How warming and deforestation is turning the Amazon basin into a source of CO2

The Amazon basin contains about half of the world's tropical rainforests, which are more effective at soaking up and storing carbon than other vegetation. Photo: AFP

Climate change and deforestation have flipped a large swathe of the Amazon basin from absorbing to emitting planet-warming CO2, a transformation that could turn humanity's greatest natural ally in the fight against global warming into a foe, researchers reported recently.

Hundreds of high-altitude air samples collected over the last decade showed that southeastern Amazon, in particular, has shifted from a "sink" to a source of carbon dioxide, the main greenhouse gas, they reported in the journal Nature.