Emission factor methodology

Two emission factors for the same activity can differ because they answer different questions: a different IPCC report, a different stretch of the life cycle, a different electricity mix, a different carbon pool. These pages explain each of those choices once, with a real example from the public libraries and how the data records it.

Pick the page that matches the difference you are looking at. If two numbers disagree, start with system boundaries, GWP values and biogenic carbon, the three most common causes. If you are choosing what to report, read market-based vs location-based electricity and spend-based vs activity-based factors. If you are about to publish or share figures, read licences. If the two numbers differ only in where they were measured, read regions. Each page ends with links into the glossary and, for developers, the matching SQL guide.