Transient simulation of the climate evolution of the last 21,000 years in CCSM3

We conducted the first synchronously coupled atmosphere-ocean general circulation model simulation of global climate evolution of the last 21,000 years using the NCAR CCSM3. With realistic climate forcings associated with greenhouse gasses, orbital forcing and continental ice sheet, as well as a reasonable melting water forcing, our model reproduces some major deglacial climate features, such as the H1 event, the BA warming and the YD event as well as the climate evolution during the Holocene. A preliminary model-data comparison shows a global climate evolution largely consistent with the reconstruction. In the mean time, our simulation also shows some model-data inconsistency, indicating potential problems on the climate model and the interpretation of the proxy data.