Geoscientific Model Development www.geosci-model-dev.net 1991-959X 1991-9603 3 1 2010 10.5194/gmd-3-123-2010 http://www.geosci-model-dev.net/3/123/2010/ http://www.geosci-model-dev.net/3/123/2010/gmd-3-123-2010.html http://www.geosci-model-dev.net/3/123/2010/gmd-3-123-2010.pdf 123 141 2010-02-12 Bergen Earth system model (BCM-C): model description and regional climate-carbon cycle feedbacks assessment J. F. Tjiputra jerry.tjiputra@bjerknes.uib.no K. Assmann M. Bentsen I. Bethke O. H. Otterå C. Sturm C. Heinze University of Bergen, Department of Geophysics, Allégaten 70, 5007 Bergen, Norway Bjerknes Centre for Climate Research, Allégaten 55, 5007, Bergen, Norway Nansen Environmental and Remote Sensing Center, Thormølensgate 47, 5006 Bergen, Norway Bert Bolin Centre for Climate Research, Svante Arrhenius väg 8 C, 106 91 Stockholm, Sweden We developed a complex Earth system model by coupling terrestrial and oceanic carbon cycle components into the Bergen Climate Model. For this study, we have generated two model simulations (one with climate change inclusions and the other without) to study the large scale climate and carbon cycle variability as well as its feedback for the period 1850–2100. The simulations are performed based on historical and future IPCC CO₂ emission scenarios. Globally, a pronounced positive climate-carbon cycle feedback is simulated by the terrestrial carbon cycle model, but smaller signals are shown by the oceanic counterpart. Over land, the regional climate-carbon cycle feedback is highlighted by increased soil respiration, which exceeds the enhanced production due to the atmospheric CO₂ fertilization effect, in the equatorial and northern hemisphere mid-latitude regions. For the ocean, our analysis indicates that there are substantial temporal and spatial variations in climate impact on the air-sea CO₂ fluxes. This implies feedback mechanisms act inhomogeneously in different ocean regions. 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