Glossary:Carbon dioxide equivalent

A carbon dioxide equivalent or CO₂ equivalent, abbreviated as CO₂-eq is a metric measure used to compare the emissions from various greenhouse gases on the basis of their global-warming potential (GWP), by converting amounts of other gases to the equivalent amount of carbon dioxide with the same global warming potential.

Carbon dioxide equivalents are commonly expressed as million metric tonnes of carbon dioxide equivalents, abbreviated as MMTCDE.

The carbon dioxide equivalent for a gas is derived by multiplying the tonnes of the gas by the associated GWP:

MMTCDE = (million metric tonnes of a gas) * (GWP of the gas).

For example, the GWP for methane is 25 and for nitrous oxide 298. This means that emissions of 1 million metric tonnes of methane and nitrous oxide respectively is equivalent to emissions of 25 and 298 million metric tonnes of carbon dioxide.

Related concepts

• Carbon dioxide emissions
• Climate change
• Global-warming potential (GWP)
• Greenhouse gas (GHG)

Statistical data

• Greenhouse gas emission statistics

Source

• European Environment Agency - Glossary, based on: IPCC Third Assessment Report, 2001