Solid-Earth geophysics and geodesy in Antarctica: achievements, current capabilities, and future directions

The Antarctic Ice Sheet (AIS) plays a major role in the global climate, providing a natural laboratory to study the processes that interlink the cryosphere, solid Earth, atmosphere, and hydrosphere. Through its ongoing mass loss, the AIS currently contributes to global-mean sea-level rise at a rate of 0.4 mm a −1 . However, its impact on and feedback with climate and sea-level changes are still poorly understood. To generate reliable sea-level projections for the future, there is an urgent need to substantially improve our knowledge of the solid-Earth properties and subsequent response to ice-mass variations in space and time. This issue has been identified as a key question by the international community, strongly supported by the Scientific Committee on Antarctic Research (SCAR). We review how state-of-the-art Global Navigation Satellite Systems (GNSS) and seismic networks in Antarctica, in combination with further ground-based, airborne and satellite-based geophysical measurements, have been used to significantly advance our understanding of solid-Earth processes and their impact on the cryosphere. Future research activities should be coordinated to answer the most urgent science questions. For example, how can we consistently test and model, respectively, a realistic mantle rheology that includes lateral inhomogeneity and transient relaxation, together with AIS mass changes on all time scales since the Last Glacial Maximum, including Holocene retreat and readvance? What processes and boundary conditions should coupled ice-sheet/gravity-rotation-deformation models include in order to realistically reflect the complex interaction between the solid Earth, ice sheet and ocean? Based on the recent achievements and the most urgent science questions, a vision is articulated for science-driven, multidisciplinary geophysical observations and corresponding technological developments. Long-term observations and improved modelling must be combined to develop precise and reliable projections for Antarctica's future mass change and associated contribution to sea-level change at both regional and global scales.