CARB Releases 2026 Guidance & Voluntary Reporting Intake for California SB 253 Compliance

Guidance for SB 253 2026 Reporting Submittals

If your company operates in California, climate reporting compliance just took a major step forward. The California Air Resources Board (CARB) officially released updated instructions for reporting calendar year/fiscal year 2025 Scope 1 and Scope 2 greenhouse gas (GHG) emissions under California’s Senate Bill 253 (the Climate Corporate Data Accountability Act).

CARB has also opened its voluntary intake platform, allowing impacted corporate entities to begin organizing their compliance data ahead of upcoming deadlines.

Here is a complete breakdown of acceptable submission formats, non-reporting exceptions, compliance deadlines, and key public disclosure considerations for your organization.

Acceptable Submission Formats for 2026 SB 253 Reporting

To accommodate varying organizational readiness during the initial 2026 reporting cycle, CARB allows companies to submit Scope 1 and Scope 2 GHG data using different data formats:

1. Existing Annual Sustainability Reports
   • Submit a current corporate annual report that already includes verified Scope 1 and Scope 2 emissions figures.
2. Third-Party Framework Submissions
   • Submit existing Scope 1 and 2 emissions data previously disclosed through recognized voluntary reporting initiatives, such as CDP or EcoVadis.
3. CARB’s Official Reporting Template
   • Complete and submit CARB’s standardized Draft Scope 1 & 2 Template.

CARB Rules for Statements of Non-Reporting

Not all businesses subject to the law had established emissions tracking systems in place when regulatory enforcement began. CARB provides a specific protocol for these entities:

• Eligibility: If your organization was not actively collecting Scope 1 and Scope 2 emissions data as of December 5, 2024, you are eligible to file an official statement of non-reporting.
• Requirements: The statement must be printed on company letterhead and explicitly declare that your entity was neither collecting data nor planning to collect data at the time the original CARB Enforcement Notice was issued.

Submission Process, Deadlines, and Fee Structures

CARB has streamlined how corporate reporting teams and legal advisors submit documentation.

How to Submit

GHG inventories or formal statements of non-reporting, can be submitted via:

• CARB’s 2026 Report Intake Platform
• Direct Email Submission: climatedisclosure@arb.ca.gov

Key Deadlines & Invoicing Rules

• Primary Submission Deadline, November 10, 2026: Scope 1 & 2 GHG inventory data OR your company’s statement of non-reporting must be submitted to CARB.
• Fee Assessment Notices, On or Before December 10, 2026, : CARB will issue annual compliance fee notices based on the statutory calculation formula outlined in § 96073 of the regulation.

⚠️ Critical Compliance Note: All uploaded emissions reports and statements of non-reporting will be made available to the public. Ensure your legal, compliance, and communications teams conduct thorough reviews prior to uploading any corporate files.

Planning for Requirements in 2027 and Beyond

While current efforts center on the 2026 Scope 1 and 2 submission window, CARB staff previewed key regulatory concepts for 2027 and future reporting cycles.

Companies should prepare for a significant step-up in reporting complexity:

• Alignment with GHG Protocol Standards: Ongoing reporting starting in 2027 will strictly require reporting entities to conduct accounting and quantification adhering to the Greenhouse Gas Protocol Corporate Standard, Scope 2 Guidance, and Scope 3 Standard. CARB noted it will static-code standards (e.g., the 2015 Scope 2 Guidance) rather than dynamic updates.
• Gross Emissions Disclosures: Covered entities will be required to disclose gross Scope 1, Scope 2, and Scope 3 GHG emissions generated during the reporting period, expressed in metric tons of CO₂e.
• Third-Party Assurance Requirements: CARB staff indicated that third-party limited assurance requirements will apply to Scope 1 & 2 starting in 2027, elevating the importance of data governance and audit trails.
• Standardized Deadlines & Fiscal Year Mapping: Under proposed concepts, annual Scope 1, 2, and 3 disclosures deadlines are to be determined for 2027. CARB clarified how fiscal year-ends dictate reporting: entities with fiscal years ending between January 1 and February 1 will report for that calendar year, while those ending after February 1 will report data from the prior fiscal year.
• Documentation of Missing/Substitute Data: Similar to California's Mandatory Reporting Regulation (MRR), reporting entities will need to document any missing parameters, explain substitute data methods or estimates used, and state the reasoning behind assumptions