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 XXIV/10: Review by the Scientific Assessment Panel of RC‑316c

Recalling decisions IX/24, X/8, XI/19 and XIII/5 of the Meeting of the Parties pertaining to new substances,

Noting that the Scientific Assessment Panel has developed procedures for assessing the ozone‑depletion potential of new substances,

  1. To invite parties in a position to do so to provide environmental assessments of RC‑316c (1,2-dichloro-1,2,3,3,4,4-hexafluorocyclobutane, CAS 356-18-3), a chlorofluorocarbon not controlled by the Montreal Protocol, and any guidance on practices that can reduce intentional releases of the substance;
  2. To request the Scientific Assessment Panel to conduct a preliminary assessment of RC‑316c and report to the Open-ended Working Group at its thirty-third meeting on the ozone‑depletion potential and global-warming potential of the substance and other factors that the Panel deems relevant;