Collaborative Research: Tectonic Influence on the Greenland Ice Sheet (TIGRIS)

Collaborative Research: Tectonic Influence on the Greenland Ice Sheet (TIGRIS) The evolution of the Greenland Ice Sheet (GrIS) strongly depends on its underlying geologic structure. Changes to the ice sheet can cause the Earth’s crust and mantle to deform, with the amount of deformation being controlled by variations in the stiffness and thickness of these geologic layers. How the solid-Earth responds can either hinder or enhance ice loss, and this ice-Earth feedback mechanism plays a critical role in determining GrIS behavior. This project aims to evaluate the stability of the GrIS under different environmental conditions by employing an advanced computer model that combines ice-sheet, atmospheric, and geologic constraints. Results from this work will inform estimates of both past and future global sea-level change. Subglacial solid-Earth parameters are largely based on geophysical observations; however, conflicting interpretations of the geologic structure beneath Greenland limit our understanding of GrIS stability. Key portions of Greenland have been under-sampled, and prior studies have often only utilized data from select seismic networks. This project will develop new, self-consistent models of the solid-Earth structure beneath Greenland by combining geophysical observations from multiple networks with those from a new seismic deployment in central-eastern Greenland. Those new solid-Earth constraints will then be incorporated into a state-of-the-art, fully coupled tectonic-atmospheric-cryospheric modeling framework to evaluate the critical thresholds for ice-sheet recovery under different environmental scenarios. Three fundamental hypotheses will be tested: (a) solid-Earth structure plays a first-order role in the long-term future evolution of the GrIS as well as its response to past warming and cooling episodes; (b) under certain projected future warming scenarios, the GrIS will not fully retreat given feedbacks that are controlled by the solid-Earth structure; and (c) the interplay between different feedback mechanisms will result in at least partial ice-sheet recovery, and the GrIS will be resilient in the long term (10-20 kyrs). This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.