Ten coupled climate-carbon cycle models were forced by
historical and SRES A2 anthropogenic emissions of CO2 for the
1850-2100 time period to study the coupling between climate change and the
carbon cycle. Each model ran two separate simulations in order to evaluate the climate-carbon
cycle feedback. All models agree that future climate change will reduce the
efficiency of the Earth system to absorb the anthropogenic CO2. A
larger fraction of CO2 will stay in the atmosphere if climate change
is accounted for. By the end of the 21st
century, this ranges between 20 ppm and 200 ppm depending on the model, the
majority of the models lying between 50 and 100 ppm. All models simulate a
negative sensitivity for both the land and the ocean carbon cycle to future
climate. However there is still a large uncertainty on the magnitude of these
sensitivities. Also, the majority of the models attribute most of the changes
to the land. Finally, most of the models locate the reduction of land carbon
uptake in the tropics. However, the attribution to changes in net primary
productivity versus changes in respiration is still subject to debate amongst
the models.
Author: P. Friedlingstein, P. Cox, R. Betts, L. Bopp, et al (pierre dot friedlingstein at cea dot fr)
Filesize: 25.02 Kb