Assurance and Verification
Assurance (or verification) is an independent third-party assessment of an organization's GHG emissions data and reporting processes. Limited assurance provides moderate confidence that the data is free of material misstatement; reasonable assurance provides a higher level of confidence similar to a financial audit.
Third-party assurance adds credibility to emissions disclosures. It is required by several regulations (CSRD mandates limited assurance moving to reasonable, SB 253 requires limited assurance, CDP encourages it) and expected by investors and customers.
Assurance engagements are typically conducted by accounting firms or specialized environmental verification bodies (e.g., SCS Global, Bureau Veritas, SGS) against recognized standards such as ISO 14064-3, ISAE 3000, or AA1000AS.
Limited assurance involves reviewing processes, performing analytical procedures, and making inquiries — resulting in a conclusion stated in the negative ("nothing has come to our attention…"). Reasonable assurance requires more extensive testing of underlying data, systems, and controls — resulting in a positive conclusion ("in our opinion, the data fairly presents…").
The quality of underlying data and evidence trails directly affects the assurance process. Organizations with well-documented data collection processes, clear factor selection rationale, and source-linked calculations complete assurance engagements faster and at lower cost. Gravity's evidence-based architecture — where every figure links back to source documents — is designed to make verification straightforward.
Frequently asked questions
What is assurance in carbon accounting? +
What is the difference between limited and reasonable assurance? +
Limited assurance involves review procedures and results in a negatively stated conclusion. Reasonable assurance requires more extensive testing of data and controls, resulting in a positively stated opinion. CSRD begins with limited assurance and will transition to reasonable assurance.
Related terms
Carbon Accounting
Carbon accounting is the systematic process of measuring, recording, and reporting the greenhouse gas (GHG) emissions produced by an organization, product, or activity. It follows standardized methodologies — most commonly the GHG Protocol — to quantify emissions across Scope 1 (direct), Scope 2 (purchased energy), and Scope 3 (value chain) categories, producing an auditable inventory that underpins disclosure, reduction planning, and regulatory compliance.
CSRD (Corporate Sustainability Reporting Directive)
The Corporate Sustainability Reporting Directive (CSRD) is the European Union's mandatory sustainability reporting law. It requires companies operating in the EU above certain thresholds to disclose environmental, social, and governance (ESG) information according to the European Sustainability Reporting Standards (ESRS), with third-party assurance.
California SB 253 (Climate Corporate Data Accountability Act)
SB 253 is a California law requiring companies doing business in the state with annual revenues exceeding $1 billion to report Scope 1, 2, and 3 greenhouse gas emissions annually, beginning with Scope 1 and 2 for reporting year 2026 and Scope 3 for reporting year 2027.
CDP (formerly Carbon Disclosure Project)
CDP is a global non-profit organization that operates the world's largest environmental disclosure system. It collects self-reported climate, water, and forest data from thousands of companies, cities, and subnational governments on behalf of investors and purchasers, scoring disclosures from A (leadership) to D– (minimal).
Data Quality (in Carbon Accounting)
Data quality in carbon accounting refers to the accuracy, completeness, consistency, and transparency of the emissions data and calculation inputs used to produce a GHG inventory. Higher data quality — using primary, measured data instead of estimates — produces more accurate and credible emission figures.