Climate of the Past Discussions www.clim-past-discuss.net 1814-9340 1814-9359 2 3 2006 10.5194/cpd-2-209-2006 http://www.clim-past-discuss.net/2/209/2006/ http://www.clim-past-discuss.net/2/209/2006/cpd-2-209-2006.html http://www.clim-past-discuss.net/2/209/2006/cpd-2-209-2006.pdf 209 232 2006-05-24 Coupled climate model simulation of Holocene cooling events: solar forcing triggers oceanic feedback H. Renssen H. Goosse R. Muscheler Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands Institut d’Astronomie et de Géophysique G. Lemaître, Université Catholique de Louvain, 2 Chemin du Cyclotron, 1348 Louvain-la-Neuve, Belgium NASA/Goddard Space Flight Center, Climate & Radiation Branch, Greenbelt, MD 20771, USA The coupled global atmosphere-ocean-vegetation model ECBilt-CLIO-VECODE is used to perform transient simulations of the last 9000 years, forced by variations in orbital parameters, atmospheric greenhouse gas concentrations and total solar irradiance (TSI). The objective is to study the impact of decadal-centennial scale TSI variations on Holocene climate variability. The simulations show that negative TSI anomalies can trigger temporary reorganizations in the ocean circulation that produce centennial-scale cooling events that are consistent with proxy evidence for Holocene cold phases. In the model, reduced solar irradiance leads to a relocation of the site with deepwater formation in the Nordic Seas, causing an expansion of sea ice that produces additional cooling. The consequence is a characteristic climatic anomaly pattern, with cooling over most of the North Atlantic region and drying in the tropics. Our results suggest that the oceans play an important role in amplifying centennial-scale climate variability.