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How will parties fund new atmospheric monitoring sites? How is the Protocol managing implementation challenges? Should it regulate new substances, which may or may not have ozone-depleting potential? How will parties address trade in obsolete equipment? Delegates began to answer these questions and more.
Final report
Summary report 8–12 July 2024
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The Montreal Protocol on Substances that Deplete the Ozone Layer was adopted to protect the Earth’s ozone layer by phasing out the production and consumption of ozone depleting substances (ODS), such as those contained in aerosol sprays, coolants, asthma inhalers, food production, and building materials, to name a few.
The major effect of a depleted ozone layer is an increase in ultraviolet (UV) radiation levels on the Earth's surface affecting human health and the environment. Increased UV radiation has been found to be responsible for certain types of skin cancers, eye cataracts, and immune deficiency disorders. It also affects terrestrial and aquatic ecosystems, altering growth, food chains, and biochemical cycles. Aquatic life just below the water’s surface, the basis of the food chain, is particularly adversely affected by high UV levels. The UV rays also affect plant growth, reducing agricultural productivity.
Since entering into force in 1989, the Montreal Protocol has been ratified by 198 parties. It has been lauded as the most successful global environmental agreement, having been successful at phasing out ozone depleting substances (ODS), including chlorofluorocarbons (CFCs), certain halons, carbon tetrachloride (CTC), methyl chloroform, methyl bromide, hydrobromofluorocarbons, and hydrochlorofluorocarbons (HCFCs). The Protocol’s reach has expanded in the last decade, with the adoption of the Kigali Amendment in 2016 to address hydrofluorocarbons (HFCs) which were a replacement for HCFCs, but are potent greenhouse gases.
The Open-ended Working Group (OEWG) of the parties to the Montreal Protocol considers the scientific and technical work which underpins the Protocol, compiled by the Technology and Economic Assessment Panel (TEAP) and the Scientific Assessment Panel (SAP). OEWG 46, which is the first meeting since the 35th Meeting of the Parties (MOP) in October 2023, has before it a number of important discussions, including on:
- Very short-lived substances, including dichloromethane, which have a significant impact on the ozone layer, especially in the lower stratosphere;
- The significant increase in the production of controlled substances used as feedstock and increased emissions of such substances;
- CTC emissions;
- Life-cycle refrigerant management;
- Enhancing the global and regional atmospheric monitoring of controlled substances;
- Nominations for critical-use exemptions for methyl bromide for 2025; and
- Energy efficiency (decision XXXV/10).
Delegates will also consider issues related to the future availability of halons and their alternatives, and possible compliance deferral for some developing country parties, an issue which emerged at the height of the COVID-19 pandemic. Further, they will address how best to strengthen the Protocol’s institutions, including combating illegal trade, which has been a growing concern in the past few years. The meeting is also expected to discuss potential changes to a form for reporting on HFC-23.
OEWG 46 will be held at the International Civil Aviation Organization (ICAO) Conference Centre in Montreal, Canada from 8-12 July 2024.
The Earth Negotiations Bulletin (ENB) writers for this meeting are Tallash Kantai; Pamela Chasek, Ph.D.; and Kaspar Sollberger, Ph.D. The Digital Editor is Ángeles Estrada. The Editor is Jessica Templeton, Ph.D.
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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