Greenland's Petermann Glacier Sheds a Manhattan-Sized Iceberg

A tabular iceberg roughly the size of Manhattan has broken away from Petermann Glacier in northwest Greenland, in what scientists say is the glacier's largest loss of floating ice since 2012 and the most significant Arctic calving event since 2020. Europe's Copernicus Sentinel-1 mission documented the breakup, in which a 76-square-kilometer section of the glacier's floating ice tongue separated on August 4, 2026.

The new "ice island" covers an area about the size of Manhattan and may be up to 150 meters thick. Radar images from Sentinel-1 showed worsening damage along the middle of the ice tongue on August 3; by the next day, the huge slab had broken away from the glacier's eastern side. An international team, including researchers from the University of Ottawa, the Universities of Stirling, Lancaster and Leeds, and Canada's Ice Service, has used Sentinel-1 to track Petermann Glacier since 2019, partly through the European Space Agency's FutureEO ARCTEX project.

Interferometric measurements collected in April had already revealed deformation and fractures within the ice tongue, giving researchers a detailed view of changes developing months before the eventual break. Adam Garbo, a PhD student at the University of Ottawa, said the team had "anticipated this break for years" and called seeing it happen "remarkable." Petermann Glacier has produced major ice islands before, including large calving events in 2008, 2010 and 2012, but its floating ice tongue had stayed comparatively stable since then.

Researchers do not expect this breakup to be the last major change: two additional large ice islands, with estimated areas of about 97 and 87 square kilometers, could eventually separate as existing rifts keep spreading across the ice tongue. Anna Crawford of the University of Stirling said large tabular icebergs are relatively common around Antarctica but far rarer in the Arctic. She said studying Arctic ice islands can help researchers understand glacier dynamics, sea-level rise and ocean conditions in other polar regions.