Plate Nº 19 · recorded October 10, 2026
Earth & ClimateReported finding
A 76-Square-Kilometer Ice Island Breaks Free From Petermann Glacier
A 76-square-kilometer ice island — about the size of Manhattan — broke free from Greenland's Petermann Glacier on August 4, the largest Arctic calving event since 2020. Radar satellites tracked the break in near-real time.
By Elena Vasquez3 min read646 words
In brief
- A 76-square-kilometer ice island broke off Petermann Glacier on August 4, 2026.
- It is the glacier's largest calving event since 2012 and the biggest Arctic loss of floating ice since 2020.
- The ice island is roughly the size of Manhattan and may reach 150 meters thick.
- Two further potential ice islands of about 97 sq km and 87 sq km may eventually detach from the same ice tongue.
- The break was documented by ESA's Copernicus Sentinel-1 radar satellites together with researchers from the University of Ottawa, the Universities of Stirling, Lancaster and Leeds, and the Canadian Ice Service.
A 76-square-kilometer slab of floating ice broke free from Greenland's Petermann Glacier on August 4, 2026, the European Space Agency reported this week. The Manhattan-sized berg is the glacier's largest calving event since 2012 and the biggest loss of floating ice recorded anywhere in the Arctic since 2020.
How big is the new ice island?
Satellites from Europe's Copernicus Sentinel-1 mission have been tracking cracks on the glacier for years. The detached "ice island" covers about 76 square kilometers, roughly the area of Manhattan, and may be as much as 150 meters thick. Radar images from August 3 showed fractures opening along the center of Petermann's floating ice tongue. One day later, the eastern section had separated.
What did the satellites reveal?
Sentinel-1 carries synthetic aperture radar, an instrument that maps surface deformation from orbit using microwave pulses. Radar waves pierce clouds and gather data day or night, a useful trait for monitoring remote polar regions.
An international team has observed Petermann with Sentinel-1 since 2019, work partly funded through ESA's FutureEO ARCTEX project. The collaborators include:
- The University of Ottawa, Canada
- The Universities of Stirling, Lancaster and Leeds in the United Kingdom
- The Canadian Ice Service of Environment and Climate Change Canada
In April 2026, interferometric measurements — a radar technique that detects millimeter-scale surface movement — revealed deformation and fractures developing inside the ice tongue months before the break.
Adam Garbo, a PhD student at 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."
Could more ice follow?
Two additional rifts threaten even larger pieces. Researchers estimate the next potential ice islands at roughly 97 and 87 square kilometers. If those rifts continue spreading, Petermann could shed hundreds of square kilometers of floating ice in coming years.
Anna Crawford of the University of Stirling noted that Arctic ice islands are far rarer than their Antarctic counterparts. "By studying Arctic ice islands, we will gain knowledge that can be transferred across polar regions," she said. "This is critical for understanding how the calving and deterioration of ice islands impact glacier dynamics, sea-level rise and the ocean environment."
How fast were the cracks spreading?
A high-resolution Sentinel-1 interferogram gave researchers a near-real-time view of how fractures raced across the ice shelf in the days before the break. The data came from a one-day repeat pass enabled by the Sentinel-1C and Sentinel-1D tandem phase, while the newly launched Sentinel-1D satellite was still being commissioned.
Molly Hammond, a PhD student at the University of Leeds who processed the Sentinel-1 data, said: "The changes we observed on Petermann Glacier were occurring very rapidly in the lead-up to the iceberg calving event, so it was incredibly exciting to monitor the crack propagation with interferometry in near-real time. This has demonstrated the incredible value of one-day repeat synthetic aperture data."
ESA's Martin Wearing framed the event as a research opportunity. "This type of large tabular iceberg is relatively rare in the Arctic, making this calving event a unique opportunity to study how such a vast ice mass drifts, evolves and eventually breaks apart," he said.
What happens to the ice island now?
Environment and Climate Change Canada is tracking the iceberg as it drifts south through Arctic waters. Large ice islands can persist in the ocean for years, slowly fragmenting into smaller, harder-to-detect pieces. Authorities are evaluating potential threats to shipping routes and offshore infrastructure.
Petermann Glacier has produced large ice islands in 2008, 2010 and 2012. The floating tongue had stayed comparatively stable since, until this August's break.
via esa.int (Original)
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