Supplier emissions data collection and engagement

Supplier emissions data is the weakest link in most corporate inventories, and it is now demanded by several parties at once: CSRD value-chain disclosures, SBTi scope 3 targets, customer questionnaires and lender due diligence. The awkward part is ownership. Procurement controls the supplier relationship and the contract, sustainability owns the method, and finance often owns the spend data used as a fallback. Programmes fail when those three groups run separate spreadsheets.

Suppliers respond in whatever form they have. Some provide verified product footprints, some return a completed questionnaire with a company-level figure, some provide an invoice or production volume, and many do not respond at all. Each answer sits at a different quality tier and uses a different boundary, unit and reference year. The GHG Protocol Scope 3 Standard defines the 15 categories these answers must eventually populate, but it does not decide which supplier should be asked what, or how an estimate improves over time.

Failures are predictable. Every supplier receives the same questionnaire regardless of materiality, nobody chases non-responders, responses cannot be mapped to scope 3 categories without manual work, estimated and measured values are mixed without flags, and suppliers never see what happened to the data they submitted. Response rates stall in the second year and the programme loses credibility internally.

Evaluate tools on category mapping, data-quality tiers and estimation hierarchy, chasing and escalation, questionnaire flexibility, supplier feedback and an audit trail that survives assurance.