Why Scope 3 is mostly guesswork — and how to fix it

For most manufacturers, Scope 3 — the emissions in your supply chain — is the largest part of the footprint, often 70–90%. It is also the least accurate, because it is almost always estimated rather than measured.

The estimation problem

The common method is spend-based: multiply how much you spent on a material by an average emission factor. It is easy, but the uncertainty is huge — error bands of ±50% or more are normal. A number with that much uncertainty is hard to defend to a regulator and easy for a competitor to undercut.

The fix everyone agrees on is primary data: use the supplier’s own measured Scope 1 + 2 emissions for the goods you bought. The problem has always been getting that data reliably.

From estimate to verified

When a supplier measures and anchors its real emissions, you can use that verified number directly instead of an industry average — and your Scope 3 stops being a guess. The more of your spend that is backed by primary, supplier-specific data, the lower your uncertainty and the stronger your position with auditors and customers.

A practical target is to cover your largest categories first: a handful of suppliers often accounts for most of your Scope 3.

What to do now

Start collecting primary, supplier-specific data for your biggest categories, keep a tamper-evident trail, and prefer partners whose data can be independently verified. That is the foundation RecoChainAI builds on.