Global warming potential

Common card · No. 203049

Global warming potential (GWP) is a measure of how much heat a greenhouse gas (GHG) traps in the atmosphere over a specific time period, relative to carbon dioxide (CO2). It is a dimensionless quantity expressed as a multiple of warming caused by the same mass of CO2. Therefore, by definition CO2 has a GWP of 1. For other gases, it depends on how strongly the gas absorbs thermal radiation, how quickly it leaves the atmosphere, and the time frame considered. For example, methane (CH4) has a GWP over 20 years (GWP-20) of 81.2 meaning that, a leak of a tonne of methane is equivalent to emitting 81.2 tonnes of CO2, both measured over 20 years. As methane has a much shorter atmospheric lifetime than CO2, its GWP is much less over longer time periods, with a GWP-100 of 27.9 and a GWP-500 of 7.95. Greenhouse gas emissions (GHG emissions) can be expressed in terms of carbon dioxide equivalent mass or just carbon dioxide equivalent (symbolized CO2e or CO2eq, also denoted CO2-e or CO2-eq) can be...

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