Glaciers in West Antarctica are moving more quickly from land into the ocean, contributing to rising global sea levels.
A 25-year record of satellite observations has been used to show widespread increases in ice speed across the Getz sector for the first time, with some ice accelerating into the ocean by nearly 50%.
The new study reports that 14 glaciers in the Getz region are thinning and flowing more quickly into the ocean. Between 1994 and 2018, 315 gigatonnes of ice has been lost, adding 0.9 mm to global mean sea level – equivalent to 126 million Olympic swimming pools of water.
The results published in the journal Nature Communications show that, on average, the speed of all 14 glaciers has increased by almost a quarter with three glaciers’ speeding up by over 44 %.
This research will help scientists determine whether glaciers in the region may collapse in the next few decades and how this could affect future global sea-level rise.
“The high rates of increased glacier speed – coupled with ice thinning – now confirms the Getz basin is in ‘dynamic imbalance’, meaning that it is losing more ice than it gains through snowfall,” said to Heather Selley, lead author of the study and a glaciologist at the Centre for Polar Observation and Modelling at the University of Leeds.
“Using a combination of observations and modelling, we show highly localised patterns of acceleration. For instance, we observe the greatest change in the central region of Getz, with one glacier flowing 391 m/year faster in 2018 than in 1994. This is a substantial change as it is now flowing at a rate of 669 m/year, a 59% increase in just two and a half decades.”
The research reports how the widely reported thinning and acceleration observed in the neighbouring Amundsen Sea glaciers, now extends over 1,000 km along the West Antarctic coastline into Getz.
By examining 25 years of ocean measurements, the research team were able to show complex and annual variations in ocean temperatures. These results suggest that the “dynamic imbalance” is mainly caused by longer-term ocean forcing, where increased heat content in the ocean is interacting with the ice and enhancing melt.
Photo credit: NASA/Brooke Medley via flickr.com/creative commons