Amazon, which is considered to be the most extensive tropical forest in the world, are gradually losing its capacity to take carbon from the atmosphere due to the increasing dying rate of trees caused by drought brought about by climate change.
"For more than 20 years the Amazon has been providing a tremendous service, taking up hundreds of millions more tonnes of carbon every year in tree growth than it loses through tree death. But both the 2005 and 2010 droughts eliminated those net gains," said Oliver Phillips, a professor at University of Leeds and co-author of the study, in a statement.
Amazon forest is considered to be one of the "green lungs" of the planet, storing up to 100 billion tons of carbon in biomass. However, a new study published in the journal Global Biogeochemical Cycles revealed that recent droughts might have lessen the carbon sink of the forest, by killing trees and slowing their growth.
To further understand the effects of drought in tree growth and the ability of the Amazon forest to take carbon from the atmosphere, researchers used of two large-scale droughts occurring just five years apart, in 2005 and 2010. Researchers also used long-term measurements from the RAINFOR network spanning nearly a hundred locations across the Amazon Basin to examine the response of trees to the droughts.
The researchers discovered that the Amazon forest temporarily loss some of its ability to store biomass during both droughts by killing many trees. Furthermore, the researchers noted slowing of the growth rate of the surviving trees during the 2010 drought.
However, Amazon's resilience made it possible for the forest to recover its ability to become a carbon sink in between the two droughts. But still, researchers warned that the Amazon may soon cave in due to the more frequent recurrence of droughts and the present temperature in the Amazon is continuously increasing.