Project OPEN (Opening sub-ice shelf cavities and exploring their impact on dense water Production and Export in NEMO global ocean models) will work to improve our understanding of the role that the under ice shelf seas play in influencing Antarctic water mass characteristics and circulation. Currently none of the climate models used to inform the Intergovernmental Panel on Climate Change (IPCC) simulate sub-ice shelf cavities, thereby excluding the role of ice-ocean interactions in their reports. An essential piece of the puzzle is thus missing from the Earth system projections that are used to inform climate change adaptation and mitigation strategies. NEMO ocean model has recently developed the capacity to explicitly represent circulation under ice shelves, thereby enabling an investigation into the influence of introducing these key processes on global ocean circulation and hence climate. We hypothesise that the sub-ice shelf cavities have a major impact on dense water production and Antarctic Bottom Water (AABW) characteristics. AABW is the densest and deepest global water mass and constitutes the lower limb of the overturning circulation, transporting heat, carbon, oxygen and nutrients around our planet’s oceans. Given the vital role that AABW plays in ocean and climate regulation, obtaining a better understanding of the dynamics at its source region, and improving model capacity to simulate these processes is a scientific top priority. The recently developed NEMO configurations including sub-ice shelf cavities are the ideal tools for this investigation and we propose to utilize these to explore dense water production and export. Project OPEN will place a postdoctoral fellow with extensive observational expertise in a group of modelling experts at Sorbonne Université, thereby facilitating a mutually beneficial exchange of skills between the fellow and the host and enabling the timely advancement of this new field of ocean science.