One of the most successful international treaties was the Montreal Protocol which banned the use of Substances that Deplete the Ozone Layer. It was ratified by all 197 members of the United Nations and signed by 28 countries on 19 December 1987. On 19 December, 1994 the United Nations General Assembly passed a resolution (49/114), to celebrate the signing of the Montreal Protocol. Since 1995, every year September 16 is observed as the International Day for the Preservation of the Ozone Layer.
Montreal Protocol is a protocol to the Vienna Convention for the protection of the Ozone Layer, designed to protect the Ozone layer by banning substances believed to be responsible for depletion of the Ozone layer. It is believed that if all the countries adhere to the treaty Ozone layer will be recovered completely by 2050. The treaty was opened for signature on 16 September 1987, and entered into force on 1 January 1989, followed by a first meeting in Helsinki, May 1989. Since then, it has undergone seven revisions, in 1990 (London), 1991 (Nairobi), 1992 (Copenhagen), 1993 (Bangkok), 1995 (Vienna), 1997 (Montreal), and 1999 (Beijing).
The protocol requires the control of nearly 100 chemical in various categories. The treaty sets out a timetable to phase out the production of chemicals, aiming to completely eliminate them. The implementation of the protocol has been adhered to in most cases, some of them even ahead of schedule and it has progressed well in developed and developing countries. The protocol doesn’t forbid the use of existing or recycled controlled substances beyond the phase-out dates. There are a few exceptions for essential uses where no acceptable substitutes have been found, for example, in metered dose inhalers (MDI) commonly used to treat asthma and other respiratory problems or halon fire-suppression systems used in submarines and aircraft.
The Ozone layer depletion is being caused by a number of commonly used chemicals. Halocarbons are chemicals in which one or more carbon atoms are linked to one or more halogen atoms (fluorine, chlorine, bromine or iodine). Halocarbons containing bromine usually have much higher ozone-depleting potential (ODP) than those containing chlorine. The man-made chemicals that have provided most of the chlorine and bromine for ozone depletion are methyl bromide, methyl chloroform, carbon tetrachloride and families of chemicals known as halons, chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs).
This year’s theme is “A healthy atmosphere, the future we want”. The Ozone layer acts as a shield from the harmful rays from the sun, thus helping preserve life on the planet. Our efforts in this mission has not only helped reduction in depletion but also addressed climate change issues.