Global Warming Potential (GWP) is a common scale for the comparison of the warming impact of different greenhouse gases in the time span of most commonly 100 years, based on their potency and longevity.
GWP is calculated in Carbon Dioxide Equivalents (CO2e) with carbon dioxide as the reference unit. For example, methane (CH4) absorbs more radiation per kilogram but stays in the atmosphere for a shorter time than CO2 (the reference unit) and its GWP is 28-34; nitrous oxide (N20) is more powerful and stays in the atmosphere longer than CO2 and its GWP is 265-298. GWP is updated regularly to reflect new research and the current concentration of greenhouse gases.