Margaret D. Andrews
Brightening the abyss of space as it spins in a mass of swirling colors is the earth. Beyond the ashen craters of the moon rises our planet, its surface a marbled canvas of blue and white.
A delicate “skin” of water and gases envelopes the earth. This moist cushion extends from the deepest point of the ocean floor to the outer reaches of the atmosphere, several hundred miles above the ground. The water, air, and soil systems of the globe work together to sustain life, and to renew and purify themselves. A constant recycling of the chemical elements necessary for life—water, minerals, oxygen, phosphorous, and carbon, among others—must take place, because no elements enter or leave the ecosphere.
The ozone layer is a fragile swath of gas that absorbs almost all of the harmful ultraviolet (UV) radiation emanating from the sun. It shields our planet like a blanket. Found in its densest concentrations at altitudes ranging from 7Ð15 miles above the earth, the ozone layer is only a few parts per million thick. Indeed, if all of the ozone in the stratosphere, a region 12Ð31 miles high, were condensed to our own atmospheric pressure, our precious ozone layer would be but the width of a dime.
Why should the condition of a canopy of molecules far above the globe concern us? The answer is that the ozone layer is a vital link among the physical components necessary to sustain life on Earth. A damaged Ozone layer allows lethal ultraviolet radiation to reach the planet. The effects of that radiation will be manifested in higher incidences of skin cancer, wide-scale depression of immune systems, increased level of smog, lower crop yields, deterioration of marine harvests. Perhaps even more significant than these sobering predictions is the relationship between ozone depletion and global warming, and the destruction of the ocean’s phytoplankton, the organisms that form the very basis of the food chain.
A documented hole in the ozone layer exists. It materializes over Antarctica each September, and scientists have noted that it has worsened each year since 1979. In the late 1980’s the gap was two times the size of the continental United States. Scientific opinion varies on the reason why the hole keeps reappearing. The reason why it exists at all, however, is clear: It can largely be blamed on the presence of chloroflourocarbons (CFC’s) in the atmosphere.
Ozone losses have been documented in other areas of the world as well. An average yearly loss of three percent of ozone has been noticed above Arosa, Switzerland, for at least 10 years. Seven hundred miles from the North Pole, Norway, a hole one-third the size of Antarctica’s has been pinpointed.
A prominent drop in ozone has been verified at three out of five Australian ozone-monitoring locations. Whether or not the loss was due to the Antarctic depletion stretching over Australia is still unknown.
CFC’s are found most commonly as the propellant in spray cans, coolant in refrigerators and air conditioners, in foam and plastic insulation, and in industrial solvents. Widespread agreement exists in the scientific community that Antarctica’s ozone loss is triggered by chlorine, from the use of CFC’s, and bromine, a component of fire retardants.
What is it about CFC’s that makes them so perilous to the ozone layer? The CFC class of molecules, ironically, was developed by industrial chemists who were seeking nonflammable substance—one that would “safely” propel deodorant out of a can, for example. These molecules are comprised of one or more carbon atoms, to which are attached chlorine and/or fluorine atoms. When the spray button on a can is pushed, the molecules enter the air, bounce off the walls and eventually find their way outside—a journey that may take days or weeks. Continuing to ricochet off trees and telephone poles, the CFC’s are lifted by wind currents and they “fly” ever upwards. Several years later, they arrive in the high atmosphere, most without having broken down or combined chemically with any other molecules along the way.
In that high atmosphere, where ozone prevails, a CFC molecule will remain for a century before it surrenders its chlorine. The chlorine, upon encountering the ozone molecule, destroys it—without destroying itself. And therein lies the truly frightening nature of the CFC: It will take years before the chlorine reenters the lower atmosphere and is removed via rainwater. During that time, one atom of chlorine can demolish 100,000 molecules of ozone.
It was in 1973 that atmospheric chemists F. Sherwood Rowland and Mario Molina of the University of California at Irvine postulated the connection between ozone depletion and CFC’s. When their report appeared in the June 1974 issue of
Nature
, shock waves reverberated through the $3 billion a year fluorocarbon industry. How could a product that had contributed so much to the ease of modern life be exposed as a hazard to populations worldwide?
Dozens of applications for CFC’s had been discovered during the World War II era. “Freon,” the trademark for CFC-12, became an internationally popular refrigeration coolant. Production increased by 4,000 percent between 1931 and 1945. Aerosol propellants against malaria were made with CFC’s 11 and 12 during the war; afterwards, hair spray and softer carpet pads, sofa and auto cushions all evolved from the wonders of CFC’s. From 1945 to 1950, the total production of CFC’s doubled when Dow Chemical Company began manufacturing Styrofoam.
As a result of the energy crisis of the 1970s, homeowners and businesspeople began looking for more efficient means of heating and insulating their residences. The fabrication of rigid foam insulation, blown with CFC-11 and CFC-12, skyrocketed. In 1985, two thirds of the insulation placed in new commercial buildings in the United States was rigid foam, as was half of the insulation in new, single family homes, and a third of the entire home reinsulation market.
Today, shoppers strolling the aisles of giant malls and employees working in skyscrapers are kept comfortable by enormous chilling units that utilize CFC’s. Families are more inclined to travel in the summer, because most of the cars sold in the United States are equipped with air conditioners. The scope of CFC use even extends to the food we buy in the supermarket. Three fourths of the American diet is refrigerated at some point before it is consumed.
The versatility of the CFC family of chemicals explains why they have pervaded our culture so thoroughly. The fastest growing CFC in use worldwide is number 113. It can clean computer microchips as well as cloths that would normally be subjected to more immediately toxic dry cleaning solutions. As a solvent, it also removes grease, glue, and dried solder from metals and plastics.
On a personal level, who hasn’t sighed gratefully when cooled by an air conditioner on a hot day? But evidence is mounting that this CFC-based form of relief has a hidden cost: our health. Illness is directly related to the ozone layer’s decline.
The NASA Ozone Trends Panel reported on the efforts of more than 100 scientists who spent almost a year and a half re-analyzing every bit of information collected from satellite and groundbased ozone data. Their conclusions?
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The hole in the layer over Antarctica was caused by the presence of CFC’s.
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The poles are not the only places where the ozone is missing; losses are occurring around the planet.
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Ozone has consistently decreased by over one-and-a-half to three percent in the last 20 years, in the area where most of the world’s population lives. The decreases were most noticeable in the winter, depending on the latitude.
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NASA further reports that the ozone layer has already declined more than two percent on a global scale. It is proceeding to degenerate far more rapidly than computer models have anticipated. Moreover, a further deterioration is imminent; tons of chemicals still being released into the atmosphere have not yet reached the ozone layer.
The effects of increased amounts of UV radiation on bacteria, soil, and mammals are not well known. However, it is known that increased exposure to humans can bring about a surge in skin cancers and an impairment of the body’s immune system. Light skinned peoples are most vulnerable to the threat of skin cancers. Scientist Carl Sagan has already written that light skinned people may need to wear protective clothing and strong sun-block ointments just to perform ordinary outdoor tasks.
Melanoma, a form of skin cancer that causes the most fatalities, is connected with extreme UV radiation exposure, as in cases of severe sunburn. It is responsible for more than half of all skin cancer deaths. Frighteningly, incidences of melanoma have sharply increased around the world within the last few years.
The AIDS virus has demonstrated all too well the inability of damaged immune systems to cope with the ravages of opportunistic disease. In the scenario of ozone depletion, increased exposure to UV-B rays (wave lengths that inflict the most biological harm on humans, animals, and plants) is expected to lower the body’s resistance to invading organisms. Although a jump in skin cancers would primarily affect the light skinned population, an immuno-deficiency caused by degraded ozone could affect virtually every single person on earth.
The threat to human health from a diminishing layer of high-atmosphere ozone is further complicated by the phenomenon known as “photochemical smog,” or ground level ozone. Stratospheric ozone guards the earth from the dangerous effects of UV radiation, and is a factor in the balance of worldwide climate. Ground level ozone is caused when atmospheric air pollutants react with hydrocarbons and nitrogen oxides under the influence of sunlight. (Hydrocarbons, organic compounds containing carbon and hydrogen, emerge from burned or somewhat burned gasoline. They are also formed in the evaporation of industrial solvents, as from refineries. Nitrogen oxides are pollutants produced by the reaction of nitrogen and oxygen when high temperatures are generated in internal combustion engines and furnaces.) The main component of smog is ground level ozone. As the high altitude ozone layer continues to erode, more UV radiation bathes the earth’s surface, quickening the photochemical process.
At ground level, ozone is a destructive gas that can burn the inner lining of the lungs. World Resource Institute claims that $4 billion worth of crops are destroyed in the United States every year by ozone at ground level. Some of these crops, such as cotton, soybeans, wheat, and corn, are global staples of clothing and diet. Tree growth is also impaired by the gas. Damage to the trees is continuing at a startling rate. It is estimated that half of the trees in many European countries suffer blight from ground level ozone as well as from acid rain.
The legacy of acid rain—ruined crops, corroded buildings, and gradual deaths of lakes and fish—is enhanced by ground level ozone. As the upper ozone layer decreases, a greater volume of hydrogen peroxide is believed to collect in the lower atmosphere, where 95 percent of our air exists. Hydrogen peroxide is one of the ingredients capable of producing acid rain
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Attitudes and Appreciations to Be Considered
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The interaction of living and nonliving things is exceedingly complex; an action of one may affect another seemingly unrelated, or a long distance away, or even after a long time.
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The natural resources that are available in any practical way to people are limited in amount and confined to a very thin layer of the earth.
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No one person or group has any more right, by destiny or decree, to the basic necessities of life than any other person or group.
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Some basic resources such as water are used by all living things, and recycled, so that what is used today has already been used many times by forms no longer living.
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Because space on earth is limited, and some discarded materials are slow to decompose or are even harmful, people must exercise increasing care in what they discard and accumulate.
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“Away” usually is just some other place on earth.
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“Take nothing but pictures; leave nothing but footprints!”
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How someone else left it for me is his or her responsibility; how I leave it for someone else is my own responsibility.
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Some environmental changes can be reversed, but others never can be.
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When the environment is affected by something, people are affected, too, because they are a part of the environment.
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Skills and Habits to Be Developed
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Minimizing waste at home or school by efficient, thoughtful use of materials.
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Taking care of both personal and public equipment to make it last.
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Sorting discarded materials efficiently so that items suitable for recycling can be recycled.
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Declining a carrying container at the store for an item that is already packaged.
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Deciding not to use aluminum foil when a biodegradable substitute will do.
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Pointing out alternative points of view, with reasons, when organisms are described as bad or good.
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Exhibiting a sympathy for living things through care of organisms borrowed for study.
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Observing carefully and keeping accurate records of changes in one or more objects or conditions in the environment.
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