Greenhouse gases differ regarding their residence time in the atmosphere and also in their global warming potential, which describes the relative contribution to the greenhouse effect and thus to global warming. As the majority of the anthropogenic greenhouse effect is caused by CO2, the impact of the other greenhouse gases is given in comparison to CO2. For this purpose, the greenhouse gas potential (GWP) of different greenhouse gases is compared with each other using the unit CO2 equivalent (CO2eq). The table shows that other greenhouse gases contribute relatively more to global warming than CO2, but occur in significantly lower concentrations in the atmosphere.

 

There are different sources for anthropogenic generation of greenhouse gases. CO2 is mostly emitted due to combustion processes of fossil energy carriers, such as coal, oil and natural gas. In addition, forestry and land use change also contribute to the anthropogenic greenhouse effect caused by CO2 emissions. CH4 originates from rice fields, cattle farming and landfills or is emitted during exploitation of fossil energies, e.g. natural gas production/extraction. Nitrous oxide (sometimes called laughing gas) mainly forms due to the excessive use of nitrogenous fertilizers in agriculture. Hydrofluorocarbons – mainly used as refrigerants – are the successors of Chlorofluorocarbons which have already been banned by the Montreal Protocol.