The impact of variable ocean temperatures on Totten Glacier stability and discharge

• Published in: Geophysical Research Letters
• Main Authors: McCormack, FS, Roberts, JL, Gwyther, DE, Morlighem, M, Pelle, T, Galton-Fenzi, BK
• Format: Article in Journal/Newspaper
• Language: English
• Published: Amer Geophysical Union 2021
• Subjects: Earth Sciences; Physical geography and environmental geoscience; Glaciology; Totten Glacier; Antarc*; Ice Sheet; Ice Shelf
• Online Access: https://doi.org/10.1029/2020GL091790; http://ecite.utas.edu.au/151704

A major uncertainty in Antarctica's contribution to future sea-level rise is the ice sheet response timescales to ocean warming. Totten Glacier drains a region containing 3.9m global sea level equivalent and has been losing mass over recent decades. We use an ice sheet model coupled to an ice-shelf cavity combined ocean box and plume model to investigate Totten's response to variable ocean forcing. Totten's grounding line is stable for a limited range of ocean temperatures near current observations (i.e., −0.95C to −0.75C), with topography influencing the discharge periodicity. For increases of ≥0.2C in temperatures beyond this range, grounding line retreat occurs. Variable ocean forcing can reduce retreat relative to constant forcing, and different variability amplitudes can cause centennial-scale delays in retreat through interactions with topography. Our results highlight the need for long-term ocean state observations and to include forcing variability in ice sheet model simulations of future change.