CGD Seminar- The Role of the Ocean in Breaking Up Tabular Icebergs

In December 2020, giant tabular iceberg A68a broke up in the deep open ocean, indicating that the breakage was not caused by collision with the seafloor. Giant icebergs comprise most of the calved ice mass from the Antarctic Ice Sheet. After calving, they drift away and transport freshwater into the Southern Ocean, which can affect ocean circulation, sea-ice formation, and the marine biosphere. In this talk, I will discuss how the A68a breakup event may have been triggered by ocean-current shear, a new breakup mechanism not previously reported. I will also present new methods to represent giant tabular icebergs and their breakup within climate models, which currently do not have any representation of them. These methods are used to simulate the A68a breakup event. Additionally, I will discuss simulations that demonstrate how the spatial distributions of icebergs and their meltwater are impacted by breakup along tabular iceberg edges, caused by ocean-induced erosion and bending. The new methods presented here will improve the fidelity of global climate simulations and open opportunities to study interactions between icebergs and other components of the climate system.