World Meteorological Organization
`Global Ozone Research and Monitoring Project—Report No. 47
`
`SCIENTIFIC ASSESSMENT OF
`
`OzoNE DEPLETION: 2002
`
`Purszzant to Article 6 oft/ze Montreal Protocol
`on .S'zzb.s‘tanc*es that Deplete the Ozone La_i=er
`
`National Oceanic and Atmospheric Administration
`National Aeronautics and Space Administration
`United Nations Environment Programme
`World Meteorological Organization
`European Commission
`
`Page 1 of 111
`
`Arkema Exhibit 1104
`
`Arkema Exhibit 1104
`
`

`
`LIST OF INTERNATIONAL AUTHORS,
`
`CONTRIBUTORS, AND REVIEWERS
`
`Assessment Cochairs
`
`Ayite'-L6 Nohende Ajavon
`Daniel L. Albritton
`
`Gerard Mégie
`Robert T. Watson
`
`Chapters and Lead Authors
`
`Controlled Substances and Other Source Gases (Stephen A. Mont:/ca and Paul J. Fraser)
`Chapter 1.
`Very Short-Lived Halogen and Sulfur Substances (Malcolm K. W. K0 and Gilles Poulet)
`Chapter 2.
`Polar Stratospheric Ozone: Past and Future (Paul/1. Newman and John A. Pyle)
`Chapter 3.
`Chapter 4. Global Ozone: Past and Future (Martyn P. Chipper/ield and William J. Randel)
`Chapter 5.
`Surface Ultraviolet Radiation: Past and Future (James 8. Kerr and Gunther Sec/mieyer)
`
`Twenty Questions and Answers About the Ozone Layer (David W. Fahey)
`
`Coordinating Editor
`Christine A. Ennis
`
`Authors, Contributors, and Reviewers
`
`Italy
`Togo
`US
`US
`Belgium
`US
`US
`
`Geir O. Braathen
`Peter Braesicke
`Guy P. Brasseur
`Bram Bregman
`Christoph Briihl
`William Brune
`James H. Burkholder
`
`Argentina
`Finland
`
`Neal Butchart
`James H. Butler
`
`US
`South Africa
`UK
`US
`Greece
`
`US
`Canada
`Albania
`US
`US
`
`US
`Austria
`
`New Zealand
`Germany
`France
`
`James Calm
`Pablo O. Canziani
`Ken S. Carslaw
`Marie-Lise Chanin
`Mian Chin
`
`Martyn P. Chipperfield
`John Christy
`Peter S. Connell
`Brian Connor
`David B. Considine
`
`R. Anthony Cox
`Derek M. Cunnold
`
`Martin Dameris
`John S. Daniel
`Richard G. Derwent
`
`UK
`
`Susana B. Diaz
`
`iii
`
`Norway
`UK
`Germany
`The Netherlands
`Germany
`US
`US
`
`UK
`US
`
`US
`Argentina
`UK
`France
`US
`
`UK
`US
`US
`New Zealand
`US
`
`UK
`US
`
`Germany
`US
`UK
`
`Argentina
`
`Alberto Adriani
`Ayité-L6 Nohende Ajavon
`Daniel L. Albritton
`Douglas R. Allen
`Georgios T. Amanatidis
`Stephen 0. Andersen
`James Anderson
`
`Gustavo A. Argijello
`Antti Arola
`
`Roger Atkinson
`Pieter J. Aucamp
`John Austin
`Linnea M. Avallone
`Alkiviadis F. Bais
`
`Mark P. Baldwin
`Stephen R. Beagley
`Pranvera Bekteshi
`Germar Bernhard
`Donald R. Blake
`
`Nicola J. Blake
`Mario Blumthaler
`
`Greg E. Bodeker
`Rumen D. Bojkov
`Olivier Boucher
`
`Michel Bourqui
`
`Page 2 of 111
`
`

`
`AUTHORS, CONTRIBUTORS, AND REVIEWERS
`
`US
`US
`US
`US
`US
`US
`Brazil
`US
`Estonia
`US
`
`Germany
`US
`US
`UK
`Canada
`US
`Canada
`UK
`Australia
`US
`US
`US
`US
`US
`France
`France
`
`Kenya
`France
`
`Kenya
`Germany
`Germany
`UK
`US
`UK
`UK
`France
`UK
`US
`US
`US
`US
`US
`
`Egypt
`Malaysia
`Japan
`Norway
`US
`US
`Colombia
`New Zealand
`Australia
`
`M.A.K. Khalil
`Peter W. Kiedron
`
`Dieter Kley
`Bjorn Knudsen
`Malcolm K.W. Ko
`Yutaka Kondo
`Yuri Koshelkov
`Karin Kreher
`
`Nickolay A. Knotkov
`Janusz W. Krzyscin
`Lambert Kuijpers
`Michael J. Kurylo
`Karin Labitzke
`Murari Lal
`
`Shyam Lal
`Ulrike Langematz
`Kathleen O. Lantz
`Neils Larsen
`Katherine S. Law
`Mark G. Lawrence
`
`J . Ben Liley
`Roger Lin
`Shaw Liu
`
`Jennifer A. Logan
`Craig S. Long
`Daniel Lubin
`A. Robert MacKenzie
`Sasha Madronich
`Emmanuel Mahieu
`
`Gloria L. Manney
`Elisa Manzini
`Céline Mari
`
`Timothy J. Martin
`W. Andrew Matthews
`
`Konrad Mauersberger
`Archie McCulloch
`
`Gordon McFadyen
`Mack McFarland
`Daniel S. McKenna
`Richard L. McKenzie
`Richard D. McPeters
`Ralf Meerkotter
`
`Gerard Megie
`Inna A. Megretskaia
`Davit Melkonyan
`Abdelwahid Mellouki
`
`Pauline M. Midgley
`Alvin J. Miller
`
`Stephen A. Montzka
`Rolf Muller
`Nzioka John Muthama
`
`Japan
`US
`Canada
`
`Tatsuya Nagashima
`Hideaki N akane
`Eric R. Nash
`
`US
`US
`
`Germany
`Denmark
`US
`
`Japan
`Russia
`New Zealand
`US
`Poland
`The Netherlands
`US
`
`Germany
`India
`India
`
`Germany
`US
`Denmark
`UK
`
`Germany
`New Zealand
`US
`Taiwan R.O.C.
`US
`US
`US
`UK
`US
`
`Belgium
`US
`
`Germany
`France
`Austria
`New Zealand
`
`Germany
`UK
`UK
`US
`US
`New Zealand
`US
`
`Germany
`France
`US
`Armenia
`France
`
`Germany
`US
`US
`
`Germany
`Kenya
`Japan
`Japan
`US
`
`Ed Dlugokencky
`Anne R. Douglass
`Katja Drdla
`Thomas Duafala
`Ellsworth S. Dutton
`Victor L. Dvortsov
`
`Ezequiel Echer
`Stephen Eckermann
`Kalju Eerme
`James W. Elkins
`
`Andreas Engel
`Christine A. Ennis
`
`David W. Fahey
`Joe Farman
`Vitali E. Fioletov
`
`Eric L. Fleming
`Ian Folkins
`Piers M. de F. Forster
`Paul J. Fraser
`Randall R. Friedl
`Ru—Shan Gao
`Rolando R. Garcia
`Marvin A. Geller
`
`Melvyn Gelman
`Christian George
`Sophie Godin-Beekmann
`Marco Gonzalez
`Florence Goutail
`Michael Graber
`Hans-F. Graf
`Volker Gnewe
`
`Joanna D. Haigh
`Patrick Hamill
`
`David B. Harper
`Neil R.P. Harris
`
`Didier Hauglustaine
`Peter H. Haynes
`Jay R. Herman
`David J. Hofmann
`James R. Holton
`Robert D. Hudson
`Drusilla Hufford
`Abdelmoneim A. Ibrahim
`
`Mohammad llyas
`Takashi Imamura
`Ivar S.A. Isaksen
`Charles H. Jackman
`Daniel J. Jacob
`
`Mauricio Jaramillo—Ayerbe
`Paul Johnston
`
`David Karoly
`Nozomi Kawamoto
`
`Jack A. Kaye
`James B. Kerr
`
`Page 3 of 111
`
`

`
`AUTHORS, CONTRIBUTORS, AND REVIEWERS
`
`UK
`US
`US
`US
`UK
`US
`UK
`Bolivia
`Greece
`UK
`US
`UK
`India
`Switzerland
`
`Germany
`Italy
`Germany
`Australia
`France
`US
`US
`France
`US
`Chile
`US
`Switzerland
`UK
`India
`US
`US
`Australia
`US
`US
`UK
`
`Germany
`US
`US
`Sweden
`US
`
`Norway
`US
`US
`Switzerland
`US
`
`Kenya
`Iran
`US
`Venezuela
`US
`
`Japan
`Japan
`US
`
`Germany
`Germany
`
`Ulrich Schumann
`
`M. Daniel Schwarzkopf
`Paul W. Seakins
`
`Gunther Seckmeyer
`Dian J. Seidel
`
`Dudley Shallcross
`Theodore G. Shepherd
`Drew T. Shindell
`Keith P. Shine
`Masanori Shitamichi
`Peter G. Simmonds
`Paul C. Simon
`
`Harry Slaper
`James R. Slusser
`Claire A. Smith
`
`Sergei Smyshlyaev
`Susan Solomon
`Johannes Stahelin
`L. Paul Steele
`Andreas Stohl
`Richard S. Stolarski
`Susan E. Strahan
`
`B.H. Subbaraya
`Christine C. Sweet
`Petteri Taalas
`Azadeh Tabazadeh
`David W. Tarasick
`
`Gary Taylor
`Manfred Tevini
`Christiane Textor
`
`Larry W. Thomason
`David Thompson
`Claudia Timmreck
`
`Darin W. Toohey
`Geoffrey C. Toon
`Adrian F. Tuck
`Jan C. van der Leun
`Michel Van Roozendael
`Michiel van Weele
`Guus J.M. Velders
`Jean Verdebout
`Mario Visca
`C. Michael Volk
`Peter von der Gathen
`
`Ray Wang
`Joe W. Waters
`Robert T. Watson
`
`Darryn W. Waugh
`Elizabeth C. Weatherhead
`
`Philipp Weihs
`Debra K. Weisenstein
`
`Ray F. Weiss
`Paul O. Wennberg
`Fei Wu
`
`Germany
`US
`UK
`
`Germany
`US
`UK
`Canada
`US
`UK
`
`Japan
`UK
`
`Belgium
`The Netherlands
`US
`UK
`Russia
`US
`Switzerland
`Australia
`
`Germany
`US
`US
`India
`US
`Finland
`US
`Canada
`Canada
`Denmark
`
`Germany
`US
`US
`
`Germany
`US
`US
`US
`The Netherlands
`
`Belgium
`The Netherlands
`The Netherlands
`
`Italy
`Italy
`Germany
`Germany
`US
`US
`US
`US
`US
`Austria
`US
`US
`US
`US
`
`John Nash
`Patrick J. Neale
`Paul A. Newman
`Samuel J. Oltmans
`Alan O’Neill
`
`Michael Oppenheimer
`David E. Oram
`
`Eduardo Palenque
`Panos Papagiannakopuolos
`David Parker
`Steven Pawson
`Stuart A. Penkett
`Sunil Kumar Peshin
`Thomas Peter
`Klaus Pfeilsticker
`Giovanni Pitari
`Ulrich Platt
`Ian Plumb
`Jean—Pierre Pommereau
`Lamont R. Poole
`Robert W. Portmann
`Gilles Poulet
`Michael J . Prather
`
`Margarita Préndez
`Ronald Prinn
`Michael H. Proffitt
`
`John A. Pyle
`S. Ramachandran
`
`V. Ramaswamy
`William J. Randel
`
`Lakshman Randeniya
`Philip J. Rasch
`A.R. Ravishankara
`Claire E. Reeves
`Markus Rex
`
`Brian A. Ridley
`Curtis P. Rinsland
`
`Henning Rodhe
`José M. Rodriguez
`Bjcirg Rognerud
`Joan E. Rosenfield
`Martin N. Ross
`
`Eugene Rozanov
`James M. Russell III
`
`Nelson A. Saboga]
`Ali A. Sabzipavar
`Ross J. Salawitch
`
`Eugenio Sanhueza
`Michelle L. Santee
`Toru Sasaki
`Yasuhiro Sasano
`Sue M. Schauffler
`Ulrich Schmidt
`Christina Schnadt
`
`Page 4 of 111
`
`

`
`AUTHORS, CONTRIBUTORS, AND REVIEWERS
`
`Donald J. Wuebbles
`Yoko Yokouchi
`Vladimir Yushkov
`
`Rodolphe J. Zander
`Francesco Zaratti
`
`US
`Japan
`Russia
`
`Belgium
`Bolivia
`
`Joseph M. Zawodny
`Christos S. Zerefos
`Xiuji Zhou
`
`Tong Zhu
`
`US
`Greece
`China
`
`China
`
`Page 5 of 111
`
`vi
`
`

`
`CONTENTS
`
`SCIENTIFIC ASSESSMENT OF OZONE DEPLETION: 2002
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`. .
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`. .
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`. .
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`. .
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`. .
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`. .
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`. ix
`.
`. xiii
`
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`PREFACE .
`EXECUTIVE SUMMARY .
`
`.
`.
`
`. .
`.
`.
`
`.
`.
`
`.
`.
`
`CHAPTER 1: CONTROLLED SUBSTANCES AND OTHER SOURCE GASES
`Lead Authors: S./1. Montzka and RJ. Fraser
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`. 1.1
`. 1.5
`
`Scientific Summary .
`1.1
`Introduction .
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`1.2
`1.3
`
`.
`.
`Halogenated Ozone—Depleting Gases in the Atmosphere .
`Halocarbon Sources Estimated from lndustrial Production .
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`
`.
`
`.
`.
`
`.
`.
`.
`.
`
`.
`.
`
`.
`.
`.
`.
`
`.
`.
`
`.
`.
`.
`.
`
`.
`.
`
`.
`.
`.
`.
`
`.
`.
`
`.
`.
`.
`.
`
`. 1.5
`.
`. 1.19
`
`. 1.21
`. 1.36
`. 1.44
`. 1.51
`
`Halocarbon Lifetimes, Ozone Depletion Potentials, and Global Warming Potentials .
`1.4
`1.5 Methyl Bromide and Methyl Chloride .
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`1.6
`Atmospheric Halocarbon Observations Compared with Expectations
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`1.7
`Other Trace Gases .
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`Halogenated Source Gases in the Future
`1.8
`References .
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`. 1.61
`. .1.7l
`
`CHAPTER 2: VERY SHORT—LlVED HALOGEN AND SULFUR SUBSTANCES
`Lead Authors: M.K. W K0 and G. Poulet
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`. 2.1
`. 2.5
`
`Scientific Summary .
`2.1
`lntroduction .
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`2.2
`
`Dynamical and Chemical Characteristics of the Upper Troposphene (UT) and the Tropical
`.
`.
`.
`Tropopause Layer (ITL) .
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`Atmospheric Chemistry of Halogenated Very Short-Lived (VSL) Substances
`.
`.
`.
`.
`.
`.
`.
`.
`.
`2.3
`Contribution of Halogenated VSL Substances to the Stratospheric Inorganic Halogen Budget
`2.4
`Estimates for the Potential Impact of Halogenated VSL Substances on Column Ozone .
`.
`.
`.
`.
`2.5
`VSL Sulfur Species and Stratospheric Aerosols .
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`2.6
`References .
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`
`CHAPTER 3: POLAR STRATOSPHERJC OZONE: PAST AND FUTURE
`
`Lead Authors: RA. Newman and J.A. Pyle
`Scientific Summary .
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`3.0
`Introduction .
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`
`.
`.
`.
`
`.
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`.
`
`.
`.
`.
`.
`.
`.
`
`. 2.7
`.
`. 2.15
`. 2.25
`. 2.34
`. 2.39
`. 2.44
`
`.
`.
`
`. 3.1
`. 3.5
`
`. 3.6
`.
`. 3.13
`. 3.41
`. 3.58
`. 3.66
`. 3.81
`
`.
`.
`.
`.
`.
`.
`.
`Trends of Ozone and Temperature in the Polar Stratosphere .
`3.1
`.
`.
`.
`.
`.
`.
`.
`Basic Polar Stratospheric Processes .
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`3.2
`.
`.
`.
`.
`.
`.
`Quantification of Polar Ozone Loss: Observations and Models
`3.3
`.
`.
`.
`.
`.
`.
`.
`Causes of Polar Stratospheric Temperature Trends .
`.
`.
`.
`.
`.
`.
`.
`.
`.
`3.4
`Chemical-Climate Modeling of the Past and Future Polar Stratosphere .
`3.5
`References .
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`.
`
`Appendix 3A: Satellite Measurements in the Antarctic and Arctic .
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`.
`.
`.
`.
`.
`
`.
`
`.
`
`. 3.104
`
`Page 6 of 111
`
`vii
`
`

`
`CONTENTS
`
`CHAPTER 4: GLOBAL OZONE: PAST AND FUTURE
`Lead Authors: M.P. Chipperfield and W.J. Randel
`Scientific Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1
`4.1
`Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5
`4.2
`Description of Past Changes in Ozone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6
`4.3
`Current Understanding of Past Changes in Stratospheric Aerosol, Water Vapor, and NO2 . . . . . . . . . . . . . . 4.25
`4.4
`Current Understanding of Past Changes in Stratospheric Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.29
`4.5
`Chemical Influence on Past Changes in Ozone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.37
`4.6
`Dynamical Influence on Past Changes in Ozone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.52
`4.7
`Implications for Climate of Updated Stratospheric Ozone Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.62
`4.8
`Future Changes in Ozone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.63
`4.9
`Synthesis of Current Understanding of Past and Future Changes in Ozone . . . . . . . . . . . . . . . . . . . . . . . . . 4.70
`References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4.72
`Appendix 4A: Description of Ozone Datasets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.85
`Appendix 4B: 2-D Model Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.90
`
`CHAPTER 5: SURFACE ULTRAVIOLET RADIATION: PAST AND FUTURE
`Lead Authors: J.B. Kerr and G. Seckmeyer
`Scientific Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1
`5.1
`Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5
`5.2
`Current Understanding of Factors Affecting Surface UV Radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5
`5.3
`Available Resources for Studying Surface UV Radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.11
`5.4
`UV Climatology, Temporal Changes, and Trends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.20
`5.5
`Expectations of UV in the Future . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.25
`References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.31
`Appendix 5A: Spectral Data Available from Databases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.43
`Appendix 5B:
`Internet Addresses for UV Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.45
`
`TWENTY QUESTIONS AND ANSWERS ABOUT THE OZONE LAYER
`Lead Author: D.W. Fahey
`Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q.1
`I.
`Ozone in Our Atmosphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q.3
`II.
`The Ozone Depletion Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q.8
`III.
`Stratospheric Ozone Depletion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q.21
`IV.
`Controlling Ozone-Depleting Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q.28
`V.
`Implications of Ozone Depletion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q.32
`VI.
`Stratospheric Ozone in the Future . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q.36
`
`APPENDICES
`A
`LIST OF INTERNATIONAL AUTHORS, CONTRIBUTORS, AND REVIEWERS . . . . . . . . . . . . . . . . . . A.1
`B
`MAJOR ACRONYMS AND ABBREVIATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B.1
`C
`MAJOR CHEMICAL FORMULAE AND NOMENCLATURE FROM THIS ASSESSMENT . . . . . . . . . . C.1
`
`viii
`
`Page 7 of 111
`
`

`
`PREFACE
`
`The present document will be part ofthe information upon which the Parties to the United Nations Montreal
`Protocol will base their fisture decisions regarding protection ofthe stratospheric ozone layer.
`
`The Charge to the Assessment Panels
`
`. the Parties
`.
`Specifically, the Montreal Protocol on Substances that Deplctc the Ozone Layer states (Article 6):
`shall assess the control measures .
`.
`. on the basis of available scientific, environmental. technical. and economic informa-
`
`tion." To provide the mechanisms whereby these assessments are conducted. the Protocol further states:
`shall convene appropriate panels of experts" and “the panels will report their conclusions .
`.
`. to the Parties."
`
`.
`
`. the Parties
`
`To meet this request. the Scientific Assessment Panel. the Environmental Effects Panel. and the Technology and
`Economic Assessment Panel have each prepared. about every 3-4 years. major assessment reports that updated the state
`of understanding in their purviews. These reports have been scheduled to be available to the Parties in advance oftheir
`meetings at which they will consider the need to amend or adjust the Protocol.
`
`The Sequence of Scientific Assessments
`
`The current 2002 report is the latest in a series of nine scientific assessments prepared by the world’s leading
`experts in the atmospheric sciences and under the international auspices of the World Meteorological Organization
`(WMO) and/or the United Nations Environment Programme (UNEP). This report is the fifth in the set of major assess-
`ments that have been prepared by the Scientific Assessment Panel directly as input to the Montreal Protocol process. The
`chronology of all the scientific assessments on the understanding of ozone depletion and their relation to the international
`policy process is summarized as follows:
`
`Em
`
`I981
`
`[985
`1987
`
`1988
`
`1989
`
`[990
`
`[991
`
`1992
`
`1992
`
`I994
`
`1995
`
`fl3
`
`Vienna Convention
`Montreal Protocol
`
`London Adjustments and
`Amendment
`
`Copenhagen Adjustments
`and Amendment
`
`Vienna Adjustment
`
`The Stratosphere 1981.‘ Theory and Measurements. WMO No.
`
`l l.
`
`Atmospheric ():one I 985. Three volumes. WMO No. I6.
`
`International Ozone Trends Panel Report I 988.
`Two volumes. WMO No. I8.
`
`Scientific Assessment ofStratospherie Ozone:
`Two volumes. WMO No. 20.
`
`1 989.
`
`Scientific Assessment ofO:one Depletion: I991. WMO No. 25.
`
`Meth_t-'l Bromide: [ts Atmospheric Science, Tee/molog_v, and
`Economics (Montreal Protocol Assessment Supplement).
`UNEP (1992).
`
`Scientific Assessment of Ozone Depletion: 1994. WMO No. 37.
`
`Page 8 of 111
`
`ix
`
`

`
`PREFACE
`
`Q Policy Process
`
`Scientific Assessment
`
`1997
`
`1998
`
`1999
`
`2002
`
`2003
`
`Montreal Adjustments
`and Amendment
`
`Beijing Amendment
`
`15"‘ Meeting ofthe Parties
`
`The Current Infonnation Needs of the Parties
`
`Scienttfic Assessment of Ozone Depletion: I 998. WMO No. 44.
`
`Scientific Assessment ofO:one Depletion: 2002. WMO No. 47.
`
`The genesis of Scierztifie Assessment of Ozone Depletion: 2002 occurred at the l 1th Meeting of the Parties to the
`Montreal Protocol in Beijing. China. at which the scope of the scientific needs ofthe Parties was defined in their Decision
`XI/l 7.5(a): “To request the Scientific Assessment Panel to include the following in the 2002 scientific assessment:
`
`(a) An evaluation of the observed trends in controlled substances and their consistency with reported production
`of ODS;
`
`(b) A quantification of the ozone-depleting impacts of new (e.g., short-lived) halogen-containing substances;
`(c) A characterization of methyl bromide sources and sinks and the likely quantitative implications of the results
`for the ozone layer;
`(d) A characterization of the known interrelations between ozone depletion and climate change including feed-
`backs between the two;
`
`(e) A description and interpretation of the observed changes in global and polar ozone and in ultraviolet radia-
`tion, as well as set future projections and scenarios for those variables, taking into account also the expected
`impacts ofclimate change. .
`
`The Assessment Process
`
`The formal planning of the current assessment was started early in 2001. At the request of the Scientific Assessment
`Panel, the Parties suggested experts from their countries who could participate in the process, and those suggestions con-
`tributed about half of the participants who served as authors, contributors, and reviewers. Furthermore, an ad hoc intema-
`tional scientific steering group also suggested participants from the world scientific community.
`In addition, this steering
`group contributed to crafting the outline ofthe assessment report. As in previous assessments, the participants repre-
`sented experts from the developed and developing world. The developing-world experts bring a special perspective to
`the process, and their involvement in the process contributes to capacity building.
`
`The information of the 2002 assessment is contained in five chapters, with most containing past trends and future
`projections associated with ozone-layer topics:
`
`Chapter 1. Controlled Substances and Other Source Gases
`Chapter 2. Very Short-Lived Halogen and Sulfiir Substances
`Chapter 3. Polar Stratospheric Ozone: Past and Future
`Chapter 4. Global Ozone: Past and Future
`Chapter 5. Surface Ultraviolet Radiation: Past and Future
`
`The interactions between the ozone layer and the climate system are varied and appear appropriately as a special section
`in most of the chapters.
`
`A special resource for the Panel’s work was the earlier report, Aviation and the Global Atmosphere. This 1999
`assessment of the impacts of aviation on ozone depletion and climate change was a collaboration of the lntergovemmental
`Panel on Climate Change (IPCC) and the Scientific Assessment Panel ofthe Montreal Protocol. The assessment had
`been requested by the International Civil Aviation Organization (ICAO). Because this comprehensive study had been
`
`Page 9 of 111
`
`

`
`PREFACE
`
`recently done, the present 2002 assessment could cite the major relevant findings ofthe [999 study and provide any
`updates of knowledge that had occurred.
`
`The initial plans for the chapters of the 2002 Scientific Assessment Panel's report were examined at a meeting that
`occurred on 27-28 June 2001 in London. United Kingdom. The Lead Authors and Coehairs focused on the content of the
`draft chapters and establishing the needs for coordination among the chapters.
`
`The first drafts of the chapters were examined at a meeting that occurred on 28-30 November 2001 in Fairfax,
`Virginia, United States, at which the Lead Authors, Cochairs, and a small group ofinternational experts focused on the
`scientific content of the draft chapters.
`
`The second drafts of the chapters were reviewed by I33 scientists worldwide in a mail peer review. Those com-
`ments were considered by the authors. At a Panel Review Meeting in Les Diablerets, Switzerland, held on 24-28 June
`2002, the responses to these mail review comments were proposed by the authors and discussed by the 74 participants.
`Final changes to the chapters were decided upon at this meeting. The Executive Summary contained herein (and posted
`on the UNEP and WMO web sites on 23 August 2002) was prepared and completed by the attendees ofthe Les Diablerets
`meeting.
`
`The 2002 State-of-Understanding Report
`
`In addition to the scientific chapters and the Executive Summary. the assessment also focuses on a set of questions
`that are frequently asked about the ozone layer. Based upon the scientific understanding represented by the assessments,
`answers to these frequently asked questions were prepared, with different readerships in mind, e.g., students and the gen-
`eral public. These questions and answers are included in this report.
`
`The final result of this two-year endeavor is the present assessment report. As the accompanying list indicates, the
`Scientific Assessment of Ozone Depletion: 2002 is the product of 275 scientists from the developed and developing world
`who contributed to its preparation and review‘ (170 scientists prepared the report and 182 scientists participated in the
`peer review process).
`
`I Participating were Albania, Argentina, Annenia, Australia, Austria. Belgium,Bolivia, Brazil, Canada, Chile. Colombia. Denmark. Egypt, Estonia,
`Finland France, Germany, Greece, India, Iran, Italy, Japan, Kenya, Malaysia, New Zealand, Norway, Poland, Russia, South Africa, Sweden, Switzerland,
`Taiwan R.O.C., The Netherlands, The People’s Republic ofChina, Togo, United Kingdom, United States ofAmerica, and Venezuela.
`
`Page 10 of 111
`
`xi
`
`

`
`EXECUTIVE SUMMARY
`
`The provisions of the [987 Montreal Protocol on Substances that Deplete the Ozone Layer include the requirement
`that the Parties to the Protocol base their future decisions on the current scientific. environmental. technical. and eco-
`
`nomic information that is assessed through panels drawn from the worldwide expert communities. To provide that input
`to the decision-making process. advances in understanding on these topics were assessed in 1989. I991. I994. and 1998.
`This information helped support discussions among the Parties that led to the subsequent Amendments and Adjustments
`ofthe I987 Protocol. The 2002 Scientific Assessment summarized here is the fifth in that series.
`
`RECENT MAJOR FINDINGS AND CURRENT SCIENTIFIC UNDERSTANDING
`
`I 998, numerous laboratory investigations. atmospheric
`Since the Scierttific Assessment of Ozone Depletion.‘
`observations. and theoretical and modeling studies have produced new key findings and have strengthened overall under-
`standing of the ozone layer and its effect on ultraviolet (UV) radiation. These advances are highlighted in the following
`summary of the current understanding of the impact of human activities and natural phenomena on the ozone layer and
`the coupling ofthe ozone layer and the climate system.
`
`Changes in Ozone-Depleting Compounds
`
`0
`
`0
`
`In the troposphere (i.e.. lower atmosphere). observations show that the total combined el'l'ecti\‘e abundance
`of ozone-depleting compounds continues to decline slowly l'rom the peak that occurred in 1992-1994. Total
`chlorine is declining. while bromine from industrial halons is still increasing. albeit at a slower rate than was
`occurring pre\'iousI)' (and as reported in the 1998 Assessment). Total tropospheric chlorine from the long- and
`short-lived chlorocarbons was about 5% lower in 2000 than that observed at its peak in 1992-1 994, and the rate of
`change in 2000 was about -22 parts per trillion (ppt) per year (-0.6% per year). The once-dominant infiuenec of
`methyl chlorofomi (CH3CCl3) on this total decline is diminishing because the atmospheric abundance of methyl
`chloroform is sharply decreasing. Total chlorine from the major chlorofluorocarbons (C FCs) is no longer increasing,
`in contrast to the slight increase that was occurring at the time ofthe 1998 Assessment. Specifically. in 2000. the
`atmospheric abundances of CFC-I l and CFC-I13 continued to decrease. while the rate ofincrease of CFC-12
`had slowed. Total tropospheric bromine from halons continued to increase at about 3% per year. which is about
`two-thirds of the rate for 1996 reported in the 1998 Assessment. The observed abundances of CFC hydrochloro-
`fluorocarbons (HCFCS). and methyl chloroform in the lower atmosphere continue to be consistent with reported
`production and estimated emissions.
`
`.=\na|_\'ses of air trapped in snow since the late 19th century have conlirmed that non-industrial sources of the
`CFCs. halons.. and major chlorocarbons were insignificant. Since the previous Assessment. analyses offim air
`(i.e., air trapped in snow above glaciers) have revealed the abundance of long-lived atmospheric species at the time
`the air became trapped. As a result, trends in the atmospheric abundance for many ozone-depleting substances have
`been traced over the past century, to well before significant industrial sources ofthe compounds existed. These
`records show that the mixing ratios of the CFCs. halons, carbon tetrachloride (CCI4), methyl chloroform, and
`HCFCS in the oldest air sampled are negligible compared with the amounts measured in today‘s background
`atmosphere. Further. the deduced 20"‘ century records for these compounds are broadly consistent with calculated
`histories based on records ofindustrial production. The data suggest that substantial natural sources exist for
`atmospheric methyl bromide (CH3Br). They also show increases throughout the 20”‘ century. but these increases do
`not allow unambiguous quantification of the industrial fraction ofmethyl bromide emissions in recent years. The
`estimate of this fraction. based on an assessment of understanding ofthe budget ofthis gas. remains at 10-40%. as
`given in the I998 Assessment.
`
`Page 11 of 111
`
`.\‘lll
`
`

`
`EXECUTIVE SUMMARY
`
`0
`
`-
`
`-
`
`The abundances of HCFCs in the lower atmosphere continue to increase. HCFCs are among the gases used as
`transition substitutes for CFC s. halons, and chlorinated solvents.
`In the year 2000, HC FCs represented 6% of total
`chlorine abundance from anthropogenic gases in the lower atmosphere. The rate ofinerease in chlorine from
`HCFCs was constant at 10 parts per trillion per year from [996 to 2000.
`
`Observations in the stratosphere indicate that the total chlorine abundance is at or near a peak. while bromine
`abundances are probably still increasing. The sum of hydrogen chloride (HCl) and chlorine nitrate (CIONOZ) is
`an effective surrogate for the abundance of stratospheric chlorine. An extended time series of ground-based meas-
`urements shows that the total stratospheric column amounts ofthese species, which have grown steadily for decades.
`have plateaucd in recent years. Further. space-based measurements of HCl in the upper stratosphere indicate a
`broadly similar behavior. There are indications that bromine abundances in the stratosphere increased during the
`1990s, but changes in stratospheric bromine are not as well characterized
`those of stratospheric chlorine. These
`stratospheric changes are consistent with expectations based on the understanding of trace—gas trends in the tropo-
`sphere, stratospheric chemistry, and atmospheric transport from the troposphere to the stratosphere.
`
`Very short-lived organic chlorine-. bromine-. and iodine-containing source gases have the potential to deplete
`stratospheric ozone. but quantitative estimation oftheir potentials is more challenging than for longer-lived
`species like CFC s. The very short-lived compounds reside in the atmosphere for a few months or less because they
`are rapidly decomposed chemically in the troposphere. Yet. a fraction oftheir emissions and the products from
`their tropospheric destruction can potentially