Ecosystem Services of the Baltic Sea—State and Changes during the Last 150 Years

We assess the ecosystem services across the entire Baltic Sea using ecosystem model simulations and historical socio-economic data. Our approach covers 150 years, aggregated for the years around 1880, 1960, and 2010. The ecosystem services assessed include commercially usable wild fish biomass and wild plant biomass, water quality regulation (nitrogen and phosphorus retention), carbon storage, biodiversity and habitats, as well as active recreation and landscape aesthetics. In 2010, the commercially usable fish biomass in the entire Baltic Sea was 9.24 million tons. The total retention of nitrogen in the Baltic Sea was 884,135 t/a, phosphorus retention was 32,058 t/a, and carbon storage was 3,668,100 t/a. Between 1880 and 2010, the Baltic Sea-wide average biodiversity index decreased from 73 to 60, the active recreational quality index decreased from 76 to 69, and the observational recreation index declined from 91 to 78. In 2010, the most monetarily significant single ecosystem service in the Baltic Sea was nitrogen retention with EUR 26,822 million/a, followed by cultural ecosystem services. Other relevant services were fish catches (EUR 277 million/a), phosphorus retention (EUR 3854 million/a), and carbon storage (202 million/a). The latter recently showed a steep increase due to rising prices for CO2 certificates.