Large-amplitude perturbation experiments to assess the unstable behaviour of AIS in the near future

The stability of the grounding lines of Antarctica is a fundamental question in term of sea level rise The strong mass loss of the Antarctic Ice Sheet (AIS) in recent years has raised concerns about the possibility of the ice sheet reaching a tipping point, beyond which it would experience rapid and irreversible loss of mass. Such a tipping point could be triggered by a combination of external forcing factors, including continued warming of the ocean and atmosphere, as well as changes in ice sheet dynamics. As shown by Urruty et al. (in review), the current mass loss and retreat is mainly due to external forcing such as melt induced by the ocean and current grounding lines are not yet engaged in an unstable retreat. But if forcing remains similar or increases, some irreversible and fast mass loss may occur as a result of grounding lines crossing a tipping point.

As part of the TiPACCs project, we are conducting experiments to evaluate the stability of the grounding lines of the AIS in the future. Building on the stability experiment described in Urruty et al. (in review), we are using the same initial state created with Elmer/Ice to perform a new set of experiments. In these experiments, we are applying large-amplitude perturbations to the grounding line of a steady-state AIS by increasing ocean temperature by 1°C, 3°C, and 5°C for periods ranging from 20 to 100 years in order to push the grounding line far from its current position. After the perturbation is removed, we then apply 80 years of constant forcing to see if an unstable position is reached. These experiments will help us better understand the stability of the grounding line at different positions that could be reached in the near future if current observed forcing trends continue.