A customer has asked your company for carbon emissions data.
Maybe the request arrived by email. Maybe it is part of a supplier questionnaire, procurement portal, tender, or disclosure process.
It might ask for Scope 1, Scope 2, Scope 3, a carbon footprint, calculation methodology, supporting evidence, or some combination of these.
If this is your first carbon-data request, the terminology can make the task look much larger than it actually is.
Do not start by buying software or trying to calculate everything.
Start with a simpler question:
What is the customer actually asking you to provide?
A request for a handful of emissions figures is different from a complete corporate greenhouse-gas inventory. And both are different from a product carbon footprint.
This guide shows you how to decode the request, identify the data you need, find the gaps, and choose a practical next step.
Carbon Request: 60-Second Triage
Before calculating anything, identify:
- Who is asking?
- What reporting period?
- Corporate or product level?
- Which scopes or Scope 3 categories?
- Are estimates acceptable?
- Which methodology?
- Is verification required?
If you cannot answer one of these questions from the request, clarification may be more useful than calculation.
First, identify what your customer actually wants
“Send us your carbon data” is not a sufficiently precise instruction.
Before collecting data or calculating emissions, determine the boundary and type of information being requested.
| If they ask for… | What you should clarify |
|---|---|
| Scope 1 | Direct emissions within the requested organizational boundary |
| Scope 2 | Purchased or acquired electricity, steam, heat or cooling |
| Scope 3 | Which value-chain categories or boundary are required |
| Corporate carbon footprint | Which entities, facilities and reporting period |
| Product carbon footprint | Which product, functional unit and methodology |
| Supplier questionnaire | Which questions, period, evidence and deadline |
| Methodology | Standard, boundaries, factors, assumptions and calculation methods |
| Verification | Whether independent assurance is actually required |
Under the current GHG Protocol Corporate Standard, corporate greenhouse-gas inventories distinguish direct and indirect emissions. The separate Scope 2 Guidance addresses purchased or acquired electricity, steam, heat and cooling, while the Corporate Value Chain (Scope 3) Standard provides a framework for value-chain emissions.
“Carbon footprint” can mean different things
If a customer asks only for your “carbon footprint,” do not assume the boundary.
A useful clarification could be:
- Do you need our corporate footprint or data for a specific product?
- Which reporting year should we use?
- Do you require Scope 1 and Scope 2 only, or Scope 3 as well?
- Is there a required standard or template?
- Are estimates acceptable?
GHG Protocol maintains separate corporate and product-level accounting guidance, so this distinction can materially change the work required.
A carbon-data request does not automatically mean a full Scope 3 inventory
A customer may request:
- Scope 1 and Scope 2 only;
- one or several Scope 3 categories;
- product-specific emissions;
- selected supplier data;
- your existing corporate inventory;
- methodology documentation;
- or answers to a structured disclosure questionnaire.
A complete Scope 3 inventory is a much broader exercise.
The current GHG Protocol Scope 3 framework organizes corporate value-chain emissions into 15 upstream and downstream categories.
But a customer email mentioning carbon does not automatically require you to calculate all 15.
Respond to the requirement actually stated.
The 7 questions to answer before calculating anything
1. Who is asking?
A sustainability team, procurement team, major customer, tender authority or disclosure platform may expect different levels of detail.
Customer-driven supplier requests already occur at significant scale. CDP reports that approximately 45,000 suppliers were requested to disclose through its Supply Chain program in 2025 by more than 270 major buyers. You can learn more through CDP Supply Chain.
2. What reporting period do they want?
Look for wording such as FY2025, calendar year 2025, previous financial year, or most recent reporting year. Do not mix figures from different periods without explaining the difference.
3. Is the request corporate or product-level?
“Provide your company’s Scope 1 and Scope 2 emissions” is fundamentally different from “provide the carbon footprint of Product X.” Confirm the boundary before collecting data.
4. Which scopes or categories are requested?
Highlight every explicit reference to Scope 1, Scope 2, Scope 3 or individual value-chain activities such as purchased goods, transport, waste, business travel or employee commuting.
5. Are estimates acceptable?
You may not have perfect primary data for every requested item. Determine whether the customer accepts calculated estimates, spend-based calculations, industry-average factors, supplier-specific values or other proxy data.
Do not silently mix different data-quality levels.
6. Is a particular methodology required?
The request may name GHG Protocol, a customer-specific method, an industry framework, a product methodology or a disclosure standard. If nothing is specified, document the methodology you choose.
7. Is independent verification required?
There is an important difference between “provide emissions data” and “provide independently verified emissions data.” Do not claim verification or assurance unless it has actually taken place.
Turn the request into a data map
Once the request is clear, map each requested output to the information needed to produce it.
| Request says | Data you may need | First action |
|---|---|---|
| Scope 1 | Fuel, vehicles, refrigerants, direct combustion records | Identify owned or controlled emission sources |
| Scope 2 | Electricity and purchased-energy consumption | Gather bills or meter records |
| Scope 3 purchased goods | Procurement quantities/spend and supplier data | Identify relevant purchases and calculation method |
| Business travel | Flights, rail, hotels and mileage | Obtain travel records |
| Product footprint | Product materials, energy, transport and boundary information | Confirm product methodology first |
| Methodology | Calculation methods, boundaries, factors and assumptions | Document before submission |
| Verification | Assurance statement or verification report | Confirm required assurance level |
This is the point where a vague request becomes a manageable project.
What if your data is incomplete?
Incomplete data does not justify invented precision.
Separate information into:
- Available
- Partial
- Estimated
- Missing
- Needs clarification
For estimated or incomplete information, record the source, reporting period, calculation method, emission factor, assumptions, exclusions and known limitations.
The official GHG Protocol Scope 3 Calculation Guidance provides category-specific calculation approaches and data options rather than one universal method for every value-chain activity.
| Requirement | Status | Next step |
|---|---|---|
| Electricity | Available | Calculate |
| Fleet fuel | Available | Calculate |
| Supplier emissions | Partial | Contact priority suppliers |
| Purchased goods | Spend data only | Select appropriate method |
| Verification | Not available | Clarify whether required |
Worked example: decode the request first
“Please provide Scope 1, Scope 2 and material Scope 3 emissions for FY2025 and describe the methodology used.”
| Requirement | Interpretation |
|---|---|
| FY2025 | Reporting period specified |
| Scope 1 | Required |
| Scope 2 | Required |
| Material Scope 3 | Requested, but “material” may need interpretation |
| Methodology | Required |
| Verification | Not explicitly requested |
Notice what we did not do: calculate anything.
The first step was to transform the sentence into requirements.
SCOPE3ANALYTICS WORKFLOW
The 6-Step Carbon Request Workflow
- 1. Capture — retain the original request, deadline and format.
- 2. Classify — identify the boundary, period, scopes, methodology and evidence requested.
- 3. Map the data — connect every requested output to the source information needed.
- 4. Assess gaps — classify data as available, partial, estimated, missing or unclear.
- 5. Calculate & document — perform the required calculations and retain assumptions, factors and evidence.
- 6. Respond & retain — submit the requested information and archive exactly what was provided.
Do you need carbon accounting software?
Not necessarily.
Software becomes valuable when it solves a process problem — not simply because the word “carbon” appears in a customer email.
| Situation | Sensible starting point |
|---|---|
| One simple request | Controlled spreadsheet/manual workflow |
| Similar requests repeat | Structured template and repeatable process |
| Multiple contributors | Lightweight software may help |
| Recurring multi-entity reporting | Dedicated carbon platform |
| Large supplier or integration requirements | Enterprise platform may be justified |
Signs that your spreadsheet process may be reaching its limit include version conflicts, repeated manual calculations, poor traceability, multiple users, uncontrolled emission factors, integration requirements or increasing assurance needs.
Next: Explore Carbon Accounting Software Intelligence →
Why are customers requesting supplier emissions data?
There is no single reason.
Customers may need supplier information to improve value-chain emissions estimates, supplier engagement, procurement processes, disclosure or environmental risk management.
CDP’s Supply Chain program is a large-scale example of this buyer-supplier relationship: participating buyers request environmental disclosure from suppliers so sustainability, procurement and other teams can better understand their upstream value chain.
This does not automatically mean every supplier receiving a request is independently subject to the same reporting obligation as the customer.
Sometimes you are being asked because your data contributes to someone else’s reporting process.
Related: Explore Supplier Carbon Data →
What should your response contain?
| Area | Include when relevant |
|---|---|
| Reporting context | Year, organizational boundary, entities or facilities |
| Results | Requested emissions and units |
| Methodology | Standard, methods and emission factors |
| Data quality | Actual vs estimated information |
| Assumptions | Proxies and material calculation assumptions |
| Exclusions | What was omitted and why |
| Verification | Actual assurance status |
| Contact | Person responsible for follow-up |
Do not describe data as independently verified unless it actually has been verified.
When should you ask your customer for clarification?
Ask before calculating whenever ambiguous wording could materially change the work.
“When you refer to our carbon footprint, do you require our corporate inventory or a product-specific footprint?”
“Which reporting year should we use?”
“Do you require Scope 1 and Scope 2 only, or specific Scope 3 categories as well?”
“Are estimates acceptable where supplier-specific primary data is unavailable?”
“Is there a required methodology or reporting template?”
“Is independent verification required?”
A short clarification email can prevent an unnecessary carbon-accounting project.
Scope3Analytics Carbon Request Checklist
Request
- ☐ Requester identified
- ☐ Deadline recorded
- ☐ Reporting period confirmed
- ☐ Corporate/product boundary confirmed
- ☐ Scope 1 requirement confirmed
- ☐ Scope 2 requirement confirmed
- ☐ Scope 3 requirement confirmed
- ☐ Relevant Scope 3 categories identified
- ☐ Required methodology identified
- ☐ Verification requirement confirmed
Data
- ☐ Existing data mapped
- ☐ Missing data identified
- ☐ Estimates clearly identified
- ☐ Emission-factor sources recorded
- ☐ Assumptions recorded
- ☐ Exclusions recorded
Response
- ☐ Calculations reviewed
- ☐ Methodology documented
- ☐ Evidence retained
- ☐ Submission archived
- ☐ Contact person identified
Frequently asked questions
Why is my customer asking for emissions data?
Customers may need better environmental information from their value chain for emissions management, supplier engagement, disclosure, procurement or risk-management purposes. CDP’s Supply Chain program is one example of buyers requesting environmental information from suppliers.
Does a carbon-data request automatically require Scope 3?
No. Read the actual request. It may ask only for Scope 1 and Scope 2, selected Scope 3 information, product-level data or another form of disclosure.
How many Scope 3 categories are there?
The current GHG Protocol Corporate Value Chain (Scope 3) Standard organizes Scope 3 emissions into 15 upstream and downstream categories.
Can estimated data be used?
Depending on the request and methodology, calculations may rely on different data types and estimation approaches. The important point is to document the method, source, assumptions and limitations rather than presenting estimated information as measured primary data.
Do I need carbon accounting software?
Not automatically. A controlled spreadsheet workflow may be enough for an isolated or relatively simple request. Software becomes more valuable as reporting frequency, users, suppliers, integrations and traceability requirements grow.
COMING SOON
Not sure what the request means?
The upcoming Carbon Request Decoder will turn a customer request into a structured breakdown of the reporting period, scopes, likely data requirements, methodology requirements, missing information and practical next steps.
Carbon Request Decoder is currently in development.
Explore our Carbon Data Tools →
About this guide
Scope3Analytics prioritizes primary sources and distinguishes official standards from our practical interpretation. This guide references current GHG Protocol corporate accounting standards and CDP supplier-disclosure information.
GHG Protocol and ISO are currently working toward harmonized and consolidated greenhouse-gas accounting standards. GHG Protocol announced further corporate-standard development updates in July 2026. Scope3Analytics will review this guide as the standards evolve.
Official update: GHG Protocol — Key Standard Development Updates.
Last reviewed: August 19, 2026