If your company falls under the Corporate Sustainability Reporting Directive, you’ve probably already wrestled with the basics of greenhouse gas accounting. But when it comes to scope 3 emissions, things get genuinely complicated. Unlike the emissions you generate directly or from the energy you purchase, scope 3 covers everything happening upstream and downstream in your value chain. That’s suppliers, logistics partners, product use, end-of-life disposal, and more. For most companies, scope 3 can account for the vast majority of their total carbon footprint, which makes it both the most important and the most difficult part of CSRD compliance to get right.
So what does this mean in practice? Whether you’re just starting your CSRD journey or trying to tighten up your reporting, understanding how scope 3 fits into the framework is a good place to start.
What CSRD actually requires for scope 3 reporting
Under CSRD, companies are required to report on their greenhouse gas emissions across all three scopes, and scope 3 is explicitly included. The reporting framework draws on the European Sustainability Reporting Standards (ESRS), specifically ESRS E1, which covers climate-related disclosures. This standard requires companies to disclose their scope 3 emissions across the relevant categories of the GHG Protocol, explain their methodology, and assess the materiality of each category for their business.
It’s worth noting that CSRD doesn’t require every company to report on every scope 3 category. The materiality assessment is key here. You need to identify which upstream and downstream categories are significant for your specific business model, and then report on those. That sounds like a relief, but in practice, conducting a thorough materiality assessment for scope 3 is itself a substantial piece of work. And if you get it wrong, you’re not just leaving gaps in your report. You’re potentially misrepresenting your actual climate impact.
It is also important to be aware of recent changes to the scope of CSRD itself. Since Directive (EU) 2026/470 (Omnibus I), the CSRD applies only to companies with more than 1,000 employees and more than €450 million in net turnover. The previous thresholds of 250 employees, €50 million in turnover, and €25 million balance sheet total have been dropped, meaning roughly 80 percent of companies previously in scope now fall outside the requirement. The new scope applies to financial years starting on or after 1 January 2027, with the first reports due in 2028. Companies that were already reporting under wave 1 but now fall below the new threshold may be exempted by Member States for financial years 2025 and 2026.
Why scope 3 is the hardest part of CSRD to get right
Scope 3 emissions are notoriously difficult to measure accurately, and that’s not just a technicality. The challenge is structural. Your scope 3 data depends almost entirely on information held by other organizations, such as your suppliers, freight providers, customers, and waste management partners. You don’t control that data, and in many cases, those organizations don’t measure it consistently or at all.
There’s also the sheer breadth of scope 3 to contend with. The GHG Protocol defines 15 categories of scope 3 emissions, covering everything from purchased goods and services to employee commuting to investments. Each category requires a different data collection approach, and the methodologies can vary significantly depending on your industry and the availability of primary data. For a manufacturer with a complex global supply chain, this is a genuinely enormous undertaking. For a professional services firm, it might look very different, but it’s still far from straightforward.
On top of that, the quality of scope 3 data tends to vary a lot. Many companies still rely on spend-based estimates or industry averages rather than actual emissions data from their suppliers. While this is an accepted methodology under certain conditions, it introduces significant uncertainty into your figures, and that uncertainty needs to be disclosed and managed.
How inaccurate scope 3 data puts compliance at risk
Getting scope 3 wrong isn’t just an inconvenience. Under CSRD, your sustainability report will be subject to limited assurance by a third-party auditor, with the expectation that this moves toward reasonable assurance over time. That means your scope 3 figures, and the methodology behind them, will face external scrutiny. If your data is based on weak assumptions or poorly documented sources, that’s going to show up.
There are a few specific ways inaccurate scope 3 data can create problems:
- Materiality gaps: If your materiality assessment misses significant scope 3 categories, your report won’t reflect your actual climate impact. Auditors and regulators can flag this as a failure to meet the spirit of the disclosure requirements, not just the letter.
- Methodology inconsistencies: Using different calculation approaches across categories, or switching methods between reporting periods without explanation, makes your data harder to verify and compare year-on-year.
- Supplier data gaps: Relying heavily on secondary data when primary data is available and obtainable suggests insufficient effort to engage your supply chain, which is something auditors will notice.
- Undisclosed assumptions: Every scope 3 estimate involves assumptions. Failing to document and disclose them clearly is a transparency issue that can undermine the credibility of your entire report.
Taken together, these issues don’t just create a compliance headache. They can damage your credibility with investors, customers, and other stakeholders who are increasingly using CSRD disclosures to make real decisions. Getting scope 3 right isn’t just about ticking a regulatory box. It’s about producing a report that actually holds up.
Practical steps to strengthen your scope 3 data collection
Improving your scope 3 data quality is a process, not a one-time fix. But there are concrete steps that make a real difference, and many companies find that even modest improvements in data collection lead to significantly more defensible reporting.
- Start with a solid materiality assessment: Before you collect a single data point, you need to know which scope 3 categories are actually relevant to your business. A well-documented materiality process gives you a clear scope for your data collection efforts and protects you from criticism that you’ve omitted significant sources.
- Prioritize direct supplier engagement: Where your biggest emissions categories involve purchased goods or services, reaching out to key suppliers to request actual emissions data is worth the effort. Even partial primary data improves your accuracy compared to spend-based estimates alone.
- Document your methodology clearly: For every category you report on, record which calculation method you used, what data sources you relied on, and what assumptions you made. This documentation is what makes your figures auditable.
- Build year-on-year consistency: Try to use consistent methodologies across reporting periods so your figures are comparable. If you change your approach, explain why and provide restated figures where possible.
- Use your data gaps as a roadmap: Rather than seeing missing data as a problem to hide, treat it as a priority list for the next reporting cycle. Disclosing where you have gaps and what you’re doing to close them is actually a sign of good reporting practice.
These steps won’t eliminate all the complexity of scope 3 reporting, but they build the kind of structured, transparent approach that holds up under scrutiny. The goal isn’t perfect data overnight. It’s a credible, improving picture of your value chain emissions that you can stand behind.
When to bring in a sustainability expert for scope 3
There’s a point in most scope 3 projects where internal teams hit a wall. It might be the complexity of the materiality assessment, the challenge of engaging a fragmented supplier base, or simply the technical demands of applying the right methodology to each emissions category. That’s when bringing in specialist support starts to make a lot of sense.
It’s worth being specific about what kind of expertise actually helps here. Scope 3 work often calls for different specialists depending on where you’re stuck. A CSRD reporting expert can help you navigate the ESRS requirements and structure your disclosure correctly. A scope 3 emissions specialist can help you design your data collection approach and select the right calculation methodologies. If your biggest scope 3 category involves manufactured products, a life cycle assessment specialist might be exactly what you need to produce credible upstream and downstream figures. The right support depends entirely on where your gaps are.
Traditional consultancies can provide this kind of help, but they often come with longer lead times and higher costs due to their structure and overhead. If you’re working against a reporting deadline or need targeted expertise for a specific piece of the puzzle rather than a full-scale engagement, a freelance specialist can be a much more practical option.
Ready to get your scope 3 reporting on track?
Scope 3 emissions are genuinely one of the trickiest parts of CSRD compliance, and you don’t have to figure it all out alone. At Dazzle, we match organizations with pre-screened sustainability freelancers who specialize in exactly the kind of work you need, whether that’s CSRD reporting, scope 3 methodology, or supply chain emissions analysis.
We work flexibly, on a project basis or an interim basis, so you get the right expertise for the right scope of work without overcommitting. And because our experts are pre-screened and ready to go, you can be working with the right person within 48 hours of reaching out. If you’re ready to strengthen your scope 3 data and approach CSRD compliance with more confidence, we’d love to help. Get in touch with our team and let’s find the right match for your challenge.
Looking for hands-on support with this? See how our CSRD consultants guide companies to compliance.
