Business Green writes that tropical rainforest carbon sinks are  under substantial threat from climate change.

The impact of global warming on tropical rainforests will be so severe that even increases in temperature that are widely regarded as "safe" could raise tree mortality rates to such a level that almost 50 billion tons of carbon dioxide is released into the atmosphere.

That is the sobering warning contained in new research from a team of Australian scientists, which suggests that even a two degree increase in average global temperatures will see the "carbon sink" effect currently provided by the world's rainforests cut in half.

It also calculates that should temperatures reach four degrees above pre-industrial levels, the rate of forest die-off will reach a level where rainforests become a net contributor to carbon dioxide in the atmosphere, potentially triggering runaway climate change.