This new paper in Nature Geoscience by Benjamin Santer and others analyses global-mean tropospheric temperatures from satellites and climate model simulations to examine whether warming rate differences over the satellite era can be explained by internal climate variability alone.
They find that in the last two decades of the twentieth century, differences between modelled and observed tropospheric temperature trends are broadly consistent with internal variability. They find that the probability that multi-decadal internal variability fully explains the asymmetry between the late twentieth and early twenty-first century results is low and that it is also unlikely that this asymmetry is due to the combined effects of internal variability and a model error in climate sensitivity. The authors conclude that model overestimation of tropospheric warming in the early twenty-first century is partly due to systematic deficiencies in some of the post-2000 external forcings used in the model simulations. This paper can be accessed on the Nature Geoscience website. Note that it is not open access.
This paper acknowledges the World Climate Research Programme’s Working Group on Coupled Modelling (WGCM) and the Coupled Model Intercomparison Project (CMIP)