Co2e

CO₂e (Carbon Dioxide Equivalent)

A carbon dioxide equivalent (CO₂e) is a standardized measure used to compare the emissions of different greenhouse gases (GHGs) based on their Global Warming Potential (GWP). It expresses the impact of each gas in terms of the amount of carbon dioxide (CO₂) that would have the same warming effect on the atmosphere.

What does CO₂e mean?

Different greenhouse gases, such as methane (CH₄), nitrous oxide (N₂O), and fluorinated gases (F-gases), have varying abilities to trap heat in the atmosphere. To make these comparable, their emissions are converted into CO₂ equivalents using the GWP of each gas. This allows scientists and companies to aggregate total emissions under a single metric — the CO₂e value.

How is CO₂e calculated?

The CO₂e value of a gas is calculated by multiplying its emitted mass by its Global Warming Potential (GWP):

CO₂e (in metric tonnes) = mass of gas (in tonnes) × GWP of the gas

CO₂ equivalents are often expressed as million metric tonnes of carbon dioxide equivalents (MMTCDE), a common unit for reporting national or corporate greenhouse gas inventories.

Why is CO₂e important?

Using CO₂e provides a unified way to:

• Compare the climate impact of different GHGs
• Communicate total emissions clearly in sustainability reports
• Track Scope 1, 2, and 3 emissions consistently across the value chain
• Support carbon accounting and Product Carbon Footprint (PCF) calculations

In sustainability and carbon accounting, CO₂e is essential for accurately measuring, comparing, and reducing emissions across products, companies, and entire supply chains.