Question: Is it possible for a big area of ice shelf to break off Antarctica and stay complete for a long time?

James Pope answered on 10 Mar 2015:

Hi SClark,

Awesome question. I have done some reading on this question because I wasn’t entirely sure of the answer. The biggest iceberg I can find to have been observed calving (breaking) off Antarctica was the catchily named B-22. It was 64km long and 85 km wide, a total of 5,440 square kilometres, or about 1/4 the size of Wales!

It came from the Thwaites Glacier in the Admundsen Sea in 2002, about a week after the collapse of the Larsen B Ice Shelf (just 3,250 square kilometres of ice there….)

The type of break that occurs determines what happens next. The Larsen B Ice shelf during its collapse disintegrated into hundreds to thousands of smaller icebergs, but B-22 stayed complete and joined a group of icebergs from that region slowly drifting up the Antarctic Peninsula.

Around Antarctica, because there is no land barriers, a series of strong winds and ocean currents (called the Antarctic Circumpolar Current) flows anti-clockwise around Antarctica. All the icebergs are inside this current, so they never escape beyond the edge of Antarctica, about 60 degrees South. They float about in the seas near Antarctica slowly melting like ice cubes in a glass but looking so much more beautiful as these images show:

https://maptia.com/alexcornell/stories/rare-flipped-iceberg

No one is entirely sure how long they last, but probably for big ones about 5-10 years maximum.

Hope this answers your question