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 XXXVI/4: Additional information on very short-lived substances

The Thirty-Sixth Meeting of the Parties,

Taking note with appreciation of the information on very short-lived substances contained in the 2022 quadrennial assessment report of the Scientific Assessment Panel,[1] the 2022 assessment report of the Medical and Chemicals Technical Options Committee of the Technology and Economic Assessment Panel[2] and the 2024 progress report of the Technology and Economic Assessment Panel,[3]

Noting that the Scientific Assessment Panel indicated in its 2022 quadrennial assessment report that chlorine emissions from very short-lived substances not controlled by the Montreal Protocol on Substances that Deplete the Ozone Layer, in particular from dichloromethane, continue to increase,

Noting also that any party that has information on alternatives to very short-lived substances and best practices for avoiding such emissions can provide such information to the Technology and Economic Assessment Panel,

Decides:

  1. To request the Technology and Economic Assessment Panel and the Scientific Assessment Panel to include the following information, as it pertains to their respective mandates, in their 2026 assessment reports, for consideration by the Open-ended Working Group of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer at its forty-ninth meeting;
    1. Updated information on dichloromethane, trichloromethane, dichloroethane, trichloroethylene and perchloroethylene, including their emissive solvent and feedstock uses and growth trends for the past five years, their ozone-depleting potential and their impact on the stratospheric ozone layer in quantifiable terms;
    2.  Any available relevant information on other anthropogenic very short-lived substances not mentioned in chapter 5.2 of the 2024 progress report of the Technology and Economic Assessment Panel, along with the methodology used, growth trends for the past five years, their ozone-depleting potential and their impact on the stratospheric ozone layer in quantifiable terms;
    3. Additional information on alternatives to the very short-lived substances, including of solvents with a low boiling point, referred to in subparagraphs (a) and (b) above in the emissive applications where they are currently used, including information on availability and accessibility, technical feasibility, performance, including the yield of the end product, economic viability, safety and sustainability, and penetration in parties operating under paragraph 1 of Article 5 of the Montreal Protocol, with a focus on very short-lived substances with significant emissive uses;
    4. A table providing information, to the extent possible, for each very short-lived substance identified in subparagraphs (a) and (b) above on estimated annual production and consumption, estimated annual emissions, the range of ozone-depleting potential estimated or evaluated by the Scientific Assessment Panel, the contribution of the substance to the total chlorine input to the stratosphere and its impact on the stratospheric ozone layer in quantifiable terms;
  2. To invite parties that have national measures concerning use and/or emissions of very short-lived substances to provide the Ozone Secretariat with information on those measures, on a voluntary basis, by 31 March 2025;
  3. To request the Ozone Secretariat to provide a compendium of national measures on the basis of the information provided in accordance with paragraph 2 above.

 

[1] World Meteorological Organization, Scientific Assessment of Ozone Depletion: 2022, executive summary, GAW Report No. 278 (Geneva, 2022).

[2] United Nations Environment Programme, Medical and Chemical Technical Options Committee 2022 Assessment Report (Nairobi, 2022).

[3] United Nations Environment Programme, Report of the Technology and Economic Assessment Panel: Volume 1 – Progress Report, May 2024 (Nairobi, 2024).