Preprints
https://doi.org/10.5194/tc-2021-120
https://doi.org/10.5194/tc-2021-120

  23 Apr 2021

23 Apr 2021

Review status: this preprint is currently under review for the journal TC.

Quantifying the potential future contribution to global mean sea level from the Filchner-Ronne basin, Antarctica

Emily A. Hill1,2, Sebastian H. R. Rosier2, G. Hilmar Gudmundsson2, and Matthew Collins1 Emily A. Hill et al.
  • 1College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, United Kingdom
  • 2Department of Geography and Environmental Sciences, University of Northumbria, Newcastle Supon Tyne, United Kingdom

Abstract. The future of the Antarctic Ice Sheet in response to climate warming is one of the largest sources of uncertainty in estimates of future changes in global mean sea level (∆GMSL). Mass loss is currently concentrated in regions of warm circumpolar deep water, but it is unclear how ice shelves currently surrounded by relatively cold ocean waters will respond to climatic changes in the future. Studies suggest that warm water could flush the Filchner-Ronne (FR) ice shelf cavity during the 21st century, but the inland ice sheet response to a drastic increase in ice shelf melt rates, is poorly known. Here, we use an ice flow model and uncertainty quantification approach to project the GMSL contribution of the FR basin under RCP emissions scenarios, and assess the forward propagation and proportional contribution of uncertainties in model parameters (related to ice dynamics, and atmospheric/oceanic forcing) on these projections. Our probabilistic projections, derived from an extensive sample of the parameter space using a surrogate model, reveal that the FR basin is unlikely to contribute positively to sea level rise by the 23rd century. This is primarily due to the mitigating effect of increased accumulation with warming, which is capable of suppressing ice loss associated with ocean–driven increases in sub-shelf melt. Mass gain (negative ∆GMSL) from the FR basin increases with warming, but uncertainties in these projections also become larger. In the highest emission scenario RCP 8.5, ∆GMSL is likely to range from −103 to 26 mm, and this large spread can be apportioned predominantly to uncertainties in parameters driving increases in precipitation (30 %) and sub-shelf melting (44 %). There is potential, within the bounds of our input parameter space, for major collapse and retreat of ice streams feeding the FR ice shelf, and a substantial positive contribution to GMSL (up to approx. 300 mm), but we consider such a scenario to be very unlikely. Adopting uncertainty quantification techniques in future studies will help to provide robust estimates of potential sea level rise and further identify target areas for constraining projections.

Emily A. Hill et al.

Status: open (until 18 Jun 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Emily A. Hill et al.

Model code and software

Úa ice flow model G. H. Gudmundsson https://doi.org/10.5281/zenodo.3706624

PICO model for the ice flow model Úa S. H. R. Rosier and R. Reese https://github.com/shrrosier/PICO_Ua

Emily A. Hill et al.

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Short summary
Using an ice-flow model and uncertainty quantification methods, we provide probabilistic projections of future sea level rise from the Filchner-Ronne region of Antarctica. We find that it is most likely that this region will contribute negatively to sea level rise over the next 300 years, largely as a result of increased surface mass balance. We identify parameters controlling ice-shelf melt and snowfall contribute most to uncertainties in projections.