4 Major Calvings From Pine Island Glacier Since 2013; Another Coming Soon - British Antarctic Survey

A close-up view of the rift separating Pine Island Glacier and iceberg B-46, as seen on an Operation IceBridge flight on November 7, 2018. NASA/ Brooke Medley

Down in the notoriously vulnerable ice sheet of West Antarctica, Pine Island Glacier seems to be breaking up faster than ever, and it’s looking like 2019 might be another busy year. The ice shelf calved major icebergs in 2013, 2015, 2017, and 2018—and now, another one is getting ready to break free.

The instability of this glacier is not just bad for the southernmost continent. It is bad for the globe. This glacier is contributing more to sea level rise than any other in Antarctica. New research has shown that since 1979, Pine Island Glacier has lost 58 billion tons of ice per year, which makes it the biggest loser of the continent. Combined with its unstable neighbor, Thwaites Glacier, these glaciers are contributing one millimeter per decade to global sea level rise.

While large ice masses can appear solid, they are actually complicated, dynamically flowing systems. Miles-thick glaciers sit on the Antarctic continent as their ice slowly flows out to sea, creating a floating ice shelf that can calve icebergs. While this movement is a normal process, the frequent calving of icebergs and glacial landward retreat can indicate something out of the ordinary is happening. As the floating ice shelves retreat and shrink, the pressure on the land-based glacier gets relieved, allowing it to flow faster towards the ocean where it can then melt and cause sea level rise.

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In December 2018, Robert Larter, a marine geophysicist from the British Antarctic Survey, pointed out on Twitter that the Sentinel-1 satellite clearly captured an actively forming rift only weeks after B-46 calved. “There is a fair chance we will see another calving event this year,” says Larter in early 2019. “You can see the fragments [in the satellite images] of the previous icebergs haven’t gone very far, so now there are a lot of icebergs stored up to come out of Pine Island Bay.” Stef Lhermitte, an assistant professor of geoscience and remote sensing at Delft University of Technology, agrees: “We expect this new rift to result in a major calving event in weeks, months, or in maximum one-and-a-half years.”


Over the years, the calving front has moved drastically landward. Stef Lhermitte

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https://www.atlasobscura.com/articles/what-is-pine-island-glacier