Did past warm periods see glacial collapse into the East Antarctic Aurora Subglacial Basin? An experiment of geologically constrained modelling.

One of the biggest uncertainties in future global sea level rise is the stability of the East Antarctic Ice Sheet and its response to anthropogenic climate change. However, to understand future glacial retreat, we must consider paleoclimate proxies to inform our models.

In a recent study, Jamieson et al. [2023, Nature Communications] discovered a relic landscape formed by rivers millions of years ago and preserved beneath the East Antarctic Ice Sheet. The existence of this landscape beneath the modern ice sheet in the Aurora Subglacial Basin region can help us constrain past glacial collapse in this region. In this investigation, we use high-resolution model simulations to better understand if the preservation of this landscape precludes significant glacial retreat into the basin in past warm periods, with a focus on the mid-Pliocene. We apply new subglacial topography maps to resolve mesoscale features within the model, and a range of geothermal heat flux maps. We use simulations with different parameterisations of glacial processes such as ocean temperature sensitivity and hydrofracture (driving marine ice cliff instabilities) to assess which processes might have influenced glacial retreat while allowing for the preservation of the relic landscape.