CO2-equivalent

An entity that compares emissions of different greenhouse gases to the global warming effect that the emission of one tonne of CO2 will have over 100 years. Other greenhouse gases sometimes have a much stronger warming effect than CO2. For example, one tonne of methane has the same greenhouse effect as 21 tonnes of CO2, while one tonne of fluorinated gas SF6 is equivalent to 23,900 tonnes of CO2.