A densely forested region of Brazil's Amazon Basin,  CREDIT: Luciana Gatti, IPEN Brazil
A densely forested region of Brazil's Amazon Basin, CREDIT: Luciana Gatti, IPEN Brazil

New study finds dry conditions in Amazon add carbon dioxide to atmosphere

5 February 2014

As climates change, the lush tropical ecosystems of the Amazon Basin may release more of the greenhouse gas carbon dioxide into the atmosphere than they absorb, according to a new study published Feb. 6 in Nature.

An international team of scientists found that the amount of yearly rainfall was the driving factor behind the amount of carbon dioxide (CO2) taken up and released from Amazonia in 2010 and 2011. During a wet year, the Amazon forests were roughly carbon-neutral: Forests "inhaled" more carbon dioxide than they "exhaled,” but biomass burning, which releases carbon dioxide, compensated for the difference. In contrast, during a very dry year forest growth stalled and biomass burning increased, resulting in the region "exhaling” substantial amounts of carbon dioxide to the atmosphere.

"Amazonia is changing: We are observing more very wet years and more very dry years,” said John Miller, one of three lead authors on the new paper, and a CIRES scientist working at ESRL's Global Monitoring Division. "If these trends continue, the region may become a net source of carbon to the atmosphere, moving carbon embedded in ecosystems into the atmosphere as greenhouse gas, thus accelerating global warming."

Read the full press release at CIRES

L. V. Gatti, M. Gloor, J. B. Miller, C. E. Doughty, Y. Malhi, L. G. Domingues, L. S. Basso, A. Martinewski, C. S. C. Correia, V. F. Borges, S. Freitas, R. Braz, L. O. Anderson, H. Rocha, J. Grace, O. L. Phillips, and J. Lloyd, (February 2014): Drought sensitivity of Amazonian carbon balance revealed by atmospheric measurementsNature, 506, 76-80. doi:10.1038/nature12957