There are six main greenhouse gases, of those six there are three very common ones: carbon dioxide, nitrous oxide, and methane. These three are most common becasue they are produced from human activity: CO2 from cars, tranportation, and the burning of fossil fuels. N20 is from farming, the use of fertilizer and when animals urinate. CH4 is pretty much from when animals burp as they digest their food, landfills, and rice paddies. All these gases occur naturally, and only make up for about 10% of infrared radiation absorbed. The other 90% comes from water vapor.
