Impacts of recent calving events on upstream flow of Pine Island Glacier and modelling of potential future scenarios

<p>Several calving events have recently occurred on the ice shelf of Pine Island Glacier, which have lead to significant retreat of the ice front by several km. Here we investigate the impact of the 2017 and 2020 calving events on upstream flow and on ice-flux across the grounding line, and quantify the impacts of potential future calving events of similar size. Using the &#218;a ice-sheet model, we conduct series of inversions for ice rheological parameters and basal sliding conditions prior to observed calving events, and then deactivate areas lost. In general agreement with Joughin et al (2021), we find that the calving events had the potential to cause changes in upstream velocity of similar magnitude as observed. Nevertheless, it appears that at least some of the observed velocity changes may equally be ascribed to modifications over time in the structural rigidity of the ice-shelf margins, which in our numerical simulations is reflected in significant changes over time in inverse estimates of ice-rheology parameters in those areas. For simulations of the near-future response of Pine Island Glacier to similar-sized calving events it can be argued that any distinction between loss of buttressing due to near-front marginal weakening and calving may be immaterial, as both processes appear to happen in tandem, and both lead to similar loss of ice-shelf buttressing.&#160;</p>