1. Report of the Scientific Assessment Panel SAP Co-chairs Ayité-Lô Ajavon (Togo) Paul Newman (USA) John Pyle (UK) A.R. Ravishankara (USA) Coordinator/Editor Chris Ennis (USA) Special thanks to: Malcolm Ko Ted Shepherd Susan Solomon with reviews and Executive Summary We are indebted to the two previous co-chairs: Daniel Albritton and Robert Watson 22 nd Meeting of the Parties to the United Nations Montreal Protocol November 8-12 Bangkok, Thailand

2. Seventh Scientific Assessment since MP Scientific Assessment of Ozone Depletion: 2010 [ Color? ] Terms of reference- The Montreal Protocol Parties interests: a)Assess the state of the ozone layer (including the ozone hole) and UV changes, and their future evolution (the best information at this date) b)Evaluate trends of ozone-depleting substances in the atmosphere c)Assess the impacts of climate change on ozone layer d)Assess the impacts of ozone layer changes on climate e) Assess approaches to evaluating very short-lived substances (likely substitutes for CFCs, transition chemicals, and new uses) f)Assess up-to-date information on HFCs and Carbon Tet (in a UNEP request)

3. Executive Summary Prologue: A Historic Perspective and Recap of 2006 Assessment Chapter 1:Ozone-Depleting Substances (ODSs) and Related Chemicals Steve Montzka (NOAA, USA); Stefan Reimann (EMPA, Switzerland) Chapter 2: Stratospheric Ozone and Surface Ultraviolet Radiation Anne Douglass (NASA, USA) ; Vitali Fioletov (Environment Canada, Canada) Chapter 3: Future Ozone and Its Impact on Surface UV Slimane Bekki (CNRS, France); Greg Bodeker (Bodeker Scientific, New Zealand) Chapter 4: Stratospheric Changes and Climate Piers Forster (University of Leeds, UK); Dave Thompson (Colorado State University, USA) Chapter 5: A Focus on Information and Options for Policymakers John Daniel (NOAA, USA); Guus Velders (Netherlands Environmental Assessment Agency, Netherlands) Twenty Questions and Answers About the Ozone Layer: 2010 Update David W. Fahey (NOAA, USA); Michaela Hegglin (University of Toronto, Canada) Assessment Report Contents To aid decision makers, students, new users… More user friendly

4. Seventh Assessment: Details Major Milestones: Executive Summary released September 16, 2010 Report to the Parties November 11, 2010 Posting on the websites: WMO: http://www.wmo.int/pages/mediacentre/press_releases/documents/ 898_ExecutiveSummary.pdf UNEP: http://ozone.unep.org/highlights.shtml Full report available to Parties in January 2011; printed April 2011 Participants: Over 300 scientists from 34 countries Roles: Cochairs; Coordinating Lead Authors; Lead Authors; Coauthors, Contributors, Reviewers First-draft preparation & review Second-draft preparation & review Final chapter preparation & document editing Third-draft preparation & review 2009 2010 2011 We are here

5. Report of the Scientific Assessment Panel 2006 1980 Now ~ 2100 ODS production, Ozone-depleting chlorine and bromine in the stratosphere Global ozone change Ultraviolet radiation change (a) (b) (c) (d) Montreal Protocol is working! 2010 ODSs Climate Change Ozone hole Global ozone Global UV Change Strengthened: Montreal Protocol is working!

6. Ozone-Depleting Substances (ODSs) The abundances of ODSs in the atmosphere are responding as expected to the controls of the Montreal Protocol. Total chlorine from ODSs continues to decline in both the lower atmosphere and the stratosphere. CFCs (not methyl chloroform) now contributing most to the chlorine decline. Carbon tetrachloride (in troposphere) is declining more slowly than expected and the exact cause is not certain. (Can provide more information at the end.) Total bromine from ODSs is declining in the lower atmosphere and is no longer increasing in the stratosphere. For the first time, the global atmospheric abundance of bromine from halons stopped increasing, and halon-1211 actually declined. Abundances of most HFCs and HCFCs are growing in the atmosphere. Some HCFCs (e.g., HCFC-22, HCFC-142b) increased faster than expected during the past four years.

7. Increasing abundances of radiatively important gases, especially carbon dioxide(CO 2 ) and methane (CH 4 ), are expected to significantly affect future stratospheric ozone through effects on temperature, winds, and chemistry. For the next few decades, the decline in ODSs will dominate the recovery of the ozone layer. As ODSs decline, climate change and other factors are expected to become increasingly more important to the future ozone layer. Ozone levels globally and at midlatitudes may even become larger than those before 1980. The Ozone Layer and Climate Change The ozone layer and climate change are intricately coupled, and climate change will become increasingly more important to the future ozone layer.

8. The ozone hole that occurs in austral springtime is projected to recover later in the century than any other region of the globe. The Antarctic ozone hole is much less influenced by climate change than other areas of the globe. ODSs primarily determine when the ozone hole will heal. Antarctic Ozone Hole

9. Control of ODSs by the Montreal Protocol has protected the ozone layer from much higher levels of depletion. Globally, the ozone layer is projected to recover to its 1980 level before the middle of this century. The Global Ozone Layer

10. Global surface UV levels have not increased significantly because the global ozone loss has been limited. If there were no MP, the surface UV levels would have been large Factors other than stratospheric ozone will determine surface UV levels in the future. Surface Ultraviolet Radiation The ozone layer and surface ultraviolet (UV) radiation are responding as expected to the ODS reductions achieved under the Montreal Protocol.

11. Control of ODSs by the Montreal Protocol also has had co-benefits for climate. The decrease in ODSs achieved under the Montreal Protocol is equivalent to a reduction of carbon dioxide (CO 2 ) that is five times larger than the target of the first commitment period of the Kyoto Protocol. Projections of HFC growth scenarios that assume no controls suggests that by 2050, GWP-weighted emissions of HFCs can be comparable to GWP-weighted emissions of CFCs at their peak in 1988. Montreal Protocol and Climate

12. Other Information for You The accelerated HCFC phase-out agreed to in 2007 is projected to reduce ozone depletion and to help reduce climate forcing. New fluorocarbons, suggested as possible replacements for HCFC and HFC that are potent greenhouse gases, are less potent greenhouse gases. Nitrous oxide (N 2 O) is known to both deplete global ozone and warm the climate. The current ODP-weighted anthropogenic emission is larger than that of any ODS. Geo-engineering: Deliberate large injections of sulfur- containing compounds into the stratosphere would alter the radiative, dynamical, and chemical state of the stratosphere and could be expected to have substantial unintended effects on stratospheric ozone levels.

13. Ozone Hole and Surface Climate The impact of ozone hole on surface climate has become more evident. There are many influences on climate from the ozone hole. The Antarctic ozone hole has caused wind pattern changes in the Southern Hemisphere lower atmosphere. Because of these changes, for example, the surface climate has warmed over the Antarctic Peninsula and cooled over the high plateau.

14. Options for further limiting future emissions of ODSs could advance recovery dates by a few years; However, the impact these potential emission reductions on future ozone levels would be less than what has already been accomplished by the Montreal Protocol. Options and Expected Gains

15. Thank you for your attention

16. Backup Slides 16

17. Emission tonnage of CFCs, HCFCs, and HFCs 195019701990201020302050 Megatonnes per year 0 2 3 1

18. Emissions derived from data reported to UNEP are highly variable and on average appear smaller than those inferred from observed trends. Although the size of this discrepancy is sensitive to uncertainties in our knowledge of how long CCl4 persists in the atmosphere (i.e., lifetime), the variability cannot be explained by lifetime uncertainties. Errors in reporting, errors in analysis of reported data, and/or unknown sources are likely responsible for the year-to- year discrepancies. Carbon Tetrachloride

19. Options and Expected Gains