Interferometric observations of Petermann acquired in April also revealed deformation and fractures within the ice tongue, providing a detailed picture of changes that developed months prior to the calving.

Adam Garbo, a PhD student from the University of Ottawa, said, “Petermann Glacier has long been one of Greenland’s largest remaining ice tongues. We’ve anticipated this break for years, and seeing it finally happen is remarkable. It’s a powerful reminder of how quickly these systems can change.”

Petermann Glacier has a well-documented history of major calving events, including the formation of large ice islands in 2008, 2010 and 2012. However, since 2012, its floating ice tongue has remained relatively stable, despite several smaller-scale calving events.

The latest calving is unlikely to be the last major change at Petermann Glacier. Two further large ice islands, with estimated surface areas of approximately 97 and 87 sq km, could detach as existing rifts continue to propagate across the floating ice tongue.

Anna Crawford, from the University of Stirling, commented, “While large, tabular icebergs are relatively common in the Southern Ocean around Antarctica, Arctic ice islands are far rarer.

“By studying Arctic ice islands, we will gain knowledge that can be transferred across polar regions. This is critical for understanding how the calving and deterioration of ice islands impact glacier dynamics, sea-level rise and the ocean environment.”