Materiality in carbon reporting is the principle of concentrating measurement effort on the emissions sources that genuinely matter — those that are large in magnitude, high-risk, or important to the company's stakeholders — rather than treating every possible source equally.
It is most often discussed in the context of Scope 3, where the GHG Protocol's 15 categories make some level of prioritisation essential. The Scope 3 Standard requires companies to assess each category against a set of materiality criteria and document which are included, which are excluded, and why.
Why it matters
A footprint that exhaustively measures trivial sources but misses a major one is misleading. Conversely, a footprint that omits an entire category without justification looks like greenwashing — even if the omitted category is genuinely immaterial.
The GHG Protocol's materiality criteria for Scope 3 include: size (likely magnitude relative to the total footprint), influence (whether the company can drive reductions), risk (regulatory, reputational, or financial exposure), and stakeholder concern (what customers, investors, and procurement bodies expect to see).
A practical example
A pure-service consultancy might reasonably exclude Scope 3 Category 11 (Use of Sold Products) — there are no products in use to track — and document the exclusion as immaterial. A SaaS company, by contrast, might find that Category 11 (the energy used by customers running the software) is one of its largest sources and must be included.
We assess materiality for every Scope 3 category during the Identify phase. See how on the methodology page.