Decision XXXV/3: Potential areas of focus for the 2026 quadrennial reports of the Environmental Effects Assessment Panel, the Scientific Assessment Panel and the Technology and Economic Assessment Panel

Noting with great appreciation the excellent and highly useful work of the members of the Environmental Effects Assessment Panel, the Scientific Assessment Panel and the Technology and Economic Assessment Panel of the Montreal Protocol on Substances that Deplete the Ozone Layer and their colleagues worldwide in preparing the panels’ 2022 assessment reports, and 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 Environmental Effects Assessment Panel, the Scientific Assessment Panel and the Technology and Economic Assessment Panel to prepare quadrennial assessment reports and submit them to the Secretariat by 31 December 2026 for consideration by the Open-ended Working Group of the Parties to the Montreal Protocol and the Meeting of the Parties to the Montreal Protocol in 2027, as well as finalizing a synthesis report in time for the Meeting of the Parties, noting that the panels should continue to exchange information during the process of developing their respective reports in order to avoid duplication, ensure consistency, and provide comprehensive information to the parties;
2. To request the assessment panels to bring to the notice of the parties any significant developments that, in their opinion, deserve such notice, in accordance with decision IV/13;
3. To encourage the assessment panels to closely involve relevant scientists from parties operating under paragraph 1 of Article 5 of the Montreal Protocol 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 2026 assessment report, to pay particular attention to the most recent scientific information, including from solar radiation modification scenarios, forward-looking projections and scenarios, and to assess the effects of changes in the ozone layer and ultraviolet radiation and their interaction with the climate system on:

(a) Human health;

(b) The biosphere, biodiversity, and the health of flora, fauna and the ecosystem, including biogeochemical processes and global cycles;

(c)  Ecosystem services, agriculture and materials, including for construction, transport and photovoltaic use, and microplastics;

5. To also request the Environmental Effects Assessment Panel, in preparing its 2026 assessment report, to assess the effects and accumulation of breakdown products from controlled substances and their alternatives, in particular any substances that are very persistent in the environment, such as perfluoro- and polyfluoroalkyl substances, including trifluoroacetic acid, in ground and surface waters and in other relevant sinks;
6. That the 2026 report of the Scientific Assessment Panel should include:

(a) An assessment of the state of the ozone layer and its future evolution;

(b) An evaluation of global and polar stratospheric ozone, including the Antarctic ozone hole and Arctic winter and spring ozone depletion and the predicted changes in these phenomena;

(c)  An updated assessment of past and projected contributions of the Montreal Protocol to mitigating climate change in terms of total avoided CO₂-equivalent emissions and avoided temperature increase;

(d) 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 top‑down estimations and available bottom-up estimations of such emissions with a view to identifying currently unknown emission sources and explaining discrepancies between emissions derived from reported information and observed atmospheric concentrations (in cooperation with the Technology and Economic Assessment Panel);

(e)  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;

(f)  An assessment of the interaction between changes in stratospheric ozone and the climate system, including consideration of related policy scenarios;

(g)  Information regarding scenarios designed to contribute further to ozone layer protection and climate change mitigation, and a presentation of their benefits in terms of impacts on total column ozone and equivalent effective stratospheric chlorine, advancing the recovery of the ozone layer, and avoiding CO₂-equivalent emissions, as relevant;

(h) Early identification and quantification of any substances that could be of concern for the ozone layer and relevant for the implementation of the Montreal Protocol and the objectives of the Vienna Convention for the Protection of the Ozone Layer, including other halogenated gases, in particular those with high global warming potential, breakdown products of controlled substances and their alternatives that are very persistent, such as perfluoro- and polyfluoroalkyl substances, including trifluoroacetic acid, N₂O and very short-lived substances such as dichloromethane, and their main sources of emissions;

(i)   An assessment of information and research related to solar radiation modification, in particular stratospheric aerosol injection and its potential effects on the ozone layer and relevant information on the potential effects of supersonic aircraft, rockets, satellites, wildfires and volcanic eruptions on the stratospheric ozone layer;

(j)  Identification and quantification of any other issues relevant to the objectives of the Vienna Convention for the Protection of the Ozone Layer and the Montreal Protocol;

7. That the 2026 report of the Technology and Economic Assessment Panel should include an assessment and evaluation of the following topics:

(a) Technical progress in the production and consumption sectors in the transition to alternatives, taking into account their technical feasibility, economic viability, safety and sustainability, and in the transition to practices that minimize or eliminate the use of controlled substances in all sectors;

(b) Process agents and feedstock uses for which the use of controlled substances is no longer required and identification of alternative pathways and technologies that can replace these uses, taking into account costs and other environmental and economic considerations;

(c)  An assessment of information relating to emissions of controlled substances from feedstock and production processes and other manufacturing processes, and identification of best practices and technologies for minimizing such emissions;

(d) The status of banks and stocks of controlled substances, including rates of recovery, recycling and reuse, their alternatives and other substances of importance to the ozone layer, including those used as feedstocks and those resulting from by-production, and the options available for managing them so as to avoid emissions to the atmosphere;

(e)  Challenges facing all parties to the Montreal Protocol in implementing obligations under the Protocol and maintaining the phase-outs already achieved, including challenges related to preventing emissions from feedstock uses and by-production, and technically and economically feasible options for addressing those challenges;

(f)  The impact of the phase-out of controlled ozone-depleting substances and the phasedown of hydrofluorocarbons and associated energy efficiency, and minimum energy performance standards and cold chain management on sustainable development;

(g)  Technical advances in developing alternatives to hydrofluorocarbons, taking into account in particular energy efficiency, safety, and suitability for use in high-ambient-temperature countries;

(h) Information on uses where hydrochlorofluorocarbons were not previously used and hydrofluorocarbons have been used and are currently used, such as electronics manufacturing;

(i)   Assessment of whether production of hydrofluoroolefins is resulting in fugitive emissions of hydrofluorocarbons;

(j)  The potential impacts of evolving policies and regulations in relation to the management of controlled substances and their alternatives and breakdown products, in particular per‑and polyfluoroalkyl substances, on the implementation of the Montreal Protocol and the selection of alternatives in relevant sectors;

(k) Information on refrigerant management, with particular attention to leakage prevention and end-of-life management.