What Are Scope 3 Emissions?

If you’ve ever looked at a corporate sustainability report, you’ve probably noticed that greenhouse gas emissions are split into three categories. Most companies have a decent handle on their direct operations. But Scope 3 emissions—the indirect greenhouse gas emissions happening across your entire value chain—are where things get complicated.

This guide breaks down what Scope 3 actually means, why it matters for your business, and how to start measuring and reducing these emissions in a practical way.

Quick answer: what are Scope 3 emissions?

Scope 3 emissions are all the indirect emissions that occur across a company’s value chain, excluding those already captured in Scope 1 (direct emissions from owned or controlled sources like fuel combustion in company vehicles) and Scope 2 (purchased electricity and energy). These are sometimes called value chain emissions or chain emissions in corporate reports and CDP disclosures.

Think of it this way: if your company buys laptops, the carbon emissions from manufacturing those laptops count as your Scope 3. If customers use your products and those products consume energy, that’s also Scope 3. The same goes for business travel, employee commuting, waste disposal, raw materials extraction, and end of life disposal of your products.

For many organisations, Scope 3 can represent 70–90% of their total emissions. CDP’s 2023 data revealed that the median corporate Scope 3 footprint is roughly 11 times larger than Scope 1 and Scope 2 combined. These scope emissions are harder to measure because they come from suppliers, logistics partners, customers, and other third parties outside a company’s direct control.

How do Scope 1, 2, and 3 emissions differ?

The greenhouse gas protocol, developed by the World Resources Institute and the World Business Council for Sustainable Development, introduced this three-scope structure in the early 2000s to help companies systematically account for their carbon footprint. Understanding the differences is essential for accurate emissions reporting.

Scope 1 covers direct emissions from sources that a reporting company owns or controls. This includes fuel combustion in company vehicles, natural gas burned in on-site boilers, and greenhouse gases generated during manufacturing processes. If you can walk out to the parking lot and see the source of the emissions, it’s probably Scope 1.

Scope 2 captures indirect emissions from purchased energy. When your offices draw electricity from the grid, or when your facilities use steam, heating, or cooling generated off-site, those emissions fall into Scope 2. Companies have moderate control here through energy efficiency improvements and renewable energy procurement.

Scope 3 encompasses everything else—all the upstream and downstream emissions in the corporate value chain that aren’t covered by Scopes 1 or 2. Upstream emissions include supply chain emissions from purchased goods and services, capital goods, business travel, and employee commuting. Downstream emissions include distribution processing, customer use of sold products, and waste generated when products reach end-of-life.

• Scope 3 is sometimes called “value chain emissions” or “chain emissions” in corporate reports and CDP disclosures, reflecting its comprehensive coverage of a company’s environmental impact beyond direct operations.

The key distinction is control. Scope 1 involves assets you own. Scope 2 involves energy you purchase. Scope 3 involves activities where you have influence but not direct control—making it both the largest category and the most challenging to address.

What are the 15 Scope 3 categories?

The GHG Protocol Corporate Value Chain (Scope 3) Accounting and Reporting Standard, first released in 2011, defines exactly 15 categories to ensure comprehensive coverage and prevent double-counting. These categories split into eight upstream categories (related to inputs and supply-side activities) and seven downstream categories (tied to outputs and customer-side activities).

Upstream categories capture emissions that occur before your products or services reach customers:

Category 1, purchased goods and services, often represents the largest share of Scope 3 for most companies. This covers emissions from the extraction, production, and transportation of everything you buy—from the laptops your employees use to the raw materials in your products. Category 2, capital goods, applies similar logic to major assets like the construction of a new warehouse or the manufacturing of heavy machinery you purchase.

Category 3 covers fuel and energy related activities not included in Scopes 1 or 2, such as the upstream processing of fuels your facilities eventually burn. Category 4, upstream transportation and distribution, accounts for inbound logistics—delivery trucks bringing components to your factory, for instance.

Category 5, waste generated in operations, captures emissions from third-party facilities treating your operational waste, whether that’s recycling, landfill, or incineration. Category 6, business travel, includes emissions from airline flights for sales staff, hotel stays, and rental cars. Category 7, employee commuting, covers daily travel between home and work. Category 8, upstream leased assets, applies when you lease equipment or facilities from others.

Downstream categories track emissions occurring after your products leave your operations:

Category 9, downstream transportation and distribution, captures logistics to end-users that you don’t directly control. Category 10, processing of sold products, applies when downstream entities further process intermediate goods you’ve sold. Category 11, use of sold products, can dominate for energy-intensive goods—think of the fuel burned by cars you manufacture or the electricity consumed by electronics you sell.

Category 12, end-of-life treatment of sold products, covers emissions from the treatment of packaging waste in municipal facilities or the disposal of products customers discard. Category 13, downstream leased assets, applies when you lease assets to others. Category 14, franchises, covers emissions from franchise operations. Category 15, investments, includes equity, debt, and project finance emissions—particularly relevant for financial institutions.

Not every category will be material for every organisation. A software company might have minimal Category 11 emissions but substantial Category 1 from data centre hardware. A car manufacturer faces enormous Category 11 from vehicle use. The GHG Protocol requires companies to consider all 15 categories when scoping a greenhouse gas inventory, then focus measurement efforts on those that are material.

Why do Scope 3 emissions matter so much?

Scope 3 is often the largest component of a company’s carbon emissions by a wide margin. Various sector analyses show that for tech firms, purchased goods and services can represent 80-95% of their footprint. For oil majors, downstream use of sold products can exceed 90% of total emissions. Ignoring Scope 3 means missing most of your climate impact.

Including Scope 3 provides a complete picture of environmental impact across the life cycle of products and services. When Microsoft disclosed its 2023 emissions, Scope 3 represented 75% of the total at 14.7 million tonnes of CO2 equivalent—primarily from data centre hardware supply chains. Without that visibility, any climate strategy would address only a fraction of actual emissions.

From a strategic perspective, understanding Scope 3 reveals where emissions and costs concentrate in your supply chain. This insight guides procurement decisions, product design choices, and investment priorities. Companies discovering that a single material or supplier accounts for a disproportionate share of emissions can target those relationships for improvement.

Investor, customer, and regulator expectations increasingly require companies to understand and manage their entire value chain emissions. The Science Based Targets initiative requires companies to set Scope 3 targets when these emissions exceed 40% of total footprint—a threshold most consumer brands, financial institutions, and technology companies easily surpass.

Many net zero emissions commitments and Paris-aligned targets set between 2020–2025 explicitly include Scope 3. Companies like Nestlé have set targets to cut Scope 3 by 50% by 2030, validated against 1.5°C pathways. For Nestlé, use of sold products (beverage consumption) represents 85% of their footprint, making Scope 3 reduction essential to any credible climate claim.

• Demonstrating credible Scope 3 management in sustainability reporting—through CDP questionnaires, TCFD-aligned reports, or integrated annual reports—delivers reputational and competitive benefits. Increasingly, major customers require suppliers to disclose Scope 3 data as a condition of doing business.

How to start measuring Scope 3 emissions

Companies rarely have perfect emissions data at first. Most improve accuracy over several reporting cycles, starting with estimates and progressively incorporating supplier-specific information. The goal is progress, not perfection from day one.

Step 1: Map your value chain. Start by documenting the flow from raw material extraction through manufacturing, distribution, product use, and end of life disposal. Identify all significant activities and the third parties involved at each stage.

Step 2: Align activities to the 15 categories. Take your value chain map and assign each activity to the appropriate Scope 3 category. This creates a structured framework for data collection and ensures completeness.

Step 3: Choose your calculation approach. Three main methods exist:

• Spend-based estimates use financial data and emission factors to convert procurement spend into carbon dioxide equivalent emissions. This is quick (sometimes just hours for initial screening) but can have uncertainty of ±50%.
• Activity-based data uses physical quantities like kilometres travelled, tonnes of material purchased, or kilowatt-hours consumed. This improves accuracy but requires more granular data.
• Supplier-specific data involves collecting actual emissions data from your suppliers, often through CDP surveys or direct engagement. This is the gold standard but depends on supplier maturity.

Step 4: Use established tools and data sources. Common resources include national greenhouse gas inventories, input-output models like USEEIO in the United States, lifecycle assessment databases like Ecoinvent, and commercial carbon accounting platforms like Persefoni or Normative.

Step 5: Engage suppliers. Early engagement with key suppliers—especially those providing high-volume or high-emission materials like steel, cement, plastics, or semiconductors—is essential for improving data quality over time.

For your first year, prioritise a handful of material categories. Purchased goods and services, upstream transportation, and business travel are common starting points because they’re often significant and data is relatively accessible. Expand coverage systematically in subsequent years.

Why Scope 3 is difficult to measure accurately

Scope 3 involves many independent actors, data formats, and geographies, making precise accounting genuinely challenging. Unlike Scope 1 where you can install meters on your equipment, Scope 3 requires piecing together information from hundreds or thousands of external parties.

Data visibility issues present the first major hurdle. Most companies have limited visibility beyond their direct (tier-1) suppliers. The steel in your product might pass through multiple intermediaries before reaching your factory floor, with each step adding uncertainty.

Inconsistent emissions factors compound the problem. Different regions, production methods, and time periods yield different emission profiles. Purchased goods manufactured in Europe versus East Asia in 2024 can have substantially different carbon intensities. Generic industry averages may not capture these variations.

The speed-accuracy trade-off forces practical compromises. High-level modelling using Environmentally Extended Input-Output (EEIO) approaches can produce estimates quickly but with ±20-50% uncertainty. Detailed primary data collection delivers <10% uncertainty but requires significant time and supplier cooperation. Most companies use hybrid approaches, applying detailed methods to their highest-impact categories.

• Organisational challenges add another layer. Scope 3 measurement typically requires coordination across procurement, finance, operations business travel, and sustainability teams. Without clear governance, data collection stalls and responsibility fragments.

Supplier response rates remain stubbornly low. Studies indicate only about 30% of suppliers respond to emissions data requests, leaving significant gaps that must be filled with estimates.

The GHG Protocol acknowledges that uncertainty is expected and accepted. The principles of relevance, completeness, consistency, transparency, and accuracy guide reporting, with the expectation that methods improve over time as sufficient data becomes available.

Regulations and reporting frameworks covering Scope 3

The regulatory landscape for Scope 3 is evolving rapidly, with 2023–2025 marking a period of significant change across major jurisdictions.

In the United States, the SEC’s 2024 climate disclosure rule does not currently mandate Scope 3 reporting. However, many companies report voluntarily to meet investor expectations and maintain alignment with global frameworks. California’s climate disclosure laws, particularly SB 253 signed in 2023, are designed to require large companies operating in the state to report Scopes 1, 2, and 3—even if they’re headquartered elsewhere.

In the European Union, the Corporate Sustainability Reporting Directive (CSRD), phased in from financial year 2024 onward, requires large companies in Europe and qualifying non-EU companies to disclose material Scope 3 emissions under the European Sustainability Reporting Standards (ESRS). This will eventually cover approximately 50,000 firms.

Globally, the International Financial Reporting Standards (IFRS) S2, released in 2023, integrates Scope 3 into sustainability standards, providing a common baseline for jurisdictions adopting these requirements.

Voluntary frameworks continue to drive disclosure where regulation doesn’t yet mandate it:

• CDP questionnaires explicitly request Scope 3 data, with 75% of the 18,000 companies reporting in 2023 including Scope 3 information—up from 50% in 2019.
• GRI Standards include provisions for value chain emissions reporting.
• TCFD-aligned reporting encourages disclosure of climate risks across the value chain.
• The Science Based Targets initiative requires Scope 3 targets as part of validated commitments when these emissions exceed the materiality threshold.

Even where Scope 3 remains voluntary, many global brands have disclosed it in sustainability reports and annual filings since the late 2010s. Early movers gain advantages in data maturity and supplier relationships that laggards will struggle to replicate.

Strategies to reduce Scope 3 emissions

While companies don’t directly control many Scope 3 sources, they can strongly influence them through procurement, design, and policy decisions. The key is focusing effort where it matters most.

Supplier-focused strategies offer the most direct path to reducing upstream emissions:

• Incorporate sustainability criteria and climate performance into procurement tenders
• Require suppliers to provide accurate data on their emissions
• Collaborate with key suppliers on energy efficiency and emissions reduction projects
• Support suppliers in setting SBTi-approved targets and transitioning to renewable energy
• Use procurement spend as leverage—Apple’s supplier program has cut emissions 40% since 2015 by mandating recycled materials and renewable energy across 300+ suppliers

Product and service design addresses emissions at the source:

• Reduce material intensity and shift to lower-carbon alternatives
• Design for extended product lifetimes, reducing replacement frequency
• Enable repair, reuse, and recycling to minimise end-of-life emissions
• Consider the use phase—products that consume less energy during operation reduce Category 11 emissions

Logistics and travel optimisation targets distribution waste generated across transportation networks:

• Optimise routes to minimise distance and fuel consumption
• Shift modes where possible—rail and sea typically have lower emissions than air
• Choose carriers with cleaner fleets and efficiency programs
• Implement travel policies favouring virtual meetings and lower-carbon options for operations business travel

Customer-side actions extend influence downstream:

• Encourage energy-efficient use of sold products through guidance and incentives
• Offer take-back or recycling programmes for end-of-life treatment
• Design products that guide users toward lower-emission behaviours

Prioritisation matters. Unilever’s Sustainable Living Plan demonstrates focused impact—by working with 500,000+ farmers on regenerative agriculture, they reduced Scope 3 by 32% (1 million tonnes CO2e) between 2008-2019. Start with your highest-emission categories, set measurable targets, and track progress quarterly or annually to achieve meaningful cost savings alongside emissions reduction.

Scope 3 and net-zero targets

Credible net-zero targets increasingly require addressing Scope 3, especially in sectors where value chain emissions dominate the footprint. A net-zero claim covering only Scopes 1 and 2 rings hollow when Scope 3 represents 80% or more of total emissions.

Many net-zero pledges announced between 2019 and 2025 originally covered only direct operations. As methodologies mature and stakeholder expectations sharpen, companies are updating these commitments to encompass the entire value chain. The Science Based Targets initiative’s Net Zero Standard explicitly requires companies to halve Scope 3 by 2030 and achieve near-zero by 2050.

SBTi and similar initiatives expect companies to set Scope 3 targets when these emissions exceed a specified share of the total footprint—typically 40%. This threshold captures most consumer brands, financial institutions, universities, and technology companies. Yale’s Lindsay Crum has noted that universities’ emissions from commuting and supply chain activities exceed on-campus Scopes 1 and 2 by 5-10 times, making Scope 3 central to any credible institutional climate commitment.

A phased approach typically works best:

1. Build a comprehensive inventory across the 15 categories
2. Identify material categories and establish baseline measurements
3. Set medium-term reduction targets aligned with global climate goals
4. Integrate Scope 3 considerations into procurement, investment, and product strategies
5. Track progress and refine methods annually

Carbon credits or offsets should be considered only after aggressive reduction of Scopes 1, 2, and 3 emissions. Many standards, including SBTi’s Net Zero Standard, are tightening rules on what counts toward net-zero claims. Companies relying heavily on offsets without demonstrating underlying emissions reduction face growing scrutiny from investors and regulators.

Including Scope 3 in net-zero planning fundamentally shifts attention from “own operations” to the entire value chain and long-term business model. It requires rethinking supplier relationships, product design, and even which markets to serve. For companies willing to engage suppliers and redesign their approach, this shift unlocks innovation—like the development of low-carbon steel and sustainable materials that wouldn’t emerge from a narrow operational focus.

Key takeaways

• Scope 3 emissions are all indirect greenhouse gas emissions across your value chain that fall outside Scopes 1 and 2, often representing 70-90% of total corporate emissions
• The GHG Protocol defines 15 categories spanning upstream (supply chain) and downstream (customer use, disposal) activities
• Measurement typically starts with spend-based estimates and improves through supplier engagement and better data collection over time
• Regulations like EU CSRD and California SB 253 are making Scope 3 disclosure increasingly mandatory, while frameworks like CDP and SBTi already expect it
• Reduction strategies focus on engaging suppliers, redesigning products, optimising logistics, and influencing customer behaviour
• Credible net zero emissions targets require addressing Scope 3, not just direct operations

Understanding your Scope 3 emissions is the foundation for meaningful climate action. Start by mapping your highest-emission categories, engage your key suppliers early, and build measurement capabilities that improve with each reporting cycle. The companies making progress today will be better positioned for regulatory compliance, investor expectations, and the competitive advantages that come from leading on sustainable development.