The world’s largest and longest-living iceberg, A23a, is breaking apart after nearly four decades adrift, with scientists warning it could vanish within weeks as it drifts into warmer waters.
Once weighing close to a trillion tonnes and measuring more than twice the size of Greater London, the colossal block of ice calved from Antarctica’s Filchner Ice Shelf in 1986 but remained grounded in the Weddell Sea for more than 30 years. It finally broke free in 2020 and has since travelled along “iceberg alley” into the South Atlantic Ocean, where warmer seas and rougher conditions are accelerating its disintegration.
Recent satellite images analysed by the EU’s Copernicus Earth observation programme show the iceberg has shrunk to less than half its original size, now measuring around 1,770 sq km (683 sq miles) and stretching 60 km (37 miles) at its widest point.
In the past few weeks alone, massive chunks of ice, some spanning 400 sq km each, have broken away, scattering smaller fragments across surrounding waters and posing hazards to shipping lanes.
Earlier this year, A23a briefly ran aground off South Georgia island, sparking fears it could block penguins and seals from reaching their feeding grounds. But by late May, it dislodged and continued northwards, picking up speed, travelling up to 20 km a day at times.
Now exposed to increasingly warm waters and powerful ocean waves, A23a’s rapid collapse marks the end of one of the planet’s most remarkable floating ice formations, a 40-year journey from Antarctica to the Atlantic.
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