Global Warming Potential

Definition

• Global Warming Potential (GWP) is a metric that compares the climate impact of different greenhouse gases (GHGs) relative to carbon dioxide (CO₂), which has a GWP of 1.

• It measures how much heat a gas traps in the atmosphere over a specific time horizon (typically 20, 100, or 500 years).

Key Factors Influencing GWP

• GWP depends on:

  • Radiative efficiency: how strongly the gas absorbs infrared radiation.

  • Atmospheric lifetime: how long the gas remains in the atmosphere.

• Gases with high radiative efficiency and long lifetimes have higher GWPs.

Examples of GWP Values (100-Year Horizon)

Gas - GWP (AR6, 100 years)

Carbon dioxide (CO₂) - 1

Methane (CH₄) - 27–30

Nitrous oxide (N₂O) - 273

HFC-134a - 1,530

SF₆ (Sulfur hexafluoride) - 24,300

These values are used in climate policy and emissions reporting.

Use in Policy and Reporting

• GWP is central to:

  • GHG inventories (e.g., national emissions reports).

  • Carbon footprint calculations.

  • Environmental Product Declarations (EPDs).

• International agreements like the Kigali Amendment use GWP to phase down high-impact gases like HFCs.

Limitations and Alternatives

• GWP does not account for temperature change timing or feedback effects.

• Alternatives include:

  • Global Temperature Potential (GTP): measures temperature change at a specific time.

  • CO₂-equivalent (CO₂e): converts emissions of any gas into the equivalent amount of CO₂ based on GWP.