Explanations of the tertiary global cooling trend
Abstract A series of General Circulation Model experiments are performed to examine the role of paleogeography as an explanation of the Tertiary global cooling trend. Systematic long-term variations in topography and land—sea distribution are potential causes of long-term climate change. However, climate model sensitivity experiments indicate a geographically related cooling during the last 20 million years, but not a long-term Cenozoic trend. Coarse resolution changes in geography throughout the Tertiary may not be the explanation of the Tertiary global cooling trend. Either a series of events, some geographically related, or another forcing factor, most probably atmospheric CO2 concentration, are offered as alternative explanations of the Tertiary global cooling trend.