To say something moves at a glacial pace is to imply sluggish, unhurried change. But what transpired over the course of 15 months at Antarctica’s Hektoria Glacier was uncharacteristically quick. Between January 2022 and March 2023, the glacier lost about 25 kilometers (15 miles) in length. That included a two-month period in which the terminus retreated more than 8 kilometers (5 miles)—the highest rate of grounded glacial ice loss observed in modern history.
A team of scientists published an analysis of Hektoria’s collapse based on a suite of remote-sensing data, finding that its particular geometry enabled the rapid change. Like many glaciers on the Antarctic Peninsula, Hektoria starts on land and extends to the sea, with the last section being a thick, floating plate of ice, or “ice tongue.” The researchers determined Hektoria lost both its ice tongue and an area of grounded ice spread over a flat plain—the latter directly contributing to sea level rise. Although Hektoria is relatively small as Antarctic glaciers go, scientists say that similar events at larger glaciers could be much more consequential.
The images above capture the scale of the loss of Hektoria’s grounded ice on the eastern Antarctic Peninsula. Note that the right image was acquired about one year after the remarkable loss of grounded ice; a cloud-free Landsat image showing the whole area was not availab …