James C. Zachos is Distinguished Professor of Earth and Planetary Sciences at the University of California Santa Cruz. He is an oceanographer recognized for his research on oceans, climate, and carbon cycle dynamics over Earth’s past. He primarily utilizes the geochemical composition of sediment archives to address questions ranging from the nature of extreme greenhouse warming and ocean acidification to the history of Antarctic glaciation. Dr. Zachos, born in the Mohave Desert of California, was raised in the northern suburbs of New York City. He graduated from SUNY College at Oneonta in 1981 with degrees in Geology and Business-Economics. He received an MS in Geology in 1984 from the University of South Carolina, and his Ph.D. in Oceanography in1988 from the University of Rhode Island?s Graduate School of Oceanography. He held a post-doctoral fellowship and Associate Researcher post at the University of Michigan from 1988 to 1992 before joining the faculty at the University of California, Santa Cruz in 1993. He is a fellow of the Geological Society of America and the American Geophysical Union, and a member of the American Academy of Arts and Sciences, the National Academy of Sciences and the Royal Netherlands Academy of Arts and Sciences.

Research Interests

James Zachos' research is oriented toward understanding how global climate (e.g., ocean temperatures, ice-sheets, and the hydrologic cycle) has responded to past changes in forcing, particularly extreme variations in greenhouse gas levels, both gradual and rapid. This also includes identifying the potential contributions of physical and biogeochemical feedbacks influencing the carbon cycle that might either amplify or damp changes in climate. To this end, he and his colleagues have used the stable isotope, trace metal, and organic chemistry of fossils extracted from marine sediment archives to resolve the scale and timing of several major climate transitions in earth's past. Their primary paleoclimate "case studies" include the Eocene/ Oligocene greenhouse to icehouse transition and inception of large scale Antarctic glaciation 34 million years ago, and the transient greenhouse thermal maxima of the early Cenozoic including the Paleocene-Eocene Thermal Maximum 56 million years ago. Their findings confirms greenhouse climate theory and broadly supports climate model estimates of global climate sensitivity to greenhouse forcing, while also supporting theory on ocean acidification, specifically estimates of the limited buffering capacity of the ocean and slow rates of natural carbon sequestration and recovery.

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Primary Section

Section 15: Geology

Secondary Section

Section 63: Environmental Sciences and Ecology