Recall that water, CFCs, CO₂, and N₂O are all greenhouse gases that can absorb IR in the atmosphere. You may have heard about CO₂ in the media as a prominent greenhouse gas, but is it really more powerful than others?

In order to understand the impact of a greenhouse gas, there are three factors we must consider:

1. The lifetime of the gas molecules in the atmosphere before they are broken down or removed in some other way from the atmosphere.
2. The concentration of the gas in the atmosphere.
3. The region of IR that the gas absorbs and how strongly the gas absorbs IR, relative to the emission spectrum of the Earth (if a gas absorbs IR in a different region than the Earth emits, it may not cause atmospheric warming).