Greenhouse Gases

Greenhouse gasses which occur naturally in our environment include water vapor(H20), Carbon dioxide (CO2), Methane (CH4), Oxides of Nitrogen (NOx) and ozone (O3).

Naturally occurring greenhouse gases are essential to life on earth considering the important role they play in the earth’s greenhouse effect. Since they slow the transference of the earth’s thermal radiation into space, these gases help keep the earth approximately 33°C warmer than it would otherwise be without them.

Unlike naturally occurring greenhouse gases, anthropomorphic (man made) greenhouse gases are believed to have caused an over accumulation of greenhouses gases in our atmosphere. This is believed to have affected an observed increase in the earth’s average surface temperature, commonly referred to as global warming.

Common anthropomorphic greenhouse gases include Carbon dioxide (CO2), Methane (CH4), Dinotrogen monoxide (N2O, a form of "NOx") and ozone (O3). The anthropomorphic production of these gases is mainly attributable to the burring of fossil fuels such as coal, petroleum and natural gas, and deforestation and agricultural ativities.

Several halogenat ed substances such as Chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and bromofluorocarons are also greenhouse gases, but not in the strictest sense. Nearly all of these substances are byproducts of industrial activities, but unlike CO2, CH4, N2O and O3, most CFCs and HCFCs do not directly slow the earth’s outward transference of thermal (infra red) radiation. Rather, they are substances which deplete stratospheric ozone, which consequently decreases the rate at which the earth’s atmosphere can filter incoming ultra violet solar radiation. Conversely perfluorocarbons (PFCs) and sulfur hexafluoride (SF6) do not deplete the ozone layer, but are potent isolative greenhouse gases.

Finally, there are several gases which no not have direct effects on global warming, but which directly or indirectly affect terrestrial and/or solar radiation absorption by influencing the formation or destruction of greenhouse gases and/or troposphere and stratospheric ozone. These gases include carbon monoxide (CO) and non-CH4 volatile organic compounds.

The following graphs provide slightly varying accounts of atmospheric percentages of greenhouse gas compositions: