MIS11 AND PRESENT INTERGLACIALS SIMULATED WITH A CLIMATE MODEL OF INTERMEDIATE COMPLEXITY

Climate simulations performed with the LLN 2-D NH climate model have confirmed that climate is largely triggered by changes in insolation forcing although atmospheric CO2 concentration is also playing an important role, in particular in the amplitude of the simulated variations. We focussed first on the Marine Isotope Stage 11 (MIS11) some 400 kyr BP, which can be considered as an analogue for future natural climate changes. Different simulations were performed to identify the conditions constraining the length of this simulated interglacial. Clearly a good phasing between CO2 concentration and insolation variations is requested to drive the climate system into glaciation at that time, mostly because insolation changes are small then. In the light of these experiments, it appears that the long interglacial simulated under natural forcings for the next 50 kyr is a robust feature.