Dr. Jessica Tierney is an Associate Professor in the Department of Geosciences at the University of Arizona. She studies past climate change (paleoclimatology) to learn how the Earth system works and what we might expect for the future. She is a Packard Foundation Fellow, an American Geophysical Union Fellow, and a lead author in Working Group I of the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report.