Formas North Sea

Impact of changing climate on circulation and biogeochemical cycles of the integrated North Sea and Baltic Sea system

A hierarchy of global and regional models is used to study climate variability of the North Sea and the Baltic Sea. For dynamical downscaling a high-resolution, coupled atmosphere/ice/ocean/land-surface model (RCA4-NEMO) with interactive biogeochemistry (SCOBI) is applied to calculate present and future climates of the North Sea and Baltic Sea region. The development and the improvement of all model components including their interactions is one major part of the project.

Specific Aims

  • The regional coupled atmosphere/sea-ice/ocean model (RCA4-NEMO) is used to investigate the role of non-linear interactions between the atmosphere and the ocean on regional climate variability.
  • Decadal variability and its causes are investigated for the hydrography and its impact on biogeochemical cycles of the North Sea including Kattegat and Skagerrak. Cause-and-effect studies are performed to study multi-year variability.
  • The impact of a changing climate on biogeochemical cycles is investigated for the North Sea. We aim to quantify the impacts on the marine ecosystem, e.g. bottom water oxygen concentrations, primary production, and their uncertainties.

The inclusion of the North Sea with its relative large heat content (compared to the Baltic Sea) provides the possibility to investigate non-linear feedbacks from the ocean-atmosphere coupling on a regional scale. These effects are studied by comparing coupled and uncoupled (i.e. atmosphere only) simulations.

Earlier studies suggest that global warming may cause among other things increased water temperatures, reduced sea ice cover and reduced salinity. Moreover, climate projections expect differential warming with larger water temperature changes in the Baltic Sea than in the North Sea having an additional effect on the transition zone in the Skagerrak and Kattegat. The new model setup enables to investigate the consequences for the North and the Baltic Sea including the sensitive Skagerrak/Kattegat region. Possible impacts on the marine ecosystem are, e.g. species distributions, growth and reproduction of organisms including zooplankton, benthos and fish.

In general, an ensemble approach is applied to quantify uncertainties for all research areas.


The project is funded by Formas. Formas promotes and supports research of the highest scientific quality and relevance in the areas Environment, Agricultural Sciences and Spatial Planning.