Does marine ice-cliff instability operate on real ice sheets?
In plain words
If an ice shelf breaks off, it may leave a tall ice cliff at the ocean edge that collapses under its own weight, exposing an even taller cliff behind it. Whether this runaway collapse really happens decides how fast Antarctica could add to sea level.
Precise statement
Determine whether ice cliffs with subaerial height above about 100 m fail faster than ice flow can replace them, producing self-sustained retreat into deepening basins, and whether this marine ice-cliff instability (MICI) is required to explain past sea-level highstands. An answer is a validated calving law for tall cliffs, including brittle and viscous failure and buttressing by melange (a mix of icebergs and sea ice), applied to Thwaites-type geometries.
What would settle it
Observations of cliff failure rates at tall calving fronts (for example Jakobshavn and Thwaites) matched by fracture-mechanics models and reproduced in paleo sea-level constraints.
Status in the literature
Unverified note
Morlighem et al. 2024 (Science Advances) found Thwaites unlikely to undergo MICI this century because ice-flow thinning lowers cliff heights.