Antarctic sea ice extent during the Holocene reconstructed from inland ice core evidence

Abstract

Interannual fluctuations in the Antarctic sea ice extent (SIE) affect the global albedo and heat balance, and they may affect global CO 2 levels. We found that the annual trend of sodium ion fluxes in the snowpack in the Dome Fuji region of East Antarctica can serve as a proxy for the present-day SIE in the southern Indian Ocean and Weddell Sea sectors. We then used sodium ion profiles obtained from the Dome Fuji ice core to reconstruct the SIE during the Holocene. We observed that (1) the beginnings of both the climatic optimum (12.0 ka BP) and neoglaciation (5.4 ka BP) in the Southern Ocean, indicated by siliceous microfossil records, are consistent with decreases (11.8 ka BP) and increases (5.4 ka BP) in the sodium ion fluxes in the Dome Fuji ice core, and (2) the interannual fluctuation in the SIE during some periods of the neoglaciation was greater than the interannual fluctuation during the climatic optimum. Copyright 2008 by the American Geophysical Union.