Carbon Footprint:
What does kg CO2e mean?

The term stands for kilograms of carbon dioxide equivalent. It is a standard unit used to measure the “carbon footprint” of different activities or products in a way that allows for a fair comparison. ¹

What the “e” means (e= equivalents)

Carbon dioxide is not the only greenhouse gas. Others, like methane (common in livestock farming) and nitrous oxide (common in fertiliser use), are actually much more powerful at trapping heat than CO2. ²

To make data easier to read, scientists convert the impact of all these different gases into the amount of CO2 that would cause the same amount of warming. ³

• 1 kg of Methane is roughly equal to 28 kg CO2e. ⁴
• 1 kg of Nitrous Oxide is roughly equal to 265 kg CO2e. ⁴

Why it is used in our audit

In the table above, the kg CO2e value tells you the total global warming impact of producing that 100g of flour—from the fertiliser sprayed on the field to the energy used by the mill—all condensed into one single, comparable number. ⁵

Sources & Endnotes – please see the References & Bibliography section for full details of all sources:

1. National Grid – What is CO2e? (www.nationalgrid.com)
2. EPA – Understanding Global Warming Potentials (www.epa.gov)
3. Climate Neutral Group – CO2 vs CO2e (www.climateneutralgroup.com)
4. IPCC – AR6 Greenhouse Gas Metrics (www.ipcc.ch)
5. Our World in Data – Environmental Impacts of Food (ourworldindata.org)