Even 2C Increase In Average Temperatures Could Cut Rainforest C Storage By 50%, Kill Countless Trees

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.

The research, which was funded by the Australian government's Marine and Tropical Sciences Research Facility, is based on data from 116 plots of rainforests around the tropics. Echoing the findings of an international study recently published in Nature, the new research found that individual trees would be stimulated by increased concentrations of CO2. But it warned that this effect would be more than offset by the increase in tree mortality resulting from higher temperatures.

David Hilbert, principal research scientist at the CSIRO Tropical Forest Research Centre in Australia, who worked on the study, said that the data suggested that the previous hope that the rates at which forests absorb CO2 would increase as concentrations of CO2 in the atmosphere increase are overly optimistic.

EDIT

http://www.businessgreen.com/business-green/news/2237656/research-warns-two-degree

The few identified negative feedback loops that could take carbon out of the environment seem woefully inadequate compared to the numerous, large positive feedback loops developing that will pump CO2, nitrous oxide and methane into the atmosphere.