Rapid fragmentation of Thwaites Eastern Ice Shelf

Abstract. Ice shelves play a key role in the dynamics of marine ice sheets by buttressing grounded and limiting rates flux to oceans. In response recent climatic oceanic change, fringing West Antarctic Sheet (WAIS) have begun fragment retreat, with major implications for ice-sheet stability. Here, we focus on Thwaites Eastern Shelf (TEIS), remaining pinned floating extension Glacier. We show that TEIS has undergone process fragmentation last 5 years, including brittle failure along shear zone, formation tensile cracks main body shelf, release tabular bergs both eastern western flanks. Simulations Helsinki Discrete Element Model (HiDEM) this pattern is associated high backstress from submarine pinning point at distal edge shelf. significant zone shear, upstream point, developed rapid acceleration shelf between 2002 2006, seeding damage Subsequently, basal melting positive feedback strain weakened TEIS, allowing accumulate. Thus, although likely diminished over time as shrunk, accumulation ensured remained weakest link system. Experiments BISICLES model indicate additional or unpinning unlikely trigger significantly increased loss WAIS, but calving remains highly uncertain. It widely recognised ice-shelf collapse can be triggered hydrofracturing and/or margins grounding points. Our results third mechanism, failure, occur if when an no longer able withstand stress imposed most circumstances, points are essential stability, thin weaken, concentration damaged may provide seeds their demise.