Germanys icebreaking research study vessel Polarstern (run by the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research). Credit: Alfred-Wegener-Institut/ Thomas Ronge
AWI professionals verify the postponed spread of the ice sheet 35 million years back.
Here, the West Antarctic Ice Sheet lying atop the continent stretches to the nearby Amundsen Sea. Due to meltwater and calving icebergs, the Thwaites Glacier, which flows into the Amundsen Sea, now loses twice as much ice as 30 years back. If the West Antarctic Ice Sheet were to collapse completely, worldwide sea levels would rise by more than 3 meters.
” The stability of the West Antarctic Ice Sheet is vital to the future development of the international sea level,” states the research studys very first author, Gabriele Uenzelmann-Neben from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). “Accordingly, scientists worldwide are working to predict the future habits of the ice in a warmer world using mathematical simulation. The more we understand about the history of the West Antarctic Ice Sheet, the more accurate we can make these models. Its more current history is well-documented, however we still know extremely little about its earlier years– particularly the formation phase. Our research study provides a crucial piece of the puzzle.”
In the course of 2 research study cruises onboard the Polarstern, the Geophysicist and her team investigated sediments in the vicinity of Pine Island Trough, a channel-like furrow in the seafloor of the shallow part of the Amundsen Sea that extends from north to south and leads straight toward the western coast of Antarctica. To gather data, the AWI group relied on the tried and shown reflection seismology technique: the Polarstern hauled a 3,000-meter-long measuring cable– or banner– behind her. These pulses penetrate the seafloor and are reflected back at geological limits– e.g. between the sediment and difficult rock– which is tape-recorded by the banners hydrophones.
The measurement data revealed a large sediment body, a sediment drift, on the eastern flank of Pine Island Trough, one with no equivalent on its western side. “Because of the Coriolis impact produced by Earths rotation, this unbalanced deposition of a sediment drift on the troughs eastern side but not the western one can just have actually been produced by a deep-water present that flowed toward the coast from north to south,” says Uenzelmann-Neben. “In order for that to occur, the ocean flow at the time of the deposition had to be similar to todays conditions, that is, the dominating westerlies and the Antarctic Circumpolar Current had to have actually lain far to the south. And comparable to today, the deep water upwelled through the trough should have been relatively warm.”
“Our study offers compelling proof that at the time of the terrific glaciation, warmer deep water upwelled near the Amundsen Sea rack and delayed the West Antarctic Ice Sheets growth to the sea,” the AWI Geophysicist explains. Armed with this extra understanding worrying the ice sheets earliest phase, projections on its future stability and ice retreat can now be enhanced.”
Recommendation: “Deep water inflow slowed offshore growth of the West Antarctic Ice Sheet at the Eocene-Oligocene shift” by Gabriele Uenzelmann-Neben, Karsten Gohl, Katharina Hochmuth, Ulrich Salzmann, Robert D. Larter, Claus-Dieter Hillenbrand, Johann P. Klages and Science Team of Expedition PS104, 21 February 2022, Communications Earth & & Environment.DOI: 10.1038/ s43247-022-00369-x.
” The stability of the West Antarctic Ice Sheet is critical to the future advancement of the international sea level,” says the research studys first author, Gabriele Uenzelmann-Neben from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). “Our research study offers compelling evidence that at the time of the great glaciation, warmer deep water upwelled near the Amundsen Sea rack and postponed the West Antarctic Ice Sheets expansion to the sea,” the AWI Geophysicist describes. Equipped with this extra knowledge worrying the ice sheets earliest stage, forecasts on its future stability and ice retreat can now be enhanced.”
Here, the West Antarctic Ice Sheet lying atop the continent stretches to the surrounding Amundsen Sea. If the West Antarctic Ice Sheet were to collapse completely, worldwide sea levels would rise by more than 3 meters.
