NSFGEO-NERC: Paleoclimate Signatures of the Climate Response to West Antarctic Ice Sheet Collapse

University Of Washington, Seattle WA

Investigators

Abstract

Steig/1602435 This award supports a project to examine the response of the climate system to changes in the Antarctic ice sheet. The Antarctic ice sheet rises into the atmosphere more than 2 kilometers above sea level, affecting atmospheric circulation in the same way a large mountain range does. Changes in ice sheet size in the past would have caused changes in atmospheric circulation, and hence climate, that should be detectable in paleoclimate data from ice and sediment cores. The project will examine the evidence for past ice sheet changes using a comparison of such data with results from numerical climate model experiments. The intellectual merit of this project is that knowing how the Antarctic ice sheet may have changed during previous warm periods is fundamental to understanding the response of ice sheets to climate change. There is evidence that West Antarctic ice sheet (WAIS) may already be in the beginning stages of collapse. The broader impact is that the outcomes of this research will inform projections of how much, and how fast, the WAIS may change in the future. The project is a joint effort between the University of Washington (Seattle, USA) and the British Antarctic Survey (Cambridge, U.K.), and is the result of independent and complementary efforts by groups from both institutions. The project will support two postdocs, and will help to encourage further international cooperative and multi-disciplinary research in this area. This project, submitted under the NSF/GEO-UK NERC lead agency opportunity (NSF 14-118) and the Paleo Perspectives on Climate Change (P2C2) solicitation, will use a combination of existing paleoclimate data and new model simulations to examine the influence of a changing Antarctic ice sheet on climate. Model-data comparisons will be used to test the hypothesis that a collapse of the WAIS occurred during the last interglacial period, and to evaluate whether the timing and rate of WAIS collapse can be constrained through the acquisition of new ice core records from Antarctica. Multiple, high-resolution, fully-coupled atmosphere-ocean general circulation models (GCMs) will be used to create an ensemble of simulations that include varying scenarios for Antarctic ice sheet change. The project will use the Community Earth System Model version 1 (CESM1), the Hadley Centre Couple Model version 3 (HadCM3), and the Max Planck institute model, ECHAM5. Using multiple models improves understanding of the key processes and provides a critical measure of the influence of model biases on the model-data comparison.