Companies are spending more time, money, and organizational energy on Scope 3 reporting than ever before. And yet, for most of them, the emissions that end up in their carbon footprint depends on something rarely examined closely: the quality of data their suppliers are actually providing.

‍

That gap matters more than most people realize, and it's widening.

‍

The hidden weakness in most Scope 3 reports

‍

When a company doesn't have verified emissions data from a specific supplier, the standard fallback is a sector-average spend-based factor. You take what you spent with a supplier, apply an industry-level emissions intensity figure, and arrive at an estimated footprint for that relationship.

‍

It works, but it's a blunt instrument.

‍

Sector averages don't distinguish if a supplier is running on renewable energy or is proactively working to decarbonize their business. They don't reflect efficiency improvements a supplier has made, and don't account for the specific mix of goods and services you're actually buying.  

‍

They are, by definition, an estimate of an estimate. And for companies facing regulatory scrutiny, investor questions, or procurement decisions tied to emissions performance, that's a real liability.

What a usable supplier factor requires

‍

Supplier-specific emission factors solve this problem, but only if they're built to a consistent standard. Not every submission that arrives with a carbon figure attached is ready to use.

‍

At Green Project, we require two things before a supplier-specific factor enters our database.

‍

1. Full scope coverage

• That means Scope 1, Scope 2, and upstream Scope 3; many suppliers calculate a narrower boundary for other reporting purposes.  

• We support suppliers to fill those gaps rather than accepting an incomplete baseline.

‍

2. No downstream Scope 3

• Including downstream emissions in a supplier-specific factor would effectively double-count them, since they're already captured in the purchasing company's own reporting. We exclude them deliberately.

‍

Why human review is non-negotiable

‍

At Green Project, every supplier submission goes through a data quality review before it's approved. Examples of the sorts of checks the we perform are:

‍

1. Industry benchmarking

• If a supplier's emissions intensity looks unusually low or high relative to their industry, that's a flag.  

• It might mean they're genuinely more efficient than their peers, or it might mean that something is missing. Either way, it warrants investigation.

‍

2. Coverage verification

• We confirm that Scope 1, Scope 2, and upstream Scope 3 are all included in the footprint calculation.  

• For any categories not included, we confirm that this is intentional because the category is not relevant for the company in question.  

‍

3. The implied margin check

• We compare the supplier's total reported spend against their revenue to back out an implied gross margin.  

• If that margin looks unreasonable, it signals the spend data may be incomplete, which means the resulting footprint won't reflect the supplier's actual operations.

‍

4. Component check

• We verify that the core emissions categories are present: energy, electricity, purchased goods and services.  

• These typically drive the majority of emissions for most businesses, and their absence requires an explanation.

‍

Getting these right requires judgment, context, and familiarity with how real companies report. That's why we've kept humans in this loop deliberately.

‍

What the number in your report represents

‍

Here's where the difference becomes tangible.

‍

Take a supplier with 12,000 tCO2e of upstream emissions on $200 million in revenue. Their emissions intensity is 60 tCO2e per $1 million of revenue. A customer spending $5 million with them can calculate 300 tCO2e for that relationship with confidence.

‍

A sector-average factor of 85 tCO2e per $1 million would have estimated 425 tCO2e for the same relationship. That's an overstatement of more than 40%.

‍

That gap is the difference between a footprint that reflects your actual supply chain and one that reflects your industry's average. For a company with dozens of significant supplier relationships, those gaps compound.

‍

A reviewed, approved supplier-specific factor gives you specific, accurate data that can withstand scrutiny from regulators, investors, and internal stakeholders alike. Just as importantly, you will be able to see and report on the decarbonization action your supplier is taking.  

‍

The path forward

‍

Scope 3 reporting is only becoming more scrutinized. The companies that will be in the strongest position are those who start treating supplier data quality as a core part of their carbon accounting practice now, not after their methodology gets questioned.

‍

At Green Project, our supplier-specific factor process is built around that principle. If you want to understand how it works in practice, or explore how your supplier data stacks up against our standards, we'd be glad to walk you through it.

‍