1. What is the mandate/provision(s) in the Montreal Protocol that determines the type of gas that will fall within its remit?

2. What definitions and technical guidance are in the Montreal Protocol and how is it determined that a new gas should be added to the Montreal Protocol?

Summary: The provisions for amending the Montreal Protocol to add new gases within its scope are fairly flexible. They enable the Parties to the Protocol, following a 4 yearly review of the available scientific, environmental, technical and economic information, to propose the insertion of new gases (or removal of existing gases) from the scope of the Protocol. The approval of at least 2/3 of the Parties to the Protocol is required for such amendments to be made.

There is no particular definition or technical guidance in the Montreal Protocol setting out how a new gas should be added to the Montreal Protocol. The key criteria is that such proposals have to be based on available scientific, environmental, technical and economic information but the preamble to the Protocol indicates that the Parties are likely to adopt amendments to the Protocol (including the insertion of new gases) if, on the basis of the “precautionary principle”, available information indicates that there is a potential risk that emissions of a particular gas could contribute to the depletion of the ozone layer.

1. The drafting of the Montreal Protocol is fairly flexible in terms of how new gases are to be added to the scope of the Protocol. In essence, any party can propose amendments to the gases covered by the Montreal Protocol, as long as the proposed amendments are based on the latest available scientific, environmental, technical and economic evidence.

Article 2(10) states that based on assessments pursuant to Article 6 of the Protocol (see below) and in accordance with the procedure of Article 9 of the Vienna Convention for the Protection of the Ozone Layer (see below), the parties to the Protocol can decide which, if any, substances should be added or removed from any annex to the Protocol and the mechanism, scope and timing of the “control measures” (e.g. limits on production or consumption of these substances) that should apply to those substances.

Article 6 requires the Parties to the Protocol to assess every 4 years (starting in 1990) the control measures set out in the Protocol on the basis of available scientific, environmental, technical and economic information. The assessment is actually carried out by a panel of experts that must be appointed at least one year ahead of the end of the 4 year period and which must present its conclusions within one year of its appointment.

The procedure set out in Article 9 of the Vienna Convention and Article 11(4) of the Protocol require the Parties to propose any amendments to the Protocol at a meeting of the Parties to the Protocol (the proposed amendments must be circulated to all Parties via the Secretariat to the Convention and the Protocol 6 months ahead of such a meeting). As in Article 6, the main requirements for a party to propose amendments to the Protocol are that the proposed amendments must take due account of relevant scientific and technical considerations.  The Parties to the Protocol are required to seek to reach a consensus on proposed amendments, failing which amendments can be agreed by a 2/3 majority of the Parties to the Protocol.

Note also the provisions of Article 2(9) of the Protocol which allow the Parties to make amendments to the control measures of existing gases covered by the Protocol and to the ozone depleting potential estimates for each substance contained in the Annexes to the Protocol.

Note that the Montreal Protocol has undergone various revisions, in particular in terms of adjustments of the control measures and ozone depleting potential estimates of the various substances covered by the Protocol. The key amendments were made in London (1990), Copenhagen (1992), Vienna (1995), Montreal (1997) and Beijing (1999).

2. There is no particular definition or technical guidance in the Montreal Protocol setting out how a new gas should be added to the Montreal Protocol. The process for adding new gases to the Protocol seems to have been left deliberately flexible, by allowing the Parties to the Protocol, following the 4 yearly technical assessment, to propose the addition of new gases to the Protocol.

The key criteria is that such proposals have to be based on available scientific, environmental, technical and economic information. Note also the wording of the preamble to the Protocol, which refers to the Parties being “determined to protect the ozone layer by taking precautionary measures to control equitably total global emissions of substances that deplete it.” This seems to indicate that new gases could be added to the Montreal Protocol on the basis of the “precautionary principle” if available  scientific, environmental, technical and economic information show that there is a risk that emissions of  a particular gas could cause harm to the ozone layer.