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World’s largest iceberg headed toward warm waters

Satellite view of an irregular chunk with low features on its surface surrounded by dark water and some rippling clouds.
The world’s largest iceberg – known as A23a – is drifting away from Antarctica. The large iceberg had been lodged on the seafloor near the southern continent for decades. Satellites are keeping track of its movements. This is a high-resolution image from the new NOAA-21 satellite taken on December 7, 2023. Image via NOAA-21/ CIRA.

World’s largest iceberg headed to warm waters

The largest iceberg in the world is a behemoth known as A23a. It spans some 40 miles (65 km) across. It’s 1,312 feet (400 m) thick. It calved from Antarctica’s Filchner Ice Shelf decades ago, in August 1986. But almost immediately it grounded on the seafloor, and so was locked in place for decades afterwards. The iceberg had been creeping forward starting in 2020, likely due to melting from below the waterline. And then, in late November 2023, the British Antarctic Survey said the iceberg was officially on the move. It’s currently heading out of the Weddell Sea and will enter into the Southern Atlantic, where, eventually, it’ll melt and disappear.

Space satellites are tracking the movement of the iceberg, including NOAA-21, a new weather satellite that just became operational this year. This satellite circles the globe 14 times a day in a polar orbit. NOAA-21 took the image of the iceberg above on December 7, 2023.

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Iceberg headed toward extinction

As the iceberg enters warmer waters, it’ll undergo melting. Still, with an iceberg that’s almost 1,500 square miles (4,000 sq km), it won’t disappear overnight. About the iceberg’s progress, NASA said:

The berg became unstuck from the seafloor in the early 2020s … Past icebergs in this area eventually … entered the Drake Passage, a turbulent body of water between South America’s Cape Horn and Antarctica’s South Shetland Islands. From there, they typically move north toward the South Atlantic and quickly melt in the region’s warmer waters.

World's largest iceberg: Part of Antarctica in white, with water in blue, and snaky path of iceberg with dates along it.
Weddell Sea near Antarctica and to the edge of the Southern Atlantic.” width=”800″ height=”607″ class=”size-full wp-image-459708″ /> This map shows the track of the world’s largest iceberg and how it has slowly been drifting in the Weddell Sea for the past years. Now it has broken free and is ready to enter warmer waters. Image via NASA Earth Observatory.

Title holder for now

A23a hasn’t always been the title holder for world’s largest iceberg. One of the other icebergs to be crowned “world’s largest” was A-76. In 2021, this large iceberg calved from Antarctica’s Ronne Ice Shelf before breaking up. And before A-76, iceberg A-68 briefly took the title in 2017 before fracturing.

Watch the animation of iceberg A23a below as it moves over the course of a month below cloudy Antarctic skies.

Bottom line: Weather satellites such as NOAA-21 are tracking the movements of the world’s largest iceberg, A23a, which is headed toward the South Atlantic.

December 13, 2023
Today's Image

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