Pine Island Glacier calved three new icebergs.

"Again and again, ... research has confirmed how Antarctica evolves in the future will depend on human greenhouse gas emissions." Twila Moon at the NSIDC

Worrisome imagery in the Arctic Sea Ice Forum reveals three calving events in mid-October at Pine Island Glacier South Western Tributary was posted in the  Arctic Sea Ice Forum. 

West Antarctica’s Pine Island Glacier ( P.I.G.) is one of the fastest-flowing ice streams in Antarctica. It is the neighboring glacier to Thwaites, a/k/a the Doomsday Glacier (due to the likely possibility that the glacier collapse would take the entirety of the West Antarctic with it).

Thwaites holds two feet of sea level rise if it were to melt completely. PIG has one and a half feet. Both glaciers are in the Amundsen Sea Embayment of the highly vulnerable West Antarctic, which holds a whopping ten feet of sea level rise. 

Sea Ice Forum blogger Stephan posted the image below.

Updated data is complex and challenging to come by with West and East Antarctica. The World Economic Forum in 2020 shared writing by Olivia Rosane of Ecowatch.  She noted that Pine Island Glacier had lost 25 percent of its ice shelf, which has the crucial role of holding back the ice stream from flowing quickly into the sea.

These glaciers have attracted attention in recent decades as their ice shelves thinned because warmer ocean currents melted the ice’s underside. From the 1990s to 2009, Pine Island Glacier’s motion toward the sea accelerated from 2.5 kilometers per year to 4 kilometers per year (1.5 miles per year to 2.5 miles per year). The glacier’s speed then stabilized for almost a decade.

Results show that what’s happened more recently is a different process, Joughin said, related to internal forces on the glacier.

From 2017 to 2020, Pine Island’s ice shelf lost one-fifth of its area in a few dramatic breaks that were captured by the Copernicus Sentinel-1 satellites, operated by the European Space Agency on behalf of the European Union. The researchers analyzed images from January 2015 to March 2020 and found that the recent changes on the ice shelf were not caused by processes directly related to ocean melting.

“The ice shelf appears to be ripping itself apart due to the glacier’s acceleration in the past decade or two,” Joughin said.

The significant breaks mentioned have appeared to have changed to a crumbling at the calving front over the past few years. Today, Pine Islands' large icebergs break up almost immediately into smaller pieces. 

The smaller pieces do not get named. They need to be at least 500 square miles. 

Instead:

Smaller pieces of ice are known as ‘growlers’ or ‘bergy bits.’ They can originate from ice shelves or glaciers but can also come from an iceberg that has broken into pieces.

Knut Christianson, a glaciologist at the University of Washington in Seattle, comments were highlighted in a media presser: excerpts from my diary in 2020. Antarctica's Pine Island Glacier has yet another major calving event.

Knut Christianson, a glaciologist at the University of Washington in Seattle who studies Pine Island, told the Post that calving is normal and to be expected, but the "mode of calving of Pine Island Glacier appears to be shifting.”

Like Howat, Christianson suggests that calving from the interior of the glacier from warmer waters undermining the glacier's base indicates that more frequent calving will occur.

“This results in smaller but more-frequent calving events,” he continued. “The persistence and net effect of this shift in calving behavior has yet to be determined as it has only occurred during the past two years, but it clearly merits continued observation.”

Saturday's calving comes just 2 months after the largest ever-recorded iceberg broke from Antarctica's Larsen C ice shelf.

Warm ocean water is eating the glacier's underbelly in the Arctic and the Antarctic, thinning them with cheeseification and fractures, softening them for calving. The ice dynamics are changing, and we all should be concerned about the consequences.

The Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research explains the grim news on why this is happening to Pine Island - Why the tongue of the Pine Island Glacier suddenly shrank.

When an ice shelf loses contact with such obstacles (known as "pinning points"), the ice stream reacts as if someone had suddenly released a giant brake. With nothing left to stop them, the ice masses rapidly flow out to sea -- at least that's the theory. Using the time series of satellite images for the Pine Island Glacier, the researchers were now able to test this thesis step by step.

Note the crumbling beginning around 2015 in the embed from climate activist Go Green. At that time, the fast ice on either flank eroded and collapsed due to the PIG ice stream rapidly accelerating. The change was spotted for the first time since satellite records began. PIG now cracks and crumbles in the center rather than at the flanks as it did pre-2015.

With a flow speed of four kilometres per year, Western Antarctica's Pine Island Glacier is one of the fastest-flowing ice streams in the Southern Hemisphere. Together with its neighbouring glaciers, every year the up to 50-kilometre-wide ice stream transports more than 300 gigatonnes of ice from the hinterland to the Amundsen Sea, and is responsible for between five and ten percent of the global sea-level rise. Scientists have already identified the cause of this rapid loss of ice: since the 1940s, warm water masses, which branch off from the Antarctic Circumpolar Current, have found their way beneath the floating part of the glacier, melting what is referred to as its ice shelf from below. As a result, the ice tongue, which is currently ca. 55 kilometres long, has been losing roughly 5.3 metres of thickness per year for the past quarter-century.

That being said, what remained unclear was why, despite this sustained melting, the Pine Island Glacier's calving front had barely retreated since the beginning of observation in 1947. Then in 2015, a calving event shifted the edge of the ice shelf 20 kilometres nearer the coast and reduced the floating ice tongue's total area to roughly 470 square kilometres.

"The direction and speed of a given glacier's flow chiefly depend on the topography of the ground below it. But for most of the ice shelves in the Antarctic, we know very little about the features of the underlying seafloor. As such, our Polarstern expedition in February 2017 was an unprecedented opportunity to map 370 square kilometres of an area that had previously largely been covered by the Pine Island Glacier's ice shelf," explains first author Dr Jan Erik Arndt from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) in Bremerhaven. With the aid of multibeam echosounders, Arndt and his colleagues were able to precisely map the seafloor.

I call the above phenomenon stretching; it sounds less harsh than being ripped apart.