A framework for observing and modelling ice-ocean interactions building on a community workshop organised by the Joint Commission on Ice-Ocean Interactions

Mass loss from the Antarctic and Greenland Ice Sheets could lead to a rise in global mean sea level of 0.25 m by 2100 and several metres by 2300 if greenhouse gas emissions remain unmitigated. Uncertainties in these estimates are strongly related to ocean-driven ice melt, which can lead to grounding line retreat, thinning and acceleration of the fast-flowing regions of both Antarctica and Greenland. The processes of ocean-driven ice melt on large spatial and temporal scales are imperfectly known, and measurements are sparse, impacting the accuracy of ice sheet and ocean model projection studies. The Joint Commission on Ice-Ocean Interactions (JCIOI) hosted the first community workshop in October 2022 with the aims to: (1) identify critical knowledge gaps surrounding processes that govern ocean-driven melt of ice sheets across a range of spatio-temporal scales; and (2) identify options to address the knowledge gaps through observing, parameterising, and modelling ice-ocean interactions, and their impacts on ice mass loss and ocean dynamics. Community discussions from the workshop highlighted the need for concurrent and sustained measurements of ice, ocean and atmosphere properties at the ice sheet-ocean interface, and making best use of existing observations to improve models, capture observed changes, better understand physical mechanisms and improve future projections. Building on the workshop outputs, we propose to develop a framework for ice-ocean observations that details the essential measurements that need to be collected, and the temporal and spatial scales on which to measure. This framework will require widespread community engagement on key scientific questions, agreement and coordination, including protocols for data collection, processing, and sharing.