GWP

Global warming potential (GWP) is a measure of how much heat a greenhouse gas traps in the atmosphere over a specific time period, relative to carbon dioxide. 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 the gas leaves the atmosphere, and the time frame considered.