Watch a 20-Mile Long Iceberg Drift Into the Southern Ocean

What's This?

A close-up of the rift that opened up across the Pine Island Glacier in 2011.

Image: NASA

By Andrew Freedman2014-04-25 16:01:04 UTC

Ever since a massive crack was discovered in Antarctica's Pine Island Glacier in 2011, NASA researchers and other scientists have kept a close watch on this area. The crack cleaved off an iceberg, now known as "Ice Island B31," which broke off from the glacier in November 2013, and has since been drifting across Pine Island Bay, a basin of the Amundsen Sea, toward the Southern Ocean.

According to the NASA's Earth Observatory, the ice island "will likely be swept up soon in the swift currents of the Southern Ocean..."

See also: West Antarctic Glaciers Speeding Toward the Sea, Study Finds

During the five-month-long Antarctic spring and summer, an instrument called the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra and Aqua satellites captured a series of images showing the movement if the ice island. NASA recently released a time-lapse video of these images, showing the journey of this massive chunk of ice:

The ice island is much larger than your ordinary iceberg. Earlier this month, the U.S. National Ice Center, which tracks icebergs in order to alert ships of their presence, reported that B31 was 20.5 miles long and 12.4 miles wide. Scientists estimated its thickness to be about 1,640 feet thick.

While such a massive ice island breaking off from an Antarctic ice sheet might seem like a sign of a coming global warming apocalypse, scientists aren't yet sure how significant this event is. “Iceberg calving is a very normal process,” said Kelly Brunt, a glaciologist at NASA’s Goddard Space Flight Center, in a NASA news story.

However, the crack that created this iceberg was well inland from the calving front of the Pine Island Glacier, which could indicate a new, more rapid era of ice melt. This would be ominous news, considering that the melting of land-based ice sheets, such as Antarctica and Greenland, already constitutes the largest contributor to global sea level rise.

A NASA satellite photograph showing the ice island, B31, drifting toward the Southern Ocean as of March 2014.

Studies have shown that the Pine Island Glacier, in particular, has been flowing into the sea much faster than it used to. A study published in March, for example, showed that the West Antarctic ice sheet, which the Pine Island Glacier is a part of, have been shedding ice at an accelerating rate, with six large glaciers in this region discharging nearly the same amount of ice as the entire Greenland ice sheet.

The study examined glaciers in the Amundsen Sea Embayment of West Antarctica, which includes the Pine Island Glacier as well as the

Thwaites, Haynes, Smith, Pope and Kohler glaciers, each of which are behemoths in their own right.

In that study, a research team from the University of California at Irvine and NASA found that the total amount of ice coming off these glaciers has increased by 77 percent since 1973, with much of that increase coming since 2000. Together, these glaciers drain one-third of the West Antarctic Ice Sheet, or about 158 million square miles of ice, the study said.

The study also found, for the first time, that West Antarctic glaciers are not only flowing faster at the point where their base meets the ocean, which is known as the grounding line. Additionally, areas as far inland as nearly 160 miles are also speeding up their march to the sea.

Video showing melting process of the Pine Island Glacier, from the European Space Agency.

In the same way that plaque slowly rots a tooth until it falls out, mild ocean temperatures are thought to be causing ice to thin and retreat at the grounding line, where these glaciers meet the sea. This is likely setting in motion a chain of events that results in a far more unstable glacier.

Illustrating the high stakes involved in the fate of West Antarctica, the study found that these six glaciers contributed about 10% of all the global average sea level rise that occurred between 2005 and 2010. If all six glaciers were to melt completely (which is not expected to happen during this century), global average sea level would rise by a catastrophic 3.9 feet, the study said.

As Discover Magazine reported, if the entire West Antarctic Ice Sheet were to melt, sea level would rise by 10 feet or more. This would affect more than 100 million people, the magazine said on its http://ift.tt/QLKSWk blog.

Have something to add to this story? Share it in the comments.

Topics: Antarctica, Climate, glacier, iceberg, sea ice, sea level rise, US & World, World