Georgia Institute of Technology College of Sciences

Ice sheets are fascinating dynamical systems that flow, fracture and melt on a wide range of time scales, presenting a range of challenging prediction problems with important implications for how coastal communities plan for sea level rise. In this talk, I will introduce a few outstanding problems concerning the evolution of Earth’s ice sheets under climate change. I will start by introduce the classical theory of “marine ice sheet instability” which describes how glacier ice flows from the land to ice which floats on the ocean, and leads to a saddle-node bifurcation in ice sheet size under climate change. Many contemporary predictions of ice sheet change hold that such a bifurcation is currently unfolding at a number of glaciers in Greenland and Antarctica and could lead to runaway ice sheet retreat even if global temperatures stop increasing in the future. I discuss our recent work on whether this bifurcation may actually play out as a sliding-crossing bifurcation, and the role of a stochastic climate system in driving the system through this bifurcation where nonlinearities cause evolution of the leading order moments of the distribution of glacier state.