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Abstract We examine the factors influencing the future of dissolved oxygen concentrations and future calcium carbonate (CaCO3) dissolution (CCD) rates. On the first topic, the importance of ocean oxygen to marine and terrestrial life is well-known, but ocean oxygen can be used for purposes other than breathing. Dissolved oxygen concentrations in the global ocean reflect changes in both physical and biogeochemical ocean processes. We present experiments that highlight the importance of remineralization in the oxygen budget and of ocean mixing in deoxygenation under a climate change scenario. We supplement these simulations with ones that make use of an adjoint-based general circulation ocean model. We show evidence that ocean oxygen provides information about ocean mixing. On the second topic, CaCO3 is known to dissolve throughout various portions of the water column, but little is known about how this will change in the future. Changes in ocean salinity, alkalinity, and mean age are most important in setting future CCD rates when a diagnostic approach is used. The most extreme future CCD rates are not uniformly determined by which future climate scenario is followed. However, on a global scale, results suggest that the ocean may buffer less against acidification if any of the geoengineering scenarios considered here are implemented than if our future emissions follow the most fossil fuel-intensive scenario. Speaker information Dr. David Trossman, by training, is a physical oceanographer but, by example, encourages earth system scientists to cross traditional disciplinary boundaries more often. David received his PhD at the University of Washington in Seattle in 2011 and eventually moved to Liverpool where he is now a Senior Research Scientist with the National Oceanography Centre. David uses numerical and statistical models as well as theory to improve existing or explore alternative observational methods to monitor basic ocean state variables, better understand ocean processes, and enhance ocean forecasting systems. Join Zoom Meeting https://uib.zoom.us/j/68304284910?pwd=2IgsDMWHuJlQw3XFHSTo3OoGBsRrhz.1 Meeting ID: 683 0428 4910 Password: 7pwZK4mG

Abstract The shared socio-economic pathways (SSPs) developed by the intergovernmental panel on climate change (IPCC) are formulated as broad, archetypal pathways the world might follow into the future. They provide information about possible human and ecological trajectories on global scale yet lack region-specific details that are important for scenario development to support policy and management at national and regional levels. Here, we consider four of the five SSPs (SSP1-nature first, SSP3 – regional rivalry, SSP4 – inequality and SSP5-world markets) and explore their implications for the Barents Sea region at the horizon of 2100. We focus on maritime sectors of particular relevance to the region: fisheries, shipping, defence, renewable energy, environmental protection, tourism, and oil and gas. We construct storylines describing the regional development of each of these sectors along the four archetypal SSPs. We then present the completed regional pathways to stakeholders representing each of the sectors, to collect feedback and make revisions where necessary. These regionalised SSPs provide a potential test-ground for future scenarios through planned ecosystem modelling. This regionalised analysis reveals that the geopolitical situation is a critical uncertainty with potentially large implications on the other marine sectors in the future. In addition, global targets such as reaching 30x30 (protecting 30% of marine areas by 2030) have potential large-scale impact on area-demanding sectors, such as fisheries, and in particular bottom trawling. The pathways presented here are suggested as a starting point for further discussions on possible future trajectories in the Barents Sea. Speaker information Cecilie Hansen is an ecosystem modeler and research professor at the Institute of Marine Research (HI). She has worked with different modelling frameworks – from simple phytoplankton models to complex ‘whole world’ models – with a focus on overall impacts from anthropogenic activities, including climate change, in the Nordic and Barents Seas .