Drought stalled Amazon forest's carbon absorption

The Amazon forest spanning across Brazil, Columbia, Peru and other South American countries is the world's largest forest covering 5.5 million square kilometers. Scientists have estimated that it stores 100 billion tonnes of carbon in its biomass. So any changes in this giant forest have global consequences. It suffered a major drought in 2010, following the 2005 drought.

A ground-breaking study led by researchers at the Universities of Exeter and Leeds, has found that the 2010 drought completely shut down the Amazon Basin's carbon sink, by killing trees and slowing their growth. Previous research has suggested that the Amazon may be gradually losing its capacity to take carbon from the atmosphere. This new study, the most extensive land-based study of the effect of drought on Amazonian rainforests to date, paints a more complex picture, with forests responding dynamically to an increasingly variable climate.The study made use of data collected during the two large-scale droughts to improve understanding of how drought affects tree growth, and therefore the rate of uptake of carbon dioxide by trees from the atmosphere.In the first basin-wide study of the impact of the 2010 drought and its interaction with previous droughts, the international team of researchers found that tree growth was markedly slowed by drought across the vast forests of the Amazon.