1. Research Needs* We are now in the accountability phase of MP, where we must closely monitor the layer through the sensitive recovery period. - Are our actions having the desired effects? - Is the ozone layer recovering? Vigilance is essential during adaptation to and mitigation of climate change. - Are there any unintended consequences to the ozone layer? [*Adapted from: Synthesis and Assessment Product 2.4: Trends in Emissions of Ozone Depleting Substances, Ozone Layer Recovery, and Implications for UV Radiation Exposure] Starting from Ravis talk on Sunday

2. Scientific Findings 1980 Now 2100 ODS production Global ozone change Ultraviolet radiation change (a) (b) (c) (d) ODS production ODS in the atmosphere Ozone levels- measured and predicted UV levels- measured and predicted Ozone-depleting chlorine and bromine in the stratosphere There is even stronger evidence since the 2002 Assessment that the Montreal Protocol is working

3. ODS are decreasing & the ozone layer is starting its recovery Climate change and ODSs will affect the future of ozone layer Decreases in ODS emissions already achieved by MP is the dominant factor in return to pre-1980 values But failure to continue compliance with the MP could delay or even prevent the recovery of the ozone layer Global ozone layer (60 o S-60 o N) is expected to recover to pre-1980 values around 2050 Return of ozone to pre-1980 levels

4. A balanced programme of atmospheric observations, laboratory measurements, modelling and data analysis. Particular plea for (continued) collection of long-term measurements for science.

5. Testing convection? O3 sondes SHADOZ + SCOUT-O3 AMMA data Pacific Samoa 14ºS Africa/Indian Ocean Reunion I 21ºS Continental Africa Niamey 12 º N July 2006 Atlantic Ascension 7ºS

6. Gaps in Our Knowledge and Future Needs 1. Continued atmospheric observations - Ozone - ODS - New releases (ascertain their ozone friendliness!) - UV and its changes Needs recognised here include the absolute necessity to maintain high quality GB observations concerns about satellite data (gaps) - hi-res ozone profiles; ODS (Cly, Bry) evolution; water vapour; ozone diagnostics.

7. Gaps and needs, continued 2. Understanding the processes that impact ozone layer - chemical processes Need for updated lab measurements, e.g. ClO dimer, ODS lifetimes - dynamical processes e.g., strengthening BD circulation; ODS lifetimes - New releases 3. Global models - Deal with stratosphere as an integral part of the Earth system - Enable better prediction of recovery and accounting CCMVal activity 4. Reporting and documentation - Better accounting for ODSs and related chemicals

8. Important that we maximise use of all resources - infrastructure, capital and human. Overlap between programmes? Overlap of data bases? Trust fund/capacity building?