The evolution of the state of the ocean on decadal time scales is influenced by both natural modes of variability and anthropogenic trends, and involves spatial patterns which are far from uniform. A leading factor governing regional ocean changes is the response of ocean circulation to atmospheric forcing variability and trends: the associated ocean transport anomalies strongly influence the geographical patterns of oceanic processes such as carbon uptake, acidification, near-bottom warming and sea level. Local rates of sea level change during the last decades, for instance, significantly differed from the global-mean rise due to circulation-related swings in the warm upper-ocean waters.
Future changes in nutrient supply and associated biological productivity as well as in oceanic carbon uptake and associated acidification, will be significantly impacted on a regional scale by the changes in the 3-D circulation, for instance, the up- and down-welling patterns in the southern ocean and in the tropics, or the deep wintertime convection in the subarctic Atlantic. A common denominator of future ocean changes at the regional scale is an over-arching influence of ocean dynamics: understanding the behavior of ocean circulation and its effect on biogeochemical fluxes in response to changing atmospheric conditions represents a prerequisite for developing capabilities in projecting the future evolution of societally relevant properties at the regional scale, such as the occurrence of species and fishing opportunities.
