Global Warming 1 Global Warming: Fact or Fiction Debbie S. Moran Columbia Southern University Global Warming 2 Global Warming: Fact or Fiction For many years now, the subject of global warming has been the cause of heated debates throughout the world. The theory is based on the idea that greenhouse gasses are accumulating in Earth's atmosphere as a result of human activities, causing surface air temperatures and subsurface ocean temperatures to rise. Debates have covered its causes and effects, and whether or not it actually exists and is a true threat to the planet. I, for one, do not believe that global warming is a real issue, but one created by environmentalists and scientists with a need for funding for additional and continuing research. I believe that research shows while there may be cyclical changes in temperature and weather on our planet, they occur naturally and not affected by man in any real way. One of the most popular theories being debated is the "greenhouse effect" which is caused by greenhouse gasses - naturally occurring gasses such as water vapor, methane, oxygen and carbon dioxide.
As the Earth is a living planet, it is constantly undergoing change. Plate tectonics continue to change the face of the planet. The sea floor is still spreading, and we still have earthquakes and volcanoes. Convection currents created by the tremendous heat and pressure at the core of the Earth move the plates. These processes release tremendous amounts of carbon dioxide and water vapor (greenhouse gasses). We know that these processes have been taking place since the beginning of time and, according to the geologic record, there have been numerous greenhouse and icehouse ages.
Additionally, we know that the motion of the Earth, known as the Milankovitch cycles, also affect the Earth's atmosphere. These Global Warming 3 cycles - the Earth's elliptical orbit, the tilt of the Earth's axis, and the procession of the equinoxes - all have an effect on the Earth in various ways. The Earth's orbit brings the planet closer to the Sun at one point in its 100,000 year trip. The Earth's tilt also changes just a few degrees over a period of 40,000 years or so, but enough to change the position of the polar ice caps relative to the Sun.
Finally, the procession of the equinoxes also moves the poles closer to or further away from the Sun over a period of approximately 23,000 years. Each of these cycles by itself may not have a noticeable effect, but taken together, the effects could be profound. Geologists have found direct relationships between these cycles and the weather extremes present during greenhouse and icehouse ages. As for the man-made greenhouse gasses, according to many environmentalists and the EPA, since the beginning of the industrial revolution atmospheric concentrations of carbon dioxide have increased nearly 30%, methane concentrations have more than doubled, and nitrous oxide concentrations have risen by about 15%.
These increases have enhanced the heat-trapping capabilities of the Earth's atmosphere. Sulfate aerosols cool the atmosphere by reflecting light back into space; however, sulfates are short-lived and vary regionally. Some scientists believe that the combustion of fossil fuels and other human activities are the primary reason for the increased concentration of carbon dioxide. The Committee on the Science of Climate Change states that temperatures are, indeed, rising with the global mean surface air temperature warmed by about 0.4-0.8^0 C during the 20th century. The Committee also states that the changes observed over the last several decades are "likely mostly due to human activities, but Global Warming 4 the Committee cannot rule out that some significant part of these changes are also reflections of natural variability". This committee believes that human-induced warming and associated sea level rises are expected to continue through the 21st century.
The secondary effects they expect include increases in rainfall rates and increased susceptibility of semi-arid regions to drought. They predict warming of 5.4^0 F by the end of the 21st century. It seems, however, that even the environmentalists have a hard time deciding if the Earth is warming up or cooling down. According to the NewScientist. com Greenhouse Timeline, it was during the 1800's that "greenhouse gasses" began to be studied and the idea of global warming was first introduced. But, during 1940 through the 1970's, worldwide cooling dampened scientific interest in the greenhouse effect. Some climatologists even predicted a new ice age.
So in light of all this evidence, is global warming actually occurring? According to Accu-Weather, the world's leading commercial forecaster, "Global air temperatures as measured by land-based weather stations show an increase of about. 45 degrees Celsius over the past century. This may be no more than normal climatic variation... [and] several biases in the data may be responsible for some of this increase". According to the Cooler Heads Coalition, a subgroup of the National Consumer Coalition, satellite data indicate a slight cooling in the climate in the last 18 years. These satellites use advanced technologies and are not subject to the "heat island" effect around major cities that alters ground-based thermometers.
They have also found the projections of future climate changes to be uncertain. Some computer Global Warming 5 models predict warming over the next century, but these models are very limited. Scientists who work on these models are quick to point out that they are far from perfect representations of reality, and are probably not advanced enough for direct use in policy implementation. It is interesting that as computer climate models have become more sophisticated, the predicted increase in temperature has been lowered. These and many other discrepancies have prompted the World Climate Report to develop a list of their top 10 fallacies about global warming and climate change. Some of the fallacies that they site are: 1.
Most climate scientists agree that disastrous global warming is here. Few recent surveys have addressed greenhouse warming. One, in 1990, demonstrated that there is a wide range of opinion on critical issues (that climate models do not accurately depict the ocean atmosphere or the possibility of attributing observed warming of about 0.5^0 C since 1890 to human impacts). 2. Model forecasts are correct, but confounded by sulfates, volcanoes, etc. They feel it is convenient to blame climate model errors on rare events such as volcanoes, El Nino, solar flares, etc.
They state that models do not do a good job of handling rudimentary atmospheric variables such as temperature, precipitation and wind. 3. Melting of the polar ice caps will cause the sea level to rise. In Antarctica, there is absolutely no evidence of increasing temperatures since the mid-1960's.
4. All bad weather is evidence of global warming. It seems that everything that occurs in our world lately has been blamed on global warming - hurricanes, droughts, fires, floods, blizzards, and even insect plagues. Other fallacies sited are: In the United States, recent years have been the warmest on record; northern hemisphere temperature increases over the last century correspond to Global Warming 6 human-induced warming; more CO 2 yields much higher surface temperatures; climate models are correct but are limited by computer technology; the climate will be more extreme; and, summers will be extremely hot and dry. None of these theories have been proven by any scientific data that is available to date. With all the uncertainty regarding projections of future climate changes, can we really say that humans are causing the climate to change?
At present, 98% of total global greenhouse gas emissions are natural. Only 2% are from man-made sources. Although the climate has warmed slightly in the last 100 years, most of that warming occurred prior to 1940, before the upsurge in greenhouse gas emissions from industrial processes. Actually, according to National Oceanic and Atmospheric Administration Climatologist Thomas Karl, in a paper published in 1989, temperatures have been showing a downward trend since their peak in 1940. Additionally, a Gallup survey indicated that only 17% of the members of the American Meteorological Society and the American Geophysical Society thought the warming of the 20th century was the result of an increase in man-made greenhouse gas emissions. In conclusion, when one takes all of the differing scientific evidence and interpretation into consideration, it would be very hard to agree with the theory "that artificial greenhouse gasses are causing unnatural global warming".
I believe that it is too large of a leap for mankind to make to think that he can actually affect the global climate that has its own checks and balances and has been in the making for some 4 billion years. Global Warming 7
Tar buck, E.J. & Lutyens, F.K. (2000).
Earth Science, (Ninth Edition), Upper Saddle River, NJ, Prentice Hall. U.S. Environmental Protection Agency (12/9/02), Global Warming - Climate, Retrieved December 9, 2002 from the World Wide Web: web Committee on the Science of Climate Change, Division on Earth and Life Studies, National Research Council (2001), Climate Change Science: An Analysis of Some Key Questions, Washington, DC, National Academy Press NewScientist.
com (12/9/2002), Climate Change, A Greenhouse Timeline, Retrieved December 9, 2002 from the World Wide Web: web Global Warming Information Page (12/11/02), Global Warming In Brief, Retrieved December 11, 2002 from the World Wide Web: web World Climate Report (12/9/02), Top 10 Global Warming Myths, Retrieved December 9, 2002 from the World Wide Web: web.