There are several different greenhouse gases (e.g. methane, (click here for full list of GHG’s)) as well as carbon dioxide and each has a different strength of effect on global warming. Carbon dioxide equivalent takes into account the different global warming potential of different greenhouse gases and expresses the cumulative effect in a common unit.

Carbon dioxide equivalent is calculated by multiplying the actual mass of emissions by the appropriate Global Warming Potential (GWP) factor. This enables emissions of different gases to be added together and compared with carbon dioxide.