A common misconception held by most people is that the "greenhouse effect" is a phenomenon mainly caused by human CO2 production. This is a gross misunderstanding; actually, the greenhouse effect is a natural occurrence. Certain gases in the atmosphere trap infrared radiation, or heat, that would otherwise escape from the earth's atmosphere into outer space, this heat is a result of the greenhouse effect which is absolutely essential to the survival of every species on earth.
The greenhouse gas that is most abundant, not to mention hating the largest effect on climate, is water vapor.
Water vapor makes up 97% of all greenhouse gases. Of the 3% of greenhouse gases not comprised of water vapor, the largest component is carbon dioxide. About 4% of the carbon dioxide going into the atmosphere is due to man-made carbon dioxide coming from the burning of fossil fuels such as coal, oil and natural gas. These fossil fuels have been trapped deep beneath the earth's surface so their introduction in to the earth's atmosphere causes an imbalance which has been alleged to cause adverse effects on the environment.
In addition to CO2, Methane (CH4), Nitrous oxide (N2O), Hydrofluorocarbons (HFCs), Perfluorocarbons (PFCs), and Sulphur hexafluoride (SF6) also constitute greenhouse gases.
The natural CO2 production corresponding to the greenhouse effect is known as the carbon cycle. Carbon dioxide is absorbed from the atmosphere into plants when they breathe, and that carbon gets stored in the body of the plant itself. When plants are burned or when alcohol made from plants is burned, the carbon dioxide that results does not necessarily represent a man-made addition to the greenhouse effect, since the carbon in plants originally came from the air, and therefore already existed as a part of the carbon cycle which transfers carbon back and forth between the atmosphere and the surface of the earth.
Burning vegetation only increases the greenhouse effect if it is done on a massive scale without the replacement of the lost vegetation. For example, massive deforestation in developing nations has not been offset by new forest growth elsewhere, and therefore represents a significant portion of man-made greenhouse gas emissions and an imbalance within the carbon cycle. In addition to natural CO2 emissions and water vapor, N20, or methane, also contributes to the greenhouse effect. Methane is produced from the decomposition of organic materials, and therefore in normal amounts does not have adverse effects on the atmosphere. There has been questions however, about whether or not manmade sources of methane, such as cattle raising and rice growing be more damaging to the environment than CO2. If this were the case, more research would be necessary before any policies involving the greenhouse effect are introduced.
There has been great controversy over whether or not a build-up of greenhouse gases from human activities is causing the earth's temperature to rise beyond natural levels, and what the effects of this possibility might be. Many people have shown distress at the plausibility or perhaps eventuality of this prospect. This concern is evident in the form of the recent United Nations convention on climate change, better known as the Kyoto protocol which dealt with industrial restrictions on account of increasing man-made CO2 emissions. Under much criticism from American industries, the Clinton administration just signed this controversial document which restricts the release of greenhouse gases into the atmosphere and exhibits a commonly held concern about the greenhouse effect.
This protocol came about because many scientists believe that rising levels of carbon dioxide emissions will cause climatic changes such as warmer, drier, weather in the northern hemisphere and wetter weather in tropical and subtropical regions. These changes could lead to decreased food production, resulting in more hunger and disease. Heart disease and stroke appear to cause more deaths in higher temperatures, and insects-spread diseases such as malaria, and waterborne disease, such as cholera, would likely increase as well. The intergovernmental Panel on Climate Change has predicted that atmospheric temperature will rise by between 1.5[degrees]C and 4.5[degrees]C by the year 2100. Such increases would cause the polar ice caps to melt and the sea level to rise by between 41 cm and 68 cm.
This rise in sea level could send salt water up crucial sources of fresh water such as the Delaware river in Philadelphia, rendering them unusable. Many scientists, through the use of complex computer models have produced possible climate outcomes, and from this data have determined that our environment is at risk and consequently, so are we. Other scientist strongly disagree and believe these complex computer models to be poor attempts at reproducing little understood climate processes. For example, currently there are no computers on earth that can adequately assess natural variables such as cloud formations which are key to understanding global warming. In fact, many people believe that man-made CO2 has positively affected the environment. For example, some plants grown in air with high concentrations of CO2 have experienced reductions in leaf nitrogen content, which results in the plants being able to use nutrients for more limiting processes. In addition, cell size in some plants has been reported to increase with atmospheric CO2 enrichments, and the number of branches produced on trees appears to increase as well, with elevated CO2 levels. There have also been reports of increased plant leaf size, plants producing more flowers, enhanced early growth of plants, and increased rates of photosynthesis all due to CO2 intensification.
In fact, so many people disagree with arrangements such as the Kyoto Protocol, that 15,000 scientist signed a petition to abolish it. A lot of scientists are under the belief that global warming, due to the alleged imbalance of the greenhouse effect, has not been proven to have occurred at all. They believe that even if it does occur, balancing mechanisms within the Earth's climate systems will minimize the impact, giving us no reason to "jump the gun" by signing mindless political agreements that potentially limit the economic growth the United States. The US has committed to reducing its CO2 emissions by 93%; most see this as an opportunity for economical disaster.
I see valid arguments on both sides, but I am the type of person that needs to see hard evidence before making any assumptions. Until I see a direct connection between global warming and the environment, I can't accept them as severe problems. As I have read about the possible implications of an imbalance of the greenhouse effect, all I have encountered are hypotheticals. I can understand the argument, but I fail to see the evidence these hypotheticals are drawn upon. Despite opposition, we are reducing our dependence on fossil fuels and preserving existing forest and planting new ones to increase the planet's CO2 removal capability. I may not see the rationalization behind these actions, but nevertheless they have the added benefit of making good environmental sense regardless of the outcome of the global warming issue.