Stabilizing effect of mélange buttressing on the marine ice-cliff instability of the West Antarctic Ice Sheet ...

• Main Authors: Schlemm, Tanja, Feldmann, Johannes, Winkelmann, Ricarda, Levermann, Anders
• Format: Text
• Language: unknown
• Published: Katlenburg-Lindau : Copernicus 2022
• Subjects: Antarctica; Pine Island Glacier; Thwaites Glacier; West Antarctica; global warming; 910; Antarctic; The Antarctic; West Antarctic Ice Sheet; Misi; Antarc*; Ice Sheet; Ice Shelf; Ice Shelves; Pine Island
• Online Access: https://dx.doi.org/10.34657/10898; https://oa.tib.eu/renate/handle/123456789/11865

Owing to global warming and particularly high regional ocean warming, both Thwaites and Pine Island Glaciers in the Amundsen region of the Antarctic Ice Sheet could lose their buttressing ice shelves over time. We analyse the possible consequences using the parallel ice sheet model (PISM), applying a simple cliff-calving parameterization and an ice mélange-buttressing model. We find that the instantaneous loss of ice-shelf buttressing, due to enforced ice-shelf melting, initiates grounding-line retreat and triggers marine ice sheet instability (MISI). As a consequence, the grounding line progresses into the interior of the West Antarctic Ice Sheet and leads to a sea level contribution of 0.6m within 100a. By subjecting the exposed ice cliffs to cliff calving using our simplified parameterization, we also analyse marine ice cliff instability (MICI). In our simulations it can double or even triple the sea level contribution depending on the only loosely constrained parameter that determines the maximum ...