Download The Global Ozone Layer

Report of the Scientific Assessment Panel
22nd Meeting of the Parties to the
United Nations Montreal Protocol
November 8-12
Bangkok, Thailand
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
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)
d)
e)
f)
Assess the impacts of climate change on ozone layer
Assess the impacts of ozone layer changes on climate
Assess approaches to evaluating very short-lived substances (likely
substitutes for CFCs, transition chemicals, and new uses)
Assess up-to-date information on HFCs and Carbon Tet (in a UNEP request)
Assessment Report Contents
Executive Summary
Prologue: A Historic Perspective and Recap of 2006 Assessment
Chapter 1:
Ozone-Depleting Substances (ODSs) and Related Chemicals
Steve Montzka (NOAA, USA);
Chapter 2:
To aid decision
makers,
students, new
users… More
“user friendly”
Stefan Reimann (EMPA, Switzerland)
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)
Seventh Assessment: Details
Participants:
 Over 300 scientists from 34 countries
Roles:
Cochairs; Coordinating Lead Authors; Lead Authors;
Coauthors, Contributors, Reviewers
We are here
2009
Second-draft
First-draft
preparation & preparation &
review
review
2010
Third-draft
preparation &
review
2011
Final chapter preparation
& document editing
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
Report of the Scientific Assessment Panel
Ultraviolet
radiation change
Global
ozone
change
Ozone-depleting
chlorine and
bromine in the
stratosphere
2010
(a)
,
ODS
production
2006
ODSs
Climate
Change
(b)
Ozone
hole
(c)
Global
ozone
Global UV
Change
(d)
1980
Now
Montreal Protocol
is working!
~ 2100
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.
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.
 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.
Antarctic Ozone Hole
 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.
The Global Ozone Layer
 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.
Surface Ultraviolet Radiation
The ozone layer and surface ultraviolet (UV) radiation are
responding as expected to the ODS reductions achieved
under the Montreal Protocol.
 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.
Montreal Protocol and Climate
 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.
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 sulfurcontaining 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 and Expected Gains
 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.
Thank you
for
your attention
Backup Slides
16
Megatonnes per year
Emission tonnage of CFCs,
HCFCs, and HFCs
3
2
1
0
1950
1970
1990
2010
2030
2050
Carbon Tetrachloride
 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-toyear discrepancies.
Options and Expected Gains