Problems of Thinning of Ozone Layer!
Ozone is a form of oxygen with three atoms instead of the normal two, and forms a fragile shield scattered in the stratosphere absorbing the sun’s ultraviolet radiation, away from the earth’s surface. It forms a 3 mm thick layer, but if it disappears or thins, all terrestrial life will be annihilated.
Near the earth’s surface, ozone is an increasingly troublesome pollutant, but safely up at a height of 20 to 30 km from the earth in the atmosphere, it is as important to life as oxygen itself.
The thinning of the ozone layer has generated global concern in the past decade. This is due to several chemical pollutants discharged by industries or produced through other chemical reactions. Chlorofluorocarbons (CFCs) are substances that are inert, inexpensive, stable, non-inflammable, non-toxic, and easy to store and produce. The population explosion is one of the causes of the increase of CFCs due to use of air conditioners, insulation, solvents and fire-killers.
In 1986, three US agencies, viz., National Aeronautics and Space Administration (NASA), National Oceanic and Atmospheric Administration (NOAA) and Federal Aviation Administration (FAA) started reporting on ground-based and satellite-based data on ozone depletion in stratosphere by the use of chemicals like halon 1301, methyl, chloroform, carbon tetrachloride, solvents FC-113, aerosols, foams and refrigeration CFC-11, and air conditioning CFC-12 that are depleting the ozone layer 4, 5, 8, 12 and 26 per cent, respectively, on global scale, because of human activities.
As far as CFC consumption is concerned, USA is on top consuming 29 per cent, followed by Russia and Europe 14 per cent, while in China and India it is merely 2 per cent. The total ozone amounts in the northern hemisphere, middle and high latitudes have decreased, sudden and unexpected decreases in the amount of spring time Antarctic zone are confirmed on 15 to 20 km in the stratosphere ozone layer.
The increase in ozone layer depletion will invite the lethal ultraviolet rays from the sun which will cause cancer, eye damage, injure plants and marine life and even reduce our immunity to diseases. The UV-B damages the genetic material DNA and also causes skin cancer. The ultraviolet radiation even reduces the efficiency of the immune system, thus impairing the body’s resistance.
Experts are of the opinion that animal and plant world would face a grim challenge if radiations are not checked. Certain crops have been found vulnerable to such radiations. Under the impact of radiations proteins in plants, microbes and animals would be affected and such changes in spatial orientation would be critical in the formed part of the reaction centre of an enzyme.
Near cities where population concentration is more, ozone could be formed near the earth’s surface having disastrous effects on human health, crops and ecosystems. It would also increase the incidence of smog in areas of industrial concentration. Ozone has had its effect on the earth’s climate by adding to the greenhouse effect.
The world is now much serious about the most dramatic evidence of ozone depletion—a “hole” in the ozone layer, which appears every spring over the Antarctica. This hole has grown over the last ten years. Till now, no clear explanation has been found to explain this phenomenon, though scientific research in this field is in progress. But, the general opinion regarding the cause of this depletion is the CFCs.
Since this is a serious problem, this becomes the duty of the developed countries, having both technology and infrastructure, to check the ozone depletion. Likewise since this is not a problem of individual nations, therefore, combined efforts can only check it.
The concern about ozone layer protection began by the late 1970s and early 1980s. In 1978, the United States banned the principal CFCs for most uses; in 1980 European Community countries placed a limit on production of CFCs and cut their use in aerosol products by 30 per cent. Sweden, Norway and Canada also placed limits on CFC use. In 1975, UNEP has also expressed serious concern about ozone depletion and also developed a World Plan of Action on the Ozone Layer.
Some of the important international actions taken on ozone protection are listed below:
1977 UNEP Coordinating Committee on the Ozone Layer established.
1985 Vienna Convention for the protection of ozone layer.
1987 Montreal Protocol on substances that deplete the ozone layer.
1988 Entry into force of the Vienna Convention.
1989 Entry into force of the Montreal Protocol.
1990 Montreal Protocol amended in London. The amendment required signatory governments to regulate consumption and production of CFCs.
1991 Establishment of interim multilateral fund to provide financial assistance to developing countries in order to facilitate control measures.
May 1992 112 states have ratified the amendment to the Montreal Protocol.
Aug 1992 Entry into force of the amendment.
Nov 1992 At Copenhagen, parties agreed to accelerate, phase out schedule, to January 1996.