If you’ve started mapping your company’s carbon footprint, you’ve probably run into the same wall most organizations hit: scope 3 emissions. These are the indirect emissions that happen across your value chain, and they often account for the majority of a company’s total carbon impact. The tricky part? A huge chunk of them comes from your suppliers. Without reliable data from them, your scope 3 carbon footprint numbers are little more than educated guesses.
Getting that data isn’t always easy. Suppliers vary wildly in how much they track, what they disclose, and how seriously they take the whole exercise. But asking the right questions changes the conversation entirely. Here’s how to approach it.
Why scope 3 emissions make supplier data critical
Scope 3 emissions cover everything that happens outside your direct operations: the goods you purchase, the transport of those goods, the use of your products by customers, and much more. For most companies, these upstream and downstream activities represent anywhere from 70 to over 90 percent of their total emissions, though the exact figure depends heavily on your industry and business model.
This matters because sustainability frameworks like the Science Based Targets initiative (SBTi) and reporting requirements under the CSRD increasingly expect companies to account for their full value chain emissions, not just what happens within their own walls. CDP disclosure also asks reporters to engage their suppliers on climate data. In short, what your suppliers do directly affects your numbers, your reporting credibility, and your ability to set meaningful reduction targets.
The good news is that supplier engagement on carbon is becoming more normalized. Many suppliers already track some form of emissions data, even if they haven’t been asked to share it. The right questions open that door.
10 questions to ask your suppliers about carbon
Before diving into the list, it helps to frame these questions as a conversation rather than an audit. Suppliers are more forthcoming when they understand why you’re asking and what you plan to do with the information.
- Do you measure your greenhouse gas emissions? This is the baseline question. It tells you immediately whether you’re working with data or starting from scratch. Some suppliers will have full scope 1, 2, and 3 inventories; others may only track energy use.
- Which scopes do you currently report on? Knowing whether a supplier covers scope 1 and 2 only, or also their own scope 3, tells you how mature their climate accounting is and how much of their impact is actually visible.
- Have you set any emissions reduction targets? Targets signal commitment. Even better if those targets are validated by SBTi, which means they’re aligned with climate science rather than just aspirational.
- Can you provide product-level or category-level carbon data? Aggregate company emissions are useful, but what you really need for scope 3 accounting is emissions data tied to the specific goods or services you’re purchasing from them.
- What methodology do you use to calculate your emissions? Not all calculation methods produce comparable results. Understanding their approach helps you assess the reliability of the numbers they share.
- Do you disclose your emissions publicly, for example through CDP? Public disclosure through CDP indicates a supplier is comfortable with transparency and has gone through a structured reporting process.
- What is your primary energy source, and are you transitioning to renewables? Energy mix is one of the biggest drivers of scope 1 and 2 emissions. A supplier still running entirely on coal-powered electricity will have a very different footprint than one using renewable energy.
- Do you have a climate or sustainability policy in place? A formal policy doesn’t guarantee action, but it does show that leadership has made some level of commitment and that there’s a framework guiding decisions.
- How do you engage your own suppliers on emissions? If your supplier is asking their suppliers the same questions, that’s a strong sign of a mature approach. It also affects your own scope 3 data further up the chain.
- Are you willing to work collaboratively on emissions reduction? This question shifts the dynamic from data collection to partnership. Some of the most effective scope 3 reductions happen when buyers and suppliers work together on shared initiatives.
Taken together, these questions build a picture that goes well beyond a single number. You learn about a supplier’s maturity, their transparency, their ambition, and their willingness to engage. That picture is far more useful for making procurement decisions than a carbon figure in isolation.
Red flags and green flags in supplier responses
How suppliers respond tells you almost as much as what they say. Some answers signal genuine engagement; others reveal that carbon tracking is still very much an afterthought.
Signs a supplier is genuinely engaged
A supplier who responds with specific data, references a recognized methodology, and mentions targets or reduction initiatives is showing you they take this seriously. Even better if they can point to third-party verification or public disclosure. Suppliers who ask clarifying questions about how you’ll use the data are often more engaged than those who just send a generic PDF.
Signs to watch out for
Vague answers like “we’re working on it” without any timeline or specifics are worth noting. So is a supplier who provides a single headline number but can’t break it down by product or explain how it was calculated. Greenwashing language, lots of sustainability buzzwords without supporting data, is another warning sign. It doesn’t necessarily mean a supplier is acting in bad faith; they may simply not have the infrastructure yet. But it does mean their data shouldn’t be taken at face value.
The most useful thing you can do with these responses is compare them across your supplier base. You’ll quickly see who’s ahead, who needs support, and where the biggest gaps in your scope 3 carbon footprint data actually are.
How to act on what suppliers tell you
Collecting supplier responses is only useful if it leads somewhere. The data you gather should feed directly into your scope 3 inventory, inform your procurement decisions, and shape how you prioritize supplier engagement going forward.
Start by identifying your highest-impact suppliers, those whose goods or services make up the largest share of your purchased emissions. These are the relationships worth investing in most, whether that means joint reduction projects, setting shared targets, or building carbon performance into your procurement criteria over time.
For suppliers who are early in their journey, consider what support you can offer. Sharing your own methodology, pointing them toward resources, or simply making clear that this matters to you as a buyer can be enough to get things moving. Large buyers have real influence over supplier behavior, and using that influence constructively tends to produce better results than simply dropping suppliers who aren’t there yet.
Finally, build this into a regular process rather than a one-time exercise. Supplier carbon data changes as companies improve their tracking and reduce their emissions. Revisiting these questions annually keeps your scope 3 picture accurate and shows suppliers that your commitment is ongoing.
Ready to take your scope 3 work further?
Supplier engagement is just one piece of the scope 3 puzzle. Once you have the data, you’ll need to analyze it, integrate it into your reporting, and turn it into a credible reduction strategy. That’s where having the right expertise makes a real difference.
At Dazzle, we match organizations with pre-screened sustainability freelancers who specialize in exactly this kind of work, from scope 3 emissions reduction to CSRD reporting and beyond. Whether you need someone for a focused project or ongoing interim support, we can connect you with the right expert within 48 hours. No lengthy procurement processes, no unnecessary overhead. Just the right person, ready to help when you need them. Get in touch with our team and let’s find your match.
