International Journal of Geosciences, 2013, 4, 978-984 doi:10.4236/ijg.2013.46090 Published Online August 2013 (http://www.scirp.org/journal/ijg) An Overlooked Term in Assessment of the Potential Sea-Level Rise from a Collapse of the West Antarctic Ice Sheet * Diandong Ren 1,2# , Mervyn Lynch 1 , Lance M. Leslie 3 1 Australian Sustainable Development Institute, Curtin University, Perth, Australia 2 Department of Imaging and Applied Physics, Curtin University, Perth, Australia 3 School of Meteorology, The University of Oklahoma, Norman, USA Email: # rendyanyun@gmail.com Received May 9, 2013; revised June 10, 2013; accepted June 20, 2013 Copyright © 2013 Diandong Ren et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT As to sea level rise (SLR) contribution, melting and setting afloat make no difference for land based ice. Melting of West Antarctic Ice Sheet (WAIS) into water is impossible in the upcoming several centuries, whereas breaking and par- tially afloat is likely as long as sea waters find a pathway to the bottom of those ice sectors with basal elevation below sea level. In this sense WAIS may be disintegrated in a future warming climate. We reassess the potential contribution to eustatic sea level from a collapse of WAIS and find that previous assessments have overlooked a contributor: slope instability after the cementing ice is removed. Over loading ice has a buttressing effect on slope movements the same way ice shelves hinder the flow of non-floating coastal ice. A sophisticated landslide model estimates a 9-mm eustatic SLR contribution from subsequent landslides. Keywords: Antarctic Ice Sheet; Landslides; Sea Level Rise 1. Introduction At present, the Earth climate is in an interglacial period and the interglacial conditions possibly could continue for another 50 kyr [1]. The relative abundance of glaciers, when compared with two of the last three interglacial periods, suggests that there is still room for sea level rise (SLR) from the current cryosphere. As the largest potential contributor to SLR, quantify- ing the Antarctic ice sheet (AIS, Figure 1) total mass balance is important in understanding the global hydro- logical cycle and its fragile polar ecosystem consequences. The AIS, especially the West Antarctica Ice Sheet (WAIS), has been actively studied [2-8]. Since much of the grounded ice in West Antarctica lies on a bed that inclines inland and extends well below sea level (Figure 2), this bathym- etry makes the ice sheet subject to the marine-ice sheet run away instability [8]. Completely melting of WAIS needs ~10 21 J of energy, enough for quenching 30 thou- sands Pinatubo-category Volcanos. This large amount of energy cannot be provided under natural conditions on century time frame. However, for marine-based ice sheets to have SLR contribution it is unnecessary for them be- ing completely meltdown. It suffices making them afloat, viable if basal melt water is effectively connected to the oceans. At present, the primary factor contributing to stability of WAIS is the existence of buttressing ice shelves. Since significant portion of WAIS’s inland ice has basal melt- ing, the gravitational driving stress cannot be balanced locally. Ice-shelves have very flat (upper/sub-aerial) sur- face elevation and do not need too much resistive stress to maintain a balance. The hydrostatic pressure from the submerged portion of ice shelves provide the primary resistive stresses for the neighbouring coastal land ice to balance their gravitational driving stress arising from un- even surface topography. Warming from underneath the marine-based ice sheet, especially that affects ice-shelf viability could unfasten this potentially fragile stability and lead to accelerated creeping of the WAIS. Ice is brit- tle at higher strain rates, especially under tension, be- cause its melting point diffusivity is around 10 −15 m 2 /s, which is much lower than the 10 −11 m 2 /s for elemental metals. Accelerated creeping thus implies breaking of * This study is supported by Curtin University of Technology. # Corresponding author. Copyright © 2013 SciRes. IJG