Assessment of Eutrophication Abatement Scenarios for the Baltic Sea by Multi-Model Ensemble Simulations

Frontiers in Marine Science

Oleg P. Savchuk¹  Bärbel Müller-Karulis¹  Erik Gustafsson¹  Anders Omstedt²  Claudia Frauen³  René Friedland³  Manja Placke³  Sandra-Esther Brunnabend³  Thomas Neumann³  Madline Kniebusch³  Matthias Gröger⁴  H. E. Markus Meier⁴  Kari J. Eilola⁴  Moa K. Edman⁴  Helén C. Andersson⁴  Christian Dieterich⁴  Ivan Kuznetsov⁵  Sofia Saraiva⁶  Vladimir Ryabchenko⁷  Alexey Isaev⁷  Bo G. Gustafsson⁸ 

[1] Baltic Nest Institute, Stockholm University, Stockholm, Sweden;Department of Marine Sciences, University of Gothenburg, Göteborg, Sweden;Department of Physical Oceanography and Instrumentation, Leibniz Institute for Baltic Sea Research Warnemünde, Rostock, Germany;Department of Research and Development, Swedish Meteorological and Hydrological Institute, Norrköping, Sweden;Institute of Coastal Research, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany;MARETEC, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal;Shirshov Institute of Oceanology, Russian Academy of Sciences, Moscow, Russia;Tvärminne Zoological Station, University of Helsinki, Hanko, Finland;

关键词: Baltic Sea;    nutrients;    eutrophication;    climate change;    future projections;    uncertainties;   

DOI  :  10.3389/fmars.2018.00440

来源: DOAJ

【 摘 要 】

To assess the impact of the implementation of the Baltic Sea Action Plan (BSAP) on the future environmental status of the Baltic Sea, available uncoordinated multi-model ensemble simulations for the Baltic Sea region for the twenty-first century were analyzed. The scenario simulations were driven by regionalized global general circulation model (GCM) data using several regional climate system models and forced by various future greenhouse gas emission and air- and river-borne nutrient load scenarios following either reference conditions or the BSAP. To estimate uncertainties in projections, the largest ever multi-model ensemble for the Baltic Sea comprising 58 transient simulations for the twenty-first century was assessed. Data from already existing simulations from different projects including regionalized GCM simulations of the third and fourth assessment reports of the Intergovernmental Panel on Climate Change based on the corresponding Coupled Model Intercomparison Projects, CMIP3 and CMIP5, were collected. Various strategies to weigh the ensemble members were tested and the results for ensemble mean changes between future and present climates are shown to be robust with respect to the chosen metric. Although (1) the model simulations during the historical period are of different quality and (2) the assumptions on nutrient load levels during present and future periods differ between models considerably, the ensemble mean changes in biogeochemical variables in the Baltic proper with respect to nutrient load reductions are similar between the entire ensemble and a subset consisting only of the most reliable simulations. Despite the large spread in projections, the implementation of the BSAP will lead to a significant improvement of the environmental status of the Baltic Sea according to both weighted and unweighted ensembles. The results emphasize the need for investigating ensembles with many members and rigorous assessments of models' performance.

【 授权许可】

Unknown