With Taller Cliffs, Marine Ice Cliff Instability Accelerates Ice Loss from Antarctica

Nature Communications, May 11

The loss of Antarctica’s buttressing ice shelves and glacier retreat due to global warming will expose immense unstable ice cliffs resting on deep ocean. These cliffs are susceptible to structural failure and will contribute to accelerated ice loss, through a process known as Marine Ice Cliff Instability (MICI). As coverage of DeConto et al. (2021) last week demonstrated, the speed and degree of MICI is an area of active work; and this modeling study looked at how MICI might occur and the dynamics that could make it either slow, or speed up ice loss. Significantly, it found that higher ice cliffs (especially 135 meters or more above the waterline) appear to overcome other dynamics that could slow collapse. In addition, once ice becomes deformed through conditions present under higher warming, such as pooling meltwater or different rates of flow above and below the waterline, rapid collapse becomes more likely. These are the kinds of conditions that would occur in West Antarctica as temperatures rise and as the ice sheet retreats further into deep basins where ice is extremely thick.

https://www.nature.com/articles/s41467-021-23070-7