Category Environment

            Although Chlorofluorocarbons are harmful to the ozone layer, we still use them in various appliances at home. CFCs are used in refrigerators, air-conditioners, solvents and aerosol sprays.

            We know that CFCs cause global warming by trapping heat in the atmosphere. They are instrumental in depleting the ozone layer as well. Once these gases are in the atmosphere, they resist breakdown and do not disappear for many decades. In fact, they can remain in the atmosphere for up to 400 years! It is, therefore, important to reduce the amount of CFCs that are released into the air. One way to do this is to use only CFC –free refrigerators and to avoid the use of air conditioners.

            We should also be careful that any deodorant, spray, solvent or cleaner that we buy is CFC-free. The developing nations of the world have agreed to find substitute chemicals for CFCs. The 1987 Montreal Protocol has reduced the worldwide stock of CFCs and other ozone-destroying compounds by 98 percent. More nations followed suit later. As a result, the ozone layer is expected to recover by the mid – 21st century.

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            The ozone layer is a delicate and sensitive region. Various factors contribute to the breaking down and depletion of the ozone concentrations in the layer. The destruction of the ozone shield will result in the sun’s harmful rays sifting through the resultant holes.

            In the mid-1980s, scientists discovered that the ozone layer was being depleted gradually. The main cause of this, they concluded, was the release of chemicals called Chlorofluorocarbons or CFCs. CFCs are used in industry in a variety of ways and have been amazingly useful in many products. Discovered in the 1930s by American chemist Thomas Midgley, CFCs came to be used in aerosol propellants, refrigerators, home insulation, plastic foam, and throwaway food containers. However, when they escaped to the atmosphere, they adversely affected the ozone particles.

            When CFCs are released into the atmosphere, strong winds can carry them up into the stratosphere where UV rays break them apart, releasing chlorine atoms. Each chlorine atom can attack, and break apart as many as 100,000 ozone molecules during the time it is in the stratosphere. The chlorine from CFCs reduces the amount of ozone in the stratosphere. CFCs also warm the earth’s atmosphere and thus can bring about climate changes all over the planet.

Why does the depletion of the ozone layer pose a danger to us?

                     Man has been instrumental in the gradual deterioration of the ozone layer. When the ozone region is exposed to CFCs, holes are formed in the ozone shield. Through these holes, ultraviolet and other harmful rays of the sun enter the earth’s atmosphere.

                    Even an apparently negligible corrosion of the ozone layer is harmful to us. Every time a small area of the ozone layer is damaged, more ultraviolet light from the sun can reach the earth. One of the most harmful consequences of ozone depletion is that it can cause skin cancer because of the exposure to UV rays. Some researchers say that a tattered ozone layer will also increase the rate of malaria.

                    The environment will also be negatively affected by ozone depletion. The life cycle of plants will change as their food chain is disrupted. Oceans will be hit hard as well. The most basic microscopic organisms such as plankton may not be able to survive if the ozone layer is depleted. The planet’s climate could be adversely affected, as rising heat would alter wind patterns resulting in climate changes throughout the world.

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            The ozone layer covers the entire earth and protects it like a shield from the hazardous rays of the sun. While the ozone shield is formed around the globe, the thickness of the layer is not the same throughout.

            The ozone in the layer is distributed unequally as it is minimum in thickness near the earth’s surface and in the exosphere. Most of it is concentrated in a layer located in the stratosphere several kilometres above the surface of the earth. The thickness of the ozone layer in a vertical column from the surface to the top of the atmosphere is called the total column ozone amount.

            Total ozone varies with latitude over the globe, with the largest values occurring at middle, and high latitudes during all seasons. Total ozone also varies with the seasons, and is in general thicker in spring and thinner during autumn in the northern hemisphere.

            Have you ever worn a pair of glare glasses? In the hot sun, the tinted glasses give comfort to our eyes and protect them from the sun’s harmful rays. The ozone layer does a similar job, protecting the life forms on Earth from the harmful rays of the sun.

            The ozone layer or ozone shield is a region of Earth’s stratosphere that absorbs most of the sun’s ultraviolet radiation. It contains high concentrations of ozone, an inorganic oxygen molecule. The ozone layer is mainly found in the lower portion of the stratosphere and also in the troposphere. The layer was discovered in 1913 by Charles Fabry and Henri Buisson, two distinguished French physicists.

            Ozone in the troposphere pollutes the air there; and this in turn helps the forming of smog. Ozone in the stratosphere protects life on Earth by absorbing some of the sun’s harmful ultra-violet rays. The ozone layer absorbs 97 to 99 percent of the sun’s medium-frequency ultra-violet light, which otherwise would potentially damage exposed life forms near the surface.

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            You must have seen pictures of the beautiful white polar bears that live near the North Pole. These majestic animals live in extreme cold and cannot live elsewhere, where there is no ice.

            However, today, the very existence of these animals is threatened because of climate change. Fondly called the white giants of the Arctic, these glorious animals spend much of their life in, around, or on the water predominantly on sea ice. However, it is a sad fact that sea ice in the Arctic is melting earlier and forming later each year, because of global warming. This means that polar bears are left with less time on the ice to hunt for food, mainly seals, and build up their fat stores for survival in the cold.

            As their ice habitat shrinks, skinnier and hungrier polar bears could become extinct by the end of this century. This would be a tragedy because polar bears help us gain an understanding of what is happening of what is happening throughout the Arctic region. If polar bears are at risk, it may also be an indication that something is terribly wrong with the entire Arctic marine eco-system too.

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