World's Largest Iceberg Is Finally on the Move

A23a was stuck on seafloor near Antarctica for decades
By Rob Quinn,  Newser Staff
Posted Nov 25, 2023 3:15 PM CST
After Almost 40 Years, World's Biggest Iceberg Is Moving North
This images provided by Maxar Technologies shows the A23a iceberg moving through the sea near Antarctica on Wednesday Nov. 15, 2023.   (Satellite image 2023 Maxar Technologies via AP)

An iceberg bigger than some small countries has broken loose from the floor of Antarctica's Weddell Sea and is on the move for the first time in nearly 40 years. At almost 1,500 square miles in area—twice as big as New York City and Los Angeles combined—A23a is the world's biggest current iceberg, a title it's had held multiple times since it calved from the Filchner-Ronne ice shelf, CNN reports. It became stuck on the seafloor almost immediately but is now drifting due to what scientists believe is part of a natural cycle, not the result of climate change.

Dr. Andrew Fleming, a British Antarctic Survey remote sensing expert, tells the BBC he asked colleagues "if there was any possible change in shelf water temperatures that might have provoked it, but the consensus is the time had just come." He says he first detected signs of movement in 2020. Strong winds and currents have now pushed A23a past the tip of the Antarctic peninsula, and the Antarctic Circumpolar Current is expected to push into "iceberg alley" in the Southern Ocean, Reuters reports. The iceberg is around 1,300 feet thick, big enough to embed the Empire State Building in it with room to spare.

Researchers say there's a chance it could get stuck again near the island of South Georgia, where its enormous size could cause problems for wildlife by blocking foraging routes. But A23a's journey will benefit the environment, the BBC reports. When it melts, mineral dust in its ice will provide nutrients for ocean food chains. "In many ways these icebergs are life-giving; they are the origin point for a lot of biological activity," says Dr. Catherine Walker, a scientist at the Woods Hole Oceanographic Institution. She was born in the same year as A23a. "I identify with it; it's always been there for me," she says. (More Iceberg stories.)

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