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 XXIII/8: Investigation of carbon tetrachloride discrepancy

Taking note of the report from the Technology and Economic Assessment Panel and the Scientific Assessment Panel indicating the existence of a discrepancy between the emissions derived from reported production and consumption data from both parties operating under paragraph 1 of Article 5 and those not so operating and those inferred from atmospheric measurements,

Noting that the Technology and Economic Assessment Panel is continuing its work and will provide information as called for in decision XXI/8 relating to carbon tetrachloride,

  1. To request the Technology and Economic Assessment Panel, in cooperation with the Scientific Assessment Panel, to continue to investigate the possible reasons for the identified discrepancy, considering in particular the extent to which the discrepancy could be due to:
    1. Incomplete or inaccurate historical reporting of carbon tetrachloride produced;
    2. Uncertainties in the atmospheric lifetime of carbon tetrachloride;
    3. Carbon tetrachloride from unreported or underestimated sources from both parties operating under paragraph 1 of Article 5 and those not so operating;
  2. To request the Technology and Economic Assessment Panel to report on its work in response to paragraph 1 above to the Twenty-Fourth Meeting of the Parties;