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Report of the Scientific Assessment Panel
SAP Co-chairsAyité-Lô Ajavon (Togo)
Paul Newman (USA)John Pyle (UK)
A.R. Ravishankara (USA)
Coordinator/EditorChris Ennis (USA)
Special thanks to:Malcolm Ko
Ted ShepherdSusan Solomon
with reviews and Executive Summary
We are indebted to the two previous co-chairs:Daniel Albritton and Robert Watson
22nd Meeting of the Parties to theUnited Nations Montreal Protocol
November 8-12Bangkok, Thailand
Seventh Scientific Assessment since MP
Scientific Assessment ofOzone 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)
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 RadiationAnne Douglass (NASA, USA) ; Vitali Fioletov (Environment Canada, Canada)
Chapter 3: Future Ozone and Its Impact on Surface UVSlimane Bekki (CNRS, France); Greg Bodeker (Bodeker Scientific, New Zealand)
Chapter 4: Stratospheric Changes and ClimatePiers Forster (University of Leeds, UK); Dave Thompson (Colorado State University, USA)
Chapter 5: A Focus on Information and Options for PolicymakersJohn Daniel (NOAA, USA); Guus Velders (Netherlands Environmental Assessment Agency,
Netherlands)
Twenty Questions and Answers About the Ozone Layer: 2010 UpdateDavid W. Fahey (NOAA, USA); Michaela Hegglin (University of Toronto, Canada)
Assessment Report Contents
To aid decision makers, students, new users… More “user friendly”
Seventh Assessment: Details
Major Milestones:Executive Summary released September 16, 2010Report to the Parties November 11, 2010
Posting on the websites:WMO: http://www.wmo.int/pages/mediacentre/press_releases/documents/
898_ExecutiveSummary.pdfUNEP: 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-draftpreparation &
review
Second-draftpreparation &
review
Final chapter preparation & document editing
Third-draft preparation &
review
2009 2010 2011
We are here
Report of the Scientific Assessment Panel
2006
1980 Now ~ 2100
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Montreal Protocol is working!
2010
ODSs
Climate Change
Ozone hole
Global ozone
Global UV Change
Strengthened: Montreal Protocol is working!
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.
Increasing abundances of radiatively important gases, especially carbon dioxide(CO2) and methane (CH4), 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.
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
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
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.
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 (CO2) 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
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 (N2O) 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.
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.
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
Thank you for
your attention
Backup Slides
16
Emission tonnage of CFCs, HCFCs, and HFCs
1950 1970 1990 2010 2030 2050
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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
Options and Expected Gains