Researchers from many countries are closely watching how the ice floes that flow along the coast of Antarctica are changing. If they become thinner and weaker, it can be a big problem.
Now a group of researchers can present new information about the condition of an enormous ice shelf in the Norwegian area of Dronning Maud Land.
The ice shelf Fimbulisen floats on the sea in Queen Maud Land in Antarctica.
Photo: Julius Lauber / Norwegian Polar Institute
There was a marked change in 2016, according to one of the authors behind a new report, oceanographer Tore Hattermann at the Norwegian Polar Institute.
He is project manager for monitoring at Fimbulisen, and has followed the project from the start.
Warmer seas
– Since 2016, the flow of hot water has increased. The warm water, deep in the sea outside the coast, has to a greater extent entered under the ice shelf and caused the ice to melt from below, he says.
In 2009/2010, they put out the measuring instruments. After 13 years, they can now present the results from what is one of the longest series of measurements carried out along the coast of Antarctica.
Equipment that, among other things, measures temperature and ocean currents is sent down through the ice at a place where the ice shelf is approx. 400 meters thick. Under the ice, it is around 500 meters down to the seabed. The instruments were placed around 10 meters below the ice shelf, and 30–50 meters above the seabed.
Photo: Norwegian Polar Institute
The report has been prepared by researchers from the Norwegian Polar Institute in collaboration with colleagues from the University of Bergen, and was presented in the international journal Nature Geoscience on Thursday.
– The temperature in the water under the ice is at times higher than the melting point. Simple physics tells us that it leads to melting, says Hattermann.
Tore Hattermann is head of the oceanography section at the Norwegian Polar Institute.
Photo: Norwegian Polar Institute
The researchers believe this is related to the fact that the circulation down in the sea has changed. The westerly winds around the continent have become stronger, which causes the warm water to come closer to the coast.
This happens in parallel with the fact that there is significantly less sea ice off the coast of Queen Maud Land. It seems to have a strengthening effect, according to the researchers.
Ice beyond the sea
Almost the entire Antarctic continent is covered by ice. There are a few mountain peaks here and there, otherwise everything is gone. Out at the coast, where the inland ice meets the sea, the ice persists in the form of ice floes that float on the water. They are like a “belt” around the entire continent.
They are a result of the inland ice on the continent constantly moving slowly out towards the sea. Around ten percent of the ice in Antarctica is ice shelves.
If the water gets warmer, also under the ice, it can cause the ice shelves to become thinner. Then they will provide less resistance, so that the ice sheet can flow faster into the sea. This can lead to increased sea level rise. That is why it is so important for researchers to follow this.
If the sea rises significantly more than today, it could have major consequences all over the world.
– Important signal
– The measurements are a signal that East Antarctica may not be as stably cold as we have thought. Other findings also indicate the same. Warm water around the continent comes closer to the coast and affects the ice shelves. We believe this development will be strengthened as a result of global warming, says Hattermann.
In recent months, there have been several reports about how warmer seas have led to far less sea ice in the western part of Antarctica, in the area of the Antarctic Peninsula.
This summer (winter in Antarctica) the ice level has been the lowest recorded at this time of year since measurements began 45 years ago. Ice that is “gone” corresponds to an area as large as Argentina.
This is a development Tore Hattermann and his colleagues are following with great interest. But in the coming summer season, it is once again the situation in East Antarctica that they focus on the most.
Towards the end of the year, when it is summer again in Antarctica, they are back on Fimbulisen to deploy new rigs that will collect data from the sea under the ice. Then the British Antarctic Survey and several other research institutions will participate.
Fimbulisen is located in Dronning Maud Land, north of the research station Troll.
Illustration: Norwegian Polar Institute
2023-09-21 15:00:00
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