By Boy Tunnel

For centuries, scientists, philosophers and theologists have toiled with the notion that the Earth's life span is finite. Predictions of nuclear destruction, internal explosion and world-wide famine exist among such authorities. Yet perhaps the most common prognostication is derived from the concept of global warming. The "real" task that surrounds this issue is whether or not global warming is a serious "problem" that must be prevented or rather a harmless and perhaps even beneficial planetary process. Regardless, no definite conclusions can be drawn from this question. To best understand the idea of global warming, we must first examine its roots. Global warming is a direct result of the "greenhouse effect". This greenhouse effect, first proposed over one hundred years ago, has since become a theory that is accepted world- wide. Put simply, the greenhouse effect is a natural phenomenon that warms the earth and enables life to exist on it. It operates on the same idea as an ordinary glass greenhouse, allowing light to get it, but not allowing for the escape of heat. The result of this is obviously a much higher temperature inside the greenhouse. Likewise, the light from the sun has little difficulty in penetrating the atmosphere and reaching the earth's surface. As the earth's surface is warmed, much of this heat is formed into infrared radiation. Because infrared rays are longer in wavelength than visible light, they are absorbed by certain gases within our atmosphere, these being "greenhouse gases". As this absorption of heat warms up the atmosphere, some of the heat is then radiated back to the Earth. Therefore, as these greenhouse gases accumulated in the atmosphere, more infrared radiation is trapped. Undoubtedly the most important greenhouse gas is carbon dioxide. Carbon dioxide (CO2) is a colorless, tasteless, invisible gas that exists in very small amounts in the air that we take in, and rather large amounts in the air that we exhale. Essentially, carbon dioxide is a waste product of the processes which we perform in order to live. Carbon dioxide, like other greenhouse gases, has the peculiar property of allowing light to pass through it, yet it efficiently absorbs or traps infrared heat, thus causing the greenhouse effect. However, unlike the other greenhouse gases, the quantity of carbon dioxide in our air is greatly and steadily increasing as a direct result of human activity. For instance, the concentration of carbon dioxide in the air has increased from approximately 290 parts per million to approximately 330 parts per million since the late nineteenth century. According to John Gribbin, this is "a trend that is certainly significant and that coincides with the growth of industry worldwide." Gribbin is simply suggesting that, due in part to the Industrial Revolution, man has sky-rocketed carbon dioxide levels to uncharacteristic measures. This is not to suggest, however, that there are not large amounts of naturally-occurring carbon dioxide in the atmosphere. In fact, naturally-occurring processes contribute about seven hundred billion tons of carbon dioxide per year to the atmosphere. The catch is that this approximate amount of carbon dioxide is equal to the amount actually absorbed by natural processes. Because there are naturally-occurring, sufficient amounts of carbon dioxide in the atmosphere, the average temperature on earth is +15 degrees Celsius as opposed to a brisk -18 degrees Celsius, just as if there were no carbon dioxide induced greenhouse effect at all. Carbon dioxide is not the only greenhouse gas that contributes to the greenhouse effect. Increased levels of methane, nitrous oxide, and more recently chlorofluorocarbons (CFCs) in the atmosphere all play a significant role in global warming. Methane occurs naturally from grazing animals, wetlands, and even termites. Human-induced sources which produce methane are cattle-raising, rice paddies, trash dumps and the production, transportation and use of natural gas itself. Most naturally occurring nitrous oxide emissions come from biological processes in soil, while the human-related nitrous oxide is found in fossil fuel combustion and the industrial production of nylon. Chlorofluorocarbons, on the other hand, do not occur naturally. They result strictly from human activity and can stay in the atmosphere for over one hundred years. Because CFCs are nontoxic, nonflammable, and very stable compounds, they were at one time quite widespread in use. Only recently have their effects on the atmosphere, such as their ability to deplete stratospheric ozone, been realized. As a result, products such as aerosol sprays have been virtually banned all over the world because of the chlorofluorocarbons that they emit into the atmosphere. Nonetheless, these other greenhouse gases, when tallied up, are estimated to contribute about the same amount to potential global warming as is carbon dioxide over the next sixty years. Therefore, it is fair to say that carbon dioxide is responsible for at least fifty per cent of the global warming that is caused by human activities.

There are numerous procedures that humans perform that contribute to an increase in the concentration of carbon dioxide in our atmosphere. Perhaps the most dominant procedure is the burning of fossil fuels. Particularly, for the past two decades and certainly today, the burning of coal is the main reason for the rapid build-up of carbon dioxide in the atmosphere. However, the burning of oil, gas, and organic matter also contribute greatly to the increased carbon dioxide concentration. It is estimated that human activity, particularly the burning of fossil fuels, generates about twenty-four billion tons of carbon dioxide per year. However, only about half of this amount is absorbed by natural processes. Some natural reservoirs or storage "sinks" where carbon dioxide is stored are coal reserves, timber, and water. Unfortunately, we have been extracting coal and timber faster that they can be replenished. Similarly, other storage sinks such as the ocean cannot keep up with storing the excess carbon dioxide that is released. This problem is made even worse, however, by the fact that the world's forests are being destroyed. According to John Gribbin, "until recently, [it was thought] that increased carbon dioxide concentration encouraged photosynthesis [in plants] stimulating plant growth on both land and sea, and removing much of the "extra" carbon dioxide from the atmosphere." The latest studies show that through the destruction of the world's plants, we produce about the same amount of carbon dioxide as the burning of fossil fuels. This is a direct result of burning wood, slash-and-burn agriculture, and oxidizing humus. Therefore, it is not difficult to see why our forests appear to be producing more carbon dioxide than they are taking in. It can be assumed then, that if we were to discontinue the excessive destruction of the biomass, it would quite likely be able to handle the extra carbon dioxide that comes from the burning of fossil fuels. The end result would most likely be the elimination of the imminent greenhouse effect. Though biomass absorbs much carbon dioxide, a significant amount is also taken up by the oceans. For instance, studies suggest that the oceans could absorb up to thirty- five per cent of the carbon dioxide produced by the burning of fossil fuel. According to Andrew Crane and Peter Liss, "three properties determine the ocean's ability to remove man-made carbon dioxide from the atmosphere: the capacity of seawater to dissolve and react with the gas...the rate at which carbon dioxide transfers from air to sea; and the rate of downward mixing of water that has absorbed carbon dioxide at the surface." Because the second and third properties depend so greatly on the first property, it then becomes the first one we shall examine. The reacting of carbonate ions which are found in seawater and dissolved carbon dioxide form bicarbonate. A good portion of carbon dioxide is used up in this process which explains why seawater absorbs approximately eight times as much carbon dioxide as distilled water. The reason for this is simply because this bicarbonate-producing reaction is not possible in distilled water. Therefore, it relies solely on dissolving in order to use up carbon dioxide. The second property basically deals with how well or how fast carbon dioxide is transferred from the air to the sea. Since it takes approximately one hundred twenty days for the top seventy-five meters of the ocean to react to a change in the concentration of atmospheric carbon dioxide, this property is perhaps the main barrier to ocean carbon dioxide intake. The third property requires a rather timely process of tens to hundreds of years. Since the surface layer of the ocean accommodates only about ten percent of the carbon dioxide that flows into the atmosphere each year, we can assume that significant amounts of water below the surface layer are absorbing carbon dioxide. This statement is a conclusion of the many studies that suggest that the oceans are a major reservoir for carbon dioxide. Though we have discussed a number of reservoirs for atmospheric carbon dioxide, the fact remains that only a percentage of fossil-fuel-induced carbon dioxide is stored in these sinks. There is still a large amount of the gas that scientists simply cannot determine where it goes. However, it has been proposed that the oceans do indeed take up more carbon dioxide than previously thought. This theory, of course, cannot be totally proven. Without question, an increase in atmospheric carbon dioxide would have some significant effects on our environment. It has been suggested that higher concentrations of carbon dioxide will naturally stimulate photosynthesis, thus eliminating some carbon dioxide and increasing crop productivity. The eventual result would be helping to solve the problem of feeding the world's population.

The most obvious consequence of an increased carbon dioxide level is of course an increase in temperature. In fact, it is estimated that over the next one hundred years, an average global warming of three to eight degrees Celsius could occur. Such a warming would likely cause ocean levels to rise as much as two to four centimeters per year. This would be due to the partial melting of the Antarctic an Greenland icecaps, (a relatively slow process), and an expansion of seawater. This expansion, a much faster process, would occur because the ocean would naturally expand as it is warmed. An increase in global temperature would also have some effect on cloud cover. The warmer Earth, with increased evaporation from the oceans, would likely become a more cloudy place. With the increased cloud cover would come more precipitation and the clouds themselves would reflect heat from the sun before it could reach the Earth. This could perhaps limit the degree of carbon dioxide warming. Aside from a change in cloud cover, warmer weather would bring warmer and longer spring, summer, and fall seasons. Winter, on the other hand, would become much colder and much shorter. This would be due to circulation changes in the atmosphere which create high pressure systems that block warm westerlies from reaching the land. Similarly, there could be an increase in storms, heat waves, droughts, and precipitation, all in places that are normally unaccustomed to such events. This would be because the temperature increase would not be uniform over the entire world. The result would be the need for humans to adapt to their new climates. Also, an increase in tropical cyclone activity would occur due to increased temperatures, though it would be impossible to predict which regions would be greatly affected. Though there are a number of predicted consequences of global warming, none of them are certain. In fact, some scientists would argue that an increase in global temperature may bring about a better place to live. However, the majority of people feel that such a situation would create an even worse place to live than the present. Therefore, we mush search to find solutions that will reduce the effects of global warming. For starters, it is no surprise that we must inhibit the amount of carbon dioxide producing activities such as burning our forests, using aerosols, and burning other fossil fuels such as coal, oil, and gas. This proposal seems logical, yet it is extremely timely. One reason for this slow process is that the governments of the world have not yet agreed upon such a proposal. Nevertheless, it is important to act now. Though we can stand a warming of a degree or two, we most certainly do not want to create a runaway global warming for our descendants which would be beyond their control. It has even been suggested that we establish a permanent disposal site for carbon dioxide, which is similar to that proposed for nuclear waste. It would involve the storage of carbon dioxide in impermeable containers located deep below the surface of the Earth. However, such a procedure has not been seriously considered for the simple fact that carbon dioxide gas is not yet considered an "official" pollutant anywhere in the world.

Regardless of how much evidence is submitted for each side, the dispute still rages on about whether or not global warming would be a "good thing" or a "bad thing". The only fact involved in such a scenario is that global warming is occurring and at some point, there will indeed be a major effect. Furthermore, there is no certain solution to the greenhouse effect, though one can assume that if we were to greatly reduce the amount of carbon dioxide entering our atmosphere, the problem would be less serious. However, this process would take hundreds of years, so there is basically no immediate solution. This solution would also greatly alter our lifestyles so it would take much adaptation on our part if we were to make it work. All in all, if we continue to practice such things as car-pooling, walking, and refusing to use aerosols, we just may help to reduce the problem. Though there will be virtually no immediate effects to the problem, we can only hope that it will provide enough time for our future generations to devise a solution to our problem. 

Endnotes

Government of Canada, Canada and Global Warming: Meeting the Challenge, 1.

I.E. Galbally and J.R. Freney, "The Biosphere, Atmospheric Composition and Climate," in Climate Change and Variability, ed. A.B. Pittock et al. (Cambridge: Cambridge University Press, 1978), 273.

"Environmental Issues, Including Global Warming, Ozone Depletion, Eutrophicatio" November 4, 1996. http://www.geocites.com/Rain Forest/1286/enup.html (November 15, 1996).

Government of Canada, 2.

Ibid., 3.

Ibid.

Galbally and Freney, 274.

John Gribbin, "Fossil Fuel: Future Shock?," in The Breathing Planet, ed. John Gribbin (Oxford: Basil Blackwell and New Scientists, 1986), 229.

Galbally and Freney, 277.

Gribbin, 232.

"Environmental Issues, Including Global Warming, Ozone Depletion, Eutrophicatio"

Gribbin, 236.

"Environmental Issues, Including Global Warming, Ozone Depletion, Eutrophicatio"

Ibid.

Ibid.

"Greenhouse Effect" April 17, 1996. http://www.science.gmu.edul-zli/ghe.html (November 15, 1996).

Gribbin, 233.

"Greenhouse Effect"

Galbally and Freney, 277.

"Greenhouse Effect"

Galbally and Freney, 256.

Ibid.

John Gribbin, "Woodman, Spare That Tree," in The Breathing Planet, ed. John Gribbin (Oxford: Basil Blackwell and New Scientist, 1986), 239.

Ibid.

Government of Canada, 16.

Andrew Crane and Peter Liss, "Carbon Dioxide, Climate and the Sea," in The Breathing Planet, ed. John Gribbin (Oxford: Basil Blackwell and New Scientist, 1986), 265.

Ibid., 262.

Ibid., 263.

Ibid.

Ibid.

Ibid., 265.

Sherwood B. Idso, "Carbon Dioxide-An Alternative View," in The Breathing Planet, ed. John Gribbin (Oxford: Basil Blackwell and New Scientist, 1986), 254.

"Environmental Issues, Including Global Warming, Ozone Depletion, Eutrophicatio"

Ibid.

Gribbin, "Fossil Fuel: Future Shock?", 234.

John Gribbin, "Hot Summers and Cold Winters Ahead," in The Breathing Planet, ed. John Gribbin (Oxford: Basil Blackwell and New Scientist, 1986), 274.

"Greenhouse Effect"

Crane and Liss, 265.

Bibliography

Crane, Andrew, and Peter Liss. "Carbon Dioxide, Climate and the Sea." In The Breathing Planet, edited by John Gribbin, 261-269. Oxford: Basil Blackwell and New Scientist, 1986.

Galbally, I.E., and J.R. Freney. "The Biosphere, Atmospheric Composition and Climate." In Climate Change and Variability, edited by A.B. Pittock et al., 269-293. Cambridge: Cambridge University Press, 1978.

Government of Canada. Canada and Global Warming: Meeting the Challenge.

Gribbin, John. "Fossil Fuel: Future Shock?." In The Breathing Planet, edited by John Gribbin, 231-237. Oxford: Basil Blackwell and New Scientist, 1986.

Gribbin, John. "Hot Summers and Cold Winters Ahead." In The Breathing Planet, edited by John Gribbin, 272-274. Oxford: Basil Blackwell and New Scientist, 1986.

Gribbin, John. "Woodman, Spare That Tree." In The Breathing Planet, edited by John Gribbin, 238-243. Oxford: Basil Blackwell and New Scientist, 1986.

Idso, Sherwood B. "Carbon Dioxide-An Alternative View." In The Breathing Planet, edited by John Gribbin, 253-260. Oxford: Basil Blackwell and New Scientist, 1986.