Scope 3 target setting: boundaries, pathways and supplier engagement

TL;DR

A credible Scope 3 target needs four things: a boundary you can defend, a pathway that matches how you actually influence emissions, an ambition level that meets the SBTi criteria you will be validated against, and governance that survives a recalculation. Start with spend-based data to get coverage fast, then upgrade the categories that carry the emissions to supplier-specific data on a written plan.

One more thing changed this year. The Corporate Net-Zero Standard V2.0 was published on 11 June 2026 and applies to validations from 1 February 2027. Until then you validate against the Near-Term Criteria V5.3.1, but the boundary work below should be done against both, because V2.0 changes which categories you are on the hook for.

Do you need a Scope 3 target?

You need a near-term Scope 3 target if your relevant Scope 3 emissions are 40% or more of scope 1, 2 and 3 combined. That is criterion C4 of the Corporate Near-Term Criteria, and it is a threshold, not a guideline. If you are under it, document the calculation, keep the working, and re-test every year, because C27 forces a recalculation the moment Scope 3 crosses 40%.

Two answers change depending on which standard you are validated against. Under the Near-Term Criteria V5.3.1, your target must cover at least 67% of total Scope 3 emissions, reported and excluded, using each category's minimum boundary from the GHG Protocol Corporate Value Chain Standard (C6). Under Corporate Net-Zero Standard V2.0, that single figure is gone: you must set a target for every category that is 5% or more of your Scope 3 emissions in categories 1 to 14 (CNZS-C14.1). Most companies find the 5% rule pulls in the same categories and then some, so run it now rather than in 2027.

Run the check below before you write a target. Each row names the criterion behind it, so a "no" tells you what to go and fix rather than just that something is missing.‍

How do you set the Scope 3 boundary?

Work through all fifteen categories, decide inclusion, and write down two methods for each one: what you are calculating with at baseline, and what you intend to upgrade to. The second column is the one auditors ask about, and it is the one most registers leave blank.

The GHG Protocol Technical Guidance gives four calculation methods for purchased goods and services, in descending order of quality: supplier-specific, hybrid, average-data and spend-based. Spend-based is the right place to start, because it covers everything you buy on day one, and the wrong place to stop, because it moves with your invoices rather than with your suppliers' actual performance. The upgrade path is the plan, not an aspiration.

The register below is filled in with a worked example for an illustrative mid-size manufacturer. The figures are there to show what a finished register looks like, not to describe any real company. Replace every one of them with your own.
Method key: SS supplier-specific, H hybrid, A average-data, S spend-based.

Which target pathway should you choose?

There are three ways to express a Scope 3 target, and the right one depends on how you actually influence the emissions rather than on which is easiest to calculate.

• Absolute reduction. A percentage cut in tonnes against the base year. The clearest to communicate and the hardest to hit while the business is growing. Near-term Scope 3 absolute targets must be aligned with a well-below 2 degrees C pathway (C18), a lower bar than the 1.5 degrees C required of scope 1 and 2 (C15).
• Intensity. Tonnes per unit of physical output or per unit of revenue. Useful where volume growth is genuine rather than an accounting artefact. Economic intensity moves with prices, so physical intensity is the more defensible of the two where a physical unit exists.
• Supplier and customer engagement. A share of the organisations you buy from, measured by emissions or by procurement spend, committing to their own science-based targets. Under C19 you state which categories are covered and what percentage of their emissions or of annual procurement spend the target covers, and the target must be fulfilled within five years of submission.

Corporate Net-Zero Standard V2.0 widens this. From 1 February 2027 you can meet the requirement with an absolute reduction target, an overarching supplier or customer alignment target based on emissions, spend or revenue, or a category-specific mix of the two (CNZS-C15). Table 3 of that standard sets out which target types are available for each category, and they are not the same across categories: use of sold products, for instance, allows emissions reduction, supplier alignment and product use alignment, but not volume alignment.

Most companies end up with a combination. An absolute target across the significant categories, and an engagement target on purchased goods and services where the emissions sit with organisations you do not control.

How ambitious does the target have to be?

Near-term Scope 3 targets must be modelled on a pathway consistent with keeping warming well below 2 degrees C (C18). Scope 1 and 2 near-term targets are held to 1.5 degrees C (C15), so the two do not run at the same rate and you should not present them as if they do. Targets cover 5 to 10 years from the submission date under C13, with a base year no earlier than 2015 and no multi-year averaging unless a sector pathway allows it.

Engagement targets carry a shorter clock. C19 caps them at five years from submission, and the suppliers you count must have targets meeting the latest Corporate Near-Term Criteria, not a general commitment to reduce.

Under V2.0 the shape changes again: near-term targets become a rolling five-year period beginning at the start of your most recent reporting period, and each cycle takes a fresh base year corresponding to the most recent year with comprehensive data (CNZS-C4.2). If you are submitting in 2026 and expect to renew after 2027, plan the data so a new base year is a refresh rather than a rebuild.

Who owns the target after sign-off?

A target is a governance commitment, and the recalculation is where most of them come unstuck. Write the policy before the target is submitted, not the first time an acquisition breaks the base year.

Four things belong in it:

• A significance threshold. V2.0 applies 5% to structural and methodology changes, so 5% is a sensible default to adopt now.
• Named triggers. Structural change (acquisitions, divestments, outsourcing), methodology change, and error correction. CNZS-C8 also requires you to reassess whether categories newly cross or fall below the 5% threshold.
• An owner and a cadence. A named person, and a fixed point in the reporting calendar where the register above is re-run rather than assumed.
• An evidence trail. Every figure with its source and its change history, so the recalculation can be explained rather than re-derived.

That last one stops being optional under V2.0. Category A companies must obtain at least limited assurance over base year scope 1, 2 and 3 emissions, from an accredited independent third party working to a recognised assurance standard (CNZS-C7). Scope 3 assurance is a different exercise from a scope 1 and 2 opinion, because the assurer follows your data back to its source. Audit-ready is the wrong word for a spreadsheet whose provenance lives in someone's inbox.
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This is where the data question turns into a delivery question. Getting a defensible baseline across fifteen categories is normally the part that takes a year of chasing.

DitchCarbon provides verified emissions data for over 2 million organisations, so procurement, sustainability and finance teams can measure and act on supply chain and portfolio emissions from one source. The calculator behind it is verified to ISO 14064-3 at limited assurance by UL Solutions, renewed annually, and DitchCarbon data has been used in emissions reports that were subsequently assured by ten different third-party assurance providers, including Big Four firms. That is the point of the assurance criterion above: the register survives contact with someone else's auditor.