THE SCIENTIFIC confirmation of the depletion of the ozone layer prompted the international community to establish a mechanism for co-operation to take action to protect the ozone layer. This was formalized by a treaty called the Vienna Convention for the Protection of the Ozone Layer, which was adopted and signed by 28 countries on 22 March 1985 in Vienna.
This led in September 1987 to the drafting of the Montreal Protocol on Ozone Depleting Layer (ODL) substances. The Protocol was signed by 24 countries and by the European Economic Community and entered into force on 1 January 1989. The treaty states that the Parties to the Montreal Protocol recognise that world-wide emissions of ozone-depleting substances (ODSs) significantly deplete and otherwise modify the ozone layer in a manner that is likely to result in adverse effects on human health and the environment.
The provisions of the Protocol include the requirement that the parties to the Protocol base their future decisions on the current scientific, environmental, technical and economic information assessed by panels drawn from the world-wide expert communities.
The principal aim of the Montreal Protocol is to protect the ozone layer by taking measures to control total global production and consumption of substances that deplete it, with the ultimate objective of eliminating them, based on developments in scientific knowledge and technological information.
The Montreal Protocol is structured around several groups of ozone-depleting substances. The groups of chemicals are classified according to chemical family and are listed in annexes to the Montreal Protocol text. Ozone-depleting substances are therefore sometimes referred to according to the annex in which they are listed in the Montreal Protocol.
The Montreal Protocol requires the control of nearly 100 chemicals, in several categories. For each group or annex of chemicals, the treaty sets out a timetable for the phase out of production and consumption of those substances, with the aim of eventually eliminating them completely.
The timetable set by the Montreal Protocol applies to consumption of ozone depleting substances. Consumption is defined as the quantities produced plus those imported, less those quantities exported in any given year. There is also a deduction for verified destruction.
Percentage reductions relate to the designated "base year" for the substance. The Protocol does not forbid the use of existing or recycled controlled substances beyond the phase out dates.
Attention was focused initially on chemicals with higher ozone-depleting potentials, including CFCs and halons. The phase-out schedule for HCFCs was more relaxed due to their lower ozone-depleting potentials and because they have also been used as transitional substitutes for CFCs.
The HCFC phase-out schedule was introduced in 1992 for both developed and developing countries, the latter with freeze in 2015 and a final phase-out by 2030 in developed countries and by 2040 in developing countries. In 2007, the Parties to the Montreal Protocol decided to accelerate notably the HCFC phase-out schedule both for developed and for developing countries.
The Montreal Protocol embodies the international agreement on the overall scope and timescales for phase-out of ozone-depleting substances (ODS), and the Multilateral Fund, through its Secretariat and the implementing agencies, provides a financial and technical support mechanism. The financial assistance to developing countries covers the agreed incremental costs, which must be determined on the basis of the indicative list of categories of incremental costs (ILCIC) adopted by the Parties to the Montreal Protocol.
However, the implementation of phase-out activities and compliance with phase-out targets is ultimately the responsibility of the governments that are Parties to the Protocol.
One of the principal objectives of the Montreal Protocol and the Multilateral Fund is to facilitate a smooth and sustainable transition from ODS- based technologies to non-ODS technologies without creating local market distortions or increasing social costs resulting from phase-out costs being passed on to the consumer.
The Protocol requires each Party to annually report its production, import and export of each of the chemicals it has committed to phasing out (most countries use no more than four or five of these chemicals). The Protocol includes a requirement for a regular assessment intended to enable the Parties to make informed decisions on the basis of the most upto-date information available on science environmental effects technology and economics.