Timescales of Antarctic ice shelf loss via basal crevassing

Alex Bradley, Niall Coffey, Ching-Yao Lai

Antarctic ice-shelves are vulnerable to collapse in a warming climate. However, when this might happen is largely unknown, propagating significant uncertainty into sea-level-rise projections. To constrain this uncertainty, we use fracture modelling to predict the timescales on which crevasses fully penetrate ice-shelves, and consider how these timescales change under future warming. We find that crevassing timescales are highly sensitive to basal-melt-rates, through effects on ice temperature, and ice-shelf strain and thinning rates. High basal-melt-rate ice-shelves have short (10s-100s years) timescales, suggesting vulnerability to crevasse-induced collapse in the coming century, whereas ice-shelves with low basal-melt-rates have extremely long (10,000s years) timescales, suggesting they are presently highly stable. However, these long timescales reduce dramatically with increased basal melting predicted in a warming climate, to 100s years using end-of-century basal-melt-rates from medium-to-high emissions scenarios. These results highlight a previously under-appreciated link between ocean warming and ice-shelf collapse, and suggest that future sea-level-rise from Antarctica is more sensitive to ocean warming than previously understood.