Some 185 years after the odour of ozone was smelled for the first time, scientists around the world began to focus their attention on reports that something unusual is going on in the atmosphere. What they discovered was shocking for many while for others it was a nightmare: A hole as big as Europe in the skies over Antarctic.
This hole was punched with the excess use of Chlorofluorocarbons (CFCs), Halons, Carbon Tetrachloride (Tehrachloromethane) and Methyl Chloroform (Tricholoroethane) etc. These gases are widely used for aerosol-spray, propellants, refrigerants, solvents and foam blowing agents. They are well suited for these and other applications because they are nontoxic and non-flammable and can be readily converted from liquid to a gas and vice versa.
The importance of stratospheric ozone layer shielding the Earth's surface from the harmful effects of solar ultra violet radiation had been recognised in a general way for almost 50 years but it was only in 1970 that environment scientists seriously began to ponder that even a small changes in ozone can have a significant impact on human.
The odour of ozone around electrical machines was reported as early as 1785 but ozone's chemical constitution was established in 1872. Ozone is an irritating, pale blue gas that is explosive and toxic, even at low concentrations.
It occurs naturally in small amounts in the Earth's stratosphere, where it absorbs solar ultraviolet radiation, which otherwise could cause severe damage to living organisms on the Earth's surface.
Under certain conditions, photochemical reactions between nitrogen oxides and hydrocarbons in the lower atmosphere can produce ozone in concentrations high enough to cause irritation of the eyes and mucous membranes.
CFC's were developed first in the 1930s but found widespread use only in the years following World War II.
They were employed with great success by US troops in the Pacific to dispense insecticides from aerosol spray cans. This led to many commercial uses, from propellants and refrigerants to foaming agents and degreasers and a host of other applications. Moreover, the use of CFC's rapidly spread from the United States to Europe and the Far East.
Investigators in early and mid 1970s began to observe that migration of people of lower attitude from the north-eastern parts of the United States to the south-western regions of the country were accompanied by an alarming rise in the incidence of skin cancer. Of course all this increase in cancer cases was not attributed to enhanced sunlight.
Other factors showed that smaller abundance of ozone at lower attitude is also the reason for the increase, while more studies suggested that the increase of skin cancer would rise with the decrease in the density of ozone.
By the time the world realised what was going on a lot of damage had been done. A panic like situation was created in the western world that rushed forward to find ways to repair the hole.
Finally in 1985, nations converged in Vienna to take "appropriate measures...to protect human health and the environment against adverse effects resulting or likely to result from human activities, which modify or are likely to modify the Ozone Layer", thus the convention (The Vienna) for the protection of the ozone layer was born.
The main thrust of the convention was to encourage research and overall co-operation among countries and exchange of information. Even so it took four years to prepare and agree. Twenty nations signed it in Vienna, but most did not rush to ratify it.
The convention provided for future protocols and specified procedures for amendment and dispute settlement.
The Vienna convention set an important precedent. For the first time nations agreed in principle to tackle a global environmental problem before its effects were felt, or even scientifically proven.
As the experts began to explore for specific measures to be taken, the journal 'Nature' published a paper in May 1985 by British scientists - led by Dr Joe Farman - about severe ozone depletion in the Antarctic.
The paper's findings were confirmed by American satellite observations and offered the first proof of severe ozone depletion and making the need for definite measures more urgent.
As a result, in September 1987, agreement was reached on specific measures to be taken and the Montreal Protocol on substances that deplete the ozone layer was signed.
MONTREAL PROTOCOL: The Montreal Protocol was adopted on 16 September 1987 at the Headquarters of the International Civil Aviation Organisation in Montreal. The Protocol came into force on 1st January 1989, when it was ratified by 29 countries and the EEC. Since then several other countries have ratified it.
The protocol was designed so that the phase out schedules could be revised on the basis of periodic scientific and technological assessments. Following such 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.
LONDON AMENDMENT: The London amendment was adopted in 1990 at the second meeting of the parties of the Montreal Protocol held in London. The amendment introduced control measures for both production and consumption for three new groups of substances, namely other halogenated CFCs, Carbon Tetrachloride and Methyl Chloroform or 1,1,1- trichloroethane. Control measures also included restrictions on trade with non-Parties.
The financial mechanism was also established (Article 10 of the protocol) for providing financial and technical assistance to developing countries to enable their compliance with their obligations under the protocol. The financial mechanism meets the agreed incremental costs of developing countries in order to enable their compliance with the control measures of the protocol.
The amendment further introduced HCFCs, but only required reporting of production and consumption data for the annex and did not introduce control measures for the annex group. The London Amendment entered into force on 10 August 1992.
COPENHAGEN AMENDMENT: The Copenhagen amendment was adopted in 1992 at the fourth meeting of the parties to the Montreal Protocol held in Copenhagen. The amendment introduced control measures for consumption only for HCFCs.
The amendment further introduced control measures for both production and consumption for two new groups of substances, namely HCFCs and Methyl Bromide. The Copenhagen amendment entered into force on 14 June 1994.
MONTREAL AMENDMENT: The Montreal amendment was adopted in 1997 at the ninth meeting of the parties to the Montreal Protocol held in Montreal. This is the only amendment that did not introduce new substances to the protocol.
Instead, the amendment introduced the requirement for licensing systems to allow control and monitoring of trade in substances controlled under the protocol. The Montreal amendment entered into force on 10 November 1999.
BEIJING AMENDMENT: The Beijing amendment was adopted in 1999 at the eleventh meeting of the parties to the Montreal Protocol held in Beijing. The amendment introduced control measures for production for HCFCs and imposed restrictions on trade with non-Parties for these HCFCs.
The amendment further introduced control measures for both production and consumption for one new group of substances, namely Bromochloromethane or BCM. The Beijing amendment entered into force on 25 February 2002.
Up till now 160 countries have signed the protocol. As elsewhere these gases in Pakistan are used mainly for the same purpose, but in plastic industry they are used by the processors of hot pots, water coolers and water bottles.
As per Montreal Protocol use of CFC should be phased out by 2010 world-wide. Pakistan has agreed to it. International Day for the preservation of the ozone layer is commemorated every year on September 16. With the global efforts to ban the production and use of these chemicals, scientists are of the view that the hole in the protective layer will soon begin to shrink and should close completely as soon as 50 years.
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