[chris (OP)]

Someone called in to the Question and Answer science phone-in radio programme this morning and asked about the giant iceberg that broke off from Antarctica recently. I had to admit that I'd not been following the story. What is the latest on it?

[jeffreyH]

It isn't of that much concern in the scheme of things. It had been breaking away for some time.

It is from the Larsen C ice shelf. I believe A and B have already gone.
http://www.bbc.co.uk/news/science-environment-40321674

[Colin2B]

Short answer is "it broke off".
Not surprised you haven't been following the story, it has beeen somewhat slow moving compared to other - even more boring - news.
It has taken years for the crack to develop, but now it have finally broken off it has become one of the largest  icebergs ever - quarter size of Wales according to some. Not the biggest ever apparently, but could sink quite a few Titanics. At one trillion tonnes it is about half the size of the largest recorded.
I wonder if anyone will write a song about how many Albert Halls it could fill?

[jeffreyH]

Interactive landsat imaging of Antarctica is available from USGS.
https://lima.usgs.gov/

Attached is a map showing the positions of the various ice shelves. Larsen C is indicated by the blue arrow.

[evan_au]

Because it was already floating, it won't raise sea levels directly.

But it has been seen in other cases that when the floating ice-shelf disintegrates, land-based glaciers now find a free opening to the sea, and speed up. This will raise sea levels.

This particular iceberg is only a small part of this particular ice shelf, but if warming continues, more of it could break away in later years, just as it did for the Larsen A & B ice shelves which extended farther from the South Pole.

See: https://en.wikipedia.org/wiki/Larsen_Ice_Shelf#Larsen_C

[chris (OP)]

Thanks; where's it headed?

[chiralSPO]

Because it was already floating, it won't raise sea levels directly.

But it has been seen in other cases that when the floating ice-shelf disintegrates, land-based glaciers now find a free opening to the sea, and speed up. This will raise sea levels.

Yes you can think of it as a stopper in a bottle. Having popped off, the glaciers behind are free to flow into the sea (only at a glacial speed though)