Floating freshwater ice is a key component of cold-regions river and lake systems. Ice creates and controls unique aquatic habitats and related biological productivity and diversity. It also poses major challenges (for example, flood threats) and opportunities (for example, transportation) for communities. Changes in freshwater-ice cover have largely mirrored trends in air temperature, with large regions of the Northern Hemisphere experiencing reductions in ice-cover duration characterized by earlier spring break ups and, to a lesser degree, later autumn freeze ups, particularly over the last 50 years. Although more dramatic changes in the timing and duration of the ice season are projected for the future, our understanding of how climate has affected or will alter the more important freshwater-ice processes (such as ice-cover composition, thickness and break-up dynamic,) remains poor. Improving our knowledge of these climate-ice relationships is the key to being able to properly adapt to, or even mitigate, future environmental change