In Earth’s far northern and southern oceans, glaciers are a common occurrence. But the recent halving of an iceberg more than six times bigger than Manhattan Island has caught the attention of scientists, including those at NASA. The roughly 255 square mile chunk of ice, known as B31, broke off of Antarctica’s Pine Island Glacier in November 2013.
As B31, up to a third of a mile thick in places, makes its way into the open ocean, US government organizations and other scientific groups have begun to monitor its movement.
“It’s one that’s large enough that it warrants monitoring,” NASA glaciologist Kelly Brunt said via telephone conference on Wednesday, 23 April 2014. “There’s a lot of shipping traffic down there. We’re not particularly concerned about shipping lanes. We know where the big [icebergs] are.” Brunt noted that the National Ice Center and other organizations keep track of dozens of icebergs in the polar regions.
NASA observers say the iceberg has floated across Pine Island Bay in the Amundsen Sea. “We are doing some research on local ocean currents to try to explain the motion properly,” said iceberg researcher Grant Bigg, of the UK’s University of Sheffield, in a statement from NASA Earth Observatory. “It has been surprising how there have been periods of almost no motion, interspersed with rapid flow.
“There were a couple of occasions early on when there might have been partial grounding or collisions with the sea floor, as B31 bounced from one side of the bay to the other,” Biggs stated.
Scientists expect that the massive iceberg will likely be swept up in the swift currents of the Southern Ocean.
Brunt noted that it’s not just the size of the iceberg, but also the unexpected location from whence it originated that has scientists especially interested. Pine Island Glacier has been a subject of close scrutiny for over twenty years, as it has been thinning and draining rapidly. Scientists speculate that this particular glacier may be an important contributor to rising sea levels. The glacial crack that eventually created the iceberg was first spotted in 2011, Brunt said.