Geophysical Research Letters

Origin of the Arctic warming in climate models



[1] There is a debate on whether the snow/ice change feedback or poleward energy transport from lower latitudes generates the observed Arctic warming amplification. There is another possibility that remotely induced warming in the Arctic can be amplified by snow/ice feedbacks. We demonstrate that this mechanism plays an important role in two independent climate models: CAM3 and ECHAM5. We also show with these two models that the June-August temperature structure in the vertical is a good indicator of how much the climate forcing from lower latitudes contributes to Arctic warming. Compared with the June-August 3D temperature trend in ERA Interim reanalysis, the CMIP3 models simulate warming at higher levels, suggesting that the models over-simulate the role of poleward energy transport in Arctic warming. This finding has implications for climate feedback and aerosol forcing.