The latest research suggests that natural sinks of carbon on land may be slowing or even turning into sources, creating climate consequences potentially worse than first thought. (critical-angle.net)
Might the natural sinks of carbon at some times be able to absorb the human additions and result in no net increase? (realclimate.org)
In response to the question whether the natural sinks of carbon might compensate for the CO2 we are putting into the atmosphere, the answer is yes, but not very quickly. (realclimate.org)