Antarctic Peninsula warming triggers enhanced basal melt rates throughout West Antarctica

Creators: Flexas, M. Mar; Thompson, Andrew F.; Schodlok, Michael P.; Zhang, Hong; Speer, Kevin

Abstract

The observed acceleration of ice shelf basal melt rates throughout West Antarctica could destabilize continental ice sheets and markedly increase global sea level. Explanations for decadal-scale melt intensification have focused on processes local to shelf seas surrounding the ice shelves. A suite of process-based model experiments, guided by CMIP6 forcing scenarios, show that freshwater forcing from the Antarctic Peninsula, propagated between marginal seas by a coastal boundary current, causes enhanced melting throughout West Antarctica. The freshwater anomaly stratifies the ocean in front of the ice shelves and modifies vertical and lateral heat fluxes, enhancing heat transport into ice shelf cavities and increasing basal melt. Increased glacial runoff at the Antarctic Peninsula, one of the first signatures of a warming climate in Antarctica, emerges as a key trigger for increased ice shelf melt rates in the Amundsen and Bellingshausen Seas.

Additional Information

© 2022 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC). Received: 9 June 2021. Accepted: 30 June 2022. We thank the editor and three anonymous reviewers for thoughtful comments. L. Padman provided insightful input to an earlier version of the manuscript. D. Bonan provided CMIP6 data. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The work is funded by NSF grants NSF OPP-1644172 (M.M.F. and A.F.T.), OPP-1643679 (K.S.), and OCE-1658479 (K.S.); National Aeronautics and Space Administration Physical Oceanography program and Cryospheric Sciences program (M.M.F., M.P.S., H.Z., and A.F.T.); and Internal Research and Technology Development program (Earth 2050 project), Jet Propulsion Laboratory, California Institute of Technology (M.M.F. and A.F.T.). Author contributions: Conceptualization: A.F.T. and M.M.F. Methodology: M.P.S. and H.Z. Formal analysis: M.M.F. and M.P.S. Investigation: M.M.F., M.P.S., A.F.T., and K.S. Funding acquisition: A.F.T., M.P.S., and K.S. Writing—original draft: M.M.F. and A.F.T. Writing—review and editing: M.M.F., A.F.T., K.S., M.P.S., and H.Z. Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. The MITgcm and user manual are available from the project website, http://mitgcm.org/. Information on the LLC 270 ocean state estimate is available at http://hdl.handle.net/1721.1/119821. The WAIS 1080 model set-up is available at https://zenodo.org/record/6842019. The 2019 R/V Nathaniel B. Palmer cruise data (NBP19-01) used in this study are available at https://data.nodc.noaa.gov/cgi-bin/iso?id=gov.noaa.nodc:0210639. The seal data are available from the Marine Mammals Exploring the Oceans Pole to Pole (MEOP-CTD) database, www.meop.net/. The authors declare that they have no competing interests.

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