# Which suppliers should I ask for emissions data first?

Canonical: https://senseible.earth/answers/which-suppliers-to-engage-first-on-scope-3

Start with the few suppliers behind most of your estimated Scope 3 emissions, not most of your spend. Rank purchases by spend or quantity times a rough factor, take the suppliers that make up about 80% of the total, then move up anyone selling CBAM goods or whom your buyer names.

## Step 1: screen every supplier roughly

1. Export a year of purchases by supplier, with spend, quantity, unit and HSN code.
2. Assign each supplier a rough factor for what they sell: a spend-based factor per rupee, or a material factor per tonne where you know the quantity.
3. Multiply and rank. The point is the order, not the exact tonnes; screening factors can be off by a wide margin and are fine for this job.

## Step 2: apply the GHG Protocol screening criteria

The Scope 3 Standard (chapter 6) suggests weighing more than size. After ranking by estimated emissions, move a supplier up the list if:

- You have influence: a large share of their sales, a long contract, or a renewal coming up.
- They create risk: CBAM-covered goods such as steel, aluminium or fertilisers, where actual data cuts your EU buyer's cost.
- A stakeholder asks: your customer, lender or an SBTi target names that category.
- You outsourced a process you used to run, such as heat treatment or plating, because those emissions used to sit in your own Scope 1 and 2.

## Who can wait

- Large spend with low emissions: software, professional services, rent. Spend-based estimates are good enough.
- Traders who resell without processing, unless you can reach the manufacturer behind them.
- One-off purchases you will not repeat next year.

## A decision rule for the first round

Ask the top five to ten suppliers by estimated emissions, plus any CBAM-goods supplier, for activity data or a product footprint. Use averages for everyone else this year, and redo the ranking each year as supplier data replaces estimates.

## Illustration: ranking six supplier groups

- Steel coil: ₹200 lakh x 4.0 t CO2e per lakh = 800 t
- Aluminium extrusions: ₹50 lakh x 5.0 = 250 t
- Plastic granules: ₹60 lakh x 1.5 = 90 t
- Machining job work: ₹80 lakh x 0.5 = 40 t
- Corrugated boxes: ₹40 lakh x 0.8 = 32 t
- 40 other suppliers: ₹170 lakh x 0.3 = 51 t
- Total: ₹600 lakh and 1,263 t; steel and aluminium are 1,050 t, about 83% of emissions on 42% of spend

Factors here are illustrations chosen to show the method, not published values. Among single suppliers, job work is second by spend but fourth by emissions.

## What Senseible does here

Senseible reads purchase invoices and keeps spend, quantity and HSN code by supplier in a separate supplier evidence trail, which gives you the list to rank. It does not apply spend-based factors; use the supplier emissions risk calculator or your own factors for the screen.

- [Supplier emissions risk calculator](https://senseible.earth/calculators/supplier-emissions-risk)
- [Supplier data collection playbook](https://senseible.earth/climate-intelligence/supplier-emissions-data-collection-playbook-msme)
- [Senseible for enterprise supply chains](https://senseible.earth/enterprise)
- [Getting data from tier 2 suppliers](https://senseible.earth/answers/how-to-get-emissions-data-from-tier-2-suppliers)

Sources: [GHG Protocol Corporate Value Chain (Scope 3) Standard (2011), chapter 6](https://ghgprotocol.org/corporate-value-chain-scope-3-standard), [GHG Protocol Technical Guidance for Calculating Scope 3 Emissions (2013)](https://ghgprotocol.org)

Last reviewed 2026-10-15.