Global warming

Slavica Bjazevic
Ms. Hummel
ENC 1101
30 July 2009
Fact or Fantasy?
There is a strong scientific consensus that global warming exist as a result of increased concentrations of greenhouse gases such as carbon dioxide, methane, nitrous oxides and chlorofluorocarbons. This increase is producing changes in the global climate, flooding of coastal lands and cities, more intense storms, the extinction ofcountless species of plants and animals, crop failures in vulnerable areas, increased drought, etc.
The greenhouse effect is the rise in temperature that the Earth experiences because certain gases in the atmosphere trap energy from the sun. Without these gases, heat would escape back into space and Earth’s average temperature would be about 60ºF colder. Because of how they warm our world, thesegases are referred as greenhouse gases. Some of these gases are produced and emitted naturally and some through human activities such as CO2, Methane, Nitrous Oxide and Fluorinated Gases (artificially created).
From the pre-industrial era to 2004, the concentrations of natural occurring gases have increased steadily by 35, 143 and 18 percent respectively (IPCC 2001; Hofmann 2004). Beginning in1950, the emissions of fluorinated gases have also increased. As the concentrations of these gases continue to rise in the atmosphere, the Earth's temperature is climbing above past levels.
The planet creates the natural carbon dioxide necessary to prevent the most damaging heat from the sun to pass through the atmosphere and make life on Earth impossible. However, our emissions of greenhouse gasesinto the atmosphere have been increasing over the years, the use of oil and gas (among others) emits large amounts of CO2 trapped in our atmosphere that has altered the natural balance of the Earth. It is estimated that the amount of carbon dioxide into the atmosphere that will be issued in the next 30 years will double or triple. According to researchers from NASA who analyzed data from thousandsof weather stations around the world, Land surface temperature in 1999 reached a historic figure, surpassing the record of 1995. Global warming, according to several researchers, including scientists from NASA, is only one of the consequences of emissions of man into the atmosphere.
Eventually with the increase of the greenhouse, the amount of warming is expected to become sufficiently large thatclimate models forecast that the average temperature at the Earth's surface could increase from 3.2 to 7.2ºF above 1990 levels by the end of this century (“Basic”, par 4).
According to the National Oceanic and Atmospheric Administration (NOAA) and the National Aeronautics and Space Administration (NASA) data, the Earth's average surface temperature has increased by about 1.2 to 1.4ºF in thelast 100 years. The eight warmest years on record (since 1850) have all occurred since 1998, with the warmest year being 2008. Most of the warming in last decades is very possible the result of human activities. Other aspects of climate are also varying such as rainfall patterns, snow and ice cover, and sea level.
An analysis of the weather the last 1000 years suggests that human activity is thedominant force behind the increase of temperature. Thomas Crowley, a geologist at University of Texas University, found that natural factors such as volcanic eruptions were the responsible for the increase of temperature until 1900; nevertheless, after 1900 natural forces have only accounted for about only one fourth of observed worldwide warming.
“We do not know of any combination of naturalmechanisms that can explain this phenomenon,” writes Jonathan Overpeck, a geoscientist at the University of Arizona, in Nature. “ So we are left with the likelihood that human-induced global warming is underway, caused by emissions of “greenhouse gases” such as carbon dioxide, and that the next century we are are going to see even more warming,” he added. (Borehole 2000)
During the last decades,...