1. Report of the Scientific Assessment Panel 20th Meeting of the Parties to the United Nations Montreal Protocol 16-20 November 2008 Doha, Qatar Cochairs: Ayité-Lo Ajavon (Togo) Paul A. Newman (USA) John A. Pyle (UK) A.R. Ravishankara (USA) Todays Summary: status of the 2010 report of the Scientific Assessment Panel

2. A birds eye view of 2010 assessment Key ongoing issues - Levels and trends of ODS and their substitutes, with emphasis on HCFCs - Levels of ozone and its trends - Our understanding of the atmospheric science as it relates to ozone layer changes What is new in science - The impact of climate change on ozone layer recovery; impact on when the layer will recover - The impact of ozone layer changes on climate and its changes Specifically the the Terms of the Parties from September 2007 (19th MOP, Decision XIX/20)

3. Contents of 2010 Science Assessment Science topics to be addressed (Decision XIX/20): assess the state of the ozone layer and its future evolution evaluate recent Antarctic ozone hole and Arctic ozone depletion behavior evaluate trends of ozone-depleting substances in the atmosphere assess the impacts of climate change on ozone layer analyze atmospheric concentrations of bromine and implications for the ozone-layer describe surface ultraviolet radiation observations and future expectations assess interaction between tropospheric and stratospheric ozone assess approaches to evaluating very short-lived substances

4. A Request to the Parties Preparatory work for the assessment has started November 4, 2008 e-mail from UNEP to the Parties, seeking nominations of participants Participation also leads to capacity building Replies requested by December 19, 2008 Previous participants need not be renominated; they will be considered again Replies to be sent to UNEP contact: Meg.Seki@unep.org

5. The 2010 Science Assessment Immediate Next Steps: Request nominations of experts o Cochairs determine Chapter structure o Determine Chapter Lead Authors o Chapter Teams form, Chapter preparation begins o Lead Author meeting to review Chapter first drafts Reviews and revisions Final review and release Nomination of Experts Determine Chapter Structure and Leads LA Meeting, First Chapter Drafts Oct-Dec 19 Dec/Jan Nov-Dec 2008 2009 Feb-Oct Prepare Chapter First Drafts 2010 Jan-July Reviews Revisions On going

6. Steps for 21010 Assessment: Dates and Tasks Draft outline completed. Lead Authors, Coauthors established Chapter outlines drafted Early 2009: Lead Authors meeting (location?). Late October: 1st drafts due; circulated for internal review. End of 2009: Internal review meeting, Lead Authors, Steering Committee, and a few others. (Washington, USA?) February 2006: 2 nd drafts complete and mail peer review starts. April: mail reviews due; third draft preparation begins. Mid-May: Third draft due; distributed to Panel reviewers. Summer 2010: Panel Review: (Les Diablerets, Switzerland ?) >Lead Authors & a few Coauthors. >~30-40 reviewers. >Final decisions on chapters. >Completed Executive Summary. Late July: Chapters completed. 30 December: preprint volume to UNEP for government distribution. March 2011: final printed copies available 2009 2010

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