S.T. Lee Lecture 2004

Antarctica's contribution to abrupt global warming events – past and future

Professor Jim Kennett, 12 August 2004

Professor of Oceanography
University of California-Santa Barbara

Synopsis of Lecture

The Earth's climate has experienced a number of abrupt major warmings (several degrees Celsius in a decade) during the past half million years. This lecture makes the case that the trigger for these events has been the warming of Antarctic waters leading to the destabilisation of methane hydrate, a solid that is widespread in sediments beneath shallow sea floor around continental margins and forms naturally through methane rising from below. The destabilisation would in turn release massive volumes of methane (a highly potent greenhouse gas) into the atmosphere, resulting in extreme though relatively brief episodes of global warming.

Explaining these abrupt warming events represents an additional challenge to climate scientists, in addition to developing an understanding of the consequences of the continuing steady rise in atmospheric greenhouse gas concentrations and related global warming projections.

Jim Kennett

The 2004 S. T. Lee Lecture in Antarctic Studies was presented by one of our most distinguished alumni, Professor James Kennett of the Department of Geological Sciences, University of California Santa Barbara. Professor Jim Kennett is Professor of Oceanography at the University of California at Santa Barbara, and a world leader in Earth Systems Science. He is internationally known for his pioneering work in establishing the field of Paleoceanography (founding editor of the Journal) and through his textbook “Marine Geology”. For many years he has led panels and cruises of the Deep Sea Drilling Project, and its successor the Ocean Drilling Program, in studying ocean history from sediment cores from key locations around the world. His recent research has highlighted the potential role of methane hydrates in abrupt climate changes. He is the editor of “Methane Hydrates in Quaternary Climate Change: The Clathrate Gun Hypothesis”.

Professor Kennett grew up in Wellington, is a graduate of Victoria University (BSc(Hons) 1962; PhD 1965) and was a member of the University’s 6th Antarctic expedition. Since then he has held University appointments at Florida State University, the University of Rhode Island prior to his appointment in 1987 as director of the Marine Science Institute at the University of California at Santa Barbara. In recent years he has been elected Fellow of the Royal Society of NZ, the Geological Society of America, and the American Geophysical Union.