Orbiting above the Earth, an astronaut can look down on our home and see the thin blue ribbon that rims our planet. That transparent blanket (our atmosphere) makes life possible. It provides the air we breathe and regulates our global temperature. And it contains a special ingredient called ozone that filters deadly solar radiation. Life is only possible because of the protection afforded by the ozone layer from harmful stellar ultraviolet radiation.
The ozone layer is located between 10 and 50 km above the Earth’s surface, called as the stratosphere. About 90% of atmospheric ozone is contained in the “ozone layer”. Its presence is of vital importance for life on earth, because it protects us from the damaging ultra-violet radiation of the sun; in particular it filters out UV-B radiation. However in recent decades, this ozone shield has been severely damaged by polluting the air with chemicals arising from human activities. The result will be increase in ultraviolet radiation at Earth’s surface, and that can have significant effects on life on Earth. It may cause damage to plants and animals. In humans it can cause skin cancer and eye problems. It also function as a general immuno-suppressant. In Marine environment it can be a cause for reduction in the numbers of phytoplankton, photosynthesising organisms. UV-B also causes direct damage to young fish and crab larva further disturbing the whole marine ecosystem.
The most severe and most surprising ozone loss was discovered to be over Antarctica breeding a significant danger to the ecosystem in Southern Hemisphere. It’s commonly called as “ozone hole” because the ozone depletion is large and localized. A thinning of the ozone layer also has been observed over other regions of the globe, such as the Arctic. Recently scientists have confirmed a 2.5 million-square km hole in the low-level ozone layer over western China’s Qinghai-Tibet Plateau.
Following the discovery of this environmental issue, researchers focused on a better understanding of this threat to the ozone layer. Monitoring stations showed that the abundances of the ozone-depleting chemicals were steadily increasing in the atmosphere. These trends were linked to growing production and use of chemicals like chlorofluorocarbons (CFCs and HCFCs). These chlorine-containing compounds, used in aerosols, refrigeration, solvents and foam insulation, have drifted up into the stratosphere. Through a complex series of chemical chain-reactions, small amounts of these compounds are able to destroy very large quantities of ozone.

The work of many scientists throughout the world has provided a basis for building a broad and solid scientific understanding of the ozone depletion process. In response to the prospect of increasing ozone depletion, the governments of the world first crafted 1985 Vienna Convention and after two years in 1987 Montreal Protocol came in picture as a global means to address this global issue. Now over 189 countries are participants that agreed to the reduction and eventual phasing-out of the manufacture and use of most of the ozone depleting substances. Montreal Protocol had played a major role in protection of ozone layer and more importantly, the industrial development of more “ozone-friendly” substitutes for the now-controlled chemicals.

While the recent positive news is encouraging, the rise of the black market trade in CFCs threatens to undermine the Protocol’s early success and further endanger the earth’s ecology. A (un)healthy black market trade in CFCs had already developed. It is difficult to predict how far the ozone layer will become depleted before it begins to recover. The troubling aspect is that if we stop manufacturing, using and even emitting all ozone depleting chemicals today, the problem will not go away immediately. Since what we have already emitted will be in the atmosphere for another 50 or more years.

It is beyond any doubt that the destruction of our ‘ozone UV shield’ will, if not checked at an early stage, result in grave consequences for our living environment.
But the question is whether the whole world is aware of it or is it only the scientific community and ministry of environment. Unless a greater awareness is shaped, saving our beloved earth will only be a daydream. It is heavy consumer and public awareness that is need of the hour.

Article Source: http://www.articleset.com