Greenhouse gases are gases that have been shown to contribute to the phenomena called the "greenhouse effect" or the idea that higher rates of certain gases in the atmosphere are causing a gradual rise in the planets temperature. Common greenhouse gases are gases that are generally released through the burning of fossil fuels. These fuels include carbon dioxide (co2), methane (CH4), Nitrous Oxide (N2o), CFCS, and Water Vapor (H2o).