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Can natural variability explain observed Antarctic sea ice trends? New modeling evidence from CMIP5
Author(s) -
Polvani Lorenzo M.,
Smith Karen L.
Publication year - 2013
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/grl.50578
Subject(s) - cryosphere , sea ice , climatology , coupled model intercomparison project , environmental science , ozone depletion , climate model , arctic ice pack , lead (geology) , natural (archaeology) , antarctic sea ice , atmospheric sciences , climate change , geology , oceanography , stratosphere , paleontology , geomorphology
The recent observed positive trends in total Antarctic sea ice extent are at odds with the expectation of melting sea ice in a warming world. More problematic yet, climate models indicate that sea ice should decrease around Antarctica in response to both increasing greenhouse gases and stratospheric ozone depletion. The resolution of this puzzle, we suggest, may lie in the large natural variability of the coupled atmosphere‒ocean‒sea‒ice system. Contrasting forced and control integrations from four state‒of‒the‒art Coupled Model Intercomparison Project Phase 5 (CMIP5) models, we show that the observed Antarctic sea ice trend falls well within the distribution of trends arising naturally in the system, and that the forced response in the models is small compared to the natural variability. From this, we conclude that it may prove difficult to attribute the observed trends in total Antarctic sea ice to anthropogenic forcings, although some regional features might be easier to explain.