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 X/8: New substances with ozone-depleting potential

The Tenth Meeting of the Parties decided in Dec. X/8:

Recalling that, under the Montreal Protocol, each Party has undertaken to control the global emissions of ozone-depleting substances with the ultimate objective of their elimination,

Recalling that decision IX/24 requested Parties to discourage the development and promotion of substances with a significant potential to deplete the ozone layer and provides a procedure for notifying such substances to the Secretariat and their evaluation by the Science Assessment Panel and the Technology and Economic Assessment Panel,

  1. That all Parties should take measures actively to discourage the production and marketing of bromochloromethane;
  2. To encourage Parties, in the light of reports from the Scientific Assessment Panel and the Technology and Economic Assessment Panel, to take measures actively, as appropriate, to discourage the production and marketing of new ozone-depleting substances;
  3. That should new substances be developed and marketed which, following application of decision IX/24, are agreed by the Parties to pose a significant threat to the ozone layer, the Parties will take appropriate steps under the Protocol to ensure their control and phase-out;
  4. That Parties should report to the Secretariat, as far as possible by 31 December 1999, and as necessary thereafter, on any new ozone-depleting substances notified and evaluated under the terms of decision IX/24 being produced or sold in their territories, including the nature of the substances, the quantities involved, the purposes for which these substances are being marketed or used and, if possible, the names of the producers and distributors;
  5. To request the Technology and Economic Assessment Panel and the Science Assessment Panel, taking into account, as appropriate, assessments carried out under decision IX/24, to collaborate in undertaking further assessments:
    1. To determine whether substances such as n-propyl bromide, with a very short atmospheric life-time of less than one month, pose a threat to the ozone layer;
    2. To identify the sources and availability of halon-1202;

      and to report back to the Meeting of the Parties as soon as possible, but not later than the Twelfth Meeting of the Parties;

      6. To request the legal drafting group which the Open-ended Working Group may establish to consider and report back to the Eleventh Meeting of the Parties through the Open-ended Working Group on the options available under the Montreal Protocol to introduce controls on new ozone-depleting substances.