From eclare at lanl.gov Mon Aug 7 17:17:39 2006 From: eclare at lanl.gov (Elizabeth Hunke) Date: Mon Aug 7 17:17:47 2006 Subject: [CCSM-Polar] AGU session: rapid decline of summer sea ice in the Arctic Message-ID: Dear Colleagues, We invite your participation in a proposed special session of the AGU December meeting titled "Rapid transition from perennial to seasonal Arctic sea ice". The session is focused on the recent loss of summertime Arctic sea ice, and similar behavior in past climate records and future climate simulations. The full text of the announcement is included below. We welcome any inquiries you may have about the session. Best Wishes, Eric DeWeaver and Cecilia Bitz C17: Rapid Transition From Perennial to Seasonal Arctic Sea Ice Description: In recent times more than half the Arctic ocean has been covered year-round by sea ice, but the Arctic is now moving rapidly towards ice-free summers. In rough agreement with observations, some - but not all - climate models predict that the transition from perennial to seasonal sea ice will occur over the entire Arctic in this century. There is also speculation that abrupt sea ice transitions played an essential role in the rapid climate changes recorded in the Greenland ice cores. Beyond its climatic impact, a rapid change from perennial to seasonal sea ice will have dramatic societal and ecological effects, and the severity of these effects will depend in part of the abruptness of the change. While the basic feedback mechanisms are known, our understanding of the climate sensitivity of sea ice is relatively primitive. We lack an understanding of the key determinants of the speed with which the transition from perennial to seasonal ice will occur. A better understanding is needed to evaluate the disparate results of climate model simulations, and to assess the extent to which sea ice change in past climates can serve as a meaningful proxy for the present transition. Thus we invite papers which examine the transition to an ice-free Arctic summer based on theory, models of varying degrees of complexity, and observations from the instrumented record. We also seek papers that investigate rapid transitions in Arctic sea ice in the paleoclimate record and/or comparable sea ice behavior in the Antarctic. In addition, we welcome papers which consider the interannual and decadal variability of sea ice, as well as those addressing the far-field effects of sea ice change. To complement purely scientific studies of the sea ice transition, we further solicit papers on the policy implications of the transition, particularly those which focus on the implications of a rapid or abrupt transition. Sponsor: Cryosphere CoSponsors: Ocean Sciences Global Environmental Change Conveners: Eric DeWeaver AOS Dept/CCR, University of Wisconsin-Madison 1225 West Dayton St Madison, WI, USA 53706 608-265-5438 deweaver@aos.wisc.edu Cecilia Bitz Atmospheric Sciences Dept, University of Washington 408 Atmospheric Sciences Building University of Washington Seattle, WA, USA 98195-1640 206-543-1339 bitz@atmos.washington.edu --