Fred Mackenzie, professor of oceanography at the University of Hawaii, will draw upon his considerable experience studying modern and ancient biogeochemical cycles to describe the ways in which the earth system likely will respond to the human acceleration of nutrient cycles. His plenary address is Recent Past and Future Feedbacks in the Climate-C-N-P Earth System (P1).

Progress in earth system science requires scientists who span traditional disciplinary boundaries. Dianne Newman, assistant professor of geobiology at the California Institute of Technology, is a leader in the application of techniques from molecular biology to geologic problems. Her plenary address is Linking Modern Anaerobic Microbial Processes to the Archean Rock Record (P2).

Instability of the Ice Age Ice Sheets: Forcing or Response of Millenial Climate Variability? is the title of Tuesday's plenary address by Shawn Marshall. A native of Ontario, with its earnest winters and landscape shaped by the great Ice Age ice sheets, Marshall received his Ph.D. in Geophysics from the University of British Columbia in 1996. His work on ice sheet physics and paleoclimatology has been highly praised. Since 2000, he has been on the Department of Geology faculty at the University of Calgary, where he researches glacier climates in the Canadian Rockies, Ellesmere Island, Greenland, Antarctica, and the Vatnajökull Ice Cap. Much honored, Marshall is a CIAR Scholar, and has won the Young Scientist award of the Canadian Geophysical Union.

Stefan Bengtson is senior curator and chair of the Department of Palaeozoology at the Swedish Museum of Natural History. Bengtson is well known for his studies of early animal evolution. He is recipient of the Walcott Medal from the U.S. National Academy of Sciences and is a member of the Royal Swedish Academy of Sciences. His plenary address is Biominerals, Skeletons, and Rocks through Time (P4).

The conference will follow three linked themes throughout its four days.

• Ancient Earth Systems
• Modern Earth System Processes
• Earth System Futures

The conference will include both specific theme sessions and general sessions. The theme sessions were proposed by the scientific community and accepted by the technical program committee as particularly appropriate for the meeting, while the general sessions are intended to provide a milieu for a wider variety of presentations addressing the three basic themes. Both types of sessions will consist of oral and poster presentations. Keynote speakers will be identified for each of these sessions in the weeks to come. We hope to find a place for all technically sound earth system science in the meeting.

The theme session co-conveners will review the submitted abstracts and select the oral presentations. Consult the theme session chair or the lead convener if you need advice about submission.