Key Takeaways

• CARB held a public workshop on July 21, 2026, to preview SB 253 regulatory concepts for 2027 and beyond (with no changes to 2026 reporting obligations).
• CARB’s December 2024 enforcement notice remains the operative guidance for 2026 reporting; companies must report only data already being collected as of the date of that notice, if any, with no assurance required.
• CARB confirmed that November 10, 2026, is the reporting deadline for greenhouse gas emissions for the prior year; CARB will publish submission guidance by September 1, 2026.
• For 2027, CARB will require mandatory reporting for the five most commonly reported Scope 3 categories; the remaining 10 will be voluntary.
• Independent third-party limited assurance of Scope 1 and 2 emissions becomes mandatory beginning with 2027 reports.
• Insurance companies will be subject to SB 253 starting in 2027; CARB proposes allowing insurers to submit existing CDI/NAIC data supplemented by any additional information needed to satisfy SB 253 requirements.
• CARB expects to publish a proposed regulation this fall.
• Six industry-specific virtual listening sessions begin August 5, 2026.
• CARB did not provide any details on its plans to issue “clarifying” revisions to the initial regulations approved by the Board in February 2026.

About the Workshop

On July 21, 2026, California Air Resources Board (CARB) staff held a virtual public workshop to preview CARB’s efforts to develop additional regulations implementing Senate Bill (SB) 253, the Climate Corporate Data Accountability Act (codified at Health and Safety Code Section 38532). The new regulation would apply to greenhouse gas (GHG) reporting beginning in 2027.

CARB staff opened the workshop by positioning SB 253 within a broader global trend toward mandatory corporate climate disclosure, noting that jurisdictions collectively representing more than two-thirds of the world’s population and approximately 60% of global GDP have enacted or are developing similar programs. Staff emphasized their intent to maximize interoperability with existing international frameworks to reduce the compliance burden for companies already reporting under other programs.

2026 Reporting: What the Workshop Confirmed

A recurring theme throughout the July 21 workshop was distinguishing 2026 reporting requirements from what CARB is proposing for 2027 and beyond. The regulatory concepts previewed at the workshop do not apply to this year’s GHG reporting, which staff confirmed will be due on November 10, 2026.

For 2026, staff confirmed:

• CARB’s December 2024 enforcement notice applies. Companies are only expected to report data that was collected or the company planned to collect, if any, as of the December 2024 notice.
• No third-party assurance is required for 2026 submissions.
• CARB’s 2025 draft emissions reporting template is optional, not mandatory.
• The deadline for reporting Scope 1 and Scope 2 GHG emissions for the preceding fiscal year is November 10, 2026, reflecting the extended timeline CARB announced on June 24, 2026, when it announced it would submit a revised initial regulation package to the Office of Administrative Law.

CARB also announced that it will publish detailed guidance for 2026 reporting, including a voluntary online intake form and instructional video, by September 1, 2026.

Several commenters sought more specificity about what will be in the September 1 guidance and the forthcoming changes to the initial implementing regulation, but CARB staff declined to preview the guidance or address the anticipated regulatory revisions.

Preview for 2027: General Reporting Requirements

The bulk of the workshop was devoted to regulatory concepts CARB intends to include in its proposed 2027 regulation. Staff organized the presentation around several thematic areas:

General Reporting Framework. All reporting under the 2027 regulation will be anchored in the five foundational principles of the GHG Protocol (GHG-P): relevance, completeness, consistency, transparency, and accuracy. CARB identified which elements of its own anticipated reporting framework are already required by the GHG-P, which are recommended by the GHG-P, and which go beyond the GHG-P.

Scope 3 Phase-In: Five Categories Required in 2027

CARB staff announced that it will phase in Scope 3 emissions reporting, rather than initially requiring reporting for all 15 Scope 3 categories. Beginning with 2027 reports, CARB will require reporting for the following five most commonly reported Scope 3 categories:

1. Purchased goods and services
2. Fuel- and energy-related activities
3. Waste generated in operations
4. Business travel
5. Employee commuting

Assurance Requirements

CARB staff confirmed that independent third-party limited assurance of Scope 1 and 2 emissions will be required beginning with 2027 reports. A reasonable assurance engagement may substitute for limited assurance.

Insurance Sector: SB 253 Exemption Ends in 2027

CARB plans to end the SB 253 exemption for insurers it adopted as part of the initial regulation beginning in 2027. This will not affect the statutory exemption for insurers under SB 261 for climate-related financial risk disclosures. To minimize duplication, staff’s proposal would allow insurance companies to rely on GHG emissions disclosures they already prepare under CDI/NAIC guidelines, supplemented by whatever additional data is needed to satisfy SB 253.

How to Engage Before CARB’s Release of the Proposed 2027 Regulation

CARB’s proposed 2027 regulation, including full draft regulatory text, a staff report, and an economic analysis, is expected this fall and will be subject to a 45-day public comment period prior to a board hearing. In the meantime, companies have several near-term engagement opportunities:

• Six industry sector-specific virtual listening sessions beginning August 5, 2026;
• Written comments accepted on an ongoing basis at climatedisclosure@arb.ca.gov; and
• A 15-day public comment period on the revised 2026 regulation package, once published.