California SB 253: November 2026 First Reporting Deadline Locked In
CARB has set November 10, 2026 as the inaugural Scope 1 and 2 emissions disclosure deadline for $1B+ revenue companies, with Scope 3 and limited assurance obligations ramping in 2027.
California's SB 253 Climate Corporate Data Accountability Act is moving from rulemaking into live compliance. CARB has confirmed November 10, 2026 as the first reporting deadline for U.S.-organized entities doing business in California with more than $1 billion in total annual revenue, covering Scope 1 and Scope 2 greenhouse gas emissions. First-year filings benefit from a good-faith flexibility standard, but 2027 brings materially heavier obligations: Scope 3 emissions reporting across five prioritized GHG Protocol categories, and limited third-party assurance for Scope 1 and 2 data. By 2030, reasonable assurance will be required. Sophisticated counsel should advise clients to lock in emissions data collection systems, vendor selection for assurance providers, and Scope 3 value-chain mapping now, because the November 2026 deadline leaves a narrow window before the more rigorous 2027 cycle. Watch for CARB's forthcoming implementing regulations clarifying reporting platform mechanics, fee structure, and verification protocols.