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Ozone Layer Depletion

Ozone is composed of three oxygen molecules and. is produced naturally by sunlight. At ground level ozone is a pollutant, but in the upper stratosphere (a segment of atmosphere extending approximately 9 miles to 30 miles above the earth's surface) it forms a layer that protects the earth from the sun's harmful ultraviolet radiation. Although ozone composes a small part of the atmosphere's total mass, it absorbs more than 99% of the sun's ultraviolet radiation.


In small doses, ultraviolet radiation can produce sunburn and has been shown to cause skin cancer in laboratory animals. In greater amounts, however A this radiation can "break apart" important biological chemicals, including DNA. A 1% depletion in the ozone layer allows 2% more ultraviolet radiation to reach the earth's surface. Scientists predict that this would raise the incidence of skin cancer by 4% to 5%.

Increased ultraviolet radiation will also cause an increase in cases of cataracts, suppress human and aniinal immune systems, damage fish larvae, kill off micro-organisms on the ocean floor that serve as food for larger marine life, give some crops 'sunburn", decrease crop yield, and damage man made products such as paints and plastic.

Chlorofluorocarbons CFC's have been shown to contribute to the greenhouse effect). This would result in a partial melting of the ice caps, a rise in sea levels, and the disruption of current weather patterns and the decline of agricultural productivity.


Steps Taken Against Ozone Layer Depletion


•    In 1985, several countries adopted the Vienna Convention for the protection of the Ozone layer. The purpose was to phase out the use of Ozone Layer depleting substances.
•    Montreal protocol was adopted in September 1987 to replaces the 96 Ozone depleting substances.
•    This agreement bore positive results. The total CFC’s consumption worldwide was reduced to 110000 tonnes in 2001 from 1.1 million tonnes in 1986.