RT Journal Article
T1 Overshooting the critical threshold for the Greenland ice sheet
A1 Bochow, Nils
A1 Poltronieri, Anna
A1 Robinson, Alexander James
A1 Montoya Redondo, María Luisa
A1 Rypdal, Martin
A1 Boers, Niklas
AB Melting of the Greenland ice sheet (GrIS) in response to anthropogenic global warming poses a severe threat in terms of global sea-level rise (SLR)1. Modelling and palaeoclimate evidence suggest that rapidly increasing temperatures in the Arctic can trigger positive feedback mechanisms for the GrIS, leading to self-sustained melting2-4, and the GrIS has been shown to permit several stable states5. Critical transitions are expected when the global mean temperature (GMT) crosses specific thresholds, with substantial hysteresis between the stable states6. Here we use two independent ice-sheet models to investigate the impact of different overshoot scenarios with varying peak and convergence temperatures for a broad range of warming and subsequent cooling rates. Our results show that the maximum GMT and the time span of overshooting given GMT targets are critical in determining GrIS stability. We find a threshold GMT between 1.7 degrees C and 2.3 C-degrees above preindustrial levels for an abrupt ice-sheet loss. GrIS loss can be substantially mitigated, even for maximum GMTs of 6 C-degrees or more above preindustrial levels, if the GMT is subsequently reduced to less than 1.5 C-degrees above preindustrial levels within a few centuries. However, our results also show that even temporarily overshooting the temperature threshold, without a transition to a new ice-sheet state, still leads to a peak in SLR of up to several metres.
PB Nature Portfolio
SN 0028-0836
SN 1476-4687
YR 2023
FD 2023-10-18
LK https://hdl.handle.net/20.500.14352/116163
UL https://hdl.handle.net/20.500.14352/116163
LA eng
NO Bochow, N., Poltronieri, A., Robinson, A. et al. Overshooting the critical threshold for the Greenland ice sheet. Nature 622, 528–536 (2023). https://doi.org/10.1038/s41586-023-06503-9
NO Beca Marie Curie
NO European Commision
NO The Arctic University of Norway
NO Research Council of Norway
NO Volkswagen Foundation
NO German Federal Ministry of Education and Research
NO National Science Foundation (EEUU)
DS Docta Complutense
RD 9 abr 2025