Stability of ice shelves and ice cliffs in a changing climate

• Published in: Annual Review of Earth and Planetary Sciences
• Main Authors: Bassis, Jeremy N., Crawford, Anna, Kachuck, Samuel B., Benn, Douglas I., Walker, Catherine, Millstein, Joanna, Duddu, Ravindra, Åström, Jan, Fricker, Helen, Luckman, Adrian
• Other Authors: University of St Andrews.School of Geography & Sustainable Development, University of St Andrews.Bell-Edwards Geographic Data Institute, University of St Andrews.Environmental Change Research Group
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2024
• Subjects: Ice sheet; Ice shelf; Iceberg; Calving; Sea level rise; Climate; 3rd-DAS; SDG 13 - Climate Action; SDG 14 - Life Below Water; AC; Antarctic; Greenland; Thwaites Glacier; Antarc*; glacier; Ice Sheet; Ice Shelf; Ice Shelves; Iceberg*
• Online Access: https://hdl.handle.net/10023/30494; https://doi.org/10.1146/annurev-earth-040522-122817

Funding: This work is funded by DoE grant C3710 and NASA grant 80NSSC22K0378 and by the DOMI- NOS project, a component of the International Thwaites Glacier Collaboration. Support was provided by the National Science Foundation (NSF) (grant 1738896) and Natural Environment Research Council (grant NE/S006605/1). C.W. acknowledges funding from NASA’s Cryosphere Program via award 80NSSC22K0380 and NSF’s Office of Polar Programs via award 2205008. R.D. acknowledges funding from NSF’s Office of Polar Programs via CAREER grant PLR- 1847173 and NASA’s Cryosphere Program via award 80NSSC21K1003. A.C. was supported by the Leverhulme Trust as an Early Career Fellow. The largest uncertainty in future sea-level rise is loss of ice from the Greenland and Antarctic Ice Sheets. Ice shelves, freely floating platforms of ice that fringe the ice sheets, play a crucial role in restraining discharge of grounded ice into the ocean through buttressing. However, since the 1990s, several ice shelves have thinned, retreated, and collapsed. If this pattern continues, it could expose thick cliffs that become structurally unstable and collapse in a process called marine ice cliff instability (MICI). However, the feedbacks between calving, retreat, and other forcings are not well understood. Here we review observed modes of calving from ice shelves and marine-terminating glaciers, and their relation to environmental forces. We show that the primary driver of calving is long-term internal glaciological stress, but as ice shelves thin they may become more vulnerable to environmental forcing. This vulnerability—and the potential for MICI—comes from a combination of the distribution of preexisting flaws within the ice and regions where the stress is large enough to initiate fracture. Although significant progress has been made modeling these processes, theories must now be tested against a wide range of environmental and glaciological conditions in both modern and paleo conditions. ▪ Ice shelves, floating platforms of ice fed by ice sheets, ...