Depletion of the Ozone Layer

Depletion of the Ozone Layer
The atmospheric ozone layer protects all living things from the harmful effects of the Sun. In recent years however, much damage has been caused to the ozone layer, causing it to decrease in size. The depletion of the ozone layer has and will continue to have many detrimental effects on all living things on this planet. A thinner layer will allow more of the sun?s ultraviolet radiation to reach the Earth?s surface. In particular, it will be the increase of UV-B rays which will have the most negative side effects. It will effect humans, plants, the Earth?s water and every other living creature. Studies have shown that for every five percent reduction in the concentration of ozone, the rate of skin cancer will rise by ten percent, due to increased exposure to the Sun?s ultraviolet rays (Environment Canada). Increased amounts of ultraviolet radiation increase the incidence of eye cataracts, which are patches of light blocking tissue which can lead to blindness (Ehrlich 120). It will also affect plants, which are sensitive to ultraviolet radiation. High levels will cause reduced stem and leaf growth in plants because photosynthetic activity is reduced or damaged. It also causes lower dry weight and affects plants? ability to take in and use water (Ehrlich 120). This in turn reduces agricultural production and the food available to animals. Greater exposure to ultraviolet rays also affects the dna of organisms. The radiation has the ability to reach the dna and alter its structure. This can impair the organisms immune system, cause stunted growth, as well as increase the risk of cancer (Dolan 260). As well, micro-organisms in the soil which produce nutrients, can die from over-exposure to ultraviolet rays, resulting in soil infertility.The Ozone Layer
The ozone layer shields the Earth and its inhabitants from the sun?s harmful ultraviolet rays. It absorbs or blocks out 95% of high frequency ultraviolet radiation. The layer is comprised of a molecule called ozone, an electrically charged form of oxygen that is produced when sunlight reacts with chemicals in the air. The ozone molecules have the ability to filter the radiation, allowing only a small fraction of it to pass through (Gribbon 56). The layer is found in the Earth?s stratosphere, with its peak concentration about twenty-five kilometres above the Earth?s surface.

CFC?s
Chlorofluorocarbons, better known as CFC?s, were introduced early in the early twentieth century and are the main culprit of the decline in the ozone layer. They were developed by General Motors and were given the original trademark of ?Freons? in 1928. CFC?s were first used as coolant fluid in refrigeration units, replacing previous solutions such as ammonia and sulphur dioxide (Ehrlich 115). They were called ?miracle? gases because they could be used safely. Unlike precious solutions that were used, they were non-toxic and non-corroding (Dolan 27). By the late 1980?s, CFC?s reached their peak manufacture. They were used as coolants in refrigeration units, air conditioners, as well as solvents in degreasers and cleaners. They were used so widely because of their stability and safety, but the stability of the molecule is also why it is so dangerous to the atmosphere. The stability disables it to be destroyed easily. This allows the gas to be released at ground level and gloat up to the stratosphere intact, often taking five years to do so (Dolan 27). Once these chemicals enter the ozone layer, they are hit by the Sun?s radiation, with enough energy to dissociate the molecule (Fisher 25). The molecules are broken down into individual components of fluorine, carbon and in particular, chlorine. The chlorine and ozone are both very reactive and take part in a reaction. The chlorine catalyses the reaction of ozone into atomic oxygen. By the end of the reaction, the ozone has transformed into oxygen while the chlorine remains unaffected (Fisher 25). This means the chlorine molecule can stay in the atmosphere, and it has been proven that a single chlorine molecule can destroy up to one hundred thousand molecules of ozone (Dolan 28).

What Can We Do?
Scientists have discovered that the ozone layer can recover from the damage cause to it. If all CFC?s were to be banned completely as of now, the earliest date the layer could recover is 2050 (Environment Canada). Since many ODS?s have been banned, the hole in the ozone layer has stopped growing, however it hasn?t gotten any smaller. Aerosol cans, fire extinguishers and insulating products such as foam, are all currently cfc free (Gribbon 57). There is now the major task of finding an alternative coolant for use in refrigerators and air conditioners. Chemical companies have been looking for other gases to use in these products but are yet to fined a suitable substitute.

Conclusion
To allow the ozone layer to recover, humans must stop all cfc emissions. Air conditioners which still use them must be banned, and production must be stopped. In doing this we will be allowing the ozone layer a chance to heal itself and to keep on protecting the Earth. We should stop the effects of these chemicals while we still can, before the Sun permanently damages the quality of life on our planet.

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