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This causes the sea to rise

Thorben Dunse in front of Etonbreen, a part of Austfonna. FOTO: Privat

This causes the sea to rise

The outflow of Basin-3 on Austfonna is surging for the first time in 140 years. It is now probably pouring more ice into the ocean than all of Svalbard's other glaciers combined.

Researchers from the University of Leeds announced last weekend their findings from the European Union's new Sentinel-1a satellite, which has been in operation for nearly a month. Using the satellite's radar, the researchers discovered parts of Austfonna are moving faster than before.

"It is clear that it set up a considerable speed in the past two or three years," said Andy Shephard, a professor at the University. "It is moving at least ten times faster than previous measurements."

Fieldwork in Svalbard
The previous measurements were made by postdoctoral researcher Thorben Dunse and his colleagues at the University of Oslo. They have considerable experience on Europe's largest ice caps and returned last week from this year's field work.

"We could not do the work where we wanted because there were so many cracks in the area," Dunse said.

Since 2004, he and his colleagues have collected data at the ground level and from remote instruments such as the German TerraSAR-X satellite. Dunse said he is not surprised by the findings of the EU researchers.

"Our measurements have shown that part of Austfonna as it is going out in the Barents Sea has a significantly higher speed than before," Dunse said. "It has surged since the fall of 2012."

Denuse's findings regarding the Austfonna surge have been accepted and will be published by the scientific journal The Cryosphere. The findings revealed by the Sentinel are noted and discussed in detail.

'Not climate change'
Several Norwegian media organizations reported the entire Austfonna ice cap is melting full speed into the ocean. This is incorrect. Austfonna is comprised of several outlet glaciers that have their own ways of transporting ice toward the coast. Some have their own names, such as Etonbreen in the western part and Bråsvellbreen in the southern area. The others, in fine Svalbard tradition, are numbered. The part now surging is called Basin-3, and goes eastward and out into the Barents Sea. Dunse said that the surge does not necessarily indicate climate change.

"It is natural and happens with many glaciers in Svalbard," he said. "But we have data on the surface melting process contributing significantly to the process. So when the climate gets warmer in the future, it may change how often glaciers surge in Svalbard."

The last time Basin-3 surged was around 1870. It was unknown when it would do so again, but researchers were guessing between 200 and 500 years.

"Now it seems that it only took about 140 years," Dunse said

Basin-3's outflow has lasted for about one-and-a-half years, and researchers expect it will continue for a few more years before it stops.

"It depends on how much ice has built up in the upper part of the glacier since the previous surge," Dunse said.

Nevertheless, the large amount of ice is worthy of discussion. The loss of mass from Basin-3 during the past year is equal to the annual mass loss from all glaciers in Svalbard from 2003 to 2008.

"The glaciers are the largest contributor to sea level changes and the surge from Europe's largest glacier means a very large contribution in a short time," Dunse said.

The front goes back

In particular, it is the 200-kilometer-long glacier front in the Barents Sea that is paying the price. The calving of that iceberg is the reason Austfonna has lost considerable mass during the past decade

"The front is set back several tens of meters every years," Dunse said.

Although surface melting and snowfall on the glacier are in balance, large areas are decreasing by several tens of meters, according to data from the ESA's CryoSat satellite. It measures the distance down into the ice using radar pulses and can detect changes in height. But despite the enormous quantities of ice now going out into the ocean, Dunse said he believes Austfonna will stabilize within the next ten years.

"There are glaciers in West Spitsbergen and the Alps that have decreased the most because they have lost large parts of their area as they are get supplied each year," he said. "But that is not the case at Ausfonna, even if it is variable how much it is supplied."


Se bildet større

Lots of ice waiting to be pushed out into the Barents sea. Basin-3 has moved rapidly since fall 2012. This picture is taken in spring 2013. FOTO: Thorben Dunse



  • A surge is a powerful and steep increase of movement by a glacier that has been "quiet" for a long time. This often results in a significant glacial thrust.
  • Glaciers have an accumulation area in their upper regions where they are supplemented by snow each winter. If a glacier is in balance with the climate, it will from the outside appear as if the glacier is stationary.
  • Surging glaciers have generally moved very slowly for a long time because, for example, the bottom part has frozen to the ground due to permafrost, allowing them to build up mass at the top due to not being transported downward. Once glaciers enter an active surging period, they dispose of excess mass at great speeds.
  • Researchers have historical knowledge of three glaciers that have surged on Austonna. They are Basin-3 (1870), Etonbreen (1920s) and Bråsvellbreen (1935-36).
  • Glaciers on Norway's mainland do not surge.

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