Teleconnections to the Baltic Sea Region: Controls, Predictability and Consequences

Teleconnections between the North Atlantic and the Baltic Sea region are shaped by the polar jet stream and are critical drivers of weather and climate in the region, thereby impacting the physical and biogeochemical properties of the Baltic Sea ecosystem. This review synthesizes how key circulation features and modes of climate variability, including the North Atlantic Oscillation, atmospheric blocking and the Atlantic Multidecadal Variability, influence the Baltic Sea region. By examining existing literature data and observational and climate model data, we summarize links to temperature, precipitation, storms and other key indicators from synoptic to multidecadal time scales. We then assess how these climate controls cascade into ecosystem relevant processes, namely oxygen dynamics, primary productivity and ocean acidification. Although physical links are already established, the pathways connecting large-scale atmospheric patterns to biogeochemistry are still poorly constrained, partly because dedicated field studies and targeted model experiments are limited. We outline priority research needs to enhance near-term predictability and reduce uncertainty in future projections for the Baltic Sea.