The Pine Island Glacier – the largest single contributor to sea-level rise in Antarctica – has entered a period of irreversible retreat, an international team of scientists has shown.
The glacier, which is some 250km (160 miles) long and 2km (1.2 miles) thick, makes up about 10 per cent of the West Antarctic ice sheet.
The current instability of the ice sheet and its related contribution to ongoing sea-level rise is well established.
And the Pine Island Glacier has receded by about 10km during the last decade, a quarter of the total ice loss from West Antarctica.
Scientists, including those from the University of Exeter, have now shown that the glacier is like to retreat about 40km, increasing its discharge into the ocean in comparison to the last decade.
The research, published in Nature Climate Change, tested three state-of-the-art ice flow models using current observations and extended these with simulations of the glacier’s evolution over the next few decades.
The work was carried out by researchers from Exeter, France, China, Finland and the British Antarctic Survey.
All of the models agreed that Pine Island Glacier has started a phase of self-sustained retreat and will irreversibly continue its recession.
They suggest it will lead to a 3-5 fold increase in the volume of ice that is lost, equivalent to a 3.5-10mm rise in sea levels over the next 20 years.
Dr Anne Le Brocq, from the University of Exeter, said: “Ongoing retreat in this region of Antarctica will have a significant impact on future sea-level change.
“It is important that we understand the risk of further sea-level rise resulting from change in this region in the future. The agreement from the three models suggests the risk of sea-level rise as a result of irreversible retreat is high.”
Dr Gael Durand, of the University of Grenoble, added: “This is the first time that three independent models have been used to predict the rate of retreat of Pine Island Glacier’s grounding line in one study.
“The models show a strong agreement and the result is a striking vision of the near future. All the models suggest that this recession will not stop, cannot be reversed and that more ice will be transferred into the ocean.”
The study received financial support from the European Union’s four-year ice2sea project and the Natural Environment Research Council.