Gizmodo contacted Christopher A. Shuman, a research scientist within the Cryospheric Sciences Laboratory at NASA Goddard Space Flight Center, who confirmed the break using the MODIS and Landsat 8 satellites.


The area drained by PIG encompasses approximately 10 percent of the West Antarctic Ice Sheet, making it a critically important geological feature in terms of its contribution to sea level rise. This is now the third major calving event produced by this ice stream in four years, the others happening in 2013 (252 square miles/652 sq km) and 2015 (225 square miles/582 sq km).

“But it isn’t the size of the bergs that are the main issue,” Shuman told Gizmodo. “It is the overall progressive retreat of the ice front with calving losses in 2013, 2015, and 2017, which is pretty rapid retreat for any very large glacier especially one this far south in Antarctica. With the first big loss in 2001, this is not a good sign for sure.” To which he added: “This is not as large a loss as in 2013 but it is a further retreat from what was a pretty stable ice front in at the beginning of this century.”


Shuman also confirmed that the rifts are forming in the center of the glacier and extending out toward the edges. This means that the rifts are forming far inland, likely the result of warm ocean water rubbing against the base of the glacier. This may explain why the calving events are happening with increased frequency (the speed of the glacier’s flow towards the sea is increasing, and it’s now moving at about 2.5 miles (4 km) per year), and why PIG appears to be thinning (the rate of thinning has quadrupled since the mid 1990s). If this current rate of thinning continues, the entire main trunk of the glacier could be afloat in about 100 years.

The West Antarctic ice sheet is separated from the ocean by a series of large glaciers, PIG included. These glaciers are holding back tremendous volumes of ice, but as this recent calving event demonstrates, perhaps for not much longer.