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 XI/17: Terms of reference for Assessment Panels

The Eleventh Meeting of the Parties decided in Dec. XI/17:

  1. To note with appreciation the excellent and highly useful work done by the Scientific, Environmental Effects, and Technology and Economic Assessment Panels and their colleagues worldwide in preparing their reports of 1998 including the Synthesis Report of 1999 and its decadal perspective of the information provided by the Panels over the period 1989-1999;
  2. To note also with appreciation, and encourage as appropriate, the ongoing fruitful collaboration of the Panels with the Subsidiary Body on Science and Technology under the United Nations Framework Convention on Climate Change, the Intergovernmental Panel on Climate Change, and the International Civil Aviation Organization;
  3. To request the three Assessment Panels to update their 1998 reports in 2002 and submit them to the Secretariat by 1 January 2003 for consideration by the Open-ended Working Group and by the Fifteenth Meeting of the Parties to the Montreal Protocol in 2003;
  4. To request the Assessment Panels to keep the Parties to the Montreal Protocol informed of any important new developments on a year-to-year basis;
  5. To request the Scientific Assessment Panel to include the following in the 2002 scientific assessment:
    1. An evaluation of the observed trends in controlled substances and their consistency with reported production of ODS;
    2. A quantification of the ozone-depleting impacts of new (e.g., short-lived) halogen-containing substances;
    3. A characterization of methyl bromide sources and sinks and the likely quantitative implications of the results for the ozone layer;
    4. A characterization of the known interrelations between ozone depletion and climate change including feedbacks between the two;
    5. A description and interpretation of the observed changes in global and polar ozone and in ultraviolet radiation, as well as set future projections and scenarios for these variables, taking into account also the expected impacts of climate change;
  6. To request the Environmental Effects Panel to continue the identification of the impacts of ozone depletion noting its association with aspects of climate change, including:
    1. An evaluation of how the combined influence of ultraviolet radiation changes due to ozone depletion and climate change factors can impact on the biosphere and on human health;
    2. A characterization of those impacts caused by ultraviolet radiation changes that may have effects on climate;