Global warming is one of the many severe environmental concerns facing the world today. The concept of global warming has gone from an abstract idea to a significant potential problem concisely. But, what does global warming refer to? Simply, it refers to the heating up of the atmosphere and is caused by what is called the greenhouse effect. Whether or not people can feel the slowly rising temperature every few years because of global warming. Indeed, the consequences of global warming are real and dangerous because of the great increase of carbon dioxide produced by us (humans).
             According to U.S Environmental Protection Agency (2000), "Energy from the sun drives the earth's weather and climate, and heats the earth's surface; in turn, the earth radiates energy back into space. Atmospheric greenhouse gases (water vapor, carbon dioxide, and other gases) trap some of the outgoing energy, retaining heat somewhat like the glass panels of a greenhouse" (Retrieved November 16, 2003, from http://yosemite.epa.gov/oar/globalwarming.nsf/content/Climate.html). As a matter of fact, these four gases are the major greenhouse gases responsible for global warming. In particular, the carbon dioxide increase will have the greatest impact on global warming.
             As we all know, carbon dioxide levels have increased continually. As Newton (1993) noted about the average temperature, "Between 1880 and 1990, the Earth's average temperature seems to have increased by about 0.5 C (0.9 F), or about 2 percent." (p. 12). In fact, this has had obvious effects on the global temperature averages as the ten hottest years on record occurred from 1980 to 1998. In addition, "methane concentrations have more than doubled, and nitrous oxide concentrations have risen by about 15%." (U.S Environmental Protection Agency, 2000, Retrieved November 16, 2003, from http://yosemite.epa.gov/oar/globalwarming.nsf/content/Climate.html). So, as the atmosphere becomes richer in these g...