what are anthropogenic sources of greenhouse gases
The primary anthropogenic sources are combustion of fossil fuel, and the decomposition of organic materials associated with wetlands, rice paddies, and livestock manure. Nitrous oxide also occurs in low concentrations relative to carbon dioxide, but it is 230 times more efficient as a greenhouse gas. These factors combine to make it a 6% contributor to total the greenhouse effect. The primary anthropogenic sources are fossil fuel combustion, fertilizers, and deforestation. The only major greenhouse gases that are not naturally occurring are the chlorofluorocarbons. They come solely from anthropogenic sources such as the production and/or use of foams, aerosols, refrigerants, and solvents. They are present at an extremely low concentration in the atmosphere, however they are 15,000 times more efficient as a greenhouse gas relative to carbon dioxide.