Interactive comment on “Projected climate change impacts on North Sea and Baltic Sea: CMIP3 and CMIP5 model based scenarios” by D. Pushpadas

North Sea. Holt et al. (2014, reference in the manuscript) found the North Sea less sensitive to production changes and projected less consequences of climate change for the North Sea compared to the global ocean, whereby Gröger et al (2013, reference in the manuscript) found the opposite, a more sensitive North Sea production to climate change. The question of regional consequences of climate change to the North Sea is therefore far from settled and our study contributes important results to the scientific debate in this respect. Moreover, it evaluates the robustness of regional projected primary production change by presenting for the first time a consistent multi-member downscaling ensemble for the North Sea and Baltic Sea. Our results thereby allow for the first time to span a range for projected primary production changes. In our opinion this is a very important result and should not only be of interest for a small number of climate scientists working on the regional scale, but also to those who further think through the risk of climate change in these regional systems, such as biologists working on consequences of climate change for different organisms or those who would further evaluate consequences of climate change for pollutants and fisheries. Our study is the first one, that presents regional downscaled projections from CMIP5 global scenarios developed for the latest IPCC assessment, and we address the research question whether the regional projected changes are different from AR4 to AR5 and whether the new AR5 scenarios result in increased convergence in regional projections (e..g. due to improved global models) compared to the earlier AR4, which is indeed the case for the North Sea primary production, but not for the Baltic Sea. More over we present a number of new results on forcing and causing mechanisms in the scenario simulations, these include variations in mixed layer depth, the role of atmospheric vs oceanic drivers and regional variations in trophic amplification.