Abstract
Inferences of climate and ice-sheet change through geological time rely on paleoenviron- mental proxies, such as oxygen isotope records or sedimentary sequences. Yet the ac- curacy of such inferences depends on the presumed constancy of the climate forcing–ice- sheet response relationship. Here we use an ensemble of 500-kyr long ice sheet simulations to show that the directionality of change in ice volume, extent, and calving flux is depen- dent on the background state of the climate. We demonstrate that under cold atmospheric conditions combined with high-amplitude glacial–interglacial changes in sub-shelf melt, ice sheets advance during cold phases and retreat as the climate warms. However, un- der warmer air temperatures with reduced glacial–interglacial ice-shelf melt variability, ice sheets advance during warm phases because of increased snowfall, and retreat dur- ing colder, drier, periods. Forced with a linear change in climate, the ice sheet switches from one of these modes to the other, and a resonant response arises at half the forcing fre- quency. These findings demonstrate that the phasing relationship between climate and sea level is not constant over time, as commonly assumed, and suggest that ice sheet behaviour under a future, warmer, climate may be substantially different from today.
| Original language | English |
|---|---|
| Journal | Communications Earth & Environment |
| Publication status | Accepted/In press - 10 Dec 2025 |
Data Access Statement
Model outputs presented in this paper are available online at https://osf.io/wbne9/overview. Figure 2a–d is available Clast abundance data from Ref.56 Megasplice data from Ref.57 at as shown in https://doi.pangaea.de/10.1594/PANGAEA.869815. as shown in Figure 2e,f are available at https://www.science.org/doi/suppl/10.1126/sciadv.adl1996/suppl file/sciadv.adl1996 data s1.zip. Ice sheet drainage divides used for Fig. 2016/drainage-basins/. SFunding
The study was funded by contracts RDF-VUW1501 and MFP- VUW2207 from the Royal Society Te Apa¯rangi, and contract RTVU2206 from the New Zealand Ministry for Business, Innovation and Employment. SRM acknowledges support from a Guggenheim Fellowship, and Heising-Simons Foundation Award #2021-2797. MEW re- ceived funding from the Deutsche Forschungsgemeinschaft (DFG–Priority Programme 527, Grant We2039/17-1. HK is funded by the Helmhotz Association “Changing Earth – Sustaining our future” program. PISM development is currently supported by NSF grant OAC-2118285. Support from the Antarctic Research Centre, Victoria University of Wellington (VUW), as well as access to the VUW cluster Ra¯poi, are both gratefully acknowledged.
