Diverse behaviors of marine ice sheets in response to temporal variability of the atmospheric and basal conditions

Olga Sergienko, Duncan Wingham

Research output: Contribution to journalArticlepeer-review


The observed retreat of the grounding line of the present-day ice sheets and the simulated grounding line retreat of ice sheets under changing climate conditions are often interpreted as indications of marine ice-sheet insta bility, driven by a positive feedback between the ice discharge and conditions at the grounding line. However, the arguments that support this feedback are valid only for steady-state conditions. Here, we assess how unconfined marine ice sheets may behave if atmospheric conditions and basal conditions evolve with time. We find that the behavior of the grounding lines can exhibit a range from unstoppable advance and retreat to irregular oscillation irrespective of the stability of the corresponding steady state configurations obtained with time-invariant conditions. Our results show that numerical simulations with a parameterization of the ice flux through the grounding line used in large-scale ice sheet models produce markedly different results from simulations without the parameterization. Our analysis demonstrates that the grounding line mi gration can be driven by the temporal variability in the atmospheric and basal conditions and not by marine ice-sheet instability, which assumes unchanging conditions. Instead, the grounding-line advance or retreat is determined by interactions between ice flow, basal processes and environmental conditions throughout the length of a marine ice sheet in addition to the circumstances at its grounding line.

Original languageEnglish (US)
JournalJournal of Glaciology
StateAccepted/In press - 2024

All Science Journal Classification (ASJC) codes

  • Earth-Surface Processes


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