2025/10/19 by Louis Saddier, Corentin Herbert, Christopher Y. S. Bull +1 · 1 voice
Earth and Planetary Sciences · Environmental Science · #Arctic and Antarctic ice dynamics #Cryospheric studies and observations #Methane Hydrates and Related Phenomena
paper · doi:10.22541/essoar.176087307.79514769/v1
openalex publication_date 2025/10/19 · openalex created_date 2025/10/21 · openalex updated_date 2026/07/22
Ice shelves fringing the Antarctic continent experience low or high basal melt rates depending on local shelf conditions, ocean circulation and intensity of ice-sea-air exchanges. Recent studies have uncovered potential cold-to-warm transitions in specific ice-shelf cavities, which could lead to a dramatic increase in sea-level rise. Here we demonstrate that brine rejection in coastal polynyas promotes bistable dynamics in ice-shelf cavities, which would be otherwise monostable, for a broad diversity of Circumpolar Deep Water temperatures. We develop a generic low-dimensional box model featuring warm and cold circulation modes and apply it to nine ice-shelf cavities. We find that most ice-shelf cavities are in a bistable regime and are therefore susceptible to irreversible abrupt transitions for a realistic range of sea-ice formation rates. Bistability is robust to changes in cavity parameterization. However, the vertical mixing scheme at the ice-shelf front can be tuned to make the transitions reversible.