Climate Sensitivity to CO2 in the Early Pleistocene--a world with smaller ice sheets

Dyez Kelsey, Santa Cruz CA

Investigators

Abstract

Dr. Kelsey A. Dyez has been awarded an EAR Postdoctoral Fellowship to carry out a research and education program at Columbia University's Lamont-Doherty Earth Observatory. This project aims to resolve the question of how atmospheric greenhouse gas concentrations vary in a world with smaller, more transient ice sheets. The goal is to test theories associated with climate forcing mechanisms, which will be beneficial for numerical modelers of climate change when the data is ultimately contributed to the National Climate Data Center. By directly comparing different methods for estimating pCO2 from the same geographic location and time period, this project may enhance networks among researchers who work on each method and will broaden the field's understanding of which (if any) additional factors play a role for either technique. For society, it is also important to understand further the mechanisms that impact climate in a world with smaller ice sheets than today. Additionally, by developing an outreach blog, co-teaching graduate and undergraduate courses, and mentoring a laboratory assistant, this project directly promotes broad participation and learning opportunities for students who may be underrepresented in the geosciences. This project will examine the links between early Pleistocene tropical and high latitude climate cycles and the carbon cycle, in the period just before high-resolution atmospheric CO2 concentration (pCO2) records are available from air bubbles trapped within ice cores. This project aims to reconstruct an early Pleistocene high-resolution record of pCO2 to resolve the frequency and phase of pCO2 variability in the early Pleistocene with respect to high-latitude and tropical climate change. Such evidence may demonstrate how and when greenhouse gas concentrations changed in the early Pleistocene and thus will improve current understanding of how carbon cycles function in a world with smaller glacial ice sheets than the late Pleistocene. The results from this project will have implications for understanding the orbital-scale carbon cycle, lysocline and pH changes in the early Pleistocene, and for theories regarding polar ocean overturning which contribute to long-term CO2 storage and release.