ozone layer is a spherical layer surrounding the earth. It is mainly lie in the lower portion of the stratosphere from about 20 to 30 kilometers above the earth. Ozone layer is very important for the earth because it provide a protection against UV (Ultraviolet) radiation of the sun so it is described as the shield of the earth. The science of ozone depletion The depletion of ozone layer became a major environmental problem by the middle of the last century after the discovery of CFCs which has been damaging our natural shield since its discovery till the current moment. Due to the importance of this matter there have been an international consensus on the science of ozone depletion has.
Our Radiant Planet: Depletion of the Ozone Layer Ozone is a relatively unstable form of molecular oxygen containing three oxygen atoms produced when upper-atmosphere oxygen molecules are split by ultra violet light. Stratospheric ozone is found in a broad band, extending generally from 15 to 35km above the earth. Although the ozone layer is surprisingly thin, it acts as a protective shield to the earth, as it filters out most of the harmful solar ultraviolet radiation (in particular UV-B) that would otherwise reach our planets surface. Humans have damaged the ozone layer by adding molecules containing chlorine and/or bromine that lead to ozone destruction. The largest group among these are chloroflurocarbons (CFC's).
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.
Despite the ozone layer, which helps block UV light and its radiation, some still gets through and can affect us. First it causes a nice looking tan, or a painful sunburn, however, deeper than that, it is wreaking havoc upon the skin cells, though this damage is cumulative, and is not visible for along time, it does great harm. In fact, ultraviolet radiation is the number one cause of skin cancer, and its occurrence is still rising. This rise in cases of skin cancer could be linked to a dramatic change in the atmosphere - the loss of ozone. Over the past decades, scientists have begun to study the atmosphere and the ozone layer.
The Ozone layer is depleting due to man made chemicals we use everyday; this depletion causes an increase in the risk of someone developing skin cancer, and is potentially life-threatening. The ozone layer is a gas that protects the earth from the dangerous UV rays emitted from the sun. (Freedman, page 2934) Due to man made chemicals, the ozone layer is depleting which causes many problems for sustainable life on earth. The rays entering the earth’s stratosphere without the ozone layer will cause damage to many things, such as someone’s eyes or immune system, aquatic life, or plants. Another one of the consequences of ozone layer depletion is that it will cause an increase in the risk of developing skin cancer.
Radiation with sufficient intensity, is capable of separating the O3 molecule, resulting in photodissociation. The cyclic process formation and decomposition of ozone provides a shield against ultraviolet radiation that enter the earth's atmosphere. If it were not for the chemical reaction of radiation and ozone in the stratosphere, these high-energy photons would penetrate the earth's surface. The ozone layer absorbers about 99% of the harmful radiation which makes it possible for animals and plants to live on the planet. In 1974, F. Sherwood Rowland and Mario Molina of the University of California proposed that chlorine from chlorofluorocarbons (CFCs) could deplete the ozone layer.
Ozone located approximately 10-25 miles above the Earth’s surface, in a part of the Earth’s atmosphere called the stratosphere is very beneficial. The ozone is a major factor that makes life possible on Earth. About 90% of the planet’s ozone is in the ozone layer. Ozone in this layer shields and filters out the Earth from 95-99 percent the sun’s ultraviolet radiation. A low level of ozone does not protect or prevent the sun’s ultraviolet rays from reaching the surface of the Earth, therefore, overexposing life on Earth causing many diseases.
But we are depleting the amount of it that we still have with chlorofluorocarbons and other harmful gases. It blocks harmful UV radiation in the atmosphere from reaching the surface and keeps us safe from the effects of radiation exposure such as skin cancer, cataracts, sun burnt eyes, and possibly the lowering of our immune system, but it also contributes to the greenhouse gas effect and affects health if it sinks down too low to the surface. (Kimbrough 8) Having ozone is like playing with fire, we need it so badly to protect us from UV rays but it can cause damaging effects such as lowering our life expectancy if we breath is directly. In the 1920’s, chlorofluorocarbons started to be used in refrigeration. Unfortunately this was the beginning of a large problem in the atmosphere.
Human activity has been the prime cause of the depletion and thus can be eradicated through human activities in order to conserve it to sustain life. The use of CFC’s have otherwise known as Ozone Depletion Substances have caused patches/ holes in the ozone layer, which protects life from direct ultra-violet rays. The exposure to these rays make humans prone to cancer and other fatal diseases and soon the earth will not be able to sustain life. To curb or totally eradicate this, countries have come together to raise awareness, provide funds and support movements to eliminate Ozone Depletion Substances to make life on earth sustainable to live on and for future generations to come.
He also claimed that by removing the natural cosmic ray effect and excessive production of CFCs, a recovery up to 20% in the Antarctic ozone hole could be predicted. If the theory by Lu is to be true, the world should plan and take action to control this over-production of CFCs. It is the task for human to control the mess that they have created by themselves, in order to save lives of 8.7 million species on earth.