Next Ice Shelf Collapse

[icefest]

I know there are many scenarios and many variables, but answer this as if GHG emmisions follow what you expect to be a realistic scenario. (Excluding any future deus ex machina)

Which ice shelf would you expect to collapse next?

[Gray-Wolf]

I've been watching a large fissure on Ross this past 9 years. The Yanks are also interested in it as when I approached Prof Grumbine he told me they were in the process of installing earth quake seismometers into the crevasse so as to have early warning of any major shifts in the section of the shelf.

The feature runs from Roosevelt Island to the middle of the shelf and so any calve would be humongous ( the ice cliffs there stand 200ft out of the sea there and is grounded on the sea bed below), much larger, and deeper into the shelf, than the 80's calve.

The worry here is that this shelf ( the size of France) is now known to have collapsed in past climate warmings. It holds back the majority of drain glaciers from E.A.I.S. so we would not only see instant sea level rise from the melt of the grounded shelf but also from the loss of the buttress to those drain glaciers. We know what happens when we lose a shelf from seeing the impacts across the Peninsula.

Early radar plots , from the early noughties , spotted a 'ruck' in the ice shelf. This lays testament to the time the ice shelf grounded itself and resisted the flow from behind ( allowing the ice to ride over itself until the new equilibrium was found. Will this feature still hold potential energy ( like a coiled spring?) ready to unleashed forward movement once the ice front has receded sufficiently?

[AbruptSLR]

icefest,

I think that the Larsen C Ice Shelf will collapse within the next three to five years, and that the Pine Island Ice Shelf will have a major calving event within the next five to eight years (but that it will not completely collapse), and I think that the current Thwaites Eastern Ice Shelf will largely collapse within the next fifteen years (but that as the Thwaites grounding line retreats some new residual ice shelf will form there).  I make other projections about the Filchner Ronne Ice Shelf and the Ross Ice Shelf in the Antarctic folder.

Best,
ASLR

[johnm33]

Other candidates, though somewhat smaller, are those between about 5 and 25 deg west.

[pikaia]

I think that the Larsen C Ice Shelf will collapse within the next three to five years, and that the Pine Island Ice Shelf will have a major calving event within the next five to eight years (but that it will not completely collapse), and I think that the current Thwaites Eastern Ice Shelf will largely collapse within the next fifteen years (but that as the Thwaites grounding line retreats some new residual ice shelf will form there).  I make other projections about the Filchner Ronne Ice Shelf and the Ross Ice Shelf in the Antarctic folder.

Would any of these collapses have any effect on sea levels?

[AbruptSLR]

pikaia,

As ice shelves are floating, when they collapse, they themselves do not contribute to sea level rise, SLR; however, all of these ice shelves buttress grounded glaciers which would experience accelerated ice flows if/when the ice shelves collapse; and it is the accelerated ice mass loss from the grounded glaciers that would contribute to accelerated SLR.

Therefore, the answer to your question is: Yes, SLR would accelerate if any one (or all) of these ice shelves collapse, but it is currently uncertain how fast this increase contribution to SLR would occur.  For example the Pine Island Ice Shelf, PIIS, buttresses the Pine Island Glacier, PIG, and if all of PIG would to be lost then sea level would be raised by over 0.3 m (1-ft), while if all of Thwaites Glacier were to be lost sea level would raise by over 0.6 m (2-ft); but again it is not know if that would happen by 2100, or by 2500.

Best,
ASLR