A metric measure used to compare the emissions from various greenhouse gases, based upon their global warming potential (GWP). Carbon dioxide equivalents are commonly expressed as “million metric tons of carbon dioxide equivalents” (MMTCO2e ). The carbon dioxide equivalent of a gas is derived by multiplying the metric tons of the gas by the associated GWP.

MMTCO2e = (million metric tons of a gas) x (GWP of the gas)