IGPP Seminar Series

Brief History and Current Status of Hypotheses for Glacial/Interglacial Carbon Dioxide Change

by Daniel Sigman

Abstract

I will review the hypotheses raised to explain glacial/interglacial changes in the atmospheric concentration of carbon dioxide. These will lead me to focus in on polar ocean processes. Reconstructions of productivity and nutrient status in the surface waters of the Antarctic and Subarctic North Pacific indicate that, during the cold stages of recent glacial cycles, these regions were more isolated from underlying nutrient- and carbon dioxide-rich deep waters, potentially explaining the larger part of the glacial/interglacial carbon dioxide change. Several physical mechanisms have been proposed for the apparent polar ocean changes. I will focus on one of these and develop from it a hypothesis for the timing of the abrupt deglaciations that characterize recent glacial cycles.
Friday, 04 April 2008
3853 Slichter Hall; Lecture at 12:00 noon; Refreshments at 11:45AM
Refreshments at 3:45 PM
Lecture at 4:00 PM