News – Glaciers in western Antarctica are moving faster from land to ocean, contributing to rising sea levels. The 25-year record of satellite observations was used for the first time to show a wide increase in the speed of ice in the Getz sector, with some ice accelerating into the ocean by almost 50%.
A new study led by the University of Leeds reports that 14 glaciers in the Getz region are thinning and pouring faster into the ocean. Between 1994 and 2018, 315 gigatons of ice were lost, adding 0.9 mm to the global mean sea level – corresponding to 126 million Olympic pools.
The results were published today (19/02/2021) in the journal Nature Communications show that on average the speed of all 14 glaciers increased by almost a quarter with the acceleration of the three glaciers by over 44%. This research will help scientists determine whether glaciers in the region could collapse in the next few decades and how this could affect future global sea level rise.
Heather Selley, lead author of the study and a glaciologist at the Center for Polar Observation and Modeling at the University of Leeds, said: “The Getz region of Antarctica is so far away that people have never set foot on much of this continent. Satellite radar altimetry records show significant thinning ice sheets.
“However, high rates of increased glacier speed – along with ice thinning – now confirm that the Getz basin is in‘ dynamic imbalance ’, meaning it is losing more ice than it is gaining with snow.
“By combining observation and modeling, we show highly localized acceleration patterns. For example, we observe the largest change in the central Getz area, with a single glacier running 391 m faster in 2018 than in 1994. This is a significant change because it now flows at 669 m / year, an increase of 59% in just two and a half decades. “
The research, funded by the Council for the Study of the Natural Environment (NERC) and the European Space Agency (ESA), reports that the general thinning and acceleration observed on neighboring Amundsen Glaciers extends over 1,000 km along the coast of West Antarctica to the Getz. .
Dr Anna Hogg, co-author of the study and climate researcher at Leeds School of Earth and Environment, said: “The pattern of glacier acceleration shows a highly localized response to ocean dynamics.
“High-resolution satellite observations from satellites such as ESA’s Sentinel-1, which collects a new image every six days, mean we can measure localized changes in speed with increasing detail.
“Consistent and extensive sampling of ice speed and ocean temperature is needed to further understand the dynamic ice loss, which now accounts for 98.8% of Antarctica’s sea-level contribution.”
Examining 25 years of ocean measurements, the research team was able to show the complex and annual differences in ocean temperatures. These results suggest that “dynamic imbalance” is mainly caused by prolonged ocean forcing, where increased ocean heat content interacts with ice and enhances melting.
Pierre Dutrieux, co-author of the study and climate researcher at the British Antarctic Survey, said: “We know that warmer ocean waters are eroding many West Antarctic glaciers, and these new observations show the impact this has on the Getz region.
“This new data will provide a new perspective on the processes that are taking place so that we can predict future changes with greater certainty.”
The research team led by the University of Leeds included colleagues from Swansea University, Columbia University, British Antarctic Research, ENVEO IT GmbH, the Institute for Remote Reading Technology in Germany, the University of Denmark, University College London and the Korean Polar Research Institute.
The study, Widespread Increase in Dynamic Imbalance in the Getz Region of Antarctica from 1994 to 2018, was published on February 19, 2021. Nature Communications. DOI: 10.1038 / s41467-021-21321-1
The researchers in this study were supported by various grants. Anna E. Hogg is supported by 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 Scholarship for Climate and Life. Tae-Wan Kim of the Korean Polar Research Institute, grant KOPRI PE20160.