Early warning signals and tipping behaviour in Greenland’s glacier periphery from large forcing ensembles

The cryosphere is considered a potential tipping element of the Earth system, yet identifying critical thresholds and early warning signals remains challenging due to the computational cost of high-complexity ice-sheet models. Here, we investigate tipping behaviour in the glacier periphery of Greenland using the Open Global Glacier Model (OGGM), exploiting its efficiency to explore a wide range of climate forcing scenarios.

We perform a large ensemble of simulations driven by (i) standard future climate scenarios up to 2100, (ii) scenario-neutral climate trajectories, and (iii) additional physically realistic and idealized forcing experiments. This ensemble approach enables systematic exploration of glacier responses across a broad forcing space, including regimes not typically sampled by comprehensive ice-sheet models. We analyze the resulting time series of glacier volume, area and mass balance for early warning signals of critical transitions, focusing on indicators of critical slowing down such as increasing variance and autocorrelation.

By comparing the emergence and robustness of these signals across forcing types, we assess whether abrupt and potentially irreversible retreat of peripheral Greenland glaciers is preceded by detectable changes in system dynamics. We further identify climatic thresholds and boundary conditions under which tipping-like behaviour is most likely to occur.

Our results aim to provide physically grounded constraints on critical forcing levels relevant to Greenland’s glacier periphery and to inform ice-sheet modelling efforts by highlighting regions of parameter space where nonlinear responses are expected. This work demonstrates the value of intermediate-complexity glacier models for advancing the detection and interpretation of tipping points and early warning signals in the cryosphere.