Abstract
A major challenge for managing impacts and implementing effective mitigation measuresand adaptation strategies for coastal zones affected by future sea level (SL) rise is ourlimited capacity to predict SL change at the coast on relevant spatial and temporalscales. Predicting coastal SL requires the ability to monitor and simulate a multitudeof physical processes affecting SL, from local effects of wind waves and river runoff toremote influences of the large-scale ocean circulation on the coast. Here we assessour current understanding of the causes of coastal SL variability on monthly to multidecadaltimescales, including geodetic, oceanographic and atmospheric aspects ofthe problem, and review available observing systems informing on coastal SL. We alsoreview the ability of existing models and data assimilation systems to estimate coastalSL variations and of atmosphere-ocean global coupled models and related regionaldownscaling efforts to project future SL changes.We discuss (1) observational gaps anduncertainties, and priorities for the development of an optimal and integrated coastal SLobserving system, (2) strategies for advancing model capabilities in forecasting shorttermprocesses and projecting long-term changes affecting coastal SL, and (3) possiblefuture developments of sea level services enabling better connection of scientists anduser communities and facilitating assessment and decision making for adaptation tofuture coastal SL change.
