A screengrab taken last Friday from a video released by the British Antarctic Survey shows the rift in the Larsen C Ice Shelf, on the Antarctic Peninsula, in February this year.
Last week, a 5,800 sq km iceberg - more than eight times the size of Singapore - calved from the ice shelf, producing one of the largest icebergs ever recorded, and providing a glimpse of how the Antarctic ice sheet might ultimately start to fall apart.
Larsen C, like two smaller ice shelves that collapsed before it, was holding back relatively little land ice, and it is not expected to contribute much to the rise of the sea.
But in other parts of Antarctica, similar shelves are holding back enormous amounts of ice, and scientists fear that their future collapse could dump enough ice into the ocean to raise the sea level by many feet. How fast this could happen is unclear.
NYTIMES
