Antarctic Glaciers Melting as Sea Water Warms

The ice sheet in West Antarctica is melting faster than expected, causing oceanographers to find ways to improve predictions of future changes in ice sheet mass.

Oceanographers from the University of Gothenburg and the US have made new observations that could help better predict future changes in ice sheet mass. Reduction of the ice sheets in both Antarctica and Greenland will greatly impact water levels of oceans around the globe. With insufficient knowledge about large glaciers in West Antarctica, it is nearly impossible for researchers to predict changing water levels accurately.

"There is a clear reduction in the ice mass in West Antarctica, especially around the glaciers leading into the Amundsen Sea," says Lars Arneborg, researcher from the Department of Earth Sciences at the University of Gothenburg.

Arneborg and his researchers studied ocean circulation in the Amundsen Sea and discovered that West Antarctica is sensitive because the ice rests on areas that sit below sea-level. Warm sea water can then penetrate beneath the ice and causes increased melting underneath the surface.

"It is therefore probably a change in the ocean circulation in the Amundsen Sea that has caused this increased melting," added Arneborg.

Until recently, researchers only used computer models to study the melting ice in Antarctica. But Arneborg and his team managed to install instruments into the Amundsen Sea, which allows them to measure the inward flow of warm sea water towards the glaciers.

"But there have been very few oceanographic measurements from the Amundsen Sea to confirm or contradict the results from the computer models. Nor has there been any winter data. Sea ice and icebergs have made it impossible to get there in the winter, and it isn't easy to have instruments in place all year round."

The team’s current observations show that the warm sea water constantly flows toward the glaciers, contrasting previous computer models that suggested a seasonal cycle.

"This shows just how important observations are for investigating whether the models we use describe something that resembles reality. Warm ocean currents have caused much more melting than any model has predicted, both in West Antarctica and around Greenland,” stated Arneborg.

The researcher say they need more time and a longer series of observations to improve models and achieve a better understanding of the ice melt. "Only then will we be able to say something about how the ice masses of the Antarctic and Greenland will change in the future," added Arneborg.

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