Decide when a carbon inventory base year needs recalculation

A carbon inventory base year should remain comparable when the organisation's structure or calculation basis changes materially. Assess the change against a documented recalculation policy, preserve the original figures and explain any restatement. Do not describe a boundary change as an operational emissions reduction.

GHG Protocol's revised Corporate Standard and its base-year adjustment material distinguish structural changes from organic growth and decline. They also address significant method changes and errors. The corporate suite is under an update process, but an update process alone does not replace the published requirements being applied to an inventory. Check the operative method and any separate reporting or target-programme rules before deciding. GHG Protocol Corporate Standard GHG Protocol base year adjustments GHG Protocol corporate standards update process

Identify the type of change before recalculating. Apply a documented significance policy consistently. Reconstruct a comparable boundary with supported data. Keep original and restated series visible, and distinguish methodological comparability from performance claims.

Ask whether the event changes the organisational structure, reflects organic activity growth or decline, changes the calculation method, improves data accuracy or corrects an error. An acquisition and increased output at an existing facility are not the same kind of event.

Document the date, affected entities and inventory categories. Review any effect on the chosen consolidation approach and historical boundary. Canadian regulatory or securities reporting, assurance engagements and voluntary target programmes may impose additional requirements; this guide does not determine which apply to a particular company.

Record the quantitative and qualitative criteria used to decide whether recalculation is needed. Consider how several smaller changes are assessed together. The policy should identify the decision owner, evidence required and treatment of unavailable historical data.

Do not present a five-percent threshold as a universal GHG Protocol rule. A particular programme may specify its own threshold or requirements, while the Corporate Standard approach requires an appropriate significance policy. Verify the actual framework being claimed rather than copying a percentage from another company's report. GHG Protocol Corporate Standard

Identify the base-year activity and emissions information for the affected operations. Check the boundary, methods, units and factor basis before combining figures. Where historical data is estimated, explain the method and uncertainty and obtain an appropriate review.

Preserve the original published series and create a reconciliation to the restated series. Record each adjustment separately so users can distinguish structural change, calculation corrections and other effects. Avoid silently overwriting an old spreadsheet and leaving no explanation of the changed baseline.

Assume an invented Canadian group reported base-year emissions of 20,000 tonnes CO2e. It later acquires an operation that existed in the base year and had a supported 5,000-tonne inventory within the relevant comparable boundary. Assume the acquisition meets the group's documented recalculation policy and no other adjustments are needed. These are invented figures and simplifying assumptions.

The illustrative restated base year is 25,000 tonnes CO2e. That change does not mean the group reduced emissions by 5,000 tonnes or generated a credit. It changes the comparison boundary so that subsequent performance can be evaluated on a supported basis.

If the acquired operation's historical data used a different method, the team would first assess compatibility and necessary adjustments. Adding the two headline numbers without that check could create a misleading baseline. If the operation did not exist in the base year, the simple example would not apply unchanged.

Explain which changes affect the inventory series and whether related targets or progress calculations require adjustment under their own rules. A recalculated base year does not automatically authorise a new target or validate a reduction claim.

Use supplier data quality in Scope 3 estimates where improved supplier data affects the historical comparison, checking whether the change is a data-quality improvement that triggers the applicable policy. Recalculate consistently across relevant periods where required by the method, and disclose practical limitations transparently.

Have the responsible technical reviewer check the change classification, significance assessment, historical evidence, calculations and disclosures. Retain the approval and source versions. Coordinate with reporting and assurance owners before replacing figures in externally used documents.

Monitor the GHG Protocol update process and other applicable frameworks, but label consultations and work in progress accurately. Do not adopt an unpublished future rule as though it were already effective or imply that an old standard became invalid merely because revision work began.

Organic growth is different from a structural change under the Corporate Standard approach. Assess the actual event and applicable method rather than treating every increase as a restatement trigger.

Apply the documented policy, consider cumulative effects and correct records appropriately. Materiality decisions and transparent recordkeeping are separate from pretending the error never occurred.

No. It establishes a changed comparison basis. Any performance conclusion needs comparable current-period data and a supported explanation of the result.

GHG Protocol Corporate Standard — Revised Corporate Standard 2004; use with applicable amendments and Scope 2 Guidance. Inventory method, not universal reporting legislation.

GHG Protocol base year adjustments — Corporate Standard supporting appendix, March 2004. Structural-change examples; no universal percentage threshold inferred.

GHG Protocol corporate standards update process — Live development page checked 2 October 2026. Development work is distinct from an adopted replacement method.

QSE Advisory is part of the QSE Advisory brand family. Preparation included AI-assisted research and drafting. Examples are hypothetical.

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