Effect of Ozone Layer of Greenhouse Effect - Research Paper Example

Effect of Ozone Layer of Greenhouse Effect Introduction Global Warming is an overall augmentation in temperature of the planet consequently leading to climatic changes. These changes are owing to heat ensnared by various green house gases encompassing carbon dioxide, methane, nitrous oxide, CFCs and ozone. It refers to the plodding changes that took place with the advent of industrialization and technological emissions. These emissions are depreciating the natural quality of atmosphere causing changes in global weather patterns thereby have adequate catastrophic potential to fetch environmental imbalance. It is manifested that the temperature of the Earth has increased by 1°F ever since 1900 and it is increasing at much rapid pace since 1970. This augmentation in the temperature of the planet is called Global Warming. Normal greenhouse gases allow only sunlight and impede other hazardous radiations from reaching the Earth’s surface. An increase in temperature is due to emancipation of various gases called as green house gases which encompass smokestacks, vehicles, fossil fuels, appending to the standard Earth’s greenhouse effect. Researchers have estimated that if this rise in temperature will continue it is going to have devastating impact on climate patterns resulting in drifts, melting of glaciers and elevation in the sea level (Climate changes). Molina and Rowland in 1974, were the first to warn about the chemical activity being displayed by the chlorofluorocarbons (CFCs) towards destruction of stratospheric ozone layer, a protective shield that prevents all the living beings on the planet from harmful radiation. CFCs have long lifetime in the atmosphere; moreover, CFCs get chemically decomposed in stratosphere as well as they catalyze the depletion of ozone. This is a matter of utmost concern and a call for policymakers and public to act on. Consequently, 24 nations together with European Community signed Montreal Protocol, today 196 governments are part of it and are in compliance with the strict controls. 98 percent of ozone depleting chemicals has been phased out worldwide. Accordingly, ozone layer is witnessing a phase of recovery which is likely to be accomplished by 2065. Without, this rigorous step, CFCs and other ozone depleting substances (ODSs) would have destroyed two-thirds of the ozone layer by 2065, millions of cancer cases would have been introduced and potentially half of the global agriculture would have been lost. It is documented that most of the ODSs are also greenhouse gases (GHGs) responsible for keeping the earth warm. Estimations bring to light that CFCs and ODSs impose damages equivalent to 24-76 gigatons of carbon dioxide per year (Andersen et al., 2013). Ozone is the most vital component of the atmosphere. Ozone is present in the atmosphere as a distinct layer of lower stratosphere, which plays an imperative role in protecting diverse life forms from getting exposed to the harmful effects of ultraviolet (UV) radiation. However, there are certain chemical agents that influence the amount of ozone present in the atmosphere as a result; ozone (O3) layer is facing its depletion. Combination of routine measurements of O3 depletion, meticulous laboratory studies and mathematical modeling of O3 in the atmosphere revealed that certain reactive substances are produced when chlorofluorocarbons (CFCs), other halogenated compounds and halons breakdown in the stratosphere layer of the atmosphere which are causing loss of O3. CFCs find widespread applications in modern society. In order to control and phase out the CFCs (Hayman, 1997). The Montreal Protocol is implemented, but formation of O3 will take several decades to reach the levels of 1980. However, the concentration of substances depleting ozone layer is diminishing and columns of ozone are not declining in the atmosphere. Moreover, mid-latitude ozone is anticipated to return to the 1980 levels prior to mid-century a little earlier than expected. At higher altitudes the recovery rate is slower. In the absence of Montreal Protocol, sun-burning cases due to UV radiation could have become thrice by 2065, especially in the mid-northern latitudes. Such an impact would have brought deleterious consequences on human health and environment. Climatic changes are credited to increase in greenhouse gases (GHGs) consequently, ozone depletion occurs, this in turn influences the climate. Thus a dual core is mutually working, climate changes influence O3 layer while O3 influences climate change (McKenzie et al., 2011). The Montreal Protocol has displayed greater impact in reducing phase-out of chlorofluorocarbons (CFCs), as compared to the Kyoto protocol implemented for reducing the concentration of greenhouse gases. Thus, even though CFCs are phased-out, an increased concentration of GHGs is throwing challenge. The GHGs are responsible for elevation in the temperature of the planet. However, GHGs are imposing jeopardy on the ozone layer; thus, GHGs are influencing the amount of stratospheric ozone. As a result of this, the temperature of the stratosphere decreases causing accelerated circulation patterns. One of the main consequences of altered circulation patterns is observed as reduction in total ozone in the tropics and raise in total ozone at mid and high latitudes. Alterations in circulation induced by changes in ozone influence patterns of rainfall and surface wind (McKenzie et al., 2011). Normal Role of GHGs Greenhouse gases such as carbon-dioxide, nitrous oxide, methane, fluorinated gases as well as ozone allow the sunlight to enter the surface of the earth. However heat of sunlight is trapped by these gases and they reflect the same in the atmosphere, this is an essential feature to keep the planet warm else there will be tremendous drop in the average temperature of the earth from 14ºC to -18ºC which would be deleterious for the living organisms (Web. Greenhouse Effect). Natural sources of GHGs Water vapor is added to the atmosphere by the process of evaporation, carbon dioxide is released by plants and animals during the process of respiration. Methane comes naturally from the swamps, low oxygen environment. Nitrous oxide is released in soil while volcanoes on land and in oceans release greenhouse gases (Web. Greenhouse Effect). Contribution of GHGs due to Human Activities Since the dawn of Industrial Revolution in 18th century, production of various commodities required to carry out day-to-day tasks has gained prevalence. As a result of such activities, large amount of greenhouse gases are being released into the atmosphere. It is estimated that GHGs concentration has increased up to 70 percent between 1970 and 2004. Uninterestingly, the concentration of CO2, which is one of the prime GHG enhanced to 80 percent as compared to concentration observed over 650,000 years (Web, Greenhouse Effect). Burning of fossil fuels, in diverse vehicles across the world, electric power plants and deforestation are some of the human activities that are responsible for enhancing CO2 concentration in the atmosphere. On the other hand, livestock farming, production of coal mining, landfills and natural gas processing are some human activities that are responsible for enhancing the methane concentration in the atmosphere. Burning of fossil fuel and agricultural activities produce nitrous oxide. Other human activities involving use of aerosol cans and refrigeration in fridge and air conditioners where fluorinated gases such as chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) are used to a greater extent. Thus human activities are the solely responsible for enhancing the concentration of GHGs in the atmosphere. Increase in the concentration of these gases is directly related to the increase in temperature of the planet, causing Global Warming (Web. Greenhouse gases). Impact of Nitrous oxide and other greenhouse gases on stratospheric ozone depletion In the past four decades a great deal of concern is generated about chemical perturbations to the ozone layer. Literature of 1970s throw light on the perturbations induced by nitrogen oxide radicals due to supersonic aircrafts in stratosphere, following this concern, later chlorine radical emitted from rocket propulsions as well as CFCs became the matter of great concern. Chlorine induced ozone depletion and became one of the major concerns in literature. Moreover, as ozone hole was discovered in 1984 (~40 percent column ozone loss which was increased to ~70 percent column ozone loss in 1990s), impact of chlorine and bromine on the stratospheric ozone gained attention. In 1980s halocarbons were produce abundantly but with the successful implementation of The Montreal Protocol, the use of halocarbons is reduced, this is depicted in the slow reduction of atmospheric chlorine levels as shown by Montzka et al. (1996) and WMO, (2011). Besides halocarbons which was a matter of great concern initially, methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2), the GHGs are gaining attention as they are found to influence stratospheric ozone. It is well shown in the study carried out by Portmann et al. (2012) through chemical model of stratosphere. They elucidated that the future evolution of ozone is dependent on GHGs especially N2O and CO2 which are known to play the lead roles since the levels of halocarbons are reduced to preindustrial age (Portmann et al., 2012). Role of N2O in depletion of O3 N2O, generated at the surface of the earth due to microbial activities, remains quite inert in troposphere. This N2O is transported to the stratosphere, in the middle of the stratosphere it is broken down by the process of photolysis N2O + hv­­ N2 + O (1D) while reaction with O (1D) cause production of N2, N2O + O (1D) N2 + O2 while N2O + O (1D) 2NO. This NO is the source of reactive nitrogen, which reacts with the lower and middle stratosphere while 10 percent of the N2O is converted to NO2 in stratosphere and transported to mesosphere. The relative load of short-lived species such as NO2 as compared to the long-lived species such as HNO3 is imperative in determining the quantity of ozone loss by nitrogen family. However, long-lived chemical elements impound reactive atoms in non-reactive forms known as reservoirs, which are gradually converted to reactive forms either by photolysis or when react with OH. Effect of NOX family on O3 diminishes from middle to lower stratosphere since HNO3 reservoir becomes stable in lower stratosphere. In a similar manner ClOx family have HCL and ClONO2 as reservoirs that are responsible for controlling the efficacy of ClOx mediated loss of ozone. Further, anthropogenic control on ozone is mediated through alterations in emission of source gases. Such alterations of source gas influence chemical families chemically as well as radiatively. These radiative modifications influence stratospheric temperatures and thereby alter the stratosphere (Portmann et al., 2012). Unlike NOx, CFC-11 and ClOx, which are responsible for inducing ozone loss, methane (CH4) enhances ozone by means of photochemical production in troposphere and lower stratosphere. Carbon dioxide display radiative effect which is responsible for cooling the stratosphere thereby cause less ozone loss through strong temperature dependent reaction (Portmann et al., 2012). The changes in ozone from 1900 to 2100 are guided by modifications in halocarbon, N2O, CO2 and CH4. With the implementation of the Montreal Protocol, the future of ozone depletion is attributed to these greenhouse gases. Recent research has enunciated that N2O is the largest ozone-destroying gas which is contributed by various human activities. It is evident that greater emission of CO2 could cause super-recovery of O3 but at the same time higher CO2 concentration directly influences the global climate and oceans (Portmann et al., 2012). The largest influence of chemical interaction is displayed between methane and the halocarbons. Increase in the concentration of methane reduces the impact of halocarbons on ozone by as much as 20 percent. However, there exists a non-negligible interaction between CO2 and N2O on O3. Nevertheless, changes in ozone are not solely attributed to the halocarbons but also considerable changes prevail due to N2O, CH4 and CO2. However, halocarbons alone cause much destruction as compared to the combined damage caused by these greenhouse gases, but the recent emission of N2O displays much greater effect as compared to the halocarbons indicating that N2O control is highly desired to control the depletion of ozone in the present scenario (Portmann et al., 2012). Conclusion Atmospheric ozone is important for absorbing UV radiation. Ozone is significant for the survival of life forms and to prevent the mutation of genes and other deleterious effects caused by UV radiations on living organisms. Pollution of troposphere by numerous pollutants including the greenhouse gases is responsible for depleting the precious ozone layer. The pollutants are responsible for rise in the level of greenhouse gases as well as other toxic substances which are responsible for increase in retention of the sun’s heat as a result there occurs an increase in temperature of the planet. Even a slight increase in the earth’s temperature can have devastating consequences which involve melting of glaciers and ice caps and elevation in the sea level. As glaciers are the prime source of freshwater there will be scarcity of fresh water and floods in the low lying areas or coastal areas. Irrigation water will not be available leading to scarcity of food and other resources. Life would be difficult it is therefore imperative to understand the consequences of preventing ozone layer from depletion by minimizing pollutants. Greenhouse gas emissions are not only responsible for increase in planet’s temperature but are also responsible for altering weather conditions encompassing rain and snow as well as precipitation. Over the centuries animals have adapted themselves to the climatic conditions of their habitats, altered climatic conditions may not be suitable for their survival as a result they may perish. In a similar manner crops and plants are also adapted to a particular climate of a geographical region, climatic modifications are going to influence food, clothing and lifestyles of the human beings to a greater extent. The situation is alarming and a stitch in time saves nine must be followed to take the desired steps to prevent the planet from catastrophe. Works Cited Andersen, S. O., Halberstadt, M.L., Borgford-Parnell, N. “Stratospheric ozone, global warming, and the principle of unintended consequences-an ongoing science and policy success story”. J Air Waste Manag Asso. 63(6), 607-47, 2013. Print. "Climate changes". Web. 26 November 2014. . “Greenhouse Effect”. Web. 26 November 2014. < http://education.nationalgeographic.com/education/encyclopedia/greenhouse-effect/?ar_a=1> Hayman, G. D. “CFCS and the ozone layer”. Br. J. Clin Pract Suppl. 89, 2-9, 1997. Print McKenzie, R. L., Aucamp, P. J., Bais, A. F., Bjorn, L. O., et al. “Ozone depletion and climate change: impacts on UV radiation”. Photochem Photobiol Sci. 10(2), 182-98, 2011. Print Montzka, S., Butler, J., Myers, R., Thompson, T., Swanson, T., Clarke, A., Lock, L. & Elkins, J. “Decline in the tropospheric abundance of halogen from halocarbons: implications for stratospheric ozone depletion”. Science, 272, 1318–1322, 1996. Print Portmann, R. W., Daniel, J. S., Ravishankara, A. R. “Stratospheric ozone depletion due to nitrous oxide: influences of other gases”. Phil. Trans. R. Soc. B, 367, 1256-1264, 2012. Print WMO (World Meteorological Organization). “Scientific assessment of ozone depletion: 2010”. Global Ozone Research Monitoring Project Report 52. Geneva, Switzerland, 516, 2011. Print Read More