The attached nine primers on prominent greenhouse gases (GHG) (or sets of GHG) are intended to give the reader basic information on (i) the relevant gas, (ii) how things have changed since preindustrial times, (iii) whether the gas is susceptible to emissions reduction or removal from the atmosphere and (iv) how that might be done.

CO₂ naturally occurs on Earth due to decomposing vegetation and biomass, natural wildfires, as well as erupting volcanoes both on land and in the oceans (outgassing). CO₂ is also anthropogenically produced, through power generation, transportation (vehicle exhaust), fossil fuel combustion, chemical production, and agricultural practices

Methane is a naturally occurring gas which can come from natural wetlands, oceans, termites, volcanoes, wildfires, and freshwater bodies. Like CO2, a large majority of methane is produced anthropogenically, from sources such as landfills, oil and natural gas systems, agricultural practices, wastewater treatment centers, and stationary combustion processes.

Nitrous oxide (N₂O) is both naturally and anthropogenically sourced. Naturally, N₂O predominantly comes from the breakdown of nitrogen in the ocean and in soils. More frequently, N₂O is found via anthropogenic sources such as fertilized fields, fossil fuel combustion, and sewage. Agriculture is the most impactful sector as it accounts for 74% of nitrous oxide emissions.

Water vapor is the most abundant (and one of the most powerful) greenhouse gas. 

Ozone is created when VOC (volatile organic compounds) and NOx (oxides of nitrogen) combine in sunlight, making it a secondary pollutant.

NF₃ is another example of an anthropogenic gas. It is a newly discovered resource in the electronics industry used for computer chips, LCD flat-screens, and solar photovoltaics.

Sulfur hexafluoride (SF₆) is unique because it is only sourced anthropogenically. There are no known natural sources of SF₆. It is a stable, fluorinated compound, indicating it has a long atmospheric lifespan.

Both CFCs and HCFCs contain fluorine, chlorine, and carbon. The difference is that hydrogen is found in HCFCs (not CFCs). Both CFCs and HCFCs have natural and anthropogenic sources, they are mostly used in air conditioners, aerosol propellants, and refrigeration. Only 16% of emittances are natural (from volcanoes and oceans).

Carbon tetrafluoride (CF₄) and hexafluoroethane (C₂F₆) are both perfluorocarbons (PFCs). There have been no identified natural sources of CF₄; all carbon tetrafluoride comes from the smelting of alumina in the process of producing aluminum.

The attached nine primers on prominent greenhouse gases (GHG) (or sets of GHG) are intended to give the reader basic information on (i) the relevant gas, (ii) how things have changed since preindustrial times, (iii) whether the gas is susceptible to emissions reduction or removal from the atmosphere and (iv) how that might be done.