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 XXI/8: Sources of carbon tetrachloride emissions and opportunities for reductions of ODS emissions

Recalling Decision XVII/10 on sources of carbon tetrachloride (CTC) emissions and opportunities for reduction, and the difficulties expressed by Technology and Economic Assessment Panel (TEAP) in reconciling reported emissions data and atmospheric concentrations,

Reiterating the concern regarding the large discrepancy between reported emissions and observed atmospheric concentrations, which suggests that emissions from industrial activity are significantly under reported and underestimated, or that atmospheric measurements of CTC emissions need to be reconciled,

Acknowledging that CTC can be emitted from processes, stockpiles or containers in the form of vapour or released from the same sources in liquid or solid waste stream(s) and via products, all of which would also be considered as emissions,

Mindful of the obligations to ensure compliance with control measures under Article 2D of the Montreal Protocol regarding production and consumption of carbon tetrachloride,

Desiring to reduce emissions to background concentration levels,

Noting the report UNEP/OzL.Pro/ExCom/58/50 of the 58th Executive Committee on emission reductions and phase-out of carbon tetrachloride in light of decision XVIII/10 of the Eighteenth Meeting of the Parties and its verbal report to the Twentieth Meeting of the Parties concluding that the rapid decrease in model-estimated bottom-up emissions (i.e. based on information from industry and Article 7 data) is significantly lower than emissions derived from atmospheric measurements for the range of scientifically determined atmospheric lifetimes.

  1. To encourage Parties having any carbon tetrachloride and other chloromethane production and/or consumption of CTC in pharmaceutical manufacturing processes to review their national data on CTC production, consumption and where possible estimated emissions and to provide any new data to the TEAP via the Ozone Secretariat by September 2010;
  2. For the purpose of clarification the reference to “emissions” in paragraph 1 means any release from processes, stockpiles, products, and waste streams, either in the form of vapour or in the form of liquid;
  3. To request the TEAP, in its next assessment report in 2011, to investigate chemical alternatives to ODS in exempted feedstock uses and investigate alternatives, including not-in-kind alternatives, to products made with such process agents and feedstocks and provide assessment of the technical and economic feasibility of reducing or eliminating such use and emissions;
  4. To request TEAP and the Scientific Assessment Panel (SAP) to review the ozone depletion potential and atmospheric lifetime of CTC with a view to possibly reconciling the large discrepancy between emissions reported and those inferred from atmospheric measurements and to report their findings in the next quadrennial review;
  5. To request the TEAP and SAP to coordinate their relevant findings, taking into account the information received in relation to paragraphs 1, 3 and 4, and report in time for the thirty-first meeting of the Open-ended Working Group for the consideration of the Twenty-third Meeting of the Parties in 2011;
  6. To encourage all parties to provide support for atmospheric research in the measurement of emissions of CTC with a particular focus on regions in which there is a need for improved data;