Clim. Dynam. (2012)

The Baltic Sea is expected to experience increased temperature, decreased sea-ice cover and reduced salinity over the coming decades as a result of global warming. These effects, in conjunction with industrial and agricultural practices, could have a significant impact on the marine ecosystem.

Markus Meier, of the Swedish Meteorological and Hydrological Institute, Norrköping, Sweden, and collaborators modelled climate changes and nutrient loads in the Baltic Sea. They used a coupled physical–biogeochemical model with a total of 16 scenario simulations, from 1961 to 2099.

Their results show that, for all scenarios, water temperature increased with increased air temperature, and salinity decreased in response to increased land runoff. Nutrient loads increased for all scenarios. Increased precipitation, which caused greater runoff, combined with increased water temperature to accelerate sedimentary organic material decomposition, leading to increased eutrophication. The authors also predict that bottom oxygen concentrations will decrease as a result of the increased organic matter and nutrient load. Current legislation to reduce nutrient load will not be sufficient, according to this study, to improve water quality at the end of the century.