Do ice-ocean feedbacks influence a regime shift of the Filchner-Ronne ice shelf cavity?

The Filchner-Ronne Ice Shelf currently has a “cold” cavity with comparably low melt rates or refreezing at the ice-ocean interface. However, it has been shown that a switch to “warm” conditions under a very strong climate warming scenario is possible within this century (Hellmer et al., 2012). In this case, modified Circumpolar Deep Water that resides at intermediate levels offshore enters the cavity and fuels a 21-fold increase in aggregated melt rates (Naughten et al., 2021), with implications for ice-shelf buttressing and thereby the dynamics of tributary ice streams and glaciers. Interactions of resulting cavity changes with the ocean could furthermore amplify or weaken the increase in ice shelf melting. Here we investigate the influence of ice-ocean feedbacks on sub-shelf melt rates and the regime shift from a “cold” to a “warm” ice-shelf cavity using standalone and coupled configurations of the ice sheet model Úa and the ocean model MITgcm (De Rydt and Gudmundsson, 2016; Naughten et al., 2021). Furthermore, we test their influence on reversibility back to “cold” conditions, and the impact of a regime shift on grounded ice dynamics.