A68

A68 is a large tabular Antarctic iceberg that calved from the Larsen C Ice Shelf in July 2017. It detached near the Antarctic Peninsula and became one of the largest recorded icebergs, attracting attention from European Space Agency, NASA, British Antarctic Survey, National Science Foundation, and media outlets such as the New York Times and the Guardian (UK newspaper). The iceberg's size, trajectory, and eventual interactions with marine ecosystems prompted studies by researchers affiliated with University of Edinburgh, University of Exeter, University of Bristol, Columbia University, and Stanford University.

Identification and Designation

The designation A68 follows the convention used by the US National Ice Center and earlier practices by the Scott Polar Research Institute to name Antarctic tabular icebergs: the letter denotes the quadrant (A for the area between 0°–90°W adjacent to the Weddell Sea and Grytviken approaches) and the number is sequential. Tracking and cataloguing employ satellite missions including Landsat 8, Sentinel-1, MODIS on Aqua and Terra, operated by agencies like NASA, European Space Agency, and NOAA. International coordination for monitoring involves entities such as the International Ice Patrol, World Meteorological Organization, and polar research stations like Rothera Research Station and Mawson Station.

Physical Characteristics

Initially, the iceberg measured roughly 5,800 square kilometres and extended about 170 kilometres in length, comparable to the size of Delaware or the island of Cyprus. Its tabular morphology featured near-vertical calving cliffs and relatively flat surface topography similar to other giant bergs such as the one from Ross Ice Shelf in earlier decades. Thickness estimates derived from satellite altimetry from ICESat-2 and airborne surveys by Operation IceBridge suggested substantial draft, influencing its buoyancy and motion under influences from the Antarctic Circumpolar Current, Weddell Gyre, and regional wind fields analyzed by European Centre for Medium-Range Weather Forecasts. The berg exhibited surface melt ponds in Antarctic summer seasons, which researchers from National Oceanography Centre (UK) and British Antarctic Survey linked to enhanced hydrofracture vulnerability seen in studies by Richard Alley and Ted Scambos.

History and Discovery

The parent remnant of the calving event had been monitored for years by satellite teams at institutions such as University of Colorado Boulder and University of Nebraska–Lincoln using imagery archives from Landsat program and synthetic aperture radar from RADARSAT. The calving that produced the iceberg occurred in July 2017, an event documented in near-real time by scientists at University of Sheffield and Cardiff University working with the Mid-Atlantic Ridge mapping networks and reporting to the Polar Research Board. Prior to calving, researchers including Jemma Wadham and Julienne Stroeve had noted rift propagation and surface melt signatures consistent with ice-shelf destabilization observed on Pine Island Glacier and Thwaites Glacier. After detachment, the iceberg drifted northward, with trajectory analyses published by teams at University of Reading and Columbia Climate School showing interactions with sea-ice fields monitored by the National Snow and Ice Data Center.

Operational Use and Impact

Although not used for transport or resource extraction by states such as United Kingdom, Argentina, Chile, Norway, or United States, the iceberg’s presence affected shipping routes and scientific operations. Vessel operators including crews from research ships like RRS James Clark Ross and RV Polarstern adjusted plans to avoid collision risk, informed by advisories from the International Maritime Organization and ice forecast products from UK Met Office. The iceberg also influenced ecological conditions near South Georgia and South Orkney Islands, where marine biologists from Scripps Institution of Oceanography, British Antarctic Survey, and British Antarctic Survey (BAS) observed shifts in krill distribution, which has implications for predators studied by teams from Whale and Dolphin Conservation and researchers tracking penguin colonies monitored by BirdLife International. Oceanographic impacts—such as freshwater input altering stratification and regional productivity—were analyzed in models developed at Woods Hole Oceanographic Institution and Lamont–Doherty Earth Observatory.

Cultural References and Legacy

The iceberg inspired coverage in outlets like BBC News, The Times (London), Reuters, and was referenced in documentaries produced by National Geographic and BBC Earth. It entered conservation and policy discourse mediated by organizations such as Greenpeace and World Wildlife Fund, and was cited in academic debates at conferences organized by SCAR and the European Geosciences Union. The event contributed to public awareness of polar change alongside historic episodes like the collapse of the Larsen A and Larsen B ice shelves and fed into curriculum materials used by institutions such as Smithsonian Institution and American Museum of Natural History. In museum and exhibition contexts, the iceberg has been featured in displays curated by Natural History Museum, London and educational programs run by Antarctic Heritage Trust.

Category:Icebergs