POLAR CLIMATE STABILITY NETWORK PROGRAM SUMMARY   The issue as to the stability of the global climate system in high northern latitudes has come to be seen as central to the understanding of our environmental future. Canada, perhaps more than any other nation save Russia, is expected to experience the most profound impacts of the ongoing greenhouse gas induced global warming, a phenomenon for which there now exists abundant evidence throughout the Arctic region. These impacts include the degradation of permafrost over the high latitude portion of the continent (Laberge and Payette,1995; Osterkamp and Romanovsky, 1999), the thinning of sea ice over the Arctic ocean (Rothrock et al., 1999; Vinnikov et al., 1999), the melt-back of mountain glaciers in high elevation regions in both the western and eastern Arctic (Dyurgerov and Meier, 2000; Arendt et a., 2002), as well as impacts upon the biosphere. Detailed numerical simulations of the coupled atmosphere, ocean, sea ice, land surface processes system, have now reached a sufficiently refined state that they have become extremely useful tools for predicting future environmental change (Houghton et al., 2001), and for measuring the robustness of these predictions of the future by demonstrating the ability of the models to deliver explanations of the marked changes of climate that have occurred in the past. The scientific issues that must be addressed in order to provide the required input to the post-Kyoto development of environmental policy involve not only the search for a more accurate understanding of secular climate change in the Arctic but also a deepening of our knowledge of the origins and nature of inter-annual and inter-decadal climate variability in the region. There remain significant outstanding issues concerning the manner in which inter-annual variability originating in the tropics is teleconnected to high latitudes, and equally important outstanding questions concerning the in situ generation of variability through the agency of the North Atlantic/Arctic Oscillation. These issues may be significantly illuminated through the analysis of paleoclimate data. Establishment of the Polar Climate Stability Network will dramatically increase Canada�s ability to monitor and to model the continuing impact of global warming at high latitude and thereby provide policy makers with the best possible information on which to base their decisions.  The work to be undertaken in the context of this Network connects strongly into the newly emerging WCRP programme CliC (Climate and the Cryosphere) and to the IGBP programme PAGES (Past Global Changes), in particular its PMIP2 (Paleoclimate Model Intercomparison Project-2) and IMAGES (Marine) components.   The group whose collective efforts will constitute the output of the Network includes both university and government laboratory based scientists who have assembled into ten primary teams.  The team leaders include many persons of exceptionally high international reputation who are major individual contributors to the overall Canadian effort in global environmental research.  Together with their own areas of expertise and accomplishments, they also bring to the proposed Network well established connections through the pivotal roles they play in the core projects of both the World Climate Research Programme and the International Geosphere-Biosphere Programme as well as in the continuing efforts of the Intergovernmental Panel on Climate Change.  The group includes scientists whose research is directed towards the analysis of climate related data from each of the terrestrial, oceanographic and atmospheric realms and scientists whose primary focus is on the modelling of whole system interactions involving the cryosphere, the atmosphere, the oceans and the biosphere.  A list of participants is provided in the following Appendix C.  The list does not include the Research Associates, Postdoctoral Fellows and graduate students who will be involved in the project.   Overall leadership of the PCSN will be provided by the Applicant with the assistance of the individual Theme Leaders who will be responsible for overseeing progress towards achievement of the goals and objectives of the individual components of the Scientific Plan of the network as a whole. The four Theme Areas under which the work of the ten individual teams will be conducted, along with the names of the persons who will be responsible for ensuring progress towards the goals in each area, are as follows (it will be important to realize that each of the Principal Investigators listed in Appendix C below will be active in working on one or more of these individual themes).   Theme I: Mechanisms of Rapid Climate Change: Oceanographic and Terrestrial                 Professor Andrew Weaver, University of Victoria Theme II: Polar Cryospheric Stability: Land Ice and Sea Ice                  Professor Garry Clarke, University of British Columbia Theme III: The Arctic/North Atlantic Oscillation and the role of the Arctic Ocean  in the          Climate System:  Paleoclimatological Perspectives                     Professor Claude Hillaire-Marcel, UQAM, GEOTOP, Montreal Theme IV: Low Latitude � High Latitude Teleconnections: Paleoceanographic Perspectives                    And Atmospheric Dynamical Interactions                    Professor Thomas Pedersen, University of Victoria   Although these key personnel for the proposed PCSN were also central to the success of the recently completed Climate System History and Dynamics Research Network, this core group has been considerably expanded for the refocusing of effort on high latitude processes that the new programme will require. In particular Marshall, Bush and Pedersen were added to the CSHD group only in 2001. Moore and Sharp have been invited to join for the specific purpose of the PCSN on account of the expertise they bring in regional climate/meteorological modelling (Moore) and in the analysis of high latitude data from ice cores (both Sharp and Moore). Further members new to the continuously evolving CSHD group include Scott, Rochon, Koerner, Calvert, and England. The linkage of the PCSN to the Northern Research Chair of England will be important to the success of the network.   Since the over-arching goal of the proposed PCSN is to develop a full understanding of climate change at high latitudes, especially focused upon understanding the impacts upon northern Canada of ongoing global warming, it is clearly necessary to involve scientists with primary expertise in each of the sub-disciplines between which interaction is required, including oceanography, atmospheric science, glaciology and palynology. It is also mandatory that the group include both persons whose work is observation based and those whose work is in the area of modelling.  No single individual could hope to encompass the full range of required expertise. Yet, by bringing together this team of outstanding persons, the necessary diversity of specialization will be available. Within the network we will be able to exchange students between laboratories and supervisors so as to ensure the best possible experience for the research students involved.   References:             Arendt, A. A., K. A. Echelmeyer, W. D. Harrison, C. S. Lingle, and V. B. Valentine. 2002. Rapid wastage of Alaska glaciers and their contribution to rising sea level. Science 297, 382-386.             Dyurgerov, M. B., and M. F. Meier, M. F. 2000. Twentieth century climate change: evidence from small glaciers. Proc. Natl. Acad. Sci. USA, 97(4), 1406-1411.             Laberge, M. J., and S. Payette. 1995. Long-term monitoring of permafrost change in a palsa peatland in northern Quebec, Canada: 1983-1993. Arct. Alp. Res., 27, 167-171.             Osterkamp, T. E., and V. E. Romanovsky. 1999. Evidence for warming and thawing of discontinuous permafrost in Alaska.. Permafrost Periglac., 10(1), 17-37.             Rothrock, D. A., Y. Yu, and G. A. Maykut. 1999. Thinning of that Arctic sea ice cover. Geophys. Res. Lett., 26, 3469-3472.             Vinnikov, K. Y., A. Robock, R. J. Stouffer, J. E. Walsh, C. L. Parkinson, D. J. Cavalieri, J. F. B. Mitchell, D. Garrett, and V. F. Zakharov. 1999. Global warming and Northern Hemisphere sea ice extent. Science, 286, 1934-1937.