"Amazon Drought Threatens To Speed Warming"
"Scientists fear billions of tree deaths in the Amazon caused by drought could turn the forest from a carbon sink to a carbon source.
Billions of trees died in the record drought that struck the basin last year, raising fears the vast forest is on the verge of a tipping point, where it will stop absorbing greenhouse gas emissions and instead increase them.
The Amazon rainforest soaks up more than a quarter of the world's atmospheric carbon, making it a critically important buffer against global warming.
A switch from a carbon sink to a carbon source could prompt further droughts and mass tree deaths, creating a feedback loop that may cause runaway climate change."Source: Sydney Morning Herald, 02/04/2011