Your Customer Asked for Carbon Data: What to Do

A customer asking for carbon data almost always wants the same core thing: a credible greenhouse-gas (GHG) footprint, calculated to a recognised standard, that they can fold into their own supply-chain emissions. The wrapper varies — a CDP questionnaire, an EcoVadis assessment, a Carbon Reduction Plan attached to a tender, or a spreadsheet emailed by a procurement team — but the underlying ask is consistent. Work out which of these you have actually been sent, respond proportionately, and don't panic: most first-time requests are answerable with a Scope 1 and 2 footprint and a short published plan.

Key takeaways

• Whatever form the request takes, it rests on a GHG Protocol footprint — Scope 1, 2 and increasingly Scope 3. Get that right once and it feeds every channel.
• The four most common channels are CDP, EcoVadis, a public-sector Carbon Reduction Plan (PPN 006 or NHS), and the buyer's own supplier questionnaire.
• The driver is your customer's Scope 3: supply-chain emissions are on average 11.4 times larger than a company's direct operations, so they cannot hit their targets without your numbers.
• Deadlines are real and current: CDP's 2026 scoring deadline is 16 September 2026, and NHS Supply Chain now requires suppliers to reach Evergreen Level 1 from April 2026.
• You rarely need everything at once. A Scope 1 and 2 footprint plus a short plan answers most first requests; build toward Scope 3 from there.

Why is my customer asking for carbon data?

Because they are under the same pressure, one tier up. Almost every large buyer now reports its own emissions, and the biggest number on that report is Scope 3 — the emissions in its supply chain. On average those supply-chain emissions are 11.4 times larger than a company's direct operations, so a buyer simply cannot show progress without data from suppliers like you.

Three forces turn that into an email in your inbox. First, science-based targets: if a customer has set an SBTi supplier engagement target, it has publicly committed that suppliers covering a chosen share of its Scope 3 — SBTi's near-term rules require a company's Scope 3 targets to cover at least 67% of its total Scope 3 emissions — will set their own targets, and it has five years to make that happen. SBTi released its Corporate Net-Zero Standard V2.0 on 11 June 2026, keeping supplier engagement central, so this pressure is intensifying, not easing. Second, disclosure programmes: through CDP Supply Chain, more than 270 corporate buyers request environmental data from suppliers, and around 45,000 suppliers were asked to disclose in 2025. Third, public procurement, where carbon plans are a formal condition of bidding.

None of this is personal. You are downstream of a target your customer has to meet, and your data is the missing piece.

Which request have you actually received?

Before you respond, identify the request precisely — the effort, cost and deadline differ sharply between them.

Request	Where it arrives	What it really needs
CDP disclosure	CDP Portal invitation from a buyer	Questionnaire response; admin fee; footprint data
EcoVadis assessment	EcoVadis platform invitation	Evidence across four themes, including GHG management
Carbon Reduction Plan	A public-sector tender (PPN 006 / NHS)	Published CRP: Scope 1, 2 and five Scope 3 categories
Supplier questionnaire	Spreadsheet or portal from the buyer	Scope 1 and 2, target status, emissions allocated to them

A CDP disclosure request

You receive this in the CDP Portal and can accept or decline. Since 2025, every disclosing company — including suppliers responding to a customer request — must pay a CDP admin fee before submitting; UK 2026 fees start at £2,450 for the Foundation tier, up around 5% on the year. To count for scoring you must submit by 16 September 2026. The good news for smaller suppliers: there is a dedicated SME questionnaire, now in its second year, and for the first time in 2026 SMEs can achieve an A score. CDP has also renamed its Supplier Engagement Rating the Supplier Engagement Assessment, which scores how well companies engage their own suppliers.

An EcoVadis assessment

EcoVadis rates you across four themes — Environment, Labour & Human Rights, Ethics, and Sustainable Procurement — with your carbon work sitting inside Environment. Medals are percentile-based: Bronze is roughly the top 35% of assessed companies, Silver the top 15%, Gold the top 5% and Platinum the top 1%, and any medal requires at least 30 out of 100 in every theme. EcoVadis also runs a separate Carbon Rating (methodology v2.0 in force from January 2026) that grades your GHG management from Insufficient to Leader. Documented measurement to the GHG Protocol is what moves the Environment score — vague commitments do not.

A Carbon Reduction Plan for a public-sector tender

If you are bidding for government or NHS work, the request is usually for a published Carbon Reduction Plan (CRP). For major central-government contracts this is governed by PPN 006, which replaced PPN 06/21 in February 2025 to align with the Procurement Act 2023 and applies above £5 million per year; the CRP requirements themselves are unchanged. A compliant plan covers Scope 1, Scope 2 and five defined Scope 3 categories, commits to UK net zero by 2050, carries board-level sign-off and is published on your website.

The NHS goes further and faster. Since April 2024 it has required a published CRP for all new procurements, applied proportionately rather than only above £5 million. NHS Supply Chain now requires suppliers to complete the Evergreen sustainable supplier assessment and reach at least Level 1 from April 2026. And from April 2027 the CRP must cover all relevant global Scope 1, 2 and 3 emissions — so if you supply the NHS, build with that horizon in mind rather than doing the minimum twice.

A buyer's own supplier questionnaire

Plenty of buyers skip the platforms and send their own spreadsheet. SBTi's supplier guidance lists what these typically ask for: whether you have a reduction target and its boundary and coverage, your annual Scope 1 and 2 emissions by source, the emissions allocated to that customer, your calculation methodology, Scope 3 by category where available, product-level footprint data if you have it, and how much of your data is third-party verified. It looks like a lot, but nearly all of it falls out of one underlying exercise.

What every one of these actually needs: a footprint

Here is the reassuring part. CDP, EcoVadis, a PPN 006 CRP and a bespoke questionnaire are four different front doors to the same building. Every one of them stands on a GHG Protocol-aligned footprint — your Scope 1 and 2 emissions to start, then the Scope 3 categories that matter to your buyers. Measure once, properly, and you can pour the same numbers into whichever format lands next.

That footprint is the service we provide. We have built GHG footprints for organisations since 2007, and our carbon reporting service produces the Scope 1, 2 and 3 numbers, methodology notes and DEFRA-factor calculations that underpin a disclosure or a plan. To be clear about the boundary: we don't file CDP for you, sit your EcoVadis assessment or validate science-based targets on your behalf — but each of those rests on a credible footprint, and that is exactly what we build. If you are starting from scratch, our guide to calculating your business carbon footprint walks through the whole process, and if the request specifically wants supply-chain numbers, how to start with Scope 3 covers the hardest part.

How to respond without over-committing

A calm, staged response beats either panic or silence.

1. Log the request and its deadline. Note which channel it is, what is actually being asked, and the real cut-off — CDP's scoring deadline and a tender's submission date are not negotiable.
2. Reply, even if the answer is "not yet fully". Declining silently is the worst option; buyers increasingly record non-response in supplier reviews. Acknowledging the request and sharing what you have keeps you in the running.
3. Build the footprint first. Scope 1 and 2 are quick once you have energy bills, fuel and travel records; add the Scope 3 categories your buyer names. This single dataset answers most of every questionnaire.
4. Publish a short plan. For public-sector work, a published CRP with board sign-off is the deliverable. For private buyers, a one-page reduction plan alongside your numbers is usually enough for a first pass.
5. Keep it current. PPN 006 expects CRPs to be reviewed within six months of your financial year-end, and CDP and EcoVadis run annually — treat this as a yearly cycle, not a one-off.

The bottom line

A carbon data request is a buying signal, not a threat. It means a customer wants to keep working with you and needs the numbers to justify it internally. Answer the specific request in front of you, but invest in the footprint underneath — because the same measured data satisfies CDP, EcoVadis, a PPN 006 plan and the next buyer's spreadsheet, and the requests are only going to get more detailed from here.