CARB releases draft reporting template for SB 253: what California companies need to know

The California Air Resources Board (CARB) has published a new draft reporting template for SB 253, the Climate Corporate Data Accountability Act. This landmark law is part of California’s climate disclosure laws and requires companies doing business in California with total annual revenues exceeding $1 billion to report their greenhouse gas (GHG) emissions each year.

CARB’s proposed reporting framework – released in Excel format – sets out the data fields that reporting entities will use to disclose Scope 1 (direct) and Scope 2 (indirect) greenhouse gas emissions beginning in 2026, covering fiscal 2025. While use of the template is voluntary for the first cycle, it marks an important step toward standardized, publicly accessible climate disclosures in the U.S.

Below, we answer the key questions about this new California law, how companies can begin preparing, and how ESG software can help manage complex emissions reporting efficiently and accurately.

What is the new template designed to do?

CARB stated that the template is intended to streamline the reporting process for large businesses and private companies subject to California’s Climate Corporate Data Accountability Act. It provides a consistent structure to capture essential emissions data and helps entities – particularly those disclosing for the first time – understand what must be publicly reported under SB 253.

The template is also designed to support good faith efforts at compliance during the first reporting timelines in 2026. Companies are encouraged to use the format to ensure data comparability across sectors and to align with the Greenhouse Gas Protocol (GHG Protocol).

CARB reiterated that the file is a guidance document, not a legally binding instrument. It does not replace or modify the bill text of California SB 253 or other climate disclosure laws, but it offers a reasonable basis for reporting entities to start organizing data, setting boundaries, and engaging third-party assurance providers.

Which greenhouse gas emissions scopes are covered in the template?

The draft CARB proposed template covers Scope 1 and Scope 2 GHG emissions, which companies must disclose starting in 2026.

• Scope 1 emissions include direct releases from owned or controlled sources – such as stationary and mobile combustion, process emissions, and fugitive emissions.
• Scope 2 emissions cover indirect emissions from purchased electricity, heating, steam, or cooling used in operations.

Each reporting entity must also indicate whether its organizational boundary is based on an equity share, financial control, or operational control approach, in line with the GHG Protocol.

While Scope 3 emissions (value chain and supply chain impacts) are not yet included in this draft, SB 253 requires disclosure of these indirect emissions beginning in 2027 for fiscal 2026. Companies will need to track emissions across their supply chains to comply with these future reporting requirements. CARB confirmed it will release a separate template and additional workshops to support that next phase of reporting requirements.

At the end of the process, CARB’s list will identify which companies are required to comply with SB 253 based on the established criteria.

What else does the template include, such as emissions data?

The draft template includes a detailed list of fields intended to make emissions disclosures more transparent and comparable. These are grouped into eight core sections:

1. Organization information – Company name, headquarters, industry (NAICS code), employer identification number, contact details, and relevant subsidiaries.
2. Third-party verification – Information about the independent third party performing limited assurance on reported GHG emissions, including the assurance provider’s contact details and verification date. The assurance provider must be independent and qualified to perform the required verification. SB 253 will require third party assurance for emissions disclosures to ensure credibility and compliance.
3. Inventory boundary – A description of entities and facilities included or excluded from the organizational boundary, along with explanations for any omissions. Note that government entities are generally exempt from SB 253’s disclosure requirements.
4. Scope 1 and 2 disclosures – Quantitative data on total GHG emissions, broken down by emission source, with intensity metrics such as emissions per million dollars of revenue.
5. Methodology – The calculation approaches, emission factors, and global warming potential (GWP) sources used to estimate carbon emissions.
6. De minimis and minor sources – Details on any immaterial sources excluded and the estimated emissions associated with those exclusions.
7. California MRR alignment – Optional fields connecting reported data to the Mandatory Reporting Regulation (MRR) for regulated facilities.
8. Emission reductions – Optional reporting for renewable electricity or renewable gas contracts that deliver measurable emissions reductions.

The template also features optional fields for future use, such as base year emissions, to support trend analysis and transparency over time. CARB may later make some of these fields mandatory as the climate disclosure program matures.

Are in-scope companies obliged to use the template under California’s climate disclosure laws?

For now, no. CARB clarified that using the template for the 2026 reporting cycle is voluntary. Entities may choose alternative formats for their emissions reporting, provided the disclosures meet the core disclosure requirements under SB 253 and are publicly disclosed in a machine-readable, accessible format.

However, companies are strongly encouraged to adopt the template early to ensure consistency with the reporting framework that will likely become standard in subsequent years. It is also expected to help firms demonstrate good faith compliance and avoid potential administrative penalties or civil penalties linked to incomplete reporting or non-compliance once mandatory rules take effect.

Where can the template be downloaded from?

The draft reporting template is available directly on CARB’s public docket and can be accessed via the Air Resources Board (CARB) website. The file is provided in Excel format with drop-down menus and free-text fields to facilitate easy data entry.

How can ESG software help with third party assurance?

For companies required to comply with California’s climate disclosure laws, the reporting process can be resource-intensive. SB 253 introduces complex data management challenges, particularly for organizations operating across multiple regions and value chains. Manual spreadsheets can quickly become inadequate as firms move toward limited third-party assurance or reasonable assurance in later years.

ESG software platforms like Sweep or similar systems can help improve efficiency, accuracy, and traceability at every stage of the reporting process:

• Automated data collection: Integrate utility data, fuel records, and supplier information to reduce manual errors.
• Boundary definition tools: Map subsidiaries and limited liability companies to ensure complete reporting entity coverage.
• Built-in validation: Apply standardized emission factors and GHG Protocol methodologies to maintain consistency.
• Assurance readiness: Create audit trails for third-party verification, reducing the time and cost of compliance reviews.
• Scenario modelling: Use analytics to identify high-impact emissions sources and evaluate climate risk reduction opportunities. Scenario modelling can help companies identify and mitigate climate risks as part of their overall risk management strategy. Access to accurate emissions data enables companies and investors to make more informed decisions about climate strategies and investments.

By adopting digital emissions data systems now, businesses can establish reasonable assurance foundations and demonstrate good faith efforts long before mandatory disclosure requirements take effect.

Looking ahead

The release of CARB’s draft SB 253 reporting template marks a pivotal milestone in the rollout of California’s climate disclosure framework. Together with SB 261, which addresses climate-related financial risk, these laws signal the most ambitious corporate climate disclosure regime in the United States.

CARB’s list of key milestones includes draft implementing rules expected in October 2025, a 45-day public comment period, and a final publicly accessible regulation by year-end. Companies doing business in California – especially those meeting the $1 billion annual revenue threshold – should use this period to prepare internal systems, engage assurance providers, and build reliable reporting processes that align with the GHG Protocol and other regulations.

The message is clear: begin preparing now. Whether through supplier engagement, improved data governance, or integrated ESG platforms, companies that act early will be better positioned to comply with California’s climate disclosure laws – and to turn compliance into credible climate action.

For more details, visit the California Air Resources Board website or download the CARB proposed SB 253 template directly from the public docket. Feedback remains open until October 27, 2025.