The 20 Minutes Before Limited Assurance: What the Auditor Will Actually Ask

Sunday evening. The limited-assurance kick-off is tomorrow. You have the Scope 1–3 totals and a folder that grew every time someone said "keep that for the auditor." The only question that matters in the room is: show me how this number was built.

01 - LIMITED ASSURANCE

What does limited assurance actually mean in 2026?

Under CSRD, sustainability reporting must be assured. After the 2026 Omnibus revisions (Directive (EU) 2026/470), that requirement stays at limited assurance. The planned path to mandatory reasonable assurance was removed. Limited is not optional, and it is not a rubber stamp.

The practitioner concludes in negative form: based on the work performed, nothing has come to their attention that the information is materially misstated. That is a lower bar than a financial audit, but it still rests on evidence and documented procedures.

Until the Commission adopts EU limited-assurance standards (deadline 1 July 2027), national practice and the CEAOB September 2024 guidelines fill the gap. In Sweden, FAR's RevR 19 covers limited review of the statutory sustainability report. From periods beginning on or after 15 December 2026, ISSA 5000 is the IAASB standard for sustainability assurance, including GHG.

02 - WHAT AUDITORS DO

What will the auditor actually do to your GHG numbers?

They will not recalculate your entire inventory. Limited assurance is risk-based: they learn your process, spot where misstatement could be material, then use inquiry, analytical review, and selective inspection on high-risk lines, often in Scope 3.

Two checks matter as much as the maths. Completeness: is the population of invoices or activity files whole for the period? Fidelity: do the lines you open in the meeting match the live inventory, or only a curated subset?

ESRS E1 already pushes you toward documentation: methods, significant Scope 3 categories, emission factors with reasons, and the share of Scope 3 on primary data. The GHG Protocol asks for an audit trail so a third party can understand how the inventory was built. The engagement tests whether that trail is real.

03 - EVIDENCE PACK

What should be in your evidence pack before the call?

Have a pack you can navigate in minutes, not a dump of every file.

Include: organisational and reporting boundary memo (year-over-year consistency); an ESRS E1-6 bridge from Scope totals to disclosed cells; Scope 3 inclusion and exclusion rationale by category; an activity-data population list from source systems, with any reconciliation to finance; an emission-factor register (source, vintage, geography or technology fit); a primary versus secondary data map; a change log for method, boundary, or factor shifts; a few pre-checked drill-downs from invoice to activity to factor to kilograms of CO₂e that match the live inventory; and a short note on who prepares and who reviews.

You do not need perfection. You need answers without a scramble.

04 - FIRST 20 MINUTES

What will they ask in the first twenty minutes?

If you can answer these seven without hunting through email, the engagement feels different for everyone in the room.

1. Show me how this reported figure was built, from source to total. Walk invoice or meter to activity to factor to the E1 cell, on a live drill-down.

2. Is the organisational and reporting boundary complete and consistent year over year? State the approach, entities in scope, and any acquisition or disposal treatment.

3. For this Scope 3 category: why included or excluded, and what method? Tie it to significance screening and name the method, including proxies where primary data is not yet available.

4. What emission factor is this , source, year, geography or technology fit? Open the register entry for the sampled line.

5. How much of Scope 3 is primary versus secondary or proxy, and where? Give the percentage and show concentration by category or supplier.

6. How do you know the activity-data population is complete? Describe extract logic and reconciliation, not only the sample invoices.

7. This line moved year over year , method or boundary change, or real activity? Separate volume and mix from accounting change, with the change log open.

05 - WHERE FILES BREAK

Where do carbon files usually break under assurance?

Orphan totals that cannot be decomposed. Factor folklore with no source or vintage. Boundary drift with no note. Curated samples while the population still has gaps. Silent method changes, such as moving from spend-based to activity-based without a clear comparative narrative. Primary-data claims without the supplier file next to the line.

CSRD does not ban spend-based methods. Limited assurance still needs a traceable basis, and spend-only lines are harder to defend when sampled. Companies that already run inventory from source documents hit fewer of these breaks, because the work sits upstream of the meeting. For why that traceability matters, see our guide on what your carbon data needs to survive an audit.

06 - HOW BARDO HELPS

How can Bardo help?

Limited assurance ends with the auditor's conclusion. No platform replaces the practitioner, and nothing guarantees a clean opinion. What a full carbon accounting setup can do is make sure you are not building that opinion on spreadsheets you cannot defend.

Bardo is a full-service carbon accounting partner: we run activity-based Scope 1–3 inventories from the invoices and ERP data you already have, at product and supplier level rather than spend averages, aligned with the GHG Protocol and CSRD / ESRS E1 disclosure needs.

Every figure is built so it can be walked back to a purchase, an activity, a method, and a sourced emission factor. When the limited-assurance team asks where a number comes from, you open a live trail instead of reconstructing one. You bring the evidence. The auditor issues the conclusion.

Companies such as Bjäre Kraft, First Camp, and Aura Group already grow their footprint this way. If you want that trail in place before the kick-off call, talk to us.

Frequently Asked Questions

1. Does CSRD ban spend-based carbon accounting?

No. CSRD does not prescribe a method, and the simplified ESRS still allow indirect data. But limited assurance requires a traceable basis, and spend-based figures are hard to trace to a specific supplier or activity.

2. Is reasonable assurance still coming under CSRD?

No. The 2026 Omnibus revisions removed the planned move to reasonable assurance. CSRD reports remain under limited assurance.

3. What is limited assurance?

A third-party auditor concludes your sustainability data is free from material misstatement. A lower bar than a financial audit, but it still requires evidence behind each number.

4. Which emissions does ESRS E1 require?

Gross Scope 1, 2, and 3 emissions, plus energy and intensity metrics, disclosed so they can be compared year over year.

5. Why does year-over-year consistency matter?

If boundaries or categories change between periods, comparisons break down, and auditors flag swings that come from bookkeeping changes rather than real performance.