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With recent positive reports that the ozone layer is healing, delegates will consider further improvements in monitoring, containing, and replacing controlled substances.
Final report
Summary report 3–7 November 2025
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2025 marks the 40th anniversary of the Vienna Convention for the Protection of the Ozone Layer. While commemorating this important milestone, parties are also preparing to leverage the success of the Convention to make further progress in protecting both the ozone layer and the climate.
In 1985 and 1987, respectively, the Vienna Convention and its Montreal Protocol were adopted to protect the stratospheric ozone layer by phasing out the production and consumption of ozone-depleting substances, including chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, methyl chloroform, and methyl bromide, among others. With the adoption of the Kigali Amendment in 2016, parties also agreed to phase down hydrofluorocarbons (HFCs), potent greenhouse gases that had replaced certain ozone-depleting substances in refrigeration and air conditioning systems.
Without the successful implementation of these multilateral environmental agreements, stratospheric ozone concentrations would have become so depleted that the Earth’s ozone layer would no longer protect humans and the environment from the sun’s ultraviolet (UV) radiation, with consequences including widespread skin cancer, eye cataracts, and immune deficiencies as well as harm to terrestrial and aquatic life.
Instead, the World Meteorological Organization’s September 2025 Ozone Bulletin reported that the Earth’s protective ozone layer is healing and the ozone hole in 2024 was smaller than in recent years. If current policies remain in place, the ozone layer is expected to recover to 1980 values (before the appearance of the ozone hole) by around 2066 over the Antarctic, by 2045 over the Arctic, and by 2040 for the rest of the world, according to the most recent quadrennial Scientific Assessment of Ozone Depletion in 2022. The next assessment will be in 2026.
Despite these successes in the last 40 years, there is more work to be done to keep the implementation of the Convention and its Protocol fit for purpose. Further improvements are needed in monitoring, containing, and replacing controlled substances. Also, some additional substances merit an assessment of their impacts on the ozone layer and the climate. Furthermore, organizational matters need attention such as how to best set up the expert assessment panels supporting the processes under the Protocol and prepare for the upcoming 2027–2029 replenishment of the Multilateral Fund for the Implementation of the Montreal Protocol (MLF).
Parties will build on the groundwork laid at the 47th Meeting of the Open-ended Working Group of the Parties to the Montreal Protocol, which was held from 7 to 11 July 2025 in Bangkok, Thailand. Draft decisions for the 37th Meeting of the Parties to the Montreal Protocol (MOP37) to consider address:
- terms of reference for the study on the 2027–2029 replenishment of the MLF;
- emissions of HFC-23;
- enhancing regional atmospheric monitoring of controlled substances;
- life-cycle refrigerant management;
- feedstock uses of controlled substances;
- management of halon 1301 and other controlled fire suppressants;
- national and regional initiatives to support the implementation of the Kigali Amendment;
- options for the organization of the Technology and Economic Assessment Panel and its technical options committees;
- further strengthening Montreal Protocol institutions; and
- classification of the State of Palestine as a party operating under paragraph 1 of Article 5 and access to support from the MLF.
MOP37 will convene from 3 to 7 November 2025 at the headquarters of the United Nations Environment Programme (UNEP) in Nairobi, Kenya, preceded by an informal meeting on facilitating the implementation of the Montreal Protocol on 2 November 2025.
The Earth Negotiations Bulletin (ENB) writers for this meeting are Kaspar Sollberger, Ph.D.; Pamela Chasek, Ph.D.; María Gutiérrez, Ph.D.; and María Ovalle. The Digital Editor is Danny Skilton. The Editor is Chris Spence.
View past and future events
Past event
Vienna Convention COP 5 and Montreal Protocol MOP 11
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20th Meeting of the Open-Ended Working Group of the Parties to the Montreal Protocol
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Montreal Protocol MOP 12
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Montreal Protocol MOP 13
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22nd Meeting of the Open-Ended Working Group of the Parties to the Montreal Protocol
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Vienna Convention COP 6 and Montreal Protocol MOP 14
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Montreal Protocol MOP 15
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1st Extraordinary Meeting of the Parties to the Montreal Protocol (ExMOP-1)
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Montreal Protocol MOP 16
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25th Meeting of the Open-ended Working Group of the Parties and 2nd Extraordinary Meeting of the Parties to the Montreal Protocol (ExMOP-2)
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Vienna Convention COP 7 and Montreal Protocol MOP 17
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26th Meeting of the Open-Ended Working Group of the Parties to the Montreal Protocol
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Montreal Protocol MOP 18
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Montreal Protocol MOP 19
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Viena Convention COP 8 and Montreal Protocol MOP 20
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29th Meeting of the Open-Ended Working Group of the Parties to the Montreal Protocol
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Montreal Protocol MOP 21
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Montreal Protocol MOP 22
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31st Meeting of the Open-Ended Working Group of the Parties to the Montreal Protocol
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Vienna Convention COP 9 and Montreal Protocol MOP 23
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32nd Meeting of the Open-Ended Working Group of the Parties to the Montreal Protocol
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Montreal Protocol MOP 24
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33rd Meeting of the Open-Ended Working Group of the Parties to the Montreal Protocol
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Montreal Protocol MOP 25
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34th Meeting of the Open-Ended Working Group of the Parties to the Montreal Protocol
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Vienna Convention COP 10 and Montreal Protocol MOP 26
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Workshop on Hydrofluorocarbon Management and 35th Meeting of the Open-ended Working Group of the Parties to the Montreal Protocol
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36th Meeting of the Open-Ended Working Group of the Parties to the Montreal Protocol
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Resumed 36th Meeting of the Open-ended Working Group of the Parties to the Montreal Protocol
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Montreal Protocol MOP 27
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37th Meeting of the Open-Ended Working Group of the Parties to the Montreal Protocol
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3rd Extraordinary Meeting of the Parties to the Montreal Protocol (ExMOP 3) and Associated Meetings
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Montreal Protocol MOP 28
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39th Meeting of the Open-Ended Working Group of the Parties to the Montreal Protocol
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Vienna Convention COP 11 and Montreal Protocol MOP 29
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Workshop on Energy Efficiency Opportunities While Phasing-Down Hydrofluorocarbons (HFCs) and 40th Meeting of the Open-Ended Working Group of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer
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30th Meeting of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer
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41st Meeting of the Open-Ended Working Group of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer (OEWG 41)
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31st Meeting of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer (MOP 31)
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42nd Meeting of the Open-ended Working Group of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer (OEWG 42)
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12th Meeting of the Conference of the Parties to the Vienna Convention (Part I) and 32nd Meeting of the Parties to the Montreal Protocol
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4th Extraordinary Meeting of the Parties to the Montreal Protocol (ExMOP-4) and 1st Part of the 43rd Meeting of the Open-ended Working Group (OEWG43)
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2nd Part of the 43rd Meeting of the Open-ended Working Group of the Parties to the Montreal Protocol (OEWG 43)
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Combined 12th Meeting of the Conference of the Parties to the Vienna Convention (Part II) and 33rd Meeting of the Parties to the Montreal Protocol
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44th Meeting of the Open-ended Working Group of the Parties to the Montreal Protocol (OEWG-44) and 5th Extraordinary Meeting of the Parties to the Montreal Protocol (ExMOP-5)
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34th Meeting of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer (MOP34)
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45th Meeting of the Open-ended Working Group of the Parties to the Montreal Protocol
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35th Meeting of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer (MOP35)
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46th Meeting of the Open-ended Working Group of the Parties to the Montreal Protocol
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13th Meeting of the Conference of the Parties to the Vienna Convention for the Protection of the Ozone Layer (COP13) and 36th Meeting of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer (MOP36)
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47th Meeting of the Open-ended Working Group of the Parties to the Montreal Protocol
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37th Meeting of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer (MOP37)
Upcoming event
48th Meeting of the Open-ended Working Group of the Parties to the Montreal Protocol
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