Current Research in EEPS Seminar: Dr. Sandra Kirtland-Turner – University of California, Riverside
Comparison between modern and ancient timescales of CO2 release through constraints on the onset duration of the Paleocene Eocene Thermal Maximum
The Paleocene-Eocene Thermal Maximum (PETM, ~56 Ma) provides a test case for investigating how the Earth system responds to rapid greenhouse-gas driven warming. Arguably the most important metric for relating the PETM to the modern is the rate of carbon emissions during the PETM onset, which requires constraints on both the mass of carbon released and the onset duration of the PETM. Yet while current rates of carbon emissions are ~10 Pg C yr-1, those proposed for the PETM span orders of magnitude — from <<1 Pg C yr-1 to greater than the anthropogenic rate. In this talk I will review a series of novel model-based methodologies that attempt to overcome traditional difficulties in constraining the PETM onset duration. I will also demonstrate how abrupt input of carbon from an isotopically depleted source, combined with elevated rates of volcanic outgassing, can account for key features from sedimentary records of the PETM and discuss what these hypotheses about the PETM origin might imply for the future carbon cycle response to anthropogenic warming.