A new generation of physically-based models for predicting ice-sheet fracture and sea level rise

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Sea-level rise is one of the most critical issues the world faces under global warming. According to the Intergovernmental Panel on Climate Change (IPCC), 10% of the world's population live in low-lying coastal regions that are susceptible to flooding. While twentieth-century sea-level rise was dominated by thermal expansion of ocean water, mass loss from glaciers and ice sheets is now the largest contributor. As a consequence, there is a need for updating IPCC sea-level rise projections, which are now thought to be on the low end of possible outcomes. However, delivering quantitative predictions of ice mass loss is not an easy task. Iceberg fracture and detachment (calving) is a complex phenomenon that occurs over long time scales and is governed by mechanical, thermal and hydraulic fracture processes. The objective of this PhD project is to develop a new generation of models for predicting iceberg calving and the associated sea-level rise. This will be achieved by including - for the first time - the physics of meltwater-driven fracture; a scientific milestone that will be made possible by bringing a new mathematical phase field paradigm to the discipline. Current empirical estimates cannot capture key physical features, such as the viscous behaviour of ice, thermal effects or the role of meltwater in driving hydraulic fractures. This PhD project will incorporate the physics of meltwater-driven fracture by developing a multi-physics finite element framework. Key elements of the work involve the combination of phase field fracture modelling, thermo-viscoelasticity and poroelasticity. Model predictions will be benchmarked against satellite and radar data.This PhD project will deliver a new generation of ice-sheet fracture models that can simulate the underlying physical mechanisms. This will bring, for the first time, quantitative insight into iceberg calving; a phenomenon referred to as the "holy grail" problem in glaciology, due to the challenges and rewards that it presents. Computer codes will be made freely available, providing the scientific community with tools to reduce uncertainty in the prediction of climate change effects. The connection with the Grantham Institute will be exploited to translate scientific findings into policy, maximising the societal impact of this PhD thesis.