The measures confirmed by CARB are designed to provide a "soft landing" for businesses as they navigate the complexities of Senate Bill 253 (SB 253), also known as the Climate Corporate Data Accountability Act. The new guidance allows companies to utilize emissions data already collected for the prior fiscal year, waives reporting requirements for certain Scope 1 and Scope 2 data if it had not been previously tracked, and permits the submission of reports without the usually mandatory limited assurance for the 2026 cycle. This regulatory flexibility reflects the immense logistical challenges inherent in establishing high-fidelity carbon accounting systems across global supply chains.
Understanding the Scope of California’s Climate Mandate
California’s climate disclosure framework represents the most ambitious corporate transparency initiative in the United States. Under SB 253, all public and private entities with total annual revenues exceeding $1 billion that "do business" in California are required to disclose their carbon footprints. This threshold is expected to capture over 5,000 corporations, including many of the world’s largest multinational firms, regardless of where they are headquartered.
The reporting requirements are bifurcated into categories defined by the Greenhouse Gas Protocol. Scope 1 emissions encompass direct emissions from sources owned or controlled by the company, such as onsite manufacturing or fleet vehicles. Scope 2 emissions include indirect emissions from the generation of purchased electricity, steam, heating, or cooling consumed by the reporting entity. While the first year focuses on these direct and energy-related footprints, subsequent years will introduce the more controversial Scope 3 disclosures, which cover all other indirect emissions in a company’s value chain, including both upstream suppliers and downstream product use.
A companion bill, SB 261 (the Greenhouse Gas Climate-Related Financial Risk Act), requires companies with revenues over $500 million to report on their climate-related financial risks in accordance with the Task Force on Climate-related Financial Disclosures (TCFD) framework. Together, these laws position California as a global leader in climate regulation, effectively setting a de facto national standard for the U.S. market.
Details of the 2026 Enforcement Discretion
The newly released guidance provides specific relief for the inaugural reporting cycle. Recognizing that many companies may not have had the infrastructure in place to capture real-time 2025 data in anticipation of the 2026 deadline, CARB is allowing the use of the most recent available fiscal year data.
Furthermore, for companies that were not actively collecting Scope 1 and Scope 2 data at the time of the 2024 initial enforcement notice, CARB will allow them to skip reporting these figures for the 2026 cycle entirely. To maintain transparency, these companies are required to submit a formal "statement of non-reporting" on company letterhead. This prevents firms from being penalized for historical data gaps while setting the expectation for full compliance in the 2027 cycle.
One of the most significant reliefs pertains to "limited assurance." Under the original text of SB 253, companies were expected to have their emissions data verified by an independent third-party auditor. However, the guidance confirms that for the 2026 reporting period, CARB will accept data submissions regardless of whether they have undergone this verification process. This move acknowledges the current shortage of qualified third-party auditors capable of handling the sudden surge in demand for climate assurance services.
Technical Reporting Flexibility and the New Intake Platform
To further ease the transition, CARB has announced that it will accept various formats for data submission. Companies are not currently forced into a single, rigid template. Instead, they can provide existing annual sustainability reports, data already reported to voluntary initiatives like the CDP (formerly the Carbon Disclosure Project), or utilize CARB’s own Draft Scope 1 and 2 Template.
Significantly, the regulator indicated that it will not mandate the use of a specific emission factor dataset for the 2026 reporting year. Emission factors are the ratios used to convert business activity—such as gallons of fuel burned or kilowatt-hours consumed—into CO2 equivalents. By allowing companies to use their preferred reputable datasets, CARB is minimizing the need for firms to recalculate existing internal metrics.
Coinciding with this guidance, CARB launched a voluntary intake platform. This digital portal is intended to serve as the primary conduit for submissions, allowing companies to familiarize themselves with the state’s reporting interface before the mandatory elements of the law fully tighten in the coming years.
Chronology of California’s Climate Disclosure Legislation
The journey to the 2026 reporting deadline has been marked by legislative ambition, corporate pushback, and regulatory refinement:
- October 2023: Governor Gavin Newsom signs SB 253 and SB 261 into law, despite expressing concerns about the aggressive implementation timeline and the potential costs to businesses.
- January 2024: Major business groups, including the U.S. Chamber of Commerce and the California Chamber of Commerce, file a lawsuit against CARB, alleging that the laws violate the First Amendment by "compelling speech" and exceed the state’s authority under the Clean Air Act.
- July 2024: CARB issues its initial enforcement notice, signaling that while the law remains in effect, the regulator would exercise discretion to help companies bridge the gap toward full compliance.
- Late 2024 – Early 2025: Legal challenges continue to move through the courts, but the state proceeds with rulemaking, insisting that the climate crisis necessitates urgent transparency.
- September 3, 2026: CARB releases the finalized guidance and the voluntary intake platform, confirming the specific reliefs for the first reporting cycle.
- November 10, 2026: The deadline for the first round of corporate climate disclosures under SB 253.
Stakeholder Reactions and Market Impact
The announcement of these reliefs has been met with a mix of relief from the business community and cautious pragmatism from environmental advocates.
Industry groups have largely welcomed the "enforcement discretion," noting that the global landscape for ESG (Environmental, Social, and Governance) reporting is currently fragmented. "The complexity of mapping Scope 1 and 2 emissions for a multi-billion-dollar enterprise is significant," noted one industry consultant. "By removing the immediate threat of penalties for missing historical data and delaying the audit requirement, CARB is allowing companies to focus on building robust, long-term reporting systems rather than rushing through a compliance exercise."
Conversely, climate transparency advocates argue that while the reliefs are understandable, they must not become a precedent for perpetual delays. Groups such as Ceres and the Sierra Club have emphasized that high-quality data is essential for investors to price climate risk accurately. They contend that California’s leadership is vital, especially as the federal Securities and Exchange Commission (SEC) faces its own legal hurdles regarding its proposed climate disclosure rules.
Broader Implications and the Path to 2027
The move by CARB is part of a broader global trend toward mandatory sustainability reporting. California’s regulations are often compared to the European Union’s Corporate Sustainability Reporting Directive (CSRD), which also mandates Scope 3 disclosures and third-party assurance. By providing these initial reliefs, California is attempting to align its timeline more closely with international peers, reducing the "reporting fatigue" for companies that operate across multiple jurisdictions.
However, the relief is strictly temporary. CARB has already begun the rulemaking process for 2027 and beyond. Future cycles will be significantly more demanding, requiring:
- Scope 3 Reporting: Companies will have to account for the carbon footprint of their entire supply chain, which often accounts for over 70% of a firm’s total emissions.
- Reasonable Assurance: The verification standard will eventually move from "limited assurance" to "reasonable assurance," a much higher bar that is comparable to the level of scrutiny applied to financial audits.
- Standardized Methodologies: CARB is expected to finalize specific GHG accounting methodologies to ensure that data is comparable across different companies and industries.
As the world’s fifth-largest economy, California’s regulatory decisions have a "Brussels Effect," where local laws become global standards. For corporations, the 2026 reliefs offer a brief window to refine their data collection processes. However, the message from CARB is clear: the era of voluntary climate disclosure is over, and the transition to a regulated, transparent carbon economy is now a permanent fixture of doing business in the Golden State.
