California’s Landmark Climate Disclosure Law Clears Legal Hurdle, Deadlines Locked for 2026

Executive Brief

California’s landmark climate disclosure law survived a major legal challenge, clearing the way for sweeping new requirements starting in 2026. At its latest workshop, the California Air Resources Board (CARB) detailed what companies must prepare for under SB 261 (climate risk) and SB 253 (climate emissions). More than 4,000 companies are expected to be impacted, with deadlines, reporting templates, and compliance costs now locked in.

Key Insights at a Glance

• Deadlines set: Climate risk disclosures due Jan. 1, 2026; Scope 1 & 2 emissions due June 30, 2026.
• Scale of impact: 4,160 companies must comply, including 2,596 that must report under both rules.
• Compliance costs: Fees will range from $1,400 to $4,000 annually per company, plus assurance costs.
• Standards alignment: Companies can prepare now using GHG Protocol, TCFD, and ISSB standards.
• Assurance required: Limited third-party assurance begins in 2026; reasonable assurance by 2030.

Deadlines Now Firm

CARB confirmed the reporting schedule:

• SB 261 climate risk disclosures due January 1, 2026.
• SB 253 emissions reports (Scope 1 & 2) due June 30, 2026.

Reporting templates will be released in September. Draft rules are expected in October, followed by a 45-day comment period, with finalization slated for December.

Who Must Comply

CARB estimates 4,160 companies fall under the new regime:

• 2,596 companies must report both climate risk and emissions.
• 1,564 companies report only on climate risk.

The rules apply to any company that is:

• Headquartered in California, or
• Generates over $735,019 in annual sales within the state (2024 threshold, inflation-adjusted).

Exemptions may include nonprofits, government agencies, and firms with only remote workers in the state. Parent companies may consolidate reporting for subsidiaries if revenue thresholds are met.

Compliance Comes With Fees

Companies should expect annual disclosure fees of $1,400–$4,000, based on CARB’s $13.9 million implementation cost spread across covered entities. Firms reporting under both SB 253 and SB 261 will pay two fees. This is in addition to costs for preparing reports and obtaining assurance.

Align With Global Standards

CARB emphasized that compliance will be based on existing international frameworks, allowing companies to prepare now:

• Emissions reporting: Greenhouse Gas Protocol for accounting, ISSA 5000, AA1000, ISO 14060 series, or AICPA for assurance.
• Climate risk reporting: TCFD, ISSB (S2 Standard), or other regulated climate risk frameworks.

CARB noted it will treat “good faith efforts” as compliant in the early years, provided companies explain reporting limitations.

Assurance Requirements

From June 30, 2026, Scope 1 and 2 emissions disclosures must be independently assured by a CARB-accredited verifier.

• 2026: Limited assurance — an opinion that no material errors were found.
• 2030: Reasonable assurance — a positive confirmation that disclosures are accurate.

Litigation Still in Play

Although the law remains on track, litigation continues. Key dates:

• Aug. 29: Defendants’ response due.
• Sept. 2: Plaintiffs’ reply filed.
• Sept. 8: Hearing on plaintiffs’ motion.
• Sept. 15: Plaintiffs request court decision.

The outcome could influence compliance timelines but, for now, CARB is proceeding full steam ahead.

Related Content: California companies call for full funding for historic climate disclosure laws