However, the range of uncertainty that must be considered has actually increased, not decreased, as a result of more recent insights into the nature of global change. This talk will explore a number of processes that have the potential to generate signifi cant surprises in Earth System functioning as global change continues to unfold.

These so-called “slumbering giants", if awakened, may well revise our definition of what constitutes “dangerous climate change", as well as focus attention on other aspects of global change. In the talk we will consider five of these slumbering giants:

(i) changes in our estimation of climate sensitivity;

(ii) chemistry of the ocean;

(iii) instabilities in the cryosphere;

(iv) transformation of the terrestrial biopshere; and

(v) vulnerability of human systems to global change.

About Will Steffen
Will Steffen is currently Science Adviser, Australian Greenhouse Office, and Visiting Fellow, Bureau of Rural Sciences, Australian Government, Canberra.

In addition, he is the Chief Scientist of the IGBP, and is a Visiting Researcher at the Centre for Transdisciplinary Environmental Research, Stockholms Universitet.

From 1998 until 2004 Steffen was the Executive Director of IGBP. His scientific interests span a broad range within the field of Earth System science, with a special emphasis on terrestrial ecosystem interactions with global change, the global carbon cycle and on adaptation to global change, particularly in relation to agriculture.

From October 2005 Steffen will be the Director of the Centre for Resource and Environmental Studies at the Australian National University in Canberra.