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Reference Standards and Verifier Accreditation for Carbon Offset Protocols

Published: November 9, 2022 by Editorial Team

The phrase “high quality, high integrity” offsets is repeatedly used by project developers, rating agencies, and end users; all seeking to define what constitutes a real and additional greenhouse gas reduction. With offsets now available from a plethora of project types, determining what makes one high-quality, and another low-quality, requires some inquiry. With so much discussion around the rigor of offsets, it is useful to understand the structures underlying protocol development.

Reference standards are often overlooked components of well-vetted carbon offset protocols. They serve as foundational frameworks for developing project methodologies outlining major concepts, principals, and procedures that projects must follow. ISO 14064-2 and the WRI GHG Protocol for Project Accounting are examples of reference standards applied in the Climate Action Reserve Offset Program Manual [1], American Carbon Registry Standard [2], and VERRA Program Guide [3]. Both ISO 14064-2 and the WRI GHG Protocol for Project Accounting provide recognized definitions for many terms specific to carbon projects. The International Organization for Standardization (ISO) and World Resources Institute (WRI) are global non-profits who bring together experts for the research and development of deployable standards that form the backbone of several recognized GHG programs [4] [5].

These reference standards are not intended to be stand-alone mechanisms for generating offsets, and should be paired with GHG programs (like CAR, ACR, or VCS) that provide further project-specific requirements. This layering of standards builds confidence for offsets generated by protocols whose program utilizes credible reference standards. Like protocols themselves, the ISO and WRI conventions are periodically updated to reflect current best-practice based on expert contribution. In today’s complex market, identifying the reference standards used for a carbon offset program or project can be a practical first step in assessing credibility.

Specifically, the ISO 14064 series consists of three documents that provide guidance for organizational GHG accounting, project level GHG accounting, and verification. In addition, the ISO 14065 standard details the requirements for third-party verification and validation activities, serving as a basis for verifier accreditation [6]. Verifiers working with CAR for example must be actively accredited by the ANSI National Accreditation Board that requires verifiers to maintain compliance with ISO 14065 provisions. Verifier accreditation can therefore be another indicator of accountability and impartiality efforts being made by reputable carbon registries.

Technical requirements such as these provide insight on some of the tools shaping carbon offset protocols and audit services in the voluntary market. Reliable reference standards and verifier accreditations demonstrate programmatic controls in place to provide carbon projects with greater assurance. Clear efforts for standardization like this will continue to be essential for layering expertise into the justification of GHG claims being made.



[1] Climate Action Reserve Program Manual
[2] American Carbon Registry Standard
[3] Verified Carbon Standard Program Details
[4] ISO 14064-2
[5] GHG Protocol Standards
[6] ISO 14065