Thinning patterns of Antarctica's biggest glacier are opposite to previously observed: Scientists

Over the past four decades, the Pine Island has contributed more to the sea level rise than any other glacier in Antarctica

In a recent study, the scientists from the University of Bristol used the latest satellite technology from the European Space Agency (ESA) and tracked the patterns of mass loss from Pine Island—Antarctica's largest glacier.

The study result, published in the journal Nature Geoscience, showed that the pattern of thinning of ice is evolving in complex ways both in space and time with thinning rates now highest along the slow-flow margins of the glacier, while rates in the fast-flowing central trunk have decreased by about a factor of five since 2007. The researchers claim that this is completely opposite of what was observed prior to 2010.

Pine Island 'contributes' the most to sea-level rise

Antarctica ice melt
The lead author undertaking satellite validation fieldwork on the Filchner Ronne Ice Shelf, West Antarctica with the Alfred Wegener Institute, Germany Jonathan Bamber, University of Bristol

Over the past four decades, Pine Island has contributed more to the sea level rise than any other glacier in Antarctica. It has become one of its most intensively and extensively investigated ice stream systems. However, several different model projections of future mass loss have given conflicting results. Some of them predicted that the mass loss could increase dramatically over the next few decades, indicating a massive contribution to sea level, while others suggest a more moderate response.

The researchers believe that at this stage it is more important to identify which is the more likely behaviour and how this vulnerable part of Antarctica is going to evolve over the coming decades.

According to the study, the rapid migration of the grounding line, the place where the grounded ice first meets the ocean, is unlikely over that timescale, without a major change in ocean forcing. Instead, the results support model simulations that imply that the glacier will continue to lose mass but not at much greater rates than present.

Why are the models producing different behaviour in the future?

Lead author Professor Jonathan Bamber from the University of Bristol's School of Geographical Sciences, said: "This could seem like a 'good news story' but it's important to remember that we still expect this glacier to continue to lose mass in the future and for that trend to increase over time, just not quite as fast as some model simulations suggested."

"It's really important to understand why the models are producing different behaviour in the future and to get a better handle on how the glacier will evolve with the benefit of these new observations," he added. "In our study, we didn't make projections but with the aid of these new data we can improve model projections for this part of Antarctica."