![]() ![]() While predictions of submarine ice loss often use ocean temperature and subglacial discharge strength together as a proxy for melt 8, 9, 10, recent studies suggest that substantial submarine melt occurs outside the region where the subglacial discharge plume is in contact with the ice, defined as ambient melt 11. In parallel, the prediction of ice-sheet melt has been shown to underestimate observed mass loss 4, with recent reviews showing that the largest uncertainties are associated with ice–ocean feedbacks 3, 4, 6, 7. Projections for future sea-level rise due to the sustained mass loss of ice sheets have large uncertainties, in part because dynamic feedbacks where glaciers terminate into the ocean are poorly constrained 2, 3, 4, 5. Tidewater glaciers are rapidly retreating, leading to ice loss in Greenland, the Antarctic Peninsula and other glacierized regions 1. Consequently, these results could increase the accuracy of modelled predictions of ice loss to better constrain sea-level rise projections globally. We extend these results to the geophysical scale to show how bubble dynamics contribute to ice melt from tidewater glaciers. We show that real glacier ice melts 2.25 times faster than clear bubble-free ice when driven by natural convection in a laboratory setting. These bubbles eject air into the seawater, delivering additional buoyancy and impulses of turbulent kinetic energy to the boundary layer, accelerating ice melt. Here we use laboratory-scale experiments and theoretical arguments to show that the bursting of pressurized bubbles from glacier ice could be a source of this discrepancy. Current model estimates can underpredict glacier melt at termini outside the region influenced by the subglacial discharge plume by a factor of 10–100 compared with observations. At the core of these projections is a model for ice melt that neglects the fact that glacier ice contains pressurized bubbles of air due to its formation from compressed snow. ![]() Feedbacks between ice melt, glacier flow and ocean circulation can rapidly accelerate ice loss at tidewater glaciers and alter projections of sea-level rise. ![]()
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