Harmful Gases Into The Earth's Atmosphere example essay topic

INTRODUCTION In the beginning man lived simply and harmoniously with earth. However, as time progressed mankind's thirst for knowledge and more economical ways of doing things led to technological advances. These advances, in turn, led to the industrial revolution, the invention of the automobile, and growth of the automobile industry. Though making life on earth more comfortable, these industries and inventions emitted harmful gases into the earth's atmosphere. Damage to the earth's ozone layer began to occur as the levels of these gases in the atmosphere increased. The depletion of the earth's ozone and the resulting greenhouse effect are now threatening the ability of earth to sustain civilization as mankind knows it today.

THE OZONE DEFINED Ozone is a dark blue gas which is highly reactive. It's triatomic molecular composition (O 3) is unlike normal oxygen as it has an extra oxygen atom in each molecule and a different atomic arrangement. (Jones et al. 303-304) In the earth's upper atmosphere, called the stratosphere, O 3 is produced when the sun's ultraviolet rays act on normal oxygen in the air.

Extending from 10 kilometers (km) to 50 km above the earth, the stratosphere has the highest concentration of ozone. (EPA, Ozone vs. Altitude 1) This is what is normally known as the "ozone layer". The ozone layer serves a vital purpose in the stratosphere as it blocks out harmful ultraviolet rays. Ozone also occurs in lower amounts in the troposphere, which is the atmospheric layer lying between the earth's surface and the stratosphere. Known at this altitude as smog, this ozone forms when the sun's ultraviolet rays strike oxygen which has mixed with industrial or automobile pollutants. (EPA, Ozone Science 1) THREATS TO THE OZONE Man-made chemicals, fossil fuels, industrial wastes, and automobile exhaust all pose a threat to the earth's ozone.

Chlorofluorocarbon (CFCs) are man-made substances which, for more than 50 years, were considered to be miracle substances because they were virtually non-toxic, nonflammable, and inexpensive to produce. (EPA, Ozone Science 1-2) These CFCs were used as solvents, refrigerants, aerosol propellants, and to blow foam plastics. Due to their stable nature, CFCs remained intact for long periods of time in the atmosphere. Over time, winds have transported them into the stratosphere where they have been subjected to high levels of radiation.

The radiation causes the CFCs to break down and release chlorine. According to the National Safety Council's Environmental Health Center, "A single chlorine atom can destroy thousands of ozone molecules before it is eventually neutralized". (3) Since the break down of CFCs is repetitive in nature it has the potential of severely depleting stratospheric ozone. Nitrogen oxides and methane are also compounds which adversely affect the stratosphere's ozone.

Nitrogen compounds are used in agricultural fertilizers wher as nitrous oxide is produced by combustion. Methane is produced by a biological reaction between bacteria and organic matter. It is given off by cows, marshes, landfills, and garbage dumps. (Schneider 21,101) Both substances are stable and react similar to CFCs in the stratosphere to deplete the ozone. Fossil fuels are the world's largest energy source. They are naturally occurring carbon or hydrocarbon fuels including oil, coal, and natural gas.

These fuels are used to heat homes and businesses as well as power industrial equipment and automobiles. One of the end products of the combustion of these fuels is carbon dioxide (CO 2). Carbon dioxide and the other byproducts of burning fossil fuels contribute to the build-up of ozone or smog in the troposphere. High levels of smog over urban areas such as Los Angeles can have detrimental effects on humans and plant life. Carbon dioxide has the ability to absorb high amounts of infrared energy, thus producing heat, and thereby warming the atmosphere. (Schneider 13-35) Efforts to decrease smog are also increasing the amount of harmful gases in the upper atmosphere.

An article in the newspaper quoting the EPA stated that, "the catalytic converter, designed to scrub smog out of automobile exhaust, is spewing greenhouse gases from tailpipes into the upper atmosphere. The converters, while breaking down smog-causing nitrogen and oxygen from car exhaust, are also rearranging the compounds to form nitrous oxide. which is more than 300 times more potent than carbon dioxide". (Lansing State Journal A 1) THE GREENHOUSE EFFECT The greenhouse effect is the gradual rising of the lower atmosphere's air temperature due to an accumulation of greenhouse gases. These gases, CFCs, CO 2, methane, nitrous oxide, and ozone, form an invisible ceiling in the troposphere. This ceiling absorbs harmful radiation from the sun and prevents the loss of energy while allowing visible light to enter.

This process helps to maintain a steady temperature on the earth. (Jones et al. 192) Advances in technology, increased industrialization, and the proliferation of automobiles has led to an artificial build-up of greenhouse gases in the atmosphere. The thinning of the ozone layer in the stratosphere has allowed more harmful ultraviolet radiation to enter the upper atmosphere. The overabundance of these gases, particularly CO 2, in the lower atmosphere, has led to increased absorption of infrared radiation. All of these changes are contributing to an alteration in the earth's climate.

"In November 1995, 2,500 leading climate scientists announced that the planet is warming because all the emissions from coal and oil burning are trapping in more of the sun's heat than is normal for our climate. Even if that warming is not yet obvious, they warned, it is already generating bizarre and extreme changes in the weather. This new period of less stable climate we have entered, is likely to cause widespread economic, social, and environmental dislocation". (Gelbspan 5) CONSEQUENCES OF GLOBAL WARMING Global warming is already causing major climatic changes throughout the world. In 1985 scientists discovered a hole in the stratospheric ozone layer over Antarctica. As reported by NASA, "New record low levels of Antarctic ozone were recorded at the South Pole Station, Antarctica, at the end of September and early October 1993, and confirmed by satellite measurements".

(National Safety Council 5) It was felt that CFCs were primarily responsible for the ozone destruction. Similar depletions were also found over the Arctic. The resultant increase in temperature has led to the melting of the polar glaciers. Consequently, sea levels are rising and major flooding has started to occur in cities and agricultural areas. Scientists believe that the current catastrophic weather events associated with El Nino may be associated with global warming. (Gelbspan 143) Coasts are being washed away, low lying areas have been flooded out, and tornadoes have destroyed entire towns.

Areas which normally experience extremely cold winters are experiencing unseasonably warm weather. Due to these significant weather changes farmers may have to switch to new crops which are more conducive to the changing climate in their region. Coastal communities will have to move inland or risk being swept out to sea. Increased health hazards are occurring as a result of increased temperatures. Mosquitos carrying diseases such as yellow fever are migrating to higher altitudes. Similarly, increased outbreaks of malaria and dengue fever are being reported at higher elevations.

Mosquito populations in temperate climates including the United States are reaching epidemic proportions. "There is a real risk of reintroducing malaria into non malarial areas, including portions of Australia, the U.S., and southern Europe". (Gelbspan 148) New outbreaks of cholera are occurring in areas experiencing severe flooding where sewage has spread into the water supply. Increased ultraviolet radiation due to the thinning ozone layer may cause damage to humans and plant life.

Increased incidences of skin cancers and cataracts are expected. "Excessive UV exposure has also been linked to suppression of the immune system, which could make people more likely to contract infectious diseases". (Mock 3) In addition, photosynthesis and plant metabolism may be impaired by the increased UV radiation. Food crops may be less productive and forest ecosystems may be less healthy. Since UV radiation can penetrate the ocean's surface, marine ecosystems are also at risk.

Higher levels of UV radiation cause plankton to be less productive. This makes the food chain vulnerable as plankton is the lowest food source on the chain. Scientists have noticed a significant decrease in fish and seabird populations. Fish and sea animals are migrating to new surroundings in search of life-sustaining water temperatures.

CONCLUSION Since the beginning of time man has striven to make life easier. Simple inventions gradually led to more sophisticated inventions. Farmers originally used horses to plow their fields. Now high-tech tractors do the work in less than half the time, thus increasing the farmer's productivity and, hopefully, his profits. Similarly, the invention of the automobile made travel easier and quicker. High speed jets have further decreased the amount of time it takes to go from one place to another.

New technological advances are being discovered every day. However, each of these inventions emits greenhouse gases into the atmosphere. Technological advances have not come without a cost. Substances such as CFCs which were once viewed as a miracle product have, instead, been found to be a deadly compound which threatens our global environment. It's stable composition made it an excellent substance for many different purposes.

However, that same stability allows these same CFCs to repetitively deplete our ozone for the next 100 years. Although scientists are now studying the harmful effects of greenhouse gases and looking for ways to diminish their impact on our environment, the damage has already been done. Unable to function efficiently and economically without the luxuries and conveniences of advanced technology, mankind continues to utilize them... Consequently, more pollutants are released into the atmosphere daily. In the meantime, researchers frantically search for safer ways to power our automobiles and machinery. The environment cannot wait for our discoveries.

It is already responding to the harm we have inflicted on it. Our glaciers are melting, our seas are rising, and our coasts are eroding away. Plants are dying from the UV exposure. Plants and animals alike are migrating to new areas to improve their chances of survival. The earth which sustains us is in need of loving care.

Unless we heed her call and immediately tend to her wounds, she will be unable to sustain us as she has in the past. Her very survival, as well as our own, depends on it.

Bibliography

Associated Press. "Smog's cut, but at a cost". Lansing State Journal 30 May 1998: A 1.
Cag in, Seth, and Philip Dray. Between Earth and Sky: how CFCs changed our world and EPA Stratospheric Protection Division. The Effects of Ozone Depletion. 24 Dec. 1997.
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Available FTP: web EPA Stratospheric Protection Division. Ozone Depletion Process. 20 July 1995.
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Ozone Science: The Facts Behind the Phaseout... 24 Dec. 1997.
Online. Netscape Internet. 28 May 1998.
Available FTP: web EPA Stratospheric Protection Division Ozone vs. Altitude. 26 Oct. 1995.
Available FTP: web Gelbspan, Ross. The Heat is On. New York: Addison-Wesley Publishing, 1997.
Jones, Gareth, et al. Environmental Science. New York: Harper Perennial, 1992.
Mock, Gregory, and Cheryl Simon Silver. "Atmosphere: conditions for ozone depletion and climate warming ripen as chlorine and greenhouse gases reach record concentrations in the atmosphere". The 1994 Information Please Environmental Almanac.
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National Safety Council. Ozone Depletion: When Less is not Enough. 1 July 1997.
Online. Netscape Internet. 27 May 1998.
WORKS CITED Schneider, Stephen H. Global Warming. San Francisco: Sierra Club, 1989.