The knowledge relating to climate sensitivity reported in AR4 (IPCC 2007a) still is timely. New research into how natural carbon sinks and carbon sources are influenced by climate change indicates, however, that the future net carbon uptake terrestrial systems could be less than formerly estimated.
There are now far more studies and information about emission pathways compared to when AR4 was published. The studies inform primarily about the two-degree target, rather than even lower temperature targets.
Measures to reduce emissions of short-lived climate forcers such as tropospheric ozone and soot may help in limiting global warming in the near term, but such measures are not sufficient to curb the warming.
The later global emissions culminate, the lower the probability of the two-degree t