Yale University
2008-2009 Distinguished Lecturer
A Cenozoic History of Atmospheric Carbon Dioxide

Results of recent studies have led scientists to assume that a strong link exists between atmospheric carbon dioxide and the Earth’s climatic character. The establishment of ancient pCO₂ (partial pressure of carbon dioxide) records not only provides evidence for or against this assumption, but also allows the exploration of linkages between the carbon cycle, biology, and tectonics.  Recent pCO₂ reconstructions, as well as isotope and sedimentological evidence for the early Paleogene, suggest the assumed CO₂-climate relationship is largely valid. For example, the decline in pCO₂ from the mid-Eocene to Oligocene tracks increasingly colder bottom-water and global temperatures.  In addition, data reconstructions show that 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) – when the relationship between climate change and CO₂ appears less robust, suggesting that climate sensitivity to CO₂ was higher, or that ocean circulation and/or tectonics played increasingly important climatic roles. Further, the evolution of CO₂ and terrestrial photosynthesis are likely linked given our recent understanding of the origin of photosynthetic pathways during the Cenozoic, as well as the probable influence that photosynthetic respiration exerted on the rate of silicate chemical weathering and CO₂ draw-down over long time scales.

Dr. Pagani’s research relies on biomarkers, as well as foraminifera from cores recovered by the Deep Sea Drilling Program, Ocean Drilling Program, and Integrated Ocean Drilling Program.

September 9, 2008 – Dickinson College
February 3, 2009 – Lawrence University
March 5, 2009 – Syracuse University
March 16, 2009 – Western Michigan University
March 20, 2009 – University of Montana-Western
April 2, 2009 – Muskingum College
May 1, 2009 – Maryland Science Center
September 18, 2009 – Florida A&M University