Upper Bound of Antarctica’s Potential Contribution to Future Sea-Level Rise

  • November 18, 2020
  • Home Page Feature,Science and Technical Highlights
  • Ice sheet models from DOE SciDAC’s ProSPect project have contributed to a multi-model intercomparison on the importance of ice-shelf buttressing to Antarctic ice sheet evolution and sea-level rise.

     

    The Science

    Ice sheet models from DOE SciDAC’s ProSPect project have contributed to a multi-model intercomparison on the importance of ice-shelf buttressing to Antarctic ice sheet evolution. The results provide an upper bound estimate for potential sea-level rise from Antarctic ice sheet dynamics.

     

    Image of MALI and BISICLES ice sheet models 200 years after all floating ice shelves are removed

    The Antarctic ice sheet 200 years after all floating ice shelves are removed. Shown are simulation results from ProSPect ice sheet models MALI (top) and BISICLES (bottom).

    The Impact

    DOE’s contributions represent the highest-resolution, highest fidelity, and largest-scale computational simulations contributed. Multiple models applied to identical experiments provide an estimate for the impacts of model structural uncertainty on sea-level projections from ice sheet models.

     

    Summary

    Antarctica’s ice shelves modulate the flow of ice to the oceans and thus the rate of sea-level rise. Structural weakening of ice shelves associated with changing climate will decrease their ‘buttressing’ effect. While the processes governing ice-shelf weakening are complex, uncertainties in the response of the ice sheet are also difficult to assess. The Antarctic BUttressing Model Intercomparison Project (ABUMIP) compares ice-sheet model responses to a decrease in ice-shelf buttressing by investigating the ‘end-member’ scenario of total and sustained loss of all ice shelves. While unrealistic, this scenario enables estimating the sensitivity of a 15-member ice sheet model ensemble to a total and sustained loss of ice-shelf buttressing. All models predict that this scenario would lead to multiple meters (1-10) of sea-level rise over the next 500 years. West Antarctic ice sheet collapse alone leads to a ~2-5 m sea-level rise. Compared to models from a decade ago, the current generation of ice-sheet models show much closer agreement in terms of their projections of mass loss and sea-level rise from marine ice sheets like Antarctica.

    Meters of sea-level equivalent increase over time from all models following removal of floating ice shelves

    Meters of sea-level equivalent (m SLE) increase over time from all models following removal of floating ice shelves (left). The ensemble-mean fraction of ice thickness reduction after 500 years (right), highlighting the vulnerability of West Antarctica to loss of its ice shelves.

    Publication

    Funding

    Contact

    • Stephen Price, Los Alamos National Laboratory
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