Alexander Thomas Bradley, Jan De Rydt, David T Bett, Pierre Dutrieux, Paul R Holland

Sea level rise contributions from Pine Island Glacier (PIG) are strongly modulated by the backstress that its floating extension – Pine Island Ice Shelf (PIIS) – exerts on the adjoining grounded ice. The front of PIIS has recently retreated significantly via calving, and satellite and theoretical analyses have suggested further retreat is inevitable. As well as inducing an instantaneous increase in ice flow, retreat of the PIIS front may result in in- creased ocean melting, by relaxing the topographic barrier to warm ocean water that is currently provided by a prominent seabed ridge. Recently published research (Bradley and others, 2022a) has shown that PIIS may exhibit a strong melting response to calving, with melting close to the PIG grounding line always increasing with ice front retreat. Here, we summarize this research and, additionally, place the results in a glaciological context by comparing the impact of melt-induced and ice-dynamical changes in the ice shelf thinning rate. We find that PIG is expected to experience rapid acceleration in re- sponse to further ice front retreat and that the mean instantaneous thinning response is dominated by changes in melting rather than ice dynamics. Over- all, further ice front retreat is expected to lead to enhanced ice-shelf thinning, with potentially detrimental consequences for ice shelf stability.