Ozone Depletion, Free Essay Sample

The ozone layer is a heavy layer in the atmosphere that surrounds the earth's surface and protects it from the sun's harmful ultraviolet radiations. It is made up of three atoms of oxygen as opposed to the two usual oxygen atoms and it forms when certain radiation separates the two atoms found in a single oxygen molecule (Rowland 38). The ozone layer was not so much appreciated until it was discovered that most common human activities cause its depletion and as a result, the earth's surface has been continuously affected by ultraviolet radiations caused by sun rays. Scientists have since been worried that such exposures might have extremely adverse effects on human health and the ecosystem (Rowland 42). Therefore, several treaties including the Montreal Protocol on Substances that deplete the ozone layer have been designed to protect and preserve it (Hand 55). Since these treaties were implemented, the ozone layer has been gradually recovering, but several research findings suggest that human-made chlorofluorocarbons along with other unregulated chemical substances are the main contributors of ozone depletion. For this reason, their focus on the main factors causing ozone depletion. This paper presents a brief history of ozone depletion, and it outlines the processes involved.

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Before delving into causes of ozone depletion, it is essential first to understand why the ozone layer is vital. One of the most critical properties of the ozone layer is its ability to obstruct harmful solar radiations, usually containing wavelengths below 290 nanometers from reaching the surface of the earth (Solomon 230). It manages to do this by absorbing the harmful ultraviolet emissions which could either injure or kill living things on the earth's surface. Scientists have predicted that depletion of the ozone layer over the past years has disrupted aquatic ecosystems as well as the terrestrial environment. Besides, UV radiation is capable of destroying organic matter because plants and other microscopic organisms floating over the water surface, which acts as food for both land and sea animals cannot thrive under severe UV radiation (Solomon 187). On the other hand, excessive UV exposure is hazardous for human beings because it puts them at a higher risk of cancer infection, especially skin cancer. According to Solomon (211), a one percent decrease in the ozone layer causes approximately 2 to 5 percent increase in skin cancer risk. Also, reduction of ozone layer also increases incidences of sunburns, cataracts and suppressed immune systems to mention but a few.

Ozone depletion is, therefore, the gradual diminishing of the earth's ozone layer, and it is one of the significant environmental concerns in the world today because it exposes the earth's surface to more ultraviolet sun rays that are harmful to all forms of living things (Rowland 45). It is to a great extent caused by human activities that lead to the release of chemical compounds that contain detrimental gases such as bromine and chlorine. These chemicals are widely referred to as Ozone Depleting Substances (ODs). These ODs are have scientifically been proven to be environmentally friendly, and they are not toxic in any way to the atmosphere. For this reason, they have gained a lot of attention among scientists over the years, and more discoveries have been made that their stability comes at a price (Rowland 44). ODs are capable of floating in the stratosphere without any form of movement. Following their nature, they have stayed in the atmosphere for a long time, and they will continue to stay up there for many more years to come. This, therefore, implies that ODs are on a constant journey to the atmosphere and they will continue contributing to ozone depletion as long as human beings allow it through their activities. While they are up there, they are broken down by the intense ultraviolet sun rays resulting into chlorine and Bromine (Rowland 36). Both of these chemicals are very harmful because they can deplete the ozone layer at very high speeds. They do this by merely breaking an atom from a single molecule of ozone. These chemicals are hazardous because a single molecule of chlorine is capable of breaking down hundreds and thousands of ozone molecules.

Some of the leading human activities that lead to ozone depletion include specific industrial processes that lead to the emission of chlorofluorocarbon gases (Solomon 215). These activities have led to a constant reduction of the concentration of stratospheric oxygen. For instance, during the southern hemisphere spring, the most substantial loss of stratospheric oxygen was experienced where the world experienced a 50% reduction in the level of oxygen (Solomon 210). More so, scientists have predicted that global oxygen level will reduce substantially across all latitudes in the next century regardless of the consistent global efforts to solve the problem. Reduced stratospheric oxygen level proceeds in increased instability of harmful Mid-ultraviolet radiation on the earth's surface as well as in the essential ecological bottom of the ocean (Solomon 225). Additionally, scientists have anticipated that aquatic life in the upper segment of the photic section will be negatively affected if UVB radiation increases due to depletion of ozone layer.

Also, more experimental affirmation indicates that more exposure to UVB radiation decreases the productivity of algae and it damages different forms of marine larvae among other organisms (Bjorn and McKenzie 360). Moreover, increased levels of UVB radiation on the ocean's surface are bound to impact various marine populations adversely. Although the application of chlorofluorocarbons is highly confined, these research findings are a clear indication that they somehow find their way into the atmosphere because they are not entirely restricted. For instance, specific fire extinguishers utilize chlorofluorocarbons which emit Halons (Bjorn and McKenzie 364). Halons are so formidable that they are capable of depleting the ozone layer ten times more than ODs ever would in a thousand years thus as long as these exceptions are made for specific fire extinguishers, there will always be a problem of ozone depletion. More efforts are being made in this century to replace chlorofluorocarbons with non-depleting substances, but as long as they are not eliminated, the ozone layer is in danger.

For instance, scientists have come up with ways to partly develop hydrofluorocarbons, a potent greenhouse gas, for vehicle air conditioners. By so doing, they have been able to reduce ozone layer depletion, but since they have not entirely replaced chlorofluorocarbons in practice, they have not been able to eliminate ozone depletion (Akanle 55). In light of this, chlorofluorocarbons are the main restricted causes of ozone layer depletion. Besides, it is also important to note that most industrialized nations have been using spray aerosols that contain CFCs for over 50 years now and this has been a significant contribution to ozone depletion for decades (Akanle 78). Just as explained above, when these CFCs reach the upper parts of the atmosphere, they are broken down by UV rays into small chlorine-containing substances. When these chlorine particles react with oxygen atoms found in the ozone, it breaks apart the ozone molecule into pieces contributing to ozone depletion (Solomon 285). Ozone depletion will continue to deteriorate as long as these industrialized nations continue to use spray aerosols and unless an alternative means of manufacturing is adopted, this problem will not seize to exist.

Consequently, ozone depletion is caused by specific natural processes such as volcanic eruptions since they can have a direct impact on the level of ozone. For instance, in 1991, the world experienced one of the most deadly volcanic eruptions of Mt. Pinatubo. This eruption did not cause an increase in the concentration of stratospheric chlorine, but it led to the production of both small and large particles referred to as aerosols, which are different from the typical consumer products (Cole-Dai,. et al 675). The role played by these aerosols is to increase the effectiveness of chlorine in destroying the ozone layer by creating a surface on the stratosphere on which CFCs containing chlorine can damage the ozone (Perkins 176). Although the volcanic eruption causes short-lived effects on the ozone, almost all the significant volcanoes that have occurred have had a substantial impact on the ozone and should more of them happen in the future; ozone depletion is bound to increase. Most people would argue that volcanic eruptions are rare but once they occur, they are catastrophic and their effects on the ozone layer cannot be ignored whatsoever.

According to Hand (40), a couple of scientists discovered an enormous hole in the ozone layer just a layer above the Antarctic and immediately after this discovery an emergency panel of the UN banned any possible use of CFCs under what is referred to as the Montreal protocol. This is because of the effects caused by CFCs when they build up in the atmosphere as discussed above. Thirty years after this discovery, the ozone layer was still blocked, and the problem of ozone layer depletion due to CFCs was thought to be no more (Hand 55). However, more research findings show that there are still threats to the fragile buffer in the atmosphere covering the ozone hole and protecting the earth's surface from the harmful ultraviolet sun rays.

It turns out that some of the most dangerous substances that are still slowly destroying the ozone layer were not included in the Montreal Protocol since the committee at the time did not consider their effects on the ozone layer destructive. Some of these substances include the dichloromethane, which is a chemical substance used in paint stripping, drug production in pharmacies and agricultural purification to mention but a few (Ravishankara, Daniel and Portmann 123). These chemical substances were thought to be so temporary that they could not reach the stratosphere in large and harmful amounts. However, this is not the case because human activities that produce dichloromethane such as vehicle exhausts are very poisonous and are capable of destroying the ozone and releasing the harmful UV rays that can cause skin cancer among other effects to human beings and other living things (Ravishankara, Daniel and Portmann 124). Manmade chemicals such as dichloromethane accelerate the formation of ozone holes, and as long as the emission of these substances is not controlled, ozone depletion will be on the rise even in the coming years.

Besides dichloromethane, 1, 2- dichloroethane is another profoundly real chemical substance that has recently been identified in the stratosphere. It is an ozone-depleting chemical substance that was not included in the Montreal Protocol because it was not deemed dangerous enough to cause ozone depletion (Ravishankara, Daniel and Portmann 123). However, more research shows that it is equally dangerous and can cause ozone depletion because it is used in PVC manufacturing, which results in dichloroethane emissions. Dichloroethane is not only expensive, but it is also toxic thus it would be expected that a lot of caution would be taken not to emit it into the atmosphere, but according to recent findings, approximately 60% of dichloromethane is issued to the atmosphere as compared to the 30% that was allegedly emitted in the 2000s (Hand 52). If precautions are not taken, PVC manufacturing will increase the percentage of dichloroethane emitted to the atmosphere even in the coming decades, and this will only accelerate ozone depletion.

Works cited

"Ozone depletion and the effects of ultraviolet radiation." Photobiology. Springer, New York, NY, 2015. 347-364.