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Abstract. Predictions of future sea-level change and ice-sheet stability rely on accurate reconstructions of sea levels for past warm intervals, such as the mid-Pliocene Warm Period (MPWP; 3.264–3.025 Ma). The magnitude of MPWP glacial cycles and the relative contribution of meltwater sources remain uncertain. We explore this issue by modeling processes of glacial isostatic adjustment for a wide range of possible MPWP ice-sheet melt zones, including North America, Greenland, Eurasia, and West Antarctica, as well as the Wilkes Basin, the Aurora Basin, and the embayment of Prydz Bay in East Antarctica. As a case study, we use a series of ice histories together with a suite of viscoelastic Earth models to predict global changes in sea level from the Marine Isotope Stage (MIS) M2 glacial to the MIS KM3 interglacial. At the Whanganui Basin (New Zealand), a location with stratigraphic constraints on Pliocene glacial–interglacial sea-level amplitude, the calculated local-sea-level (LSL) rise is on average ∼ 15 % lower than the associated change in the global mean sea level (GMSL) in the ice-sheet scenarios explored here. In contrast, the calculated LSL rise over the deglaciation from MIS M2 to MIS KM3 at Enewetak Atoll is systematically larger than the GMSL change by 10 %. While no single LSL observation (field site) can provide a unique constraint on the sources of ice melt observed during this period, combinations of observations have the potential to yield a stronger constraint on GMSL change and to narrow the list of possible sources.
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The Influence of the Solid Earth on the Contribution of Marine Sections of the Antarctic Ice Sheet to Future Sea‐Level Change
Abstract Seismic tomography models indicate highly variable Earth structure beneath Antarctica with anomalously low shallow mantle viscosities below West Antarctica. An improved projection of the contribution of the Antarctic Ice Sheet to sea‐level change requires consideration of this complexity to precisely account for water expelled into the ocean from uplifting marine sectors. Here we build a high‐resolution 3‐D viscoelastic structure model based on recent inferences of seismic velocity heterogeneity below the continent. The model serves as input to a global‐scale sea‐level model that we use to investigate the influence of solid Earth deformation in Antarctica on future global mean sea‐level (GMSL) rise. Our calculations are based on a suite of ice mass projections generated with a range of climate forcings and suggest that water expulsion from the rebounding marine basins contributes 4%–16% and 7%–14% to the projected GMSL change at 2100 and 2500, respectively.
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- PAR ID:
- 10372643
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 49
- Issue:
- 15
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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