The 1985 Vienna Convention for the Protection of the Ozone Layer was the first framework for co-operative activities to protect the ozone layer. Here, parties agreed to co-operate with each other in scientific research to improve the understanding of the atmospheric processes, to share information on ODS production and emissions and to implement preventive measures to control ODS emissions. The Vienna Convention, adopted in March 1985 and signed by 21 states, does not contain legally binding controls or targets.
Upon the discovery of the seasonal “ozone hole” in Antarctica in the 1985, governments recognized the need for stronger measures to respond to the problem of ozone depletion. Thus, the Montreal Protocol on Substances the Deplete the Ozone Layer was signed on September 16, 1987 and entered into force on January 1, 1989. In this international agreement, signed by 188 developed and developing countries to date, committed to phase-out or gradually stop their production and consumption of ozone depleting substances like chlorofluorocarbons or CFCs (CFC-11, 12, 113, 114, and 115) and Halons (1211, 1301, 2402).
The Montreal Protocol is dynamic, so has had several amendments and adjustments. The Protocol was adjusted to accelerate the phase-out schedules in London in 1990, Copenhagen in 1992, Vienna in 1995, Montreal in 1997 and Beijing in 1999. It has been amended to introduce other kinds of control measures and to add new controlled substances to the list:
* 1990 London Amendment included additional CFCs (CFC-13, 111, 112, 211, 212, 213, 214, 215, 216, 217) and two solvents (carbon tetrachloride and methyl chloroform)
Developing countries have a grace period of ten (10) years before they must start their phase-out schedules. The phase-out schedules cover both the production and consumption of the target substances.