California's Initial Climate Disclosure Regulation Takes Effect as First SB 253 Reporting Deadline Approaches

October 20, 2026

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By: Kenneth J. Markowitz, Stacey H. Mitchell, Andrew Oelz, Samantha Z. Purdy, Charles Edward Smith

The California Air Resources Board (CARB) recently announced that the California Office of Administrative Law approved its initial regulation implementing aspects of the state's corporate climate disclosure laws, effective October 12, 2026. Originally adopted by CARB in February, the regulation establishes an initial fee framework and formalizes November 10, 2026, as the first reporting deadline under SB 253, California's corporate greenhouse gas (GHG) emissions disclosure law. To facilitate initial reporting, CARB has launched a voluntary online submission platform for covered companies to provide contact information and submit Scope 1 and Scope 2 emissions reports. Companies alternatively may submit their information by email. In September, CARB also published updated reporting guidance and issued reminder letters to potentially covered entities. SB 253 generally applies to U.S.-based companies with more than $1 billion in annual revenues that do business in California, with Scope 3 reporting requirements scheduled to begin in 2027.

Why It Matters: CARB’s formal approval of the regulation marks another significant step toward implementation of California's climate disclosure program, notwithstanding legal challenges to SB 253, as well as broader federal efforts to scale back mandatory GHG reporting. With the first reporting deadline less than a month away, potentially covered companies should confirm their applicability assessments, finalize Scope 1 and Scope 2 emissions data and determine their preferred submission method. Although using CARB's reporting platform is voluntary, the underlying reporting and compliance deadlines are not. The development also underscores the increasingly divergent federal and state approaches to corporate climate disclosure, reinforcing the importance of maintaining emissions reporting capabilities even as federal requirements increasingly are eliminated. We have written extensively regarding SB 253 and related compliance matters, most recently here.

Our team continues to closely monitor developments related California’s climate disclosure regime and is available to advise regarding any compliance or reporting questions you may have.

Frequently Asked Questions

SB 253 generally applies to U.S.-organized companies doing business in California with total annual revenues in excess of $1 billion. Both public and private companies that meet these criteria are subject to the law’s reporting requirements.

Covered companies must report their greenhouse gas emissions, beginning with Scope 1 and Scope 2 emissions. Scope 3 reporting requirements are scheduled to begin in 2027.

The first reporting deadline under SB 253 is November 10, 2026. The regulation approved by the Office of Administrative Law formalizes this date.

The regulation, originally adopted by CARB in February 2026, establishes an initial fee framework and formalizes November 10, 2026, as the first reporting deadline under SB 253. The regulation became effective October 12, 2026.

CARB has launched a voluntary online submission platform for covered companies to provide contact information and submit Scope 1 and Scope 2 emissions reports. Companies alternatively may submit their information by email.

No. Using CARB’s reporting platform is voluntary. However, the underlying reporting and compliance deadlines are not. Covered companies must report regardless of which submission method they choose.