Aquatic ecosystem services are important for human wellbeing, but they are much less studied than terrestrial ecosystem services. The objectives of this study are to broaden, itemize and exemplify the human‐nature interactions in modeling the future provision of aquatic ecosystem services. We include shared socioeconomic and representative concentration pathways, used extensively in climate research, as drivers of change for the future development of the Baltic Sea. Then we use biogeochemical and ecosystem models to demonstrate the future development of exemplary supporting, provisioning and cultural ecosystem services for two distinct combinations of regionally downscaled global climate and socioeconomic futures. According to the model simulations, the two global futures (“Sustainable well‐being” vs. “Fossil‐fuelled development”) studied lead to clearly deviating trajectories in the provision of marine ecosystem services. Under the “Sustainable well‐being”‐scenario primary production decreases by 20%, catches of demersal fish increases and the recreation opportunities increase significantly by the end of the ongoing century. Under the “fossil‐fuelled development”‐scenario primary production doubles, fisheries focus on less valued pelagic fish and the recreation possibilities will decrease. Long‐term projections of aquatic ecosystem services prepared for alternative global socioeconomic futures can be used by policy makers and managers to adaptively and iteratively adjust mitigation and adaptation effort with plausible future changes in the drivers of water pollution.

BalticSTERN (Systems Tools and Ecological-economic evaluation – a Research Network) is a research network with partners in all countries around the Baltic Sea.

The aim of the network is to combine ecological and economic models to make cost-benefit analyses and identify cost-effective measures to improve the environmental state of the Sea.

Results from BalticSTERN research during the period of 2009-2012 is presented in this final report aimed at decision makers. Supplementing this final report there are Background Papers (BG Papers), published on the BalticSTERN website and on the website of the Swedish Agency for Marine and Water Management.

This final report gives an overview and presents main results, while the BG Papers explore policy and research questions, as well as methods and results in more detail. Focus is on eutrophication, but some case studies on fish and fishery, oil spills and invasive species have also been undertaken within BalticSTERN and are discussed in a wider perspective in this report.