Multiyear to decadal climate variability is a fundamental aspect of the global climate system. Major international efforts are underway to provide predictions that can help decision-maker planning for the next several years to decades, but the key mechanisms driving such long-term variations, and the differing sources of predictability on multiyear vs. decadal timescales, are still not fully understood. Processes both within ocean basins and inter-basin interactions are considered important at these timescales, but to-date the magnitude of these influences remains unknown, as is the impact of atmospheric/terrestrial processes. Separation of natural decadal variability from externally-forced components is also critical but challenging. This session invites contributions examining mechanisms of internal multiyear to decadal variability in the oceans, land, and/or atmosphere, studies attempting to isolate the internal and anthropogenically forced components and their interactions in observational and model datasets, and related prediction efforts using empirical/machine learning, theoretical and modeling approaches.