Building a SHA-256 audit trail for emission factor provenance in WordPress

Carbon accounting tools have a trust problem that most developers don't think about until it's too late. A sustainability officer files a CSRD disclosure. An auditor asks: "Where does this emission factor come from?" The tool says 2.57 kg CO₂e/litre for diesel. The auditor wants the source workbook, the specific tab, the row number, and the date someone verified the cell against the published file. Without that, the number is a claim, not evidence. Most carbon platforms can't answer that questio