Editorial note

The 1987 Montreal Protocol to the Vienna Convention is the only Protocol to date adopted under the ozone layer treaty regime. The Montreal Protocol sets forth specific legal obligations, including limitations and reductions on the calculated levels of consumption and production of certain controlled ozone-depleting substances. Its negotiation and conclusion, shortly after the 1985 Vienna Convention, were prompted by new scientific evidence indicating that emissions of certain substances were significantly depleting and modifying the ozone layer and would have potential climatic effects (Preamble). The absence of scientific evidence that actual harm was occurring required the international community to take ‘precautionary measures to control equitably total global emissions’ of substances that deplete the ozone layer (Preamble).

The original text of the Montreal Protocol was adopted in 1987 and has been subsequently modified on several occasions. In 1990 the Second Meeting of the Parties to the Montreal Protocol adopted the first Adjustment and Amendments to the Montreal Protocol (London Adjustment and Amendment). The 1990 Montreal Protocol Amendments introduced important changes. The Preamble was amended to include reference to the need to take into account the ‘developmental needs of developing countries’, the provision of ‘additional financial resources and access to relevant technologies’, and the ‘transfer of alternative technologies’. The definition of ‘controlled substances’ and ‘production’ was amended (Article 1(4) and (5)), and a definition of ‘transitional substances’ was introduced (Article 1(9)). The amended definition of ‘production’ excludes ‘recycled’ and ‘reused’ amounts (Article 1(5)).