The Antarctic Ice Sheet (AIS) response to past warming consistent with the 1.5–2°C “safe limit” of the United Nations Paris Agreement is currently not well known. Empirical evidence from the most recent comparable period, the Last Interglaciation, is sparse, and transient ice-sheet experiments are few and inconsistent. Here, we present new, transient, GCM-forced ice-sheet simulations validated against proxy reconstructions. This is the first time such an evaluation has been attempted. Our empirically constrained simulations indicate that the AIS contributed 4m to global mean sea level by 126ka BP, with ice lost primarily from the Amundsen, but not Ross or Weddell Sea, sectors. We resolve the conflict between previous work and show that the AIS thinned in the Wilkes Subglacial Basin but did not retreat. We also find that the West AIS may be predisposed to future collapse even in the absence of further environmental change, consistent with previous studies.
Bibliographical noteFunding Information:
NRG acknowledges funding from Royal Society of New Zealand contract VUW‐1501. Simulations on which this work is based were funded by US National Science Foundation (NSF) through grant numbers AGS‐1503032 (to PUC and AEC), AGS‐1502990 (to FH), 1559040 (to AD), and OPP‐1443437 (to AEC). FH gratefully acknowledges the NOAA Climate and Global Change Postdoctoral Fellowship program, administered by the University Corporation for Atmospheric Research. High‐performance computing support from Yellowstone ( http://n2t.net/ark:/85065/d7wd3xhc ) and Cheyenne ( http://www.doi.org/10.5065/D6RX99HX ) was provided by NCAR's Computational and Information Systems Laboratory, sponsored by the NSF. This research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, which is supported by the Office of Science of the US Department of Energy under contract number DE‐AC05‐00OR22725. AD gratefully acknowledges the U.S. Fulbright Scholar Program. CSMT and CJF acknowledge support from the Australian Research Council (ARC), including Linkage Project (LP120200724) and Discovery Project DP210103621, supported by Antarctic Logistics and Expeditions. NRG, TRN, RHL, RMM, DPL, NANB, and GBD acknowledge support from Ministry for Business, Innovation and Employment contracts RTUV1705 (NZSeaRise) and ANTA1801 (Antarctic Science Platform). PISM is supported by NASA grant numbers NNX13AM16G and NNX13AK27G.
© 2021. American Geophysical Union. All Rights Reserved.
- General Earth and Planetary Sciences
- sea-level rise
- climate change