Title: Understanding and modeling interactions between the ice sheets and the climate system over the coming centuries
Abstract: Over the past three decades, observations have shown that both the Antarctic and Greenland Ice Sheets have been losing mass at an increasing rate. Glaciers and ice sheets have become today the largest contributors to sea level rise, but their contribution over the next century remains a key uncertainty in sea level rise projections. Understanding the past and future behavior of the ice sheets and their interactions with the other components of the Earth system remains scientifically and technically challenging. I will first show how climate forcings, and the ocean in particular, strongly affect ice sheet dynamics through ocean-induced melting under floating ice shelves of Antarctica. The best way to capture these interactions is to tightly couple the ice sheet and ocean models. I will present simulations of the Amundsen Sea Sector of West Antarctica performed with a coupled ice-sheet-ocean model that demonstrate the improved agreement with the observed pattern of glacial retreat using a coupled model. Model coupling at the scale of the entire Antarctic coast remains however completely impractical and we have to develop parameterizations to represent the relevant ocean processes. I will use an ensemble of simulations of the Antarctic ice sheet over the 21st century to assess the role of the melt parameterizations and its importance relative to other sources of uncertainty in ice sheet projections. I will conclude with some future research directions and challenges.