[M-IS08] Global climate change driven by the Southern Ocean and the Antarctic Ice Sheet

[MIS08-P01] Sea-level and ice-sheet variations during the last interglacial period estimated from the GIA model

*Jun'ichi Okuno^1,2,3, Yoshiya Irie² (1.Research Organization of Information and Systems, 2.National Institute of Polar Research, 3.SOKENDAI)

Keywords:Glacial Isostatic Adjustment, Sea level change, Antarctic Ice Sheet, Last interglacial

An accurate prediction of future polar ice sheet melt and sea level rise due to global warming requires understanding ice sheet fluctuations during past warm periods. During the last interglacial (LIG: ~125,000 years ago), slightly warmer than preindustrial, the sea level was 6-9 m higher than today, and both Greenland and Antarctic ice sheets were significantly smaller than today. The ice volume changes from relative sea level (RSL) observations are based on local geographical and geological data. However, it is not easy to accurately extract only the information on the volume variations of the ice sheets because these also include the deformation of the solid Earth. Solid Earth deformation is due to GIA (Glacial Isostatic Adjustment) effects induced by load redistributing ice and ocean water. In other words, the scenario of ice volume change in the warm Earth can be substantially rewritten depending on isostasy estimates. In this study, we construct a numerical model to estimate the effect of GIA with high accuracy for the LIG period and to obtain basic information on the change in both polar ice sheet volumes during LIG period through comparison with data on RSLs in the region far from the former ice sheets. In this presentation, we will show the theoretical characteristics of the RSL during the LIG period as considered from the GIA numerical modeling and discuss the melting volume of the Antarctic ice sheet and its temporal variation.