What is Scope 3?

The GHG Protocol Framework: Scope 1, 2, and 3

The Greenhouse Gas Protocol Corporate Accounting and Reporting Standard — the dominant global framework for corporate emissions accounting — divides a company’s carbon footprint into three concentric rings called scopes.

Scope 1 covers direct emissions from sources owned or controlled by the reporting company: combustion of natural gas in a boiler, fuel burned in company vehicles, process emissions from on-site chemical reactions. If it comes out of your chimney or exhaust pipe, it is Scope 1.

Scope 2 covers indirect emissions from purchased electricity, steam, heat, or cooling. The combustion happens at a power plant that you don’t own, but your purchasing decision drives demand for it. Scope 2 is calculated by multiplying energy consumption (kWh) by the carbon intensity of the grid supplying it (gCO₂e/kWh). A factory in China drawing 100,000 kWh per month from a grid running at 565 gCO₂e/kWh generates roughly 56,500 kgCO₂e of Scope 2 emissions each month.

Scope 3 captures everything else: all indirect emissions that occur in a company’s value chain, both upstream (suppliers) and downstream (customers and end-of-life). The GHG Protocol defines 15 distinct Scope 3 categories. They range from the raw materials purchased from suppliers (Category 1) to how customers use the product after they buy it (Category 11) to what happens to the product when it is eventually discarded (Category 12).

Why Scope 3 Dominates Corporate Footprints

For most manufacturers and retailers, Scope 3 is not a footnote — it is the main event. Studies across sectors consistently find that 70–90% of a company’s total emissions sit in Scope 3. For a consumer electronics brand, the figure is typically at the upper end of that range: Apple’s 2024 environmental report shows that more than 99% of the company’s total greenhouse gas footprint falls in Scope 3.

This concentration happens for a structural reason. Modern supply chains are global and deeply specialised. A smartphone brand may assemble devices in one country, source chips from another, use displays manufactured in a third, and sell into dozens of markets. The energy consumed at each link in that chain is owned by a separate legal entity. Each entity’s Scope 1 and Scope 2 emissions are, from the brand’s perspective, Scope 3.

The implication for climate accounting is significant: a company can achieve net-zero Scope 1 and Scope 2 emissions — switching its offices and owned facilities entirely to renewable energy — and still be responsible for tens of millions of tonnes of CO₂e per year through its purchasing decisions and the products it designs.

The 15 Scope 3 Categories

The GHG Protocol organises Scope 3 into 15 categories, split between upstream (related to purchased inputs) and downstream (related to sold products):

Upstream categories:

1. Purchased goods and services
2. Capital goods
3. Fuel- and energy-related activities (not in Scope 1 or 2)
4. Upstream transportation and distribution
5. Waste generated in operations
6. Business travel
7. Employee commuting
8. Upstream leased assets

Downstream categories: 9. Downstream transportation and distribution 10. Processing of sold products 11. Use of sold products 12. End-of-life treatment of sold products 13. Downstream leased assets 14. Franchises 15. Investments

Category 1: Purchased Goods and Services is the most material category for most manufacturers and is the direct source of embodied carbon. It encompasses the emissions embedded in every input a company buys: steel, plastics, electronic components, chemicals, packaging. Measuring it requires knowing the carbon intensity of each input, which in turn requires either supplier-specific emissions data (rare and difficult to obtain) or average emission factors from lifecycle databases.

For the Climate Cost Index, Category 1 is essentially the entire product footprint. The CCI calculates the Scope 3 contribution to a product’s cradle-to-gate emissions by aggregating Category 1 emission factors for all major input materials and components, weighted by the mass or value of each.

Why Scope 3 Is Hard to Measure

Several structural features make Scope 3 data challenging to collect and verify:

Supply chain opacity. Most brands have direct relationships with their Tier 1 suppliers but limited visibility into Tier 2 and beyond. The emissions from smelting the aluminium that a Tier 1 supplier used to make an enclosure — a Tier 2 relationship — may be invisible to the final brand without active supply chain mapping.

No standardised reporting. Unlike Scope 1 and Scope 2, where regulators in many jurisdictions require disclosure, Scope 3 reporting remains largely voluntary. The data that does exist varies in methodology, system boundary, and verification level, making cross-company comparisons unreliable.

Attribution and double-counting. When a chip manufacturer’s Scope 1 and Scope 2 emissions become a smartphone brand’s Scope 3 Category 1, the same tonne of CO₂e appears in two different companies’ footprints. This is a feature, not a bug — the GHG Protocol acknowledges it — but it complicates aggregate accounting.

Activity data gaps. Even willing suppliers may lack the internal data systems to provide accurate emissions figures. Many smaller manufacturers have never conducted a lifecycle assessment or measured their energy consumption by product line.

How the CCI Handles Scope 3

The CCI is designed specifically to address the measurement challenge for end consumers. Rather than relying on voluntary corporate disclosures, it assembles a product-level footprint from the bottom up, using:

• Peer-reviewed lifecycle assessment (LCA) databases such as ecoinvent and the US LCI Database, which contain material-level emission factors derived from process data
• Manufacturer-published environmental reports (Apple Product Environmental Reports, Samsung Galaxy environmental fact sheets) where these have been third-party verified
• Industry association datasets and government inventories for primary materials
• Proxy factors for categories where primary data is unavailable

The Scope 3 figure in a CCI score represents the upstream supply chain emissions attributable to making one unit of the product. For a smartphone at 75 kgCO₂e, 62 kgCO₂e (83%) is Scope 3 — the emissions embedded in chips, glass, battery cells, and other purchased components, traced through the supply chain to their origin.

Because Scope 3 data carries more uncertainty than Scope 1 or Scope 2, the CCI applies a conservative (upper-bound) methodology and assigns a confidence rating to each score. A “high” confidence rating indicates that at least one verified manufacturer report is available to anchor the estimate. A “low” confidence rating indicates reliance on industry averages and proxies, which may overstate or understate the true figure by 20–40%.

What This Means for Buyers

For an individual purchasing decision, Scope 3 awareness matters in two ways.

First, the products you buy carry embodied Scope 3 emissions that will never appear in utility bills or at the pump. A laptop, a pair of jeans, a piece of flat-pack furniture — each has a supply chain footprint that is fixed at the moment of manufacture. Choosing a product with a lower CCI score is the only way to reduce that footprint.

Second, aggregated purchasing signals influence what manufacturers invest in. When large institutional buyers — corporations, governments, universities — specify lower-carbon products in procurement, they create demand for cleaner supply chains. Scope 3 is how that demand signal propagates back through the value chain to the smelter, the fab, and the farm.