Iceberg 5x the Size of Manhattan Breaks Off Pine Island Glacier

The Pine Island Glacier, the fastest-retreating glacier in Antarctica, lost another massive chunk of ice earlier this week.

A 115-square-mile section calved off the ice shelf on Oct. 29. That’s roughly the five times the size of Manhattan.

The piece was expected to take weeks or months to break off after the first cracks were observed about a month ago, according to Stef Lhermitte, an assistant professor in the Department of Geoscience and Remote Sensing at Delft University of Technology in the Netherlands.

But “I was a bit surprised” it broke off that quickly, he told Live Science. “It turned out to be on the quick side.”

This GIF of satellite imagery shows just how rapidly the rift across Pine Island Glacier, also known as PIG, was formed.

In early 2000 large PIG calving events happened every ~5 yrs (2001, 2007, 2011), but since 2013 there were 4 of them (2013, 2015, 2017, 2018). Consequently, the glacier front retreated strongly from the 1972-2013 range and it is now ~5km further inland than in 2015-2017 2/2 pic.twitter.com/8O7gPyQAmh

— Stef Lhermitte (@StefLhermitte) October 30, 2018

The newly formed iceberg eventually broke into smaller pieces. “Iceberg B-46 did not live very long, as it already fragmented in several pieces today, one day after calving from Pine Island Glacier,” Lhermitte tweeted Tuesday.

PIG is the fastest shrinking on the planet and is contributing to sea level rise faster than any other glacier, according to the iSTAR science program, which works to understand the stability of the West Antarctic Ice Sheet.

Lhermitte explained that large PIG calving events used to occur about every five years (2001, 2007, 2011), but four events have occurred in recent years ( 2013, 2015, 2017, 2018). The largest calving event was in July 2013, when a section roughly eight times the size of Manhattan of PIG’s ice shelf sloughed away.

Scientists are not completely sure why the region’s melting has accelerated, but it could be attributed to the region’s increasingly warmer waters melting the ice shelf from below.

“That depends on climate, but this warm water getting there is also driven by how the wind patterns change,” Lhermitte told LiveScience. “It’s very difficult to say that this is climate change because we’re still figuring out how it all works.”

Comparison of the 2018 Pine Island Glacier calving front with historical 1973-2011 data by @JoeMacGregor shows how much PIG has retreated from the 1973-2013 range. pic.twitter.com/ifxmk85hMo

— Stef Lhermitte (@StefLhermitte) October 30, 2018