Definitions for "Carbon Dioxide Equivalent"
The amount of carbon dioxide by weight emitted into the atmosphere that would produce the same estimated radiative forcing as a given weight of another radiatively active gas. Carbon dioxide equivalents are computed by multiplying the weight of the gas being measured (for example, methane) by its estimated global warming potential (which is 21 for methane). "Carbon equivalent units" are defined as carbon dioxide equivalents multiplied by the carbon content of carbon dioxide (i.e., 12/44).
Different greenhouse gases have different levels of impact on global warming. Emissions of greenhouse gases are often measured in CO2 equivalents. A tonne of each individual greenhouse gas is adjusted to be expressed in terms of how many tonnes of CO2 would be needed to produce the same global warming impact over 100 years.
A measure used to compare different greenhouse gases based on their contribution to climate change. The UNFCCC currently (2005) uses global warming potentials (GWPs). The GWPs are calculated as the ratio of the radiative forcing of one kilogram of greenhouse gas emitted to the atmosphere to that of one kilogram of CO2 over a period of time (100 years).