Rapid change in contemporary ice sheets poses a major challenge for predicting future sea‑level rise, in large part because many key processes operate beyond the range of modern observations. Paleo ice sheets provide critical natural experiments for exploring these processes, yet paleo and modern ice sheet communities often use different data, modeling approaches, and forums for knowledge exchange. This session aims to bridge that divide by bringing together researchers working on modern and paleo ice sheets to explore shared processes, transferable methods, and common uncertainties. We welcome contributions that integrate geological and geophysical observations, numerical modeling, model-data comparison, and theory across temporal scales. Particular emphasis is placed on insights into marine ice sheet instability, ice-ocean interactions, ice stream dynamics, and solid Earth processes. By fostering dialogue across communities, this session seeks to strengthen physically grounded projections of future ice sheet change and sea‑level rise.