HR: 14:25h
AN: PP43E-04 INVITED    [Abstracts]
TI: A Cenozoic History of Atmospheric Carbon Dioxide
AU: * Pagani, M
EM: mark.pagani@yale.edu
AF: Yale University, 210 Whitney Avenue, New Haven, CT 06520, United States
AB: Much is assumed about atmospheric carbon dioxide and the climatic character of the Cenozoic, with long- and short-term global temperature changes commonly ascribed to parallel changes in pCO₂. Recent pCO₂ reconstructions, isotope, and sedimentological evidence for the early Paleogene suggest this relationship is largely valid. For example, the decline in pCO₂ from the mid-Eocene to Oligocene tracks increasingly colder bottom-water and global temperatures, while the hyperthermals of the Eocene, such as the Paleocene-Eocene thermal maximum (PETM) and associated ocean acidification, undeniably resulted from massive inputs of carbon. However, there are times — during the Miocene (~24-5 Ma) and the Eocene- Oligocene climate transition (~34 Ma) — when the linkage between climate change and CO₂ appears less robust, suggesting that climate sensitivity to CO₂ changed over time or that ocean circulation and/or tectonics played increasingly important climatic roles. While the evidence indicates that large-scale changes in carbon dioxide occurred during the Cenozoic, parallel changes in the saturation state of the ocean with respect to calcium carbonate minerals are lacking unless the rate of CO₂ change was extraordinarily rapid.
DE: 0325 Evolution of the atmosphere (1610, 8125)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting