Global warming & human activities - Essay Example

These alterations threaten to transform the global environment. As one author imagined it, “The year is 2035. In New York, palm trees line the Hudson River … Phoenix is in its third week of temperatures over 130 degrees … Holland is under water. Bangladesh has ceased to exist … in central Europe and in the American Midwest, decades of drought have turned once fertile agricultural lands into parched deserts (Rifkin, 1988).” Composition of Greenhouse Gases Methane and carbon dioxide primarily constitute the greenhouse gases.

They also consist of water vapor and trace amounts of other gases including ozone, nitrous oxide, and HCFCs. Greenhouse gases “trap” some of the sun’s infrared radiation within Earth’s atmosphere, similar to a greenhouse. As the levels of greenhouse gases in the atmosphere increase, they trap more of the sun’s heat in the earth’s atmosphere, which has a number of effects on the earth’s environment. Were it not for greenhouse gases, most of the sun’s energy would radiate back out into space, leaving the earth cold and lifeless with an average temperature of minus 18 degrees C (0.

4 degrees Fahrenheit) (Miller). . Increasing levels of greenhouse gases, like carbon dioxide (CO2 ), in the atmosphere since pre-industrial times have been well documented. There is no doubt this atmospheric buildup of carbon dioxide and other greenhouse gases is largely the result of human activities. Combined with unnaturally elevated levels of naturally occurring gases, global warming is exacerbated by anthropogenic emissions of additional greenhouse gases into the atmosphere. To illustrate the problem, under pre-Industrial Revolution conditions, global levels of carbon dioxide were around 275 parts per million (ppm).

Carbon dioxide levels increased from 275 ppm to 346 ppm between 1860 and 1986, primarily due to the burning of fossil fuels and deforestation (Flavind & Tunali, 1995). Plants convert carbon dioxide to oxygen and are one effective way to absorb carbon dioxide from the atmosphere. Deforestation has resulted in a reduction in the carbon dioxide to oxygen conversion. It is estimated that deforestation contributes 1.0 to 2.5 billion tons of carbon dioxide emissions annually (Oppenheimer & Boyle, 1990).

It is thought that global levels of carbon dioxide in the atmosphere will reach 550 ppm sometime between 2040 and 2100; however, most analysts believe those levels will be reached closer to the middle of the twenty-first century (Rifkin). It is estimated that over the next 100 years the temperature will increase about 1.98 degrees C (3.6 degrees Fahrenheit). Such a severe temperature change would most likely cause an increase in heat waves and drought, the spread of infectious diseases, and the disruption of ecosystems worldwide.

Furthermore, increased global temperatures is causing the melting of ice in both polar regions, resulting in a rise in sea level, predicted by