Challenges in Global Climate Modeling of Deep Time

Kiehl, Jeffrey ¹; Shields, Christine ^1
1 National Center for Atmospheric Research, Boulder, CO.

Global climate models of the coupled atmosphere-ocean-land-cryosphere system provide one of the most comprehensive means to understand Earth’s climate system. Simulating deep time climates with these models provides a means of evaluating the models robustness and a tool to explore the sensitivity of the system to increased greenhouse gases. Use of these models can also aid the geological community in providing a tool for global synthesis of site specific observations. Global climate modeling of deep time requires a number of key pieces of information, e.g. paleogeography, paleotopography, and paleobathymetry. This presentation will discuss key geologic data inputs and the sensitivity of deep time climate simulations to these data. The role of various climate forcing factors such as continental position and levels of greenhouse gases will be used to indicate the relative importance to climate response. Examples from fully the coupled Community Climate System Model (CCSM3) simulations for time slices ranging from the latest Ordovician up to the period of the Paleocene-Eocene Thermal Maximum will be presented. Major challenges in our ability to model the climate system will also be discussed with specific recommendations for new data and modeling capabilities that will help reduce uncertainties in understanding climates of deep time.

AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009