An Antarctic outlet glacier engaged in an irreversible retreat

Mount Herschel, Antarctica

Press release issued: 13 January 2014

An international team of researchers has shown that Pine Island Glacier (PIG), the primary contributor to sea-level rise from Antarctica, has entered a period of self-sustained retreat and its discharge to the ocean will likely increase in comparison to observations from the last decade.

The research led by the Laboratoire de Glaciologie et de Géophysique de l'Environment (LGGE) CNRS-Université Grenoble Alpes together with the University of Bristol, British Antarctic Survey, Natural Environment Research Council, Chinese Academy of Sciences, Institut Universitaire de France, CSC-IT Center for Science Ltd, and the University of Exeter, is published today in Nature Climate Change.

The current imbalance of the West Antarctic ice sheet and its related net contribution to ongoing sea-level rise is now well established. In particular, PIG has receded by about ten kilometres during the last decade and alone contributes 25 per cent of the total ice loss from West Antarctica. However, the future evolution of PIG remains poorly constrained with the possibility that it may lead to self-sustained retreat in what is known as the marine ice sheet instability.

Tony Payne, Professor of Glaciology in the University’s School of Geographical Sciences, said: “Over the last 30 years, Pine Island Glacier was the major contributor to sea level rise from Antarctica however it is unclear whether this will continue into the future. We have shown that the glacier’s current retreat will indeed continue for many decades.”

As a result of the European Union’s four-year ice2sea project, and for the first time, three state-of-the-art ice-sheet models are tested against current observations and their simulations of PIG’s evolution over the next few decades compared. All of the models agreed that PIG has started a phase of self-sustained retreat and will irreversibly continue its recession over many tens of kilometres. This leads to a 3-5 fold increase in mass loss when compared to the current observations, equivalent to a 3.5-10 mm sea-level rise over the next 20 years.

Paper: Retreat of Pine Island Glacier controlled by marine ice-sheet instability, L. Favier, G. Durand, S. L. Cornford, G. H. Gudmundsson, O. Gagliardini, F. Gillet-Chaulet, T. Zwinger, A. J. Payne and A. M. Le Brocq, Nature Climate Change, published online 12 January 2014.