Assessment for Decision-Makers Scientiic Assessment of Ozone Depletion: 2014 World Meteorological Organization United Nations Environment Programme National Oceanic and Atmospheric Administration National Aeronautics and Space Administration European Commission

• Main Authors: Huret, Nathalie, Legras, Bernard
• Other Authors: Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Centre National de la Recherche Scientifique (CNRS)-Université Paris Sciences et Lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Sciences et Lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Centre National de la Recherche Scientifique (CNRS)-Université Paris Sciences et Lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Sciences et Lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales Paris (CNES), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X), Institut Polytechnique de Paris (IP Paris)-Institut Polytechnique de Paris (IP Paris)-École nationale des ponts et chaussées (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS-PSL, École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL), World Meteorological OrganizationUnited Nations Environment ProgrammeNational Oceanic and Atmospheric AdministrationNational Aeronautics and Space AdministrationEuropean Commission, Assessment for Decision-Makers WMO Global Ozone Research and Monitoring Project – Report No. 56 Scientic Assessment of Ozone Depletion: 2014
• Format: Report
• Language: English
• Published: CCSD 2014
• Subjects: [SDU]Sciences of the Universe [physics]; [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; Antarctic; Arctic; The Antarctic; Antarc*
• Online Access: https://insu.hal.science/insu-01130275; https://insu.hal.science/insu-01130275v1/document; https://insu.hal.science/insu-01130275v1/file/ADM_2014OzoneAssessment_Final.pdf

Actions taken under the Montreal Protocol have led to decreases in the atmospheric abundance of controlledozone-depleting substances (ODSs), and are enabling the return of the ozone layer toward 1980 levels.• The sum of the measured tropospheric abundances of substances controlled under the MontrealProtocol continues to decrease. Most of the major controlled ODSs are decreasing largely as projected, andhydrochlorofluorocarbons (HCFCs) and halon-1301 are still increasing. Unknown or unreported sources of carbontetrachloride are needed to explain its abundance.• Measured stratospheric abundances of chlorine- and bromine-containing substances originating from thedegradation of ODSs are decreasing. By 2012, combined chlorine and bromine levels (as estimated by EquivalentEffective Stratospheric Chlorine, EESC) had declined by about 10–15% from the peak values of ten to fifteen years ago.Decreases in atmospheric abundances of methyl chloroform (CH3CCl3), methyl bromide (CH3Br), and chlorofluorocarbons(CFCs) contributed approximately equally to these reductions.• Total column ozone declined over most of the globe during the 1980s and early 1990s (by about 2.5% averagedover 60°S to 60°N). It has remained relatively unchanged since 2000, with indications of a small increase in totalcolumn ozone in recent years, as expected. In the upper stratosphere there is a clear recent ozone increase, whichclimate models suggest can be explained by comparable contributions from declining ODS abundances and upperstratospheric cooling caused by carbon dioxide increases.• The Antarctic ozone hole continues to occur each spring, as expected for the current ODS abundances. The Arcticstratosphere in winter/spring 2011 was particularly cold, which led to large ozone depletion as expected under theseconditions.• Total column ozone will recover toward the 1980 benchmark levels over most of the globe under full compliancewith the Montreal Protocol. This recovery is expected to occur before midcentury in midlatitudes and the Arctic, andsomewhat ...