Which greenhouse gas is most directly compared to other gases in terms of global warming potential?

Carbon dioxide is the reference gas for measuring global warming potential (GWP) because it is the most prevalent greenhouse gas emitted by human activities and serves as the baseline against which the effects of other greenhouse gases are compared. Its GWP is defined as one, and other gases are assessed in relation to this standard.

For instance, methane has a GWP of 25 over a 100-year period, meaning it has a much stronger heat-trapping ability in the atmosphere than carbon dioxide, but it is less abundant. Nitrous oxide is also much more effective at warming the Earth than carbon dioxide, with a GWP of 298, yet it is not produced in as large quantities. Chlorofluorocarbons (CFCs) are used in refrigeration and aerosol propellants, and they have very high GWPs, but their application has been limited due to international agreements like the Montreal Protocol.

In essence, while all these gases significantly contribute to the greenhouse effect, carbon dioxide is the baseline for GWP comparisons, making it the most directly comparable greenhouse gas in this context.