The recent rapid retreat of an Antarctic glacier could be unprecedented, a new study suggests, a finding which could have major implications for future sea-level rise.
The researchers found that Hektoria Glacier retreated by more than 8km (5 miles) in just two months in late 2022.
The authors believe it could be the first modern example of a process where the front of a glacier resting on the seabed rapidly destabilises.
But other scientists argue that this part of the glacier was actually floating in the ocean – so while the changes are impressive, they are not so unusual.
Floating tongues of glaciers extending into the sea – called ice shelves – are much more prone to breaking up than glacier fronts resting on the seabed.
That Hektoria has undergone huge change is not contested. Its front retreated by about 25km (16 miles) between January 2022 and March 2023, satellite data shows.
But unravelling the causes is like a whodunnit mystery, according to study lead author Naomi Ochwat.
The case began way back in 2002 with the extraordinary collapse of an ice shelf called Larsen B in the eastern Antarctic Peninsula, losing approximately 3250 sq km (1250 sq miles) of ice shelf.
Larsen B had been effectively holding Hektoria Glacier back. Without it, Hektoria's movement sped up and the glacier thinned.
However, in early 2022, the sea-ice that had stabilized Hektoria broke up, leading to further ice loss.
During late 2022, the study suggests that the front of the glacier was resting on the seabed, and thus retreated at an unprecedented rate of 8.2km in two months - nearly ten times faster than any previously recorded grounded glacier retreat.
This astounding shift raises concerns, as similar circumstances might occur at other glaciers in Antarctica, with potential catastrophic implications for global sea levels.
Nonetheless, a division exists within the scientific community concerning this glacier's behavior, calling for more data and collaboration to understand the mechanisms driving such rapid changes.
