What's driving change at the Vanderford Glacier, East Antarctica?

The Aurora Subglacial Basin contains 7 m of global sea level equivalent (SLE). The Totten Glacier is currently the dominant outlet glacier of the Aurora Subglacial Basin; however, neighbouring the Totten Glacier, the smaller Vanderford Glacier drains a region containing 0.67 m of SLE. Vanderford Glacier is the fastest retreating glacier in East Antarctica, with over 18 km of grounding line retreat in the last two decades. The warmest modified circumpolar deep water in East Antarctica has been observed offshore the Vanderford Glacier, highlighting the potential vulnerability of this region to a warming climate. Here, we run transient simulations of the Ice-sheet and Sea-level System Model to examine the sensitivity of the Vanderford Glacier to key drivers of mass loss, namely sub-ice shelf basal melt and ice-front retreat. Simulations show that grounding line retreat is more sensitive to changes in basal melt than ice-front retreat, except for scenarios of extreme ice-front retreat. We show that the rate and extent of grounding line retreat comparable with observations only occurs under high magnitude basal melt conditions, while a similar extent of grounding line retreat occurs under the extreme ice-front retreat scenarios, but the temporal response of the grounding line is lagged. Given that grounding line retreat similar to observations is only achieved with basal melt magnitudes far exceeding those indicated by satellite remote sensing, our results highlight the need for methods to better estimate basal melt in this vulnerable region.