Global warming is an environmental issue that is now increasingly under media focus. It refers to the gradual increase of the temperature of the earth’s lower atmosphere as a result of the increase in greenhouse gases since the Industrial Revolution. The temperature of the atmosphere near the earth’s surface is warmed through a natural process called the Greenhouse Effect (Cline, 1992). The Greenhouse Effect refers to the phenomenon whereby carbon dioxide and other gases trap long-wave infrared radiation (heat) within the lower levels of the atmosphere.
Visible, shortwave light comes from the sun to the earth, and as it does so, it passes through a blanket of thermal, or greenhouse, gases composed largely of water vapor, carbon dioxide, methane, nitrous oxide, and ozone (Splash, 2002). Those gases, such as carbon dioxide (CO2 ), nitrous oxide (N2 O), certain chlorofluorocarbons (CFCs), methane (CH4 ), tropospheric ozone (O3 ), and water vapor, that are transparent to solar radiation but opaque to long-wave radiation, are termed greenhouse gases (GHGs) (Splash, 2002).
The infrared radiation that is reflected off the surface of the earth does not pass easily through the thermal blanket. Some of it is trapped and reflected downward, keeping the planet at an average temperature suitable to live, about 60 degrees Fahrenheit (16 degrees Celsius). Growth in industry, agriculture, and transportation since the Industrial Revolution has produced additional quantities of natural greenhouse gases plus chlorofluorocarbons and other gases, augmenting the thermal blanket (Splash, 2002).
It is generally accepted that this increase in the number of greenhouse gases is trapping more heat and increasing global temperatures, making a process that has been beneficial to life potentially disruptive and harmful. Today the world’s industrialized nations, such as the United States, England, West Germany, and Japan, are enjoying a quality of life unsurpassed in human history. Regrettably, however, that lifestyle is being bought at enormous environmental costs. And one of these costs is global warming caused by the greenhouse effect. The less-developed nations of South America, Africa, and Asia are also contributing to the greenhouse problem, but on a much smaller scale (Owens, 1989).
Anthropogenic emissions of CO2 from fossil fuel combustion were hypothesized as climate-altering at the end of the last century (Splash, 2002). Among factors that may be contributing to global warming is the burning of coal and petroleum products (sources of carbon dioxide, methane, nitrous oxide, ozone); deforestation, which increases the amount of carbon dioxide in the atmosphere; methane gas released in animal waste; and increased cattle production, which contributes to deforestation, methane production, and use of fossil fuels (Splash, 2002).
The Greenhouse Effect was first studied in the early nineteenth century by the French mathematician Fourier who speculated that certain atmospheric gases might prevent re-radiation of heat, so warming the surface of the Earth (Jamieson, 1988). Surface warming due to the greenhouse gases maintains a livable climate, and their entire removal from the atmosphere would reduce Earth’s surface temperature by 33°C (Firor, 1989). However, the operation of this radiative balance mechanism has become a matter of concern because of the rate at which anthropogenic emissions of GHGs are increasing and the long residence times of some of these gases.
Evidence has been accumulating that sustained, human-induced warming of the Earth’s lower troposphere has been in progress since about 1980, accelerating during the 1990s (Johansen, 2002). During 1997 and 1998, the global temperature set records for 15 consecutive months; July of 1998 averaged 0.6 of a degree F. higher than July of 1997, an enormous increase if maintained year to year. The year 1998 was the warmest of the millennium, topping 1997 by a quarter of a degree F. (Christianson, 1999). The outcome of the Greenhouse Effect is seen through scientific studies. During the 20th cent., the atmospheric temperature rose 1.1 degrees Fahrenheit (0.6 degrees Celsius), and the sea level rose several inches (Johansen, 2002).
Owen (1989) points out some benefits of the Greenhouse effect: the cost of heating homes, stores, and factories would be somewhat less; the sub-Arctic grasslands, now populated largely by lemmings and caribou, may warm up sufficiently to attract not only human settlement, but agricultural and industrial development as well; the added carbon dioxide in the atmosphere could bring increased rainfall as well as a longer growing season in places such as Canada, Europe, and northeast Africa (Owen, 1989).
Some projected, longer-term results of global warming include melting of polar ice, with a resulting rise in sea level and coastal flooding; disruption of drinking water supplies dependent on snow melts; profound changes in agriculture due to climate change; extinction of species as ecological niches disappear; more frequent tropical storms; and an increased incidence of tropical diseases. An increase in the global average temperature of only 4 degrees C would result in a thermal expansion of the warmed-up seawater, melting of glaciers such as the Antarctic ice cap, and, therefore, a rise in ocean levels. Indeed, such melting has already begun, as evidenced by the slab of ice that broke off from the Antarctic ice field in 1987 and splashed into the Ross Sea (Owen, 1989). The chunk was so huge that its loss reshaped Antarctica’s shoreline.
The Bay of Whales is now gone forever. A 3.3 foot (1 meter) rise in ocean levels by 2035 would cause the seas to move 100 feet (30 meters) further inland along the shores of the United States, thus reshaping the coastline. Along the Atlantic and Gulf shores, major portions of Florida and Louisiana would be flooded (Owen, 1989). Billions of dollars of property, including homes, factories, chemical storage tanks, railroads, and highways would be inundated.
It is estimated that the city of Charleston, South Carolina, alone would sustain $650 million in flood damage. Boston, New York City, Baltimore, Norfolk, Miami, Mobile, New Orleans, and Houston would likely experience similar destruction. Millions of people would be forced to relocate; human stress, anxiety, and discomfort would be severe (Splash, 2002). The salty water of the rising seas would gradually “invade” brackish water estuaries such as the Chesapeake Bay, with the result being massive contamination of breeding and nursery habitats used by valuable food fish such as red snapper, bluefish, striped bass, and flounder (Splash, 2002).
Moreover, saltwater would seep into water-holding layers of porous rock and pollute the drinking water on which millions of people depend. Several of the leading weather experts in the United States are confident that the searing heat experienced in 1988 was indeed the result of the greenhouse phenomenon (Splash, 2002). In Ohio, the Environmental Protection Agency issued an ozone warning because the hot air acted like a lid over Cleveland, Columbus, and other cities and caused a serious buildup of the health-threatening gas. Health authorities throughout the United States advised the aged and those with heart or respiratory problems to remain indoors and reduce their physical activity during extreme heatwaves.
The Greenhouse effect can also lead to frequent and severe droughts and also increase the frequency and severity of dust storms and hurricanes. There is likely to be a growth in the number and severity of forest fires. The greenhouse Effect can lead to the extinction of wildlife. During the last thermal rise, thousands of years ago, several warm-climate species expanded their ranges northward as far as Canada (Splash, 2002). Many plants and animals were not able to adjust to the thermal shift and became extinct.
The crucial point is that these extinctions were caused by a warm-up of 5 degrees C throughout thousands of years. Today, however, greenhouse scientists predict an equivalent temperature rise in only 61 years. Because of the greenhouse effect, soil scientists predict that the dust storms of the future will be even worse. Greenhouse expert Walter Orr Roberts writes, “The Dust Bowl of the 1930s was the greatest climatic disaster in the nation’s history. But it will seem like child’s play compared to the Dust Bowls of the 2040s” (Splash, 2002)
In 1989, the Environmental Protection Agency advocated several policy options that, in aggregate, could reduce the rate of global warming by 60%, to about 1 degree C per century (Splash, 2002).
These policy recommendations are: reduce carbon dioxide emissions from cars by switching from gasoline to cleaner-burning fuels such as methane, making more extensive use of mass transit, mandating that all new cars have a minimum fuel efficiency of 50 miles per gallon, and eventually converting to electric-powered vehicles; impose a carbon dioxide user tax on all fossil fuels; promote energy conservation by recycling paper, glass, and metals and using garbage and crop residues as sources of fuel; greatly expand the development of solar energy so that the use of fossil fuels can be reduced; develop large “energy plantations” of fast-growing trees as burning this wood would not result in any net increase in atmospheric carbon dioxide, the amount of gas released would only be equaling the amount taken in by the trees when they were alive; and finally halt the destruction of forests in the tropics.
More aggressive adjustments include a gradual worldwide shift away from the use of fossil fuels, the elimination of chlorofluorocarbons, and the slowing of deforestation by restructuring the economies of developing nations.
The United Nations has sponsored a series of conferences involving over 40 countries. The first was held in Washington, D.C., in early 1989 (Splash, 2002). In 1992, at the United Nations Conference on Environment and Development, over 150 nations signed a binding declaration on the need to reduce global warming. In 1994, however, a UN scientific advisory panel, the Intergovernmental Panel on Climate Change, concluded that reductions beyond those envisioned by the treaty would be needed to avoid global warming (Splash, 2002). A UN Conference on Climate Change, held in Kyoto, Japan, in 1997 resulted in an international agreement to fight global warming, which called for reductions in emissions of greenhouse gases by industrialized nations. Not all industrial countries, however, immediately signed or ratified the accord.
In 2001 the G. W. Bush administration announced it would abandon the Kyoto Protocol; because the United States produces about one-quarter of the world’s greenhouse gases, this was regarded as a severe blow to the effort to slow global warming. Despite the American move, most other nations agreed later in the year (in Bonn, Germany, and in Marrakech, Morocco) on the details necessary to convert the agreement into a binding international treaty, which came into force in 2005 after ratification by more than 125 nations (Johansen, 2002).
In 2006, California enacted legislation that called for cutting carbon dioxide emissions by 25% by 2020; the state is responsible for nearly 7% of all such emissions in the United States (Johansen, 2002). In 2007 President George W. Bush called for the world’s major polluting nations to set global and national goals for the reduction of greenhouse gas emissions, but the nonbinding nature of the proposed goals provoked skepticism from other nations that favored stronger measures (Johansen, 2002). It is hoped that these conferences will lead eventually to an International Law of the Atmosphere, with provisions for the significant reduction of greenhouse gas emissions throughout the world.
There are however barriers to the implementation of these measures. The first major barrier is the world’s soaring population. The number of people on earth is projected to double in the next half-century. The problem is at once very simple, and also astoundingly complex. Increasing human populations, rising affluence, and continued dependence on energy derived from fossil fuels are at the crux of the issue. Improved automobile mileage, reforestation projects, energy efficiency in construction, and national support for mass transit are among simple adjustments that could significantly lower the negative effects of greenhouse gases.
Bibliography
Christianson, Gale E. (1999). Greenhouse: The 200-Year Story of Global Warming. Walker and Company. New York.
Cline, R. William (1992). The Economics of Global Warming. Institute for International Economics. Washington, DC.
Firor, John. (1990). The Changing Atmosphere: A Global Challenge. Yale University Press. New Haven.
Johansen, E. Bruce (2002). The Global Warming Desk Reference. Greenwood Press. Westport, CT.
Johansen, E. Bruce (2002). The Global Warming Desk Reference. Greenwood Press. Westport, CT.
Owen, S. Oliver (1989). The Heat Is on; the Greenhouse Effect and the Earth’s Future. The Futurist. Volume: 23. Issue: 5.
Splash, L. Clive (2002). Greenhouse Economics: Value and Ethics. Routledge Publishers. London. Publication Year: .