Scope 3 covers indirect value-chain emissions that are outside a reporting company's Scope 1 and Scope 2 boundary. Under the GHG Protocol, upstream emissions from purchased fuels can fall in Category 3, while combustion on a vessel owned or controlled by the reporting company is normally Scope 1. Charter and lease arrangements can change the classification, so the company's consolidation approach must be set before the calculation.
The GHG Protocol Scope 3 Standard permits calculation with activity data and emission factors, including estimates where primary data is unavailable. IFRS S2 also requires disclosure of the measurement approach, inputs, and assumptions used for Scope 3. More specific supplier data can be useful, but only when its lifecycle boundary, gases, global-warming potentials, allocation method, units, and reporting period fit the inventory method.
A supplier's lifecycle CI should not be copied into a corporate inventory without reconciliation. Multiply only compatible activity data and factors, keep well-to-tank and tank-to-wake boundaries clear, document exclusions, and retain the source and version of each factor. Report significant estimation uncertainty rather than presenting a modelled value as direct measurement.
Scope 3 inventories of different companies can overlap by design because one company's direct emissions can appear in another company's value chain. That overlap does not by itself prove an error. The reporting company should prevent duplicate entries within its own inventory and should not claim exclusive ownership of a reduction unless the applicable claim standard and evidence support that statement.
Verdaxis records supplier-declared CI, method, feedstock, origin, and certification fields for relevant listings. It does not currently prepare a company's Scope 3 inventory, retire environmental attributes, or provide assurance over those declarations. Use the platform record as a commercial data input and review the underlying evidence before using it in a report or reduction claim.