You walk into verification with the record, not a spreadsheet. The auditor never asks "what is the number"; they ask "where did the number come from". If you can answer, you have a calculation. If you cannot, you have a claim. The difference between the two is called the chain of evidence.
The four links
- The activity record. Fuel, electricity, raw materials: how much, where, when. No record, no calculation.
- The emission factor, with its version. Which factor, which version, multiplied with which GWP set? A number without a version is that year's fashion.
- Supplier data. Scope 3 inputs live in a record that says whose they are and when they arrived — not in an inbox.
- The edit and export trail. Who changed the figure, when, and what left the building in which format. The chain is kept around the number's history, not the number.
Where the chain snaps
It usually snaps at a single link: the unversioned factor. A factor that was right three years ago is still in the maths today and nobody notices, because where the factor lives was never written down. Or supplier data: "it was in an email," and the email is gone.
We build this chain on UpcyCarbon: each emission links to an activity record, a factor and a GWP set, and edits and exports are both recorded with who made them and when. Product footprints come out in an EPD-ready structure, aligned with openLCA. What opens in the audit is not a spreadsheet. It is the chain itself.
