PAOC Colloquium – Alex Robel (Georgia Tech)

Towards Stochastic Ice Sheet Dynamics: Theory and Applications

Predictions of the future evolution of ice sheets are subject to considerable uncertainty due to poorly understood glaciological processes, emissions uncertainty, and internal variability of the climate system. In this talk, I explain a theoretical framework, based on ideas from statistical mechanics, which predicts the principal moments in a stochastic model of ice sheet evolution. The theory indicates that, as in the broad class of unstable systems, ice sheet instabilities have the tendency to exponentially widen and skew the distribution of project future ice sheet state. This theory explains many statistical features of a large ensemble of simulations of the future rapid retreat of Thwaites Glacier in West Antarctica, in addition to other parameter-perturbed ice sheet projection ensembles. I also describe our recent efforts to develop large-scale stochastic models of ice sheet evolution, and what they reveal about the substantial biases inherent in deterministic ice sheet modeling. Finally, I map out plans to use stochastic ice sheet models for novel estimates of (1) the irreducible uncertainty in ice sheet projections, and (2) the role of humans in causing recent ice sheet changes.

About this Series: The PAOC Colloquium is a weekly interdisciplinary seminar series that brings together the whole PAOC community. Seminar topics include all research concerning the physics, chemistry, and biology of the atmospheres, oceans and climate, but also talks about e.g. societal impacts of climatic processes. The seminars take place on Monday from 12-1pm. Contact paoc-colloquium-comm@mit.edu for more information and Zoom password.