What to Know About Scope 3 Emissions and Why They Matter

The Greenhouse Gas (GHG) Protocol, the most widely adopted global standard for corporate emissions accounting, divides corporate emissions into three categories, commonly referred to as Scope 1 2 3 emissions. Scope 1 covers direct emissions from sources a company owns or controls, such as fuel combustion in on-site boilers or company vehicles. Scope 2 covers indirect emissions from purchased energy, primarily electricity, heat, or cooling. Both are relatively straightforward to measure. Scope 3, however, is categorically different. It encompasses all indirect emissions across an organization's broader footprint—upstream and downstream—that fall outside Scope 2. The GHG Protocol organizes these into fifteen categories, spanning purchased goods and services, employee commuting, business travel, product use, and end-of-life treatment of sold products. In most industries, Scope 3 accounts for 70% to over 90% of a company’s total carbon footprint.

The defining challenge of scope 3 emissions is that they originate outside an organization's direct operational control. Reductions require influence over suppliers, customers, logistics partners, and end users, not simply upgrading internal processes or energy sources. Regulatory momentum is building in response. The EU’s Corporate Sustainability Reporting Directive (CSRD) began phasing in from financial year 2024, initially for large companies already subject to the previous Non-Financial Reporting Directive, with mandatory Scope 3 disclosure among its requirements. At the international level, IFRS S2, the climate disclosure standard published by the International Sustainability Standards Board (ISSB) and effective from January 2024, has been adopted or is under active adoption in around 30 jurisdictions globally, covering more than half of world greenhouse gas emissions. Investors and procurement teams are following the same trajectory, making Scope 3 accountability a growing commercial expectation, not only a regulatory one.

Measuring and managing Scope 3 emissions requires thinking in systems. The value chain model, which traces how value is created from raw material extraction through production, distribution, and product disposal, provides the structural framework for this work. By mapping each stage, organizations can identify where Scope 3 concentrations are highest and prioritize action accordingly. For a food and beverage company, upstream stages such as agriculture and ingredient sourcing may dominate the emissions profile. For a consumer electronics brand, it may be component manufacturing or energy consumed by customers over a product’s lifetime. This visibility enables targeted decarbonization strategies rather than vague, unfocused commitments.

Transportation and distribution, both upstream and downstream, is one of the most significant and actionable Scope 3 categories. Supply chain logistics cover the movement of goods at every stage: raw materials arriving at factories, finished products reaching distribution centers, and last-mile delivery to customers. According to a 2018 IEA estimate, freight transport accounts for approximately 8% of global greenhouse gas emissions; a share expected to grow alongside rising e-commerce volumes. Addressing logistics-related Scope 3 emissions requires modal shifts, meaning switching to lower-carbon transport modes such as from air freight to sea, as well as route optimization and collaboration with lower-emission carriers. These emissions are often invisible in practice, buried in third-party carrier data, making systematic measurement a prerequisite for meaningful reduction. That measurement challenge is itself part of a broader data problem that defines Scope 3 work.

Underpinning all Scope 3 measurement is rigorous carbon accounting, the systematic process of quantifying an organization's greenhouse gas emissions. For Scope 3, this involves applying emission factors to convert activity data into carbon-equivalent figures, choosing appropriate calculation methods, and maintaining consistent boundary definitions across reporting periods. Data remains the central challenge. Unlike Scope 1 and 2, which draw on internal fuel and utility records, Scope 3 data must be gathered from across an organization's supply chain network, often hundreds of suppliers, many in regions with limited reporting infrastructure. Leading practice takes a tiered approach: spend-based estimates for lower-priority suppliers, and direct engagement with strategic partners for primary activity data. The GHG Protocol's Corporate Value Chain (Scope 3) Standard is the primary reference for this work. ISO 14064, developed by the International Organization for Standardization, provides additional technical guidance on GHG quantification, monitoring, and verification. The Science Based Targets initiative (SBTi) requires companies to set Scope 3 targets, with supplier engagement targets as one qualifying mechanism, when Scope 3 represents 40% or more of total emissions; a threshold that applies to the vast majority of companies.

Beyond regulatory compliance, organizations that actively manage Scope 3 emissions gain tangible advantages: stronger relationships with sustainability-conscious customers, greater supply chain resilience, and reduced exposure to carbon pricing. The IPCC’s Sixth Assessment Report makes clear that achieving the Paris Agreement’s 1.5°C target demands rapid, deep reductions across all sectors, and Scope 3 emissions cannot be left out of that equation.