Bo Gustafsson
The HELCOM Baltic Sea Action Plan eutrophication segment includes a management cycle aiming for specified improved conditions in the sea and that is based on the best available scientific information gained from modeling and data analysis. On the basis of monitoring and assessment, ecological objectives are set and indicators developed. Quantitative targets that represent a good environmental status are established. In the following step, the relationships between pressure (i.e. nutrient loads for eutrophication) and target variables are established by means of physical-biogeochemical modeling using the BALTSEM model. The pressure-response relationships differ for the various regions within the Baltic Sea because of differences in e.g. circulation, ecosystem and loads. The result of the modeling is the basin-wise Maximum Allowable Input (MAI) of nutrients that will result in a development towards reaching the targets. The basin-wise load reduction needed to meet MAI is divided between the countries according to polluter pays principles, and what is considered fair burden and is in agreement with the Helsinki Convention and by this Country Allocated Reduction Targets (CART) are established. HELCOM asked Baltic Nest Institute (BNI) calculate MAI and CART using the BNI Nest decision support system, in order to present results for decision by the environmental ministers of the HELCOM countries on October 3, 2013. In this presentation, I will show how have found the optimal MAI by means of ecosystem modelling and the intricate construction and calculation of a set of CARTs that can be accepted by all countries. In addition, I will share our experiences of the challenges that we experienced in the long processes of making our scientific work so useful for and accepted by managers and stakeholders, that the results can be basis for concrete political decisions on load reductions.
D5, Descriptor 5, modelling, eutrophication, HELCOM, Baltic Sea, modeling, good environmental status, nutrient loads, BALTSEM, Maximum Allowable Input, MAI,
Workshop of the Network of Experts for ReDeveloping Models of the European Marine Environment
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