Glaciers in West Antarctica are moving faster from land into the ocean, contributing to rising global sea levels. A 25-year record of satellite observation was used to show for the first time a widespread increase in ice speed across the Getz region, with some ice accelerating into the ocean by nearly 50%.
The new study, led by the University of Leeds, reports that 14 glaciers in the Getz region are thinning and flowing faster into the ocean. Between 1994 and 2018, 315 gigatonnes of ice were lost, adding 0.9 mm to the average sea level – the equivalent of 126 million Olympic water tanks.
The results were published today (19/02/2021) in the journal Nature Communication show that, on average, the speed of the 14 glaciers has increased by almost a quarter with three glaciers accelerating by more than 44%. This research will help scientists find out if glaciers in the region could collapse in the next few decades and how this could affect future sea level rise.
Heather Selley, lead author of the study and a geologist at the Center for Polar Observation and Modeling at the University of Leeds, said: “The Getz region of Antarctica is so remote that most people have never set foot. this country. . Satellite radar altimetry records have shown a significant thinning of the ice sheet.
“However, the high levels of glacier velocity – combined with the thinning of ice – now confirm that the Getz basin is in a ‘dynamic imbalance’, meaning that it is losing more ice than he gets through snow.
“Using a combination of ideas and modeling, we show very localized acceleration patterns. For example, we monitor the largest change in the central Getz region, with one glacier flowing 391 m / year faster in 2018 than in 1994. a big change as it now flows at 669 m / year, a 59% increase in just two and a half decades. ”
The research, funded by the Natural Environment Monitoring Council (NERC) and the European Space Agency (ESA), reports how the widely reported thinning and acceleration of Amundsen’s glaciers is now extending over 1,000 km along the West Antarctic coast to Getz.
Dr Anna Hogg, co-author of a study and climate researcher at Leeds School of Earth and Environment, said: “The pattern of glacier acceleration shows the very local response to ocean dynamics.
“High-resolution satellite observations from satellites such as ESA’s Sentinel-1, which collects a new image every six days, allow us to measure local speed changes with greater accuracy.
“Regular and extensive sampling of both ice speeds and ocean temperatures is needed to advance our understanding of dynamic ice loss, which now accounts for 98.8% of Antarctica’s sea level contribution.”
By studying 25 years of sea measurements, the research team was able to reveal complex and annual changes in ocean temperatures. These findings suggest that the “dynamic imbalance” is largely caused by long-term ocean deposition, where more ocean heat interacts with the ice. and increasing melting.
Pierre Dutrieux, co-author of a study and climate researcher at the British Antarctic Survey, said: “We know that warmer ocean waters erode much of the glaciers of Western Antarctica, and these new ideas are show the impact this is having on the Getz region.
“This new data will provide a new perspective on the processes taking place so that we can predict future change with greater certainty. ”
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The research team led by the University of Leeds included colleagues from Swansea University, the University of Colombia, British Antarctic Studies, ENVEO IT GmbH, the German Institute of Remote Sensing Technology, the University of Denmark, University College London and the Polar Research Institute Korea.
The study, Widespread rise in dynamic imbalances in the Getz region of Antarctica from 1994 to 2018, is published 19 February 2021 in Nature Communication. DOI: 10.1038 / s41467-021-21321-1
Researchers in this study were supported by a number of grants. Anna E. Hogg received support from the NERC DeCAdeS project (NE / T012757 / 1) and the ESA Polar + Ice Shelves project (ESA-IPL-POE-EF-cb-LE-2019-834). Pierre Dutrieux was supported by the NSF awards 1643285, 1644159, and the Columbia University Climate and Life Alliance. Tae-Wan Kim from the Korea Polar Research Institute, KOPRI PE20160 grant.
Getz ice shelf photo credit: Pierre Dutrieux
For more information, contact Ian Rosser in the University of Leeds press office at [email protected]
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