What is CO₂e?

What is CO₂e?

CO₂e (Carbon Dioxide Equivalent) is a standardized metric used to express the impact of various greenhouse gases (GHGs) in terms of the warming potential of carbon dioxide (CO₂). It provides a way to compare and quantify the effects of different gases within a single, consistent framework.

Key Greenhouse Gases Included in CO₂e

• Carbon Dioxide (CO₂): The baseline gas with a Global Warming Potential (GWP) of 1.
• Methane (CH₄): A potent greenhouse gas with a GWP of approximately 25-30 over 100 years, meaning 1 ton of CH₄ is equivalent to 25-30 tons of CO₂e.
• Nitrous Oxide (N₂O): A highly potent gas with a GWP of approximately 265-298 over 100 years, meaning 1 ton of N₂O is equivalent to 265-298 tons of CO₂e.

How Does It Work?

When a project reduces or avoids emissions of CH₄ or N₂O, those reductions are converted into CO₂e using their GWP. For example:

• Reducing 1 ton of CH₄: Equivalent to 25-30 tons of CO₂e. The project earns 25-30 carbon credits (if verified).
• Avoiding 1 ton of N₂O: Equivalent to 265-298 tons of CO₂e. The project earns 265-298 carbon credits.
• Capturing 1 ton of CO₂ directly: Equals 1 ton of CO₂e. The project earns 1 carbon credit.

Why Use CO₂e?

• Standardization: CO₂e allows all GHG reductions to be expressed in a single unit, simplifying comparison and trading.
• Inclusion of Non-CO₂ Gases: Ensures potent gases like CH₄ and N₂O are accounted for, even though they are less prevalent than CO₂ in total emissions.
• Practicality for Carbon Markets: Using CO₂e enables seamless integration of diverse projects (e.g., reforestation, methane capture, fertilizer management) into the same marketplace.

Summary

CO₂e is a unified metric that includes reductions of CO₂, CH₄, N₂O, and other greenhouse gases. Each gas's warming effect is weighted by its GWP relative to CO₂. Whether a project reduces CO₂, CH₄, or N₂O, its climate impact is translated into CO₂e for carbon credit accounting. This framework ensures that all GHG reductions, regardless of the gas, contribute equitably to climate mitigation efforts.