Images provide clues to rising seas

Huge troughs and channels carved into Antarctica’s continental shelves by glaciers thousands of years ago could help scientists to predict future sea-level rise, according to a report by British and German scientists in the journal Geology. Using sonar technology, the scientists captured images that provide new clues about the speed and flow of the West Antarctic Ice Sheet.


The scientists — from the British Antarctic Survey and Germany’s Alfred Wegener Institute — captured the most extensive, continuous set of images of the seafloor around the Amundsen Sea shoreline indentation ever taken. This region is a major drain point of the West Antarctic sheet and considered by some to be the most likely site for the initiation of major ice-sheet collapse. 

The sonar images reveal an “imprint” of the ice sheet as it was at the end of the last ice age, around 10,000 years ago. At that time, the extent of ice-coverage on the Antarctic continent was much greater than it is today. The exposed seabed troughs and channels indicate that the controlling mechanisms that move ice towards the coast and into the sea are more complex than previously thought. 

“One of the greatest uncertainties for predicting future sea-level rise is Antarctica’s likely contribution,” said lead author Rob Larter of the British Antarctic Survey. “It is very important for scientists and our society to understand fully how polar ice flows into the sea. … Our research tells us more about how the ice sheet responded to warming at the end of the last ice age, and how processes at the ice-sheet bed controlled its flow. This is a big step toward understanding of how the ice sheets are likely to respond to future warming.” 

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