Abdul 1 Paula Abdul Dr. Koster CRTW 201 19 April 2005 Depleting The Ozone Layer What would the Earth be like if the ozone layer were to be non existent? Scientists and environmentalists have extensively studied the effects of the depletion of the ozone layer for the planet Earth. Ozone depletion environmental issues - climate changes and global warming may lead to global catastrophe endangering millions of people and animal lives (Ozone Environmental Changes). The ozone layer protects us from the harmful UV-rays and all other types of dangerous gasses. It is a safety net for all of the inhabitants of the Earth. The depletion of stratospheric ozone due to the effects of ozone-depleting substances, such as volatile organohalogens, emitted into the atmosphere from industrial and natural sources has increased the amount of ultraviolet radiation reaching the earth's surface (Laturnus). There are different ways to protect the Earth from letting the ozone layer disintegrate. What would be some of the things that the inhabitants on Earth can do to protect it? Should the government have a law passed that brings about stiffer guidelines to avoid destroying the ozone layer? This is an important issue that needs to be addressed. There will be a discussion on the negative effects of ozone depletion and how it affects life, as we know it. There is another argument on what the earth would be like if the ozone layer becomes nearly non existent. At one point, there was a complete awareness of this earthly problem, but obviously the government officials seem to have ignored the problem as if it will go away. Mankind is literally killing the Earth. What are we going to do about this issue?
Abdul 2 Ozone is extremely rare in our atmosphere. It averages about three molecules of ozone for every 10 million air molecules. In spite of this small amount, ozone plays a vital role in the atmosphere. Ozone is mainly found in two regions of the Earth s atmosphere. About 90% of the ozone lives in a layer that begins between 6 and 10 miles (10 and 17 kilometers) above the Earth s surface and extends up to about 30 miles (50 kilometers). This region is called the stratosphere. The ozone is the region that is commonly known as the ozone layer. The remaining ozone is in the lower region of the atmosphere, which is commonly called the troposphere (Ozone Basics). The ozone molecules in the stratosphere and the troposphere are chemically identical, because they all consist of three oxygen atoms and have the chemical formula O3. However, they have very different roles in the atmosphere and very different effects on humans and other living beings. Stratospheric ozone (sometimes referred to as "good ozone") plays a beneficial role by absorbing most of the biologically damaging ultraviolet sunlight (called UV-B), allowing only a small amount to reach the Earth's surface. The absorption of ultraviolet radiation by ozone creates a source of heat, which actually forms the stratosphere itself (a region in which the temperature rises as one goes to higher altitudes). Ozone thus plays a key role in the temperature structure of the Earth's atmosphere. Without the filtering action of the ozone layer, more of the Sun's UV-B radiation would penetrate the atmosphere and would reach the Earth's surface. Many experimental studies of plants and animals and clinical studies of humans have shown the harmful effects of excessive exposure to UV-B radiation (Ozone Basics). At the Earth's surface, ozone comes into direct contact with life-forms and displays its destructive side (hence, it is often called "bad ozone"). Because ozone reacts strongly with other molecules, high levels of ozone are toxic to living systems. Several studies have documented the
Abdul 3 harmful effects of ozone on crop production, forest growth, and human health. The substantial negative effects of surface-level troposphere ozone from this direct toxicity contrast with the benefits of the additional filtering of UV-B radiation that it provides (Ozone Basics). Since ozone plays more than one role it leads to two separate issues dealing with the environment. One issue is the increase of ozone in the troposphere. This ozone is a major component of what we know as smog. It is a problem in very large cities and is beginning to be a problem in some rural areas as well. There is also interest both publicly and scientifically about the loss of ozone in the stratosphere. There are measuring devises that are on the ground as well as satellites measuring the decrease in the amount of stratospheric ozone in the earth s atmosphere (Ozone Basics). Over some parts of Antarctica, up to 60% of the total overhead amount of ozone (known as the column ozone) is depleted during the Antarctic spring (September-November) (Ozone Basics). This phenomenon is known as the Antarctic ozone hole. In the Arctic Polar Regions, similar processes occur that have also led to significant chemical depletion of the column ozone during late winter and spring in 7 out of the last 11 years. The ozone loss from January through late March has been typically 20-25%, and shorter-period losses have been higher, depending on the meteorological conditions encountered in the Arctic stratosphere. Smaller, but still significant, stratospheric decreases have been seen at other, more-populated regions of the Earth. Increases in surface UV-B radiation have been observed in association with local decreases in stratospheric ozone, from both ground-based and satellite-borne instruments (Ozone Basics). There are so many people that take this issue lightly or ignore this issue to gain profit. It is not each day that you hear about the depletion of the ozone layer in news or weather reports. However the hole still exists and will continue to enlarge. So many people are naïve about this
Abdul 4 issue and that is scary. If the ozone layer were to breakdown, we do not know what the possibilities for life would be. It is very important for people to know about this issue because if we continue on the damaging path that we are on now, extreme amounts of ozone will be lost and chaos would erupt. More than two decades of studies by the International Research Community, according to the Stratospheric Ozone: Monitoring and Research in NOAA, there was scientific evidence that man-made chemicals were the cause for the depletion of the ozone layer. The chemical elements that created this ozone-depleting compound are bromine, carbon, chlorine, fluorine, and hydrogen. These chemical elements are usually described by the general term halocarbons. The elements chlorine, fluorine, and carbon create the compound chlorofluorocarbons. This compound is usually abbreviated as CFCs (Ozone Basics). Chlorofluorocarbon along with carbon tetrachloride and methyl chloroform are the three key man-made compounds which cause major depletion in the ozone layer. These compounds are used in many applications. It is found in air conditioning, cleaning of electronics components, foam blowing, and refrigeration. Another important group of man-made halocarbons is the halons, which contain carbon, bromine, fluorine, and (in some cases) chlorine and have been mainly used as fire extinguishants (Ozone Basics). Chlorofluorocarbons were first created in 1928 as non-toxic, non-flammable refrigerants by chemist working for the US General Motor Company, and were first produced commercially in the 1930's by DuPont. The first Chlorofluorocarbon was CFC-12, a single carbon with two chlorines and two Fluorines attached to it. Today many different CFC's are produced and worldwide consumption in 1988 was estimated at over billion kilograms (Sparling). Although these compounds are depleting our ozone layer, they are essential for everyday life.
Abdul 5 Fig.1-Wher the artic ozone is being destroyed http://users.aber.ac.uk/ias/hss/topics/ozone_hole.jpg The history of known ozone depletion started in Antarctica. In 1956, there were ground based measurements of the Ozone in Halley Bay, Antarctica. Two decades later, there were satellites that were used to have measurements of the ozone. The satellite Nimbus-7 carried a TOMS (total ozone mapping spectrometer, and a SBUV (solar backscatter UV meter). The TOMS finally broke on May 7th, 1993, but today there are several different satellites measuring concentrations of ozone and other atmospheric gases. Gases in the troposphere and lower stratosphere are sampled by weather balloons or by airplanes such as the ER-2 managed by NASA (Sparling). As shown in Figure 1, satellites are used at its maximum. In 1974 M.J.Molina and F.S.Rowland published a laboratory study demonstrating the ability of CFC's to catalytically breakdown Ozone in the presence of high frequency UV light. Further studies estimated that the ozone layer would be depleted by CFC's by about 7% within 60yrs and based on such studies, the US banned CFC's in aerosol sprays in 1978. Slowly various
Abdul 6 nations agreed to ban CFC's in aerosols but industry fought the banning of valuable CFC's in other applications (Sparling). A large shock was needed to motivate the world to get serious about phasing out CFC's and that shock came in a 1985 field study by Farman, Gardinar and Shanklin. Published in _Nature_, May 1985, the study summarized data that had been collected by the British Antarctic Survey showing that ozone levels had dropped to 10% below normal January levels for Antarctica (Neal 36). Many people use aerosol sprays in everyday life for various reasons. If the government had not banned the use of these chemicals from the aerosol sprays, there would have been an increase in the depletion of the ozone layer. Fig. 2- Ozone Depletion Process http://www.environ.com/globalwarming/process.gif Scientists discovered in 1985 that the ozone layer was thinning during the spring months in Antarctica. The scientists named this phenomenon the ozone hole. As previously stated,
Abdul 7 the scientific evidence shows that human-made chemicals are responsible for the creation of the Antarctic ozone hole and are also likely to play a role in global ozone losses. Ozone Depleting Substances (ODS) have been used in many products which take advantage of their physical properties (e.g. chlorofluorocarbons (CFCs) have been used as aerosol propellants and refrigerants) (The Ozone Layer). CFCs are broken down by sunlight in the stratosphere, producing halogen (e.g. chlorine) atoms, which subsequently destroy ozone through a complex catalytic cycle. Ozone destruction is greatest at the South Pole where very low stratospheric temperatures in winter create polar stratospheric clouds (PSCs). Ice crystals formed in PSCs provide a large surface area for chemical reactions, accelerating catalytic cycles. The destruction of ozone also involves sunlight, so the process intensifies during spring time, when the levels of solar radiation at the pole are highest, and PSC's are continually present (The Ozone Layer). According to Duden, in her book The Ozone Layer, the ozone is being protected by a global treaty. It is a necessity to protect and preserve the ozone. Everyone around the world has to do something about it because it could happen anywhere. In the summer of 1987, there were representatives from 43 countries that met in Montreal, Canada to discuss about the protection of the ozone layer. After this meeting, they signed a global treaty on protecting the ozone. This treaty was later named the Montreal Protocol (29). Shown in Figure 3 is a picture stating that consumers in the United Kingdom have been CFC free since 1989.
Abdul 8 Fig. 3- No CFCs http://www.bama.co.uk/images/cfcs.jpg The government introduced new laws for regulation. Some have already proposed laws to cut down on the chemicals that destroy ozone. Environmental groups are teaching people what they can do to help. Volunteers make phone calls and visit homes. They tell people about the ozone problem. They encourage people to ask for laws to protect the ozone layer (32). Duden, gave suggestions about how a person can help save the ozone layer and here are her tips: Don t buy aerosol cans with CFCs Try not to buy machines or any other items that contain CFCs Stay away from polystyrene foam. (This is often called Styrofoam.) Do not buy fire extinguishers that contain halon. Use fans instead of air conditioners. Fans do not use CFCs Try to use the air conditioner as little as possible Watch the packaging that you buy that could possibly contain CFCs (35-36).
Abdul 9 These warnings are the safeguards to help us protect our environment against harmful ultraviolet rays. We all love to live in luxury with our air conditioners on and the cooling of our foods, especially in the summer. However, we all must realize that this use is at the expense of our environment. The use of refrigerants and Styrofoam is still dominant. We will eventually have to figure out another way to cool ourselves and preserve our food. Once we do, our lives will change forever.
Abdul 10 Works Cited Duden, Jane. The Ozone Layer. New York: Macmillan, 1990. Gleason, Karen L. Ozone Basics Stratospheric Ozone: Monitoring and Research in NOAA. 24 April 2001. 6 April 2005. <http://www.ozonelayer.noaa.gov/science/basics.htm>. Laturnus, Frank, Gunila Oberg, Teresia Svensson, Christian Wiencke. Ultraviolet radiation affects emission of ozone-depleting substances by marine macroalgae: Results from a laboratory incubation study. Copyright Thomson 2005. 15 December 2004. BasicBIOSIS. Dacus Library, Winthrop University. 6 April 2005. <http://0-newfirstsearch.oclc.org.library.winthrop.edu/webz/ FSFETCH?fetchtype=fullrecord:sessionid=sp07sw04-46554-e7pjywnprfcv52:entitypagenum=3:0:recno=1:resultset=1:format=FI:next=html/record.html:bad=er ror/badfetch.html:entitytoprecno=1:entitycurrecno=1:numrecs=1>. Neal, Phillip. Ozone depletion in the ozone layer. Conservation: The Ozone Layer. London: B.T. Batsford, 1993. Ozone to Environmental Changes. Ozone. 6 April 2005. <http://ozone.org/>. Sparling, Brien. Ozone Depletion, History and politics. 30 May 2001. NASA. 6 April 2005 <http://www.nas.nasa.gov/about/education/ozone/history.html>. The Ozone Layer. 7 August 2003. EUROPA. 6 April 2005 <http://www.europa.eu.int/comm/environment/ozone/ozone_layer.htm>.