Key documents

In 1974 scientists published their first scientific hypotheses that chemicals we produced could harm the stratospheric ozone layer. The ozone layer protects the earth against excessive ultraviolet radiation, which could cause damage and mutations in human, plant, and animal cells. The scientists found that the chlorofluorocarbon gases (CFCs), which were widely used and viewed as posing no harm, could migrate to the stratosphere, remain intact for decades to centuries, and by releasing chlorine, break down the ozone layer.

In 1977 the United Nations Environment Programme (UNEP) concluded a World Plan of Action on the Ozone Layer, which called for intensive international research and monitoring of the ozone layer, and in 1981, UNEP’s Governing Council authorized UNEP to draft a global framework convention on stratospheric ozone protection. The Vienna Convention, concluded in 1985, is a framework agreement in which States agree to cooperate in relevant research and scientific assessments of the ozone problem, to exchange information, and to adopt “appropriate measures” to prevent activities that harm the ozone layer. The obligations are general and contain no specific limits on chemicals that deplete the ozone layer.

During the Vienna Convention negotiations, countries discussed a possible protocol that would provide specific targets for certain chemicals, but no consensus was reached. The UNEP regional seas agreements had provided a precedent in which States negotiated a framework convention and at least one protocol, which countries were required to ratify at the time they joined the convention. The Vienna Convention went forward on its own, however, and was opened for signature in March, 1985. A working group under UNEP began negotiations on a protocol, and the Montreal Protocol was concluded in September, 1987, only nine months after the formal diplomatic negotiations opened in December, 1986. It went into effect on January 1, 1989. A State must be party to the Vienna Convention in order to become a party to the Montreal Protocol. The Vienna Convention and the Montreal Protocol established the precedent in UNEP for completing a framework agreement, followed later by one or more Protocols. This precedent has been used frequently since then, as in the Kyoto Protocol to the United Nations Framework Convention on Climate Change and the Cartagena Protocol on Biosafety to the Convention on Biological Diversity.

The Montreal Protocol on Substances that Deplete the Ozone Layer was designed to reduce the production and consumption of ozone depleting substances in order to reduce their abundance in the atmosphere, and thereby protect the earth’s fragile ozone Layer. The original Montreal Protocol was agreed on 16 September 1987 and entered into force on 1 January 1989.

The Montreal Protocol includes a unique adjustment provision that enables the Parties to the Protocol to respond quickly to new scientific information and agree to accelerate the reductions required on chemicals already covered by the Protocol. These adjustments are then automatically applicable to all countries that ratified the Protocol. Since its initial adoption, the Montreal Protocol has been adjusted six times. Specifically, the Second, Fourth, Seventh, Ninth, Eleventh and Nineteenth Meetings of the Parties to the Montreal Protocol adopted, in accordance with the procedure laid down in paragraph 9 of Article 2 of the Montreal Protocol, certain adjustments and reductions of production and consumption of the controlled substances listed in the Annexes of the Protocol. These adjustments entered into force, for all the Parties, on 7 March 1991, 23 September 1993, 5 August 1996, 4 June 1998, 28 July 2000 and 14 May 2008, respectively.

The Parties to the Montreal Protocol have amended the Protocol to enable, among other things, the control of new chemicals and the creation of a financial mechanism to enable developing countries to comply. Specifically, the Second, Fourth, Ninth and Eleventh Meetings of the Parties to the Montreal Protocol adopted, in accordance with the procedure laid down in paragraph 4 of Article 9 of the Vienna Convention, four Amendments to the Protocol – the London Amendment (1990), the Copenhagen Amendment (1992), the Montreal Amendment (1997) and the Beijing Amendment (1999). Unlike adjustments to the Protocol, amendments must be ratified by countries before their requirements are applicable to those countries. The London, Copenhagen, Montreal and Beijing Amendments entered into force on 10 August 1992, 14 June 1994 10 November 1999 and 25 February 2002 respectively, only for those Parties which ratified the particular amendments.

In addition to adjustments and amendments to the Montreal Protocol, the Parties to the Protocol meet annually and take a variety of decisions aimed at enabling effective implementation of this important legal instrument. Through the 22nd Meeting of the Parties to the Montreal Protocol, the Parties have taken over 720 decisions. The decisions adopted by the Parties are included in the reports of the Meetings of the Parties and, along with other documents considered during the meetings.