Which Carbon Inventory Standard Should Companies Use? ISO 14064 vs GHG Protocol
Companies preparing to start a greenhouse gas inventory encounter two mainstream international standards: ISO 14064 and the GHG Protocol. Which meets Taiwanese regulatory requirements? Which is better suited to internal carbon management and sustainability reporting? For those responsible for inventories or sustainability reports, this article explains the differences, how to use the standards together, and the latest IFRS S2 developments, helping you meet regulations while strengthening international communication and emissions reduction strategies.
What to decide after reading If you came for emission factors, ISO 14064, CBAM, or carbon data, the next step is to check whether activity data, emission factor versions, and supporting evidence can be traced.
Table of Contents
Updated on October 6, 2026. This update adds the ISO/GHG Protocol harmonisation partnership and adjustments to Taiwan's IFRS adoption.
Which Standard Fits Which Situation?
For Third-Party Verification and Regulatory Compliance: Use the ISO 14064 Series
If your company operates in a high-emitting industry and is required to conduct mandatory inventories, registration and verification under the Climate Change Response Act, ISO 14064-1 is the best choice. Combining it with third-party verification under ISO 14064-3 can meet Taiwanese regulatory and international verification requirements.
If your company is subject to the greenhouse gas inventory standards applicable under the Financial Supervisory Commission's (FSC) greenhouse gas inventory disclosure rules, you can use either the GHG Protocol or ISO 14064-1, with assurance under ISAE 3410 or ISO 14064-3.
For Internal Carbon Management and International Initiative Disclosures: Prioritise the GHG Protocol
If your company reports to CDP, sets science-based emissions reduction targets through SBTi, or responds to supply chain decarbonisation requirements, the GHG Protocol offers clear scope classifications and detailed Scope 3 categories (15 in total), providing a more comprehensive view of its carbon footprint.
For Both Verification and Management: Combining the Two Is the Most Robust Approach
Many companies use the GHG Protocol to guide inventory methodology and the ISO 14064 series as the structural basis for reporting and verification.
The GHG Protocol provides detailed classifications and calculation methods for Scopes 1, 2 and 3, including how to collect data, estimate and quantify each emission source. It is suitable for planning inventory boundaries, compiling emission inventories and tracking carbon footprints. ISO 14064-1 provides a standardised framework defining principles and requirements for organisational greenhouse gas quantification and reporting, including how to design, manage and present overall inventory results. Third-party verification under ISO 14064-3 then helps ensure consistency and international credibility. This approach enables companies to understand their emission sources effectively and produce formal reports supported by verification and regulatory compliance, balancing practicality and compliance.
Turn this article into your next step
If this article touches disclosure, carbon inventory, or report preparation, use the system or database to check how peers handle it.
What Do Taiwanese Regulations Require?
Ministry of Environment (formerly the Environmental Protection Administration):
- Under Article 21 of the Climate Change Response Act, designated emission sources must complete an inventory, registration and verification each year.
- Official guidance explicitly states that inventories may refer to ISO 14064-1 and the GHG Protocol, while ISO 14064-3 is recommended for verification.
Financial Supervisory Commission (FSC):
- The Sustainable Development Roadmap requires all TWSE/TPEx-listed companies to complete inventories by 2027. On September 23, 2026, the FSC and Ministry of Environment announced adjustments to the adoption pathway: Phase 2 and 3 companies no longer need assurance of parent-company-only Scope 1 and 2 emissions information, and approximately 560 listed companies are required to adopt IFRS Sustainability Disclosure Standards. Scope 3 disclosure becomes voluntary for Phase 3 companies. This does not remove all inventory or group assurance obligations. Entities regulated by the Ministry of Environment must still follow its inventory and verification requirements; financial, insurance, and securities and futures businesses follow their respective rules. Source: FSC announcement of September 23, 2026; for details, see IFRS Phase 3 Adjustments.
- The GHG Protocol is expected to be the required standard under IFRS S2, with an exception: if a jurisdictional authority or the exchange on which an entity is listed requires a different measurement method, the entity may use that method instead. IFRS S2 generally requires disclosure of Scopes 1, 2 and 3; Taiwanese companies must still determine their actual disclosure obligations based on their adoption phase and the regulator's transition measures.
How Does IFRS S2 Regulate GHG Information?
The international sustainability disclosure standard IFRS S2 explicitly requires companies to conduct inventories under the GHG Protocol and disclose comprehensive Scope 1, 2 and 3 emissions information.
Under the September 2026 adjustment package, Scope 3 disclosure is voluntary for Taiwan's Phase 3 companies. The actual application of the policy package remains subject to regulations formally issued by the authorities. A reminder: the GHG Protocol is the only GHG inventory standard explicitly named in IFRS S2, but companies requiring verification under Taiwanese law can also apply ISO 14064.
The Two Standards Will Be Harmonised
On September 9, 2025, ISO and the GHG Protocol announced a partnership to harmonise the ISO 1406X series, including ISO 14064-1, with the GHG Protocol Corporate, Scope 2 and Scope 3 standards, working toward jointly branded, dual-logo international standards. They will also jointly develop a product carbon footprint standard. For now, the two sets of standards remain separately applicable. Companies should conduct inventories under current requirements and monitor the publication schedule for the harmonised versions.
Source: ISO and GHG Protocol partnership announcement.
From Choosing Standards to Taking Action: Building a Credible Carbon Inventory System
As the world moves toward net zero and transparent disclosure, companies need inventories not just for compliance but to build carbon information systems that support emissions reduction targets, investment decisions and brand trust. Whether you choose the rigour of ISO 14064 or the flexibility and detail of the GHG Protocol, the key is: "Be clear about your goals. The right tools help you go further, faster."
Companies are advised to adopt a combined strategy, building a carbon inventory framework that meets regulatory requirements, initiative commitments and investor expectations while preparing for IFRS S2 and the net-zero transition.
References
Taiwan Ministry of Environment greenhouse gas portal
ISO 14064 IFRS S2 SBTi GHG Protocol Carbon Inventory Standards
FAQ
View AllWhen should a company choose the ISO 14064 series for its carbon inventory?
If a company operates in a high-emitting industry and must conduct mandatory inventories, registration and verification under the Climate Change Response Act, ISO 14064-1 is the best choice. It should be paired with third-party verification under ISO 14064-3 to meet Taiwanese regulatory and international verification requirements.
Which carbon inventory standard should companies use for CDP reporting or SBTi emissions reduction targets?
Companies reporting to CDP or setting science-based emissions reduction targets through SBTi should prioritise the GHG Protocol. Its clear scope classifications and detailed Scope 3 categories (15 in total) help provide a comprehensive picture of their carbon footprint.
What specific carbon inventory requirements apply to companies under Taiwanese law?
Under Article 21 of the Climate Change Response Act, designated emission sources in Taiwan must complete an inventory, registration and verification annually. Inventories are advised to refer to ISO 14064-1 and the GHG Protocol, with verification under ISO 14064-3.
Turn Carbon Data into an Auditable Workflow
Use DCarbon to calculate emissions with the emission factors you configure and organize activity data and supporting evidence, so inventory data stays traceable, reviewable, and ready for customer requests.
How to decide the next stepTurn the regulation or factor requirements in the article into a data checklist first. If data crosses sites or departments, or needs verification, then evaluate whether system-based management is needed.