The Montreal Protocol on Substances that Deplete the Ozone Layer

The Montreal Protocol on Substances that Deplete the Ozone Layer is a global agreement to protect the Earth’s ozone layer by phasing out the chemicals that deplete it. This phase-out plan includes both the production and consumption of ozone-depleting substances. The landmark agreement was signed in 1987 and entered into force in 1989.

The parties to the Protocol meet once a year to make decisions aimed at ensuring the successful implementation of the agreement. These include adjusting or amending the Protocol, which has been done six times since its creation. The most recent amendment, the Kigali Amendment, called for the phase-down of hydrofluorocarbons (HFCs) in 2016. These HFCs were used as replacements for a batch of ozone-depleting substances eliminated by the original Montreal Protocol. Although they do not deplete the ozone layer, they are known to be powerful greenhouse gases and, thus, contributors to climate change.

The Montreal Protocol provided a set of practical, actionable tasks that were universally agreed on. The Protocol has successfully met its objectives thus far and continues to safeguard the ozone layer today. Thanks to the collaborative effort of nations around the world, the ozone layer is well on its way to recovery.

Decision XXXI/2: Potential areas of focus for the 2022 quadrennial reports of the Scientific Assessment Panel, the Environmental Effects Assessment Panel and the Technology and Economic Assessment Panel

Noting with great appreciation the excellent and highly useful work of the members of the Scientific Assessment Panel, the Environmental Effects Assessment Panel and the Technology and Economic Assessment Panel and their colleagues worldwide in preparing their 2018 assessment reports, in particular the efforts made to condense vast amounts of pertinent information into a concise and understandable form for better use by policymakers, 

  1. To request the Scientific Assessment Panel, the Environmental Effects Assessment Panel and the Technology and Economic Assessment Panel to prepare quadrennial assessment reports and submit them to the Secretariat by 31 December 2022 for consideration by the Open-ended Working Group and the Meeting of the Parties in 2023, and to present a synthesis report by 30 April 2023, noting that the panels should continue to exchange information during the process of developing their respective reports in order to avoid duplication and to provide comprehensive information to the parties to the Montreal Protocol;
  2. To request the assessment panels to bring to the notice of the parties any significant developments which, in their opinion, deserve such notice, in accordance with decision IV/13;
  3. To encourage the assessment panels to closely involve relevant scientists from Article 5 parties with a view to promoting gender and regional balance, to the best of their ability, in producing the reports;
  4. To request the Environmental Effects Assessment Panel, in preparing its 2022 assessment report, to pay particular attention to the most recent scientific information together with future projections and scenarios to assess the effect from changes in the ozone layer and ultraviolet radiation, and their interaction with the climate system, as well as the effects of breakdown products from controlled substances and their alternatives on:             
    1. The biosphere, biodiversity and ecosystem health, including on biogeochemical processes and global cycles; 
    2. Human health;
    3. Ecosystem services, agriculture and materials, including for construction, transport, photovoltaic use and microplastics;     
  5. That the 2022 report of the Scientific Assessment Panel should include:            
    1. An assessment of the state of the ozone layer and its future evolution;       
    2. An evaluation of global and polar stratospheric ozone, including the Antarctic ozone hole and Arctic winter/spring ozone depletion and the predicted changes in those phenomena;
    3. An evaluation of trends in the top-down derived emissions, abundances and fate in the atmosphere of trace gases of relevance to the Montreal Protocol, in particular controlled substances and other substances of importance to the ozone layer, which should include a comparison of bottom-up and top-down estimations of such emissions with a view to addressing unidentified emission sources and discrepancies between reported emissions and observed atmospheric concentrations;
    4. An evaluation of consistency with reported production and consumption of those substances and the likely implications for the state of the ozone layer, including its interaction with the climate system;     
    5. An assessment of the interaction between changes in stratospheric ozone and the climate system, including possible future policy scenarios relating to ozone depletion and climate impacts;
    6. Early identification and quantification, where possible, of any other issues of importance to the ozone layer and the climate system, consistent with the objectives of the Vienna Convention for the Protection of the Ozone Layer and the Montreal Protocol;   
    7. An assessment of information and research related to solar radiation management and its potential effect on the stratospheric ozone layer;       
    8. Relevant information on any newly detected substances that are relevant for the Montreal Protocol;
  6. That, in its 2022 report, the Technology and Economic Assessment Panel should include an assessment and evaluation of the following topics:      
    1. Technical progress in the production and consumption sectors in the transition to technically and economically feasible and sustainable alternatives and practices that minimize or eliminate the use of controlled substances in all sectors;
    2. The status of banks and stocks of controlled substances and the options available for managing them so as to avoid emissions to the atmosphere;  
    3. Challenges facing all parties to the Montreal Protocol in implementing Montreal Protocol obligations and maintaining the phase-outs already achieved, especially those on substitutes and substitution technologies, including challenges for parties related to feedstock uses and by‑production to prevent emissions, and potential technically and economically feasible options to face those challenges;   
    4. The impact of the phase-out of controlled ozone-depleting substances and the phase‑down of HFCs on sustainable development;   
    5. Technical advancements in developing alternatives to HFCs suitable for usage in countries with high ambient temperatures, particularly with regard to energy efficiency and safety.

.