Antarctic Sea Ice Expansion and The Consequences of Missing Processes in Global Climate Models

Antarctic sea ice has expanded in nature, but almost no global climate model reproduces the magntitude and character of the observed trends. I will present the case for key deficiencies in models that could explain their incorrect response. The first is a lack of explicit basal ice-shelf meltwater, which is instead parameterizedcrudely to give mass balance of the Antarctic ice sheet and shelves. The second is a lack of ocean waves. The third is the zonal symmetry of stratospheric ozone trends when prescribed and/or biases in the ozone distribution in models with ozone predicted. The fourth is a misrepresentation of recent trends in the tropical sea surface temperature, and the attendant errors in atmospheric teleconnection to the Antarctic. I will show integration results that illustrate how and why the first and last of these deficiencies give rise to expanding sea ice. Finally, I will discuss how sea ice physics plays a role in combination with these missing processes.