The world's largest iceberg is on the move for the first time in more than three decades, scientists have said.
At almost 1,500 square miles, the Antarctic iceberg "A23a" is roughly two-and-a-half times the size of London.
Since breaking off West Antarctica's Filchner-Ronne Ice Shelf in 1986, the iceberg - which once hosted a Soviet research station - has largely been stranded after its base became stuck on the floor of the Weddell Sea.
Satellite images revealed that the iceberg, weighing nearly a trillion tonnes, was drifting quickly past the northern tip of the Antarctic Peninsula, aided by strong winds and currents.
Oliver Marsh, a glaciologist with the British Antarctic Survey, said it was rare to see an iceberg of this size moving and that scientists were watching its trajectory closely.
"Over time it's probably just thinned slightly and got that little bit of extra buoyancy that's allowed it to lift off the ocean floor and get pushed by ocean currents," Marsh said. A23a is also among the world's oldest icebergs.
It's possible A23a could again become grounded at South Georgia island. That would pose a problem for Antarctica's wildlife. Millions of seals, penguins, and seabirds breed on the island and forage in the surrounding waters. Behemoth A23a could cut off such access.
In 2020, another giant iceberg, A68, stirred fears that it would collide with South Georgia, crushing marine life on the sea floor and cutting off food access.
Such a catastrophe was ultimately averted when the iceberg broke up into smaller chunks — a possible end game for A23a as well.
