Antarctic glacier’s alarming retreat is the fastest ever seen

Scientists have documented what they say is the fastest retreat of an Antarctic glacier in modern history.

The Hectoria Glacier on the Antarctic Peninsula has shrunk 25 kilometers in just 15 months, collapsing at a rate 10 times faster than current records.

Naomi Coverage from the University of Colorado Boulder and her colleagues attribute the rapid decline to the vulnerability of Hectoria's configuration, which pushed its thinning trunk across a flat seafloor known as an ice plain. This triggered a sharp surge in iceberg production.

Researchers warn that the collapse mechanism could threaten other Antarctic glaciers, with serious implications for sea level rise.

“The question is, was Hectoria the ultimate participant in a case that was caused by a perfect storm of events, or is there a recipe for disaster somewhere else?” – says Ochvat.

Hectoria's problems began in early 2022, when a mass of sea ice broke away from the front of a city-sized glacier and its floating tongue of ice broke apart. The removal of this stabilizing ice subjected the glacier to new stresses, causing its rate of flow and thinning to increase.

But the most dramatic changes occurred on the icy plain, where Hectoria's trunk, previously resting on flat rock, appears to have become so thin that its mass ended up resting only very lightly on the seafloor.

According to the researchers, the entire section floated almost instantly, exposing weak points in the trunk and beginning its destruction. Floating forces broke off icebergs, causing “glacial earthquakes” that were detected by seismic sensors. In November and December 2022, the glacier lost 8 km in length.

Team Member Ted Scamboswho also works at the University of Colorado Boulder, called the lightning destruction “shocking” and warned that the retreat “changes what's possible” for important glaciers elsewhere on the continent.

However, this analysis has generated controversy. Fraser Christie from Airbus Defense and Space reports that there is “substantial disagreement” in the glaciology community as to where exactly Hectoria landed entirely on the bedrock due to a lack of high-precision satellite records.

Anna Hogg from the University of Leeds, UK, says her team's measurements showed that the ice above the claimed ice plain was always “fully floating”, ruling out collapse caused by buoyancy.

Christine Batchelor at Newcastle University, UK, were also skeptical of the team's explanations. “If this piece of ice was indeed floating, as has been the subject of much previous debate, then the headline essentially boils down to the much less unusual 'icebergs breaking off from an ice shelf,'” she says.