California SB 253 D-Day: First Corporate GHG Reports Due November 10, 2026
The Moment U.S. Climate Disclosure Has Been Waiting For
November 10, 2026 is not just another regulatory date on a sustainability calendar — it is the first time any U.S. jurisdiction has successfully required large corporations to publicly disclose verified greenhouse gas emissions. California's Senate Bill 253, the Climate Corporate Data Accountability Act, reaches its inaugural reporting deadline today, with the California Air Resources Board (CARB) now empowered to enforce submissions from every U.S.-organized entity generating more than $1 billion in annual revenue that does business in the state.
How the Deadline Was Confirmed
The road to November 10 was not straightforward. CARB originally targeted a June 30 deadline, shifted it to August 10, and then — following a regulatory withdrawal to make clarifying revisions — extended it by a further three months to November 10. That date became legally binding when California's Office of Administrative Law approved CARB's revised regulation on October 12, 2026, as reported by both PwC and Morgan Lewis. The same regulation codified first-year enforcement relief and confirmed that Scope 3 emissions reporting is not yet required, with that obligation phasing in from 2027. No third-party assurance is required for this initial filing cycle, though limited assurance on Scope 1 and 2 data will be mandated beginning in 2027, according to KPMG's regulatory tracker.
What Companies Must File — and What Comes Next
For the 2026 cycle, covered companies must report Scope 1 (direct) and Scope 2 (purchased energy) emissions using any of the frameworks CARB has indicated it will accept. CARB's voluntary online intake platform, reporting guidance, and instructional materials launched on September 1, 2026, giving filers their first concrete picture of the submission process. Fee-determination notices from CARB are expected to follow on December 10, 2026. Beginning in 2027, the program expands to include Scope 3 value-chain emissions and requires limited assurance on Scope 1 and 2 data.
The Federal Void That Made California the Floor
The urgency around today's SB 253 deadline is amplified by the collapse of federal climate disclosure requirements. The SEC's March 2024 climate rule was stayed within weeks of adoption and has never been enforced. In May 2026, the SEC formally proposed rescinding the rule entirely, arguing it exceeded its statutory authority; the public comment period closed on August 3, 2026, and a final rescission vote is expected in late 2026 or early 2027, according to the SEC's own filings with the Eighth Circuit. With no federal mandate in force, SB 253 has become, as Jones Day's September 2026 analysis put it, the only U.S. emissions reporting obligation now moving toward actual implementation.
EU Context: CSRD Omnibus Reshapes European Obligations
Across the Atlantic, the EU's own disclosure landscape has been substantially redrawn. The Omnibus I Directive — formally published as Directive (EU) 2026/470 and in force since March 18, 2026 — narrowed CSRD scope to companies with more than 1,000 employees and €450 million in net turnover, cutting the number of covered entities from roughly 50,000 to around 5,000. A simplified set of ESRS reporting standards, reducing mandatory data points by 61%, is expected to apply from financial year 2027, according to analyses by Freshfields and Coolset. For now, the most immediate and enforceable climate disclosure obligation on earth falls not to Brussels or Washington, but to Sacramento — and its deadline is today.