Scope 3 supplier and subcontractor emissions
Most Scope 3 data sits with the businesses you buy from. Emitt asks each supplier and subcontractor for their own figure, follows up, and keeps what comes back with its evidence.
What are Scope 3 emissions?
Scope 3 emissions are the indirect emissions in your value chain that aren't Scope 2. Upstream covers things like what you buy and how it reaches you; downstream covers what happens to what you sell. The GHG Protocol's Scope 3 Standard sorts them into 15 categories, and AASB S2 uses the same categories.
| # | Category | In Emitt today |
|---|---|---|
| 1 | Purchased goods and services | Figures your suppliers report |
| 2 | Capital goods | Not calculated |
| 3 | Fuel- and energy-related activities | Not calculated |
| 4 | Upstream transportation and distribution | Figures your carriers report |
| 5 | Waste generated in operations | Waste to landfill, from contractor dockets |
| 6 | Business travel | Not calculated |
| 7 | Employee commuting | Not calculated |
| 8 | Upstream leased assets | Not calculated |
| 9–15 | Downstream: transportation and distribution, processing, use and end-of-life of sold products, downstream leased assets, franchises, investments | Not calculated |
Category 1 and 4 figures in Emitt are what each supplier or carrier reports for what they supplied or hauled to you. Emitt doesn't calculate those categories itself. Waste to landfill is calculated from your contractor's dockets with the NGA Factors, for example 1.2 t CO₂e per tonne of commercial and industrial waste in the 2026 edition.
Why is Scope 3 hard to report?
Because the data belongs to someone else. Your bills and fuel cards show your own Scope 1 and 2. Scope 3 depends on what your suppliers, carriers and subcontractors burned and bought, and only they hold those records.
The usual fallback is an estimate from spend: dollars multiplied by an industry-average factor. AASB S2 allows that kind of secondary data, and calls data from suppliers about specific activities primary data. Getting it means asking each supplier, then following up. Being asked costs suppliers too, and Treasury's 2026 consultation asked how to set clearer boundaries on supplier information requests, particularly for small businesses.
How supplier requests work in Emitt
You choose suppliers from your directory and the site and month you need, and Emitt emails each one a personal link. They report their own emissions for what they supplied or hauled to you, without creating an account, and the figure lands in your records exactly as reported.
- Pick who to ask. Suppliers, carriers and subcontractors from your directory, for a site and period. Ask once or every month, quarter or year, and add a note if you need to.
- They answer through a link. No account and no password. The link opens only that one request, and they can forward it to the colleague who knows the figures.
- Emitt follows up. Emitt sends reminders, and the tracker shows who has reported, who is overdue and what each supplier sent.
- It lands as reported. Each line becomes a Scope 3 record on that site, with the figure exactly as the supplier gave it and any statement they attach kept as evidence. The audit log names the request and the supplier it came from.
- Kept apart from your headline. Scope 3 is reported separately from your Scope 1 and 2 total.
What does a supplier see?
A short form on an Emitt page, sent on your behalf. It names your company, the site, the period and the due date, then asks for their figures:
- Goods and services you supplied. What they supplied, the emissions figure in tonnes or kilograms of CO₂e, how they allocated it to you, whether the figure has been verified, and their own reference.
- Freight you carried to this site. The same, with the route or mode in place of the goods.
- A statement, if they have one. One PDF, PNG or JPEG for the return, kept with every line as evidence.
The form tells them plainly: "Your figures are recorded exactly as you report them, as your share of your own emissions. Emitt never estimates or changes them." See the form on the homepage.
When does AASB S2 need Scope 3?
From your second reporting year. AASB S2 lets you leave Scope 3 out of the first annual reporting period in which you apply it, so a Group 2 company with a 30 June year end reports Scope 3 from 2027–28.
Statements about Scope 3 in reports for financial years starting before 1 January 2028 have modified liability: only ASIC, or a criminal prosecution, can act on them. Under ASSA 5010, Scope 3 gets limited assurance from your second year and reasonable assurance from your fourth.
If you supply a company that reports, expect to be asked. ASIC's guidance notes that reporting entities may ask for information from their value chain, including small businesses and farmers. AASB S2 explained.
What Emitt doesn't do for Scope 3
- Spend-based estimates, or environmentally extended input-output (EEIO) factors.
- Estimate a figure for a supplier that hasn't replied. They show as outstanding.
- Screen which of the 15 categories are relevant or material to you.
- Check a supplier's figure. Emitt records whether the supplier says it has been verified.
- Run supplier engagement programs, set supplier targets or score suppliers.
- Calculate business travel, commuting, capital goods or any downstream category.
Scope 3 questions
Do suppliers need an Emitt account to report their emissions?
No. Each supplier or subcontractor gets a personal link for the site and period you ask about. It opens only that request and needs no password.
Does Emitt estimate Scope 3 when a supplier doesn't reply?
No. Emitt records each figure exactly as the supplier reports it and never estimates one. A supplier that hasn't replied shows as outstanding in the tracker, not as an estimate in your total.
Which Scope 3 categories does Emitt cover?
Waste to landfill (category 5), calculated from your waste contractor's dockets with the NGA Factors, and the figures suppliers and carriers report for what they supplied or hauled to you (categories 1 and 4). Other categories aren't calculated.
When do we need Scope 3 for AASB S2?
From your second reporting year. AASB S2 lets you leave Scope 3 out of the first annual reporting period in which you apply it.
Last reviewed: 9 October 2026. Sources: the GHG Protocol, ASIC RG 280, AASB S2, ASSA 5010 and Treasury's 2026 consultation.
See your own emissions in Emitt.
We're onboarding a small number of Australian businesses in the beta. Bring last year's bills and fuel card exports, and we'll set you up with your own data on the first call.