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An Iceberg Eight Times the Size of Manhattan Finally Split from Antarctica

While the new iceberg, which is as big as a large city, is certainly a behemoth, it's far from the largest ever.
The rift between the Pine Island Glacier and the newly formed iceberg maxed out at around 50 meters wide before the iceberg split off. Photo: NASA

Back in October, 2011, NASA scientists first noticed a large crack forming in the Pine Island Glacier in West Antarctica, and it's grown ever since. On Monday, the growth reached its natural end, creating a massive iceberg approximately eight times the size of the island of Manhattan, which is now floating in the Amundsen Sea.

The new iceberg is 720 square kilometers (278 square miles) in area.

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The new iceberg is shown on the left side of this satellite image, via DLR

Nina Wilkens of the Alfred Wegener Institute, which first documented the calving via satellite, said, "The larger crack on the Pine Island Glacier extended initially to a length of 28 kilometers. Shortly before the birth of the iceberg, the gap then widened bit by bit so that it measured about 540 kilometers at its widest point."

As for the connection to climate change, AWI Professor Angelika Humbert is cautious, noting that "creation of cracks in the ice shelf and the development of new icebergs are natural processes." However, Humbert says that the Pine Island Glacier is the fastest moving glacier in Antarctica, moving four kilometers a year from the Hudson mountains to the sea.

This remarkable speed is aided by changes in wind direction that have now occurred in the Amundsen Sea. New wind patterns now bring warm sea water under the region's main ice shelf, which melts it from below.

The position of the Pine Island Glacier, via AWI

The Pine Island Glacier is part of an ice shelf that is 200 to 1200 meters thick, extending from the land of West Antarctica into the ocean, where the ice extends to a depth of up to 4000 meters. Interestingly, large areas of West Antarctica are actually below sea level.

Humbert noted that because of these geographically conditions, "The danger therefore exists that these large ice masses will become unstable and will start to slide." At some future point, should the entire West Antarctic ice shield flow into the ocean, it alone would contribute an additional 3.3 meters to the rising global sea level.

Should the Pine Island Glacier itself melt entirely, something which could happen if the nearby Thwaite's Glacier also retreats, it would contribute roughly half a meter to sea level rise.

While the new iceberg, which is as big as a large city, is certainly a behemoth, it's far from the largest ever. In 2001, a section of the Ross Ice Shelf broke off, creating an iceberg 11,000 square kilometers (4,247 square miles) in size.