Global Warming Potential (GWP) is best described as:

• A. It measures the relative heat-trapping effect of a substance.
• B. It indicates the odor threshold of a substance.
• C. It describes the relative heat-trapping potential of a gas compared to carbon dioxide.
• D. It tracks fuel efficiency of refrigerant systems.

Answer: (C)

Global Warming Potential measures how much heat a greenhouse gas traps in the atmosphere relative to carbon dioxide over a specified time horizon. The best description is that it describes the relative heat-trapping potential of a gas compared to carbon dioxide, because carbon dioxide serves as the reference with a GWP of 1 and other gases are scaled against it. This metric combines how strongly a gas absorbs infrared radiation (radiative efficiency) with how long it stays in the atmosphere (lifetime), and the chosen time horizon (commonly 100 years) influences the numeric value. The odor threshold or fuel efficiency of systems aren’t related to GWP, so those options don’t describe what GWP measures.