The implications of ocean freshening from accelerating Antarctic Ice Sheet melt are poorly understood. Coastal freshening may alter abyssal ocean heat storage and the transport of open ocean heat to ice shelf grounding lines, with poorly constrained consequences for sea-level rise. This talk will outline the results of a recent high-resolution simulation study working towards addressing these uncertainties.
We ran 2 enhanced meltwater simulations using a 0.1º global ocean—sea-ice model with the aim of identifying feedbacks to further melt. Our results point to 3 key mechanisms by which coastal freshening may alter ocean temperatures near ice shelf grounding lines. These mechanisms interplay to generate a spatially variable continental shelf temperature response to freshening, with positive and negative feedbacks to melt dominating different stretches of Antarctic coastline. Off the continental shelf, we find the freshening triggers persistent warming at depth as the formation and export of cold Dense Shelf Water slows. The work highlights the importance of resolving dynamics at the Antarctic shelf margin and representing the full circumpolar domain when simulating interactions and feedbacks between Antarctic land-ice and oceans.