EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Antarctic Ice Sheet tipping points in the last 800,000 years

David Chandler1, Petra Langebroek1, Ronja Reese2, Torsten Albrecht3, and Ricarda Winkelmann3
David Chandler et al.
  • 1NORCE Norwegian Research Centre and Bjerknes Centre for Climate Research, Bergen, Norway (
  • 2Department of Geography and Environmental Sciences, Northumbria University, Newcastle, UK
  • 3Potsdam Institute for Climate Impact Research (PIK), Potsdam, Germany

Stability of the Antarctic Ice Sheet in the present-day climate, and in future warming scenarios, is of growing concern as increasing evidence points towards the prospect of irreversible ice loss from the West Antarctica Ice Sheet (WAIS) with little or no warming above present. Here, in transient ice sheet simulations for the last 800,000 years (9 glacial-interglacial cycles), we find evidence for strong hysteresis between ice volume and ocean temperature forcing through each glacial cycle, driven by rapid WAIS collapse and slow recovery. Additional equilibrium simulations at several climate states show this hysteresis does not arise solely from the long ice sheet response time, instead pointing to consistent tipping-point behaviour in the WAIS. Importantly, WAIS collapse is triggered when continental shelf bottom water is maintained above a threshold of 0 to 0.25°C above present, and there are no stable states for the WAIS in conditions warmer than present. Short excursions to warmer temperatures (marine isotope stage 7) may not initiate collapse (‘borrowed time’), while the more sustained interglacials (stages 11, 9, 5e) demonstrate an eventual WAIS collapse. Cooling of ca. 2°C below present-day is then required to initiate recovery. Despite the differing climatic characteristics of each glacial cycle, consistency between both the transient and equilibrium behaviour of the ice sheet through several cycles shows there is some intrinsic predictability at millennial time scales, supporting the use of Pleistocene ice sheet simulations and geological evidence as constraints on likely future behaviour.

How to cite: Chandler, D., Langebroek, P., Reese, R., Albrecht, T., and Winkelmann, R.: Antarctic Ice Sheet tipping points in the last 800,000 years, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-8341,, 2023.