Assessment of human impact on the marine CARBon system in arctic regions (A-CARB)

Carbon dioxide is the most important manageable forcing agent of climate change. Large amounts are emitted through fossil fuel burning. Prediction of future climate change and planning of mitigation strategies requires that thorough knowledge of the facto rs that control the distribution of anthropogenic CO2 among its three reservoirs ( vegetation/soil, the oceans, and the atmosphere) is implemented in Earth system models whose performance have been assessed against at set of validation data. This proposa l seeks funding for a three year project that aims to bring forth both knowledge and validation data for the Arctic Mediterranean Seas (AMS). This will be used to assess the performance of several Earth system models implemented within the European Integr ated Project CARBOOCEAN. Specifically it is intended to: -Quantify concentrations of anthropogenic carbon dioxide through implementing a novel technique which does not require pre-industrial reference carbon concentrations nor use of transient ocean tr acers. -Quantify annual to decadal changes of ocean carbon chemistry through converting interior ocean carbon chemistry variations to temporal variations in the surface of water mass formation regions. -Use the results to validate Earth system models w ith respect to their ability to reproduce (i) pre-industrial carbon chemistry of the region, (ii) current anthropogenic carbon concentrations, and (iii) feedbacks on the Atlantic high latitude carbon system. The results will moreover be used to assess t he current degree of ocean acidification. Ocean acidification is brought around by the dissolution of anthropogenic CO2 in sea water, it lowers the calcium carbonate saturation state and may have detrimental effects on biogenic calcifiers like corals and coccolithophorids. The results from this project will be used to quantify how much the CaCO3 saturation state has decreased and to make simple predictions of the future development of the saturation state.