Integrating Climate and Ecosystem Dynamics in the Southern Ocean (ICED) programme: Preliminary report of the ICED–CCAMLR Projections Workshop, 5 to 7 April 2018

Climate change will alter the structure and functioning of Southern Ocean ecosystems and affect the ecosystem services they provide. The impacts of climate change will require development of conservation and management strategies that anticipate and adapt to potential changes in krill population dynamics. A recent collaborative workshop between the Integrating Climate and Ecosystem Dynamics in the Southern Ocean (ICED) programme and CCAMLR brought together a range of ecologists, physical and ecological modellers and fisheries scientists to consider the development of projections of the impacts of climate change upon krill in Area 48. Here we present the preliminary findings of this workshop: ‘Developing projections of the future state of Southern Ocean ecosystems: Incorporating uncertainties associated with climate variability and change in CCAMLR’s decision making’ held at CCAMLR Headquarters, 5-7 April 2018. The Workshop highlighted the high level of natural spatial and temporal variability of the ecosystem in Area 48. The current suite of scenarios of future changes in physical, chemical and ecological drivers across the region are highly uncertain and global climate models do not resolve ocean and sea-ice processes that are important within Area 48. As a result of that uncertainty, signals of projected changes in SST and sea-ice are not distinguishable from model variability before ~2050. Surface waters are expected to warm and sea ice concentrations reduce, but the position of the polar front is not expected to change during this century. The changes expected by the end of the century are likely to cause distribution shifts and reconfiguration of food webs, with both positive and negative effects. The Workshop highlighted our poor understanding of krill recruitment processes, the key driver of variability in krill populations across the region, and particularly their links to sea ice. It also emphasized the need for a systematic development of krill population models and high spatial resolution ecosystem models. The Workshop noted the importance of developing a joint approach between ICED and CCAMLR to improve scenarios and ecosystem models and develop quantified model projections of ecosystem change in support of decision making for conservation and management. A final version of the report and agreed statements will be submitted as a Working Paper for consideration at SC-CAMLR-XXXVII.