ABRUPT CLIMATE CHANGE SYMPOSIUM
Friday, April 15, 2005
2:30 - 3:15 PM

Thomas Stocker - University of Bern, Switzerland
"Irreversible Climate Transitions: Future Trouble?"

Records from ice cores and marine sediments send us a clear message: ocean circulation and atmospheric temperatures can change within decades. More alarmingly, recent analyses demonstrate that such changes can occur after slow but steady changes of the background climate, once a threshold is crossed. This finding is relevant for the question of whether the northern extension of the Gulf Stream will be altered in response to the ongoing global warming. Climate models tell us that not only the amount of warming, but also the rate of the warming will be critical whether or not such large-scale ocean circulation changes will occur and whether they will be irreversible.

Thomas Stocker is Professor of Climate and Environmental Physics at the University of Bern and head of the Division of Climate and Environmental Physics of the Physics Institute since 1993. He developed the first climate models of intermediate complexity, and he investigates the role of the carbon cycle in the climate system, in particular, the impact of abrupt climate changes on the biogeochemical cycles. He is the coordinator of the chapter "Global Climate Projection" in the forthcoming Fourth Assessment Report of the UN Intergovernmental Panel on Climate Change (IPCC).