The largest iceberg globally, roughly the size of Dubai, which spans 4,114 square kilometres, has started moving after more than 30 years. Weighing nearly a trillion metric tonnes and covering 4,000 square km, Iceberg A23a, born in 1986 from West Antarctica’s Filchner-Ronne Ice Shelf, has been stationary in the Weddell Sea. Recent satellite images show it’s now rapidly drifting past the northern tip of the Antarctic Peninsula, propelled by strong winds and currents.
A23A, The World’s biggest iceberg is on the move after being stuck to the ocean floor for more than 30 years. It split from the Antarctic coastline in 1986 but soon grounded in the Weddel Sea to become an ice island. The behemoth is 4,000 sq km (1,500 sq miles) in area, more… pic.twitter.com/VR01Gk6B4s
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Dr Andrew Fleming, a remote sensing expert from the British Antarctic Survey, shared insights with the BBC, saying, “I asked a couple of colleagues about this, wondering if there was any possible change in shelf water temperatures that might have provoked it, but the consensus is the time has just come.”
According to glaciologist Oliver Marsh from the British Antarctic Survey, it’s unusual to witness such a massive iceberg in motion, prompting close monitoring by scientists. The iceberg is expected to enter the Antarctic Circumpolar Current, directing it toward the Southern Ocean through “iceberg alley,” where similar giants are commonly found.
The reason for A23a’s sudden movement remains unclear. Marsh suggests it may have slightly thinned over time, gaining enough buoyancy to lift off the ocean floor and be propelled by currents. There’s a possibility it could become grounded again on South Georgia Island, posing a threat to the local wildlife population, including millions of seals, penguins, and seabirds.
According to the Guinness World Records, unlike many large icebergs that detach from Antarctica and float away, A-23a’s movement has been limited. The record for the largest current iceberg frequently changes hands as new icebergs calve off the Antarctic continent and break into smaller fragments. The former record holder, A76, detached from the Ronne Ice Shelf in the Weddell Sea in May 2021 but has since fragmented into three pieces. Consequently, the new record goes back to A-23a.