United Nations Environment Programme
   Ozone Secretariat


Treaties and Ratification

Vienna Convention          Montreal Protocol            Status of Ratification

The issue of ozone depletion was first discussed by the Governing Council of the United Nations Environment Programme (UNEP) in 1976. A meeting of experts on the ozone layer was convened in 1977, after which UNEP and the World Meteorological Organization (WMO) set up the Coordinating Committee of the Ozone Layer (CCOL) to periodically assess ozone depletion. Intergovernmental negotiations for an international agreement to phase out ozone depleting substances started in 1981 and concluded with the adoption of the Vienna Convention for the Protection of the Ozone Layer in March 1985.

The Vienna Convention encourages intergovernmental cooperation on research, systematic observation of the ozone layer, monitoring of CFC production, and the exchange of information.

The Montreal Protocol on Substances that Deplete the Ozone Layer was adopted in September 1987. It was designed so that the phase out schedules could be revised on the basis of periodic scientific and technological assessments. The Protocol was adjusted to accelerate the phase out schedules. It has also been amended to introduce other kinds of control measures and to add new controlled substances to the list.

Governments are not legally bound until they ratify the Protocol as well as the Amendment. Unfortunately, while most governments have ratified the Protocol, ratification of the Amendment and their stronger control measures lag behind.

  © Ozone Secretariat 2004