Recovery of Ozone Layer Would Come Sooner If…

Additionally, earlier phase out of relatively small remaining uses of ODSs, which are currently exempted for reasons of essentiality and criticality to society, would hasten ozone recovery, the report says. Altogether, preventing those emissions can speed up the recovery of the ozone layer by about 11 years.

Assessment for Decision Makers

“Scientific Assessment of Ozone Depletion: 2014” is the quadrennial report of the Scientific Assessment Panel (SAP) of the Montreal Protocol on Substances that Deplete the Ozone Layer.

A summary document of the report, the “Assessment for Decision Makers”, was published in September 2014 by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO). The full report, released today, provides more details on the previously released findings.

The SAP assesses the state of the depletion of the ozone layer and relevant atmospheric science issues every four years and provides Parties to the Montreal Protocol with critical information as they undertake their ozone protection activities and address challenges under the Protocol.

First Signs of an Upward Ozone Trend, But…

The report indicates that the ozone layer is showing the first signs of an upward ozone trend. Further, the ozone layer is on track to recovery to 1980 benchmark levels-the time before significant ozone layer depletion- by the middle of this century, thanks to concerted international action to phase out ODSs.

Although over 2.2 million metric tonnes of ODSs have been phased out over time by the nations of the world under the provisions of the Montreal Protocol, 640,000 metric tonnes of HCFCs remain to be phased out.

The assessment report projects that atmospheric ODS amounts will continue to decline through the 21st century, assuming continued compliance with the Montreal Protocol. Since ODSs are also potent global warming gases, the Protocol has significantly contributed to climate change mitigation, having averted more than 135 billion tonnes of carbon dioxide equivalent emissions.

… Benefits Could Be Significantly Offset

The report warns that the climate benefits of the Montreal Protocol could be significantly offset by projected increases in emissions of hydrofluorocarbons (HFCs) that are being used to replace ODSs.

HFCs, which are not ozone-depleting substances but are global-warming gases, are increasing in the atmosphere and future emissions could make a large contribution to climate change.

The large HFC climate effects could be avoided by replacing high-global-warming potential (GWP) HFCs with low-GWP HFCs and other alternatives, the report notes.

The SAP presented the report’s findings during the Joint 10th Meeting of the Conference of the Parties to the Vienna Convention and the 26th Meeting of the Parties to the Montreal Protocol held in Paris 17 – 21 November 2014.

282 Scientists from 36 Countries

The report was prepared and reviewed by 282 scientists from 36 countries (Argentina, Australia, Austria, Belgium, Botswana, Brazil, Canada, People’s Republic of China, Comoros, Costa Rica, Cuba, Czech Republic, Denmark, Finland, France, Germany, Greece, India, Israel, Italy, Japan, Korea, Malaysia, New Zealand, Norway, Poland, Russia, South Africa, Spain, Sweden, Switzerland, The Netherlands, Togo, United Kingdom, United States of America, Zimbabwe.)

Co-Chairs of the ozone assessment are: Prof. Ayité Lô Nohende Ajavon, Université de Lomé, Togo; Prof. John Pyle, University of Cambridge and National Centre for Atmospheric Science, UK; Dr. Paul Newman, NASA/ Goddard Space Flight Center, USA; Prof. A.R. (Ravi) Ravishankara, Colorado State University, USA.

The “Scientific Assessment of Ozone Depletion: 2014″ report can be downloaded here.

The press release for the summary document can be accessed from the UNEP News centre.

*Source: UNEP Report).