How to reduce Scope 3 emissions

Scope 3 covers everything outside your own operations, which is where most organisations hold most of their footprint and almost none of their control. Reduction still follows the same four steps: find the hotspots, pick the categories worth working on, act with the organisations you buy from or invest in, and track it against a baseline you can defend.

What are Scope 3 emissions, and why are they the hardest to reduce?

Scope 3 is every indirect emission in your value chain: the goods and services you buy, the transport that moves them, the use and disposal of what you sell, and, for financial institutions, the emissions of the companies you lend to and invest in. The GHG Protocol Scope 3 Standard notes that for many companies the majority of total emissions sit in Scope 3.

They are hard to reduce for one structural reason. The emissions belong to other organisations, so you cannot switch them off, only influence them. Every lever is indirect: what you buy, who you buy it from, how you design the product, and what you ask of the suppliers and portfolio companies who actually own the emissions.

Where do you start if you do not know where your Scope 3 emissions are?

Start with a spend-based screen across all fifteen categories, then improve only what matters. Map your general ledger or purchase ledger to the GHG Protocol categories, apply industry factors, and read off which categories carry the weight. It will be approximate, and it is still enough to tell you where to spend the next six months.

The purpose of the first pass is direction, not accuracy. A screen that puts 60% of your footprint in purchased goods and services has done its job, even if the figure moves by a fifth once supplier-specific data replaces the proxies. What you cannot do is wait for good data before starting, because the data improves as a result of engagement, not before it.

Which Scope 3 categories should you target first?

The ones that are large and that you can influence, which is usually a shortlist of two or three. For manufacturers and most service businesses it is Category 1, purchased goods and services, and Category 2, capital goods. For makers of energy-consuming products it is Category 11, use of sold products. For banks, insurers and asset managers it is Category 15, investments, which is where PCAF applies.

Score each category on size and on leverage. A large category with one concentrated supplier is a better first target than a larger one spread across a thousand accounts. Then work inside the category rather than across the whole footprint, because a target you can attribute to named counterparties is one you can actually report progress against.

How do you get suppliers to reduce their emissions?

Ask for three specific things rather than general commitment: a measured Scope 1 and Scope 2 figure, a reduction target with a date, and one named action for the coming year. Concentrate on the suppliers inside your priority categories, and make the request part of the commercial relationship rather than a separate sustainability exercise.

What moves a supplier is a reason and a return. Show them their figure next to their sector, show them the two changes that would move it most, and tell them how it affects their standing with you at the next renewal. Investors run the same play with portfolio companies, and it works for the same reason: the ask is specific and the consequence is visible.

Keep the burden low. A supplier fielding the same request from thirty customers in thirty formats will answer none of them well. Supplier engagement covers how teams run this without adding to the pile.

Do you need accurate data before you can start reducing Scope 3?

No, but you need to know how accurate your data is, and where. Proxy data is fine for a screen and useless for measuring a reduction, because a spend-based figure falls when you spend less and not when your supplier decarbonises. So the sequence is: screen on proxies, replace proxies with supplier-specific data in the categories you have chosen, then set the target on that.

Track data quality as its own metric alongside the emissions total. PCAF's data quality scores do this formally for financed emissions, and the same logic applies to a supply chain: record the method behind each line, and report how much of the footprint rests on primary data. 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, with numbers you can defend within 2 weeks rather than after a survey round. See how it works.

How does procurement reduce Scope 3 emissions?

By changing what gets bought and who gets awarded. Procurement is the only function that touches most of Category 1, so a weighted carbon criterion in a tender, a supplier emissions figure in the scorecard, and a reduction clause in a renewal do more than any awareness programme.

Three places to put it. In the sourcing decision, as a scored criterion with a stated weight. In the contract, as a data commitment and a target. In the supplier review, as a tracked number next to cost and service. Category managers need the emissions figure inside the tools they already use for this to stick, which is why the data belongs in the P2P and ERP systems rather than in a separate carbon platform. Integrations covers where it lands.

Can product design reduce Scope 3 emissions?

Yes, and it is often the largest single lever, because design decisions fix the material and energy profile of everything that follows. Lower-carbon material substitution cuts Category 1. Energy efficiency cuts Category 11, use of sold products. Durability, repairability and reuse cut both, plus Category 12 at end of life.

The constraint is timing. A design change takes a product cycle to reach the footprint, so it belongs in the three to five year plan while sourcing and supplier engagement carry the near-term reduction. Product carbon footprints are what connect the two: they tell you which component to redesign rather than which supplier to email. Our PCF evaluator checks supplier PCFs and EPDs into PACT-aligned data.

Does industry collaboration help reduce Scope 3 emissions?

It helps most where your own leverage is smallest. A supplier that is 2% of your spend and 20% of a competitor's will not restructure for you alone, and shared sector requests reach further than individual ones. Sector initiatives also reduce duplicated effort, because a supplier answering one aligned request instead of thirty different ones has time left to act.

Use the shared standards rather than inventing formats: CDP for disclosure, PACT for product carbon footprints, PCAF for financed emissions, SBTi for target validation. Alignment is not a reduction on its own, and it is what makes the reductions comparable and reportable.

How do you set and track a Scope 3 reduction target?

Set the baseline first, on a stated method and boundary, then a target with a percentage, a base year and a target year. SBTi requires a Scope 3 target where Scope 3 is more than 40% of the total, and validates it against a sector pathway, which is the most common route to a target other people will accept.

Then track at the level you can act on: counterparty, group, account, portfolio and category, rather than one company-wide total that moves for reasons nobody can attribute. Restate the baseline when a method changes, and record why, because an unexplained drop reads as an accounting change to an auditor and to anyone reading the report. Every figure carrying its source and change history is what makes that restatement defensible instead of awkward.

How long does it take to reduce Scope 3 emissions?

Longer than a reporting cycle, and the stages are predictable. A defensible baseline takes weeks. A first round of supplier or portfolio company engagement takes a couple of quarters. A measured reduction in the reported figure usually lands in the year after that, once better data and actual changes arrive together.

Say that plainly in internal plans. Targets sold on faster arithmetic than this are the ones abandoned in year two, and the organisations that keep going are the ones that agreed in advance what year one would look like.