consistently below-average annual rainfall in the past several decades as well as the rare occurrence of a pronounced drought in both 2005 and 2010.  The rainforest is still struggling to rebound to previous levels of health, and the millions of people dependent on the Amazon River have experienced a shortage of food and fresh water.

The damages incurred by the rainforest ecosystems are also damaging the ability of the area to act as a carbon sink.  The Amazon, because of its rich plant life, has long been able to absorb more carbon dioxide from the atmosphere than it releases.  Now, because of the prolonged lack of adequate rainfall, the forest may not be healthy enough to act as a carbon sink, and may begin releasing carbon dioxide as trees die.

“If drought events continue, the era of intact Amazon forest buffering the increase in atmospheric carbon dioxide may have passed,” the scientists wrote in a paper published yesterday in the journal Science.

Both the 2005 and 2010 droughts were the result of a “very, very unusual” weather pattern linked to higher sea surface temperatures in the Atlantic Ocean, said lead author Simon Lewis, a tropical forests expert at the University of Leeds.

But the scientist said it’s not clear whether the droughts are the product of a random shift in weather patterns or whether they are driven, at least in part, by climate change.

“Which of those is correct at this stage is unknown, but the droughts being driven by atmospheric greenhouse gas concentrations is in line with some of these global circulation models,” Lewis said.

Read more: Scientific American>>

 


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About the Author

Karl Burkart is the Digital Communications Director for the GCCA, the Global Call for Climate Action, and TckTckTck, a network of 400+ diverse organizations working around the world for greater action on the growing problem of climate change. Karl also blogs on technology and the environment for a variety of publications. You can follow him on Twitter @greendig.

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