A Supplier Carbon Questionnaire Just Arrived From the Biggest Customer — Here Is How to Respond With No Existing Data

A supplier carbon questionnaire is not a test of how much carbon has been reduced.

It is a test of whether emissions have been measured, documented, and disclosed at all.

That distinction matters enormously for any supplier receiving one for the first time with no prior data. The questionnaire is not asking for a perfect carbon programme — it is asking for evidence that measurement has started, boundaries have been defined, and data sources have been documented. 56% of suppliers currently struggle to provide the necessary emissions data their corporate customers request — yet many of those same suppliers could build a credible first response in four to six weeks using data they already hold.

The gap between no data and a submittable response is smaller than it appears. Here is exactly how to close it.

Not all supplier carbon questionnaires are the same. Before collecting a single data point, identify the specific platform or framework the customer is using — because each has different questions, different scoring logic, and different evidence requirements.

The three most common formats a supplier will encounter are:

The questions across platforms are more similar than they appear. When EcoVadis asks "Do you have an environmental policy?" and CDP asks "Does your company have a climate change policy?" and a customer's custom questionnaire asks "Have you documented environmental commitments?" — they all want the same evidence. Understanding this overlap is what makes an efficient first response possible.

Most supplier carbon questionnaires ask for three distinct types of carbon data, and confusing them is where first responses most commonly fail.

Many first-time questionnaire responses fail because the supplier conflates corporate-level Scope 1 and 2 data with product-level PCF data. They are different calculations, use different methodologies, and serve different purposes. Confirming which the customer actually needs before beginning any calculation prevents wasted effort.

For a first response with no prior data, Scope 1 and Scope 2 are the right starting point. They are faster to calculate, require only internal operational data, and form the foundation that all other carbon disclosures build on.

Multiply each fuel or energy quantity by the appropriate emission factor from a recognised database. The EPA supply chain questionnaire serves as a simple way to collect emissions-specific information from suppliers — and information reported in response can also be leveraged to complete aspects of other questionnaires, such as CDP. The EPA publishes emission factors for all common fuel types used in US operations.

For an initial Scope 1 and 2 calculation, a spreadsheet is sufficient. What it does require is documented data sources — invoice references, meter readings, or consumption logs — so that the figures can be traced back to primary evidence if questioned.

Companies may be expected to meet a specific scoring threshold to maintain preferred vendor status, or be expected to remediate a poor score or a specific gap in performance. Submitting a questionnaire without supporting documentation typically scores lower than submitting with partial data but strong evidence.

The minimum evidence set for a first carbon questionnaire response includes:

Even small steps — like adding an ESG clause to purchase orders or tracking electricity usage but not full emissions — can contribute to an EcoVadis score. If truly no practices are in place for a question, selecting 'not in place' where available is better than guessing or overstating.

Every first-time response will have gaps. The correct approach to unanswerable questions is transparency, not avoidance.

Approach the questionnaire systematically, focus on data quality over perfection, and treat it as infrastructure investment rather than compliance burden.

Several common first-response mistakes actively harm a supplier's questionnaire score and credibility.

If questionnaires are being received from multiple customers, resist the temptation to treat each as a one-off project. Create a master document mapping common questions to evidence. The questions are more similar than they appear across platforms.

The Scope 1 and Scope 2 inventory built to answer this questionnaire is the same baseline needed for next year's questionnaire, for internal reduction target-setting, for any future PCF calculation, and for regulatory disclosure if supply chain transparency requirements expand. Building supplier relationships and data infrastructure takes 12–18 months minimum. The first questionnaire response is not a one-time task — it is the beginning of a data programme that compounds in value over subsequent years.

The evidence library — policy documents, emissions calculations, data quality statements — becomes reusable across CDP, EcoVadis, custom questionnaires, and any future certification or verification process. Investing in building it properly the first time eliminates the scramble at every subsequent request.