California SB 253 Deadline Looms, ISSB Launches Nature Disclosure Draft at COP17

California's Climate Disclosure Clock Is Now Running

With less than three weeks to go, large U.S. companies that do business in California are racing to meet the most imminent mandatory climate-reporting deadline in the country. On October 12, 2026, the California Office of Administrative Law approved CARB's California Corporate Greenhouse Gas Reporting and Climate-Related Financial Risk Disclosure Initial Regulation, which became effective the same day. CARB's notice confirms November 10, 2026 as the first yearly deadline for GHG emissions reporting under SB 253.

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. CARB originally submitted the regulation to OAL in May, withdrew it in June to make clarifying changes and defer the first reporting deadline from August 10 to November 10, issued modified text in July, and resubmitted the package to OAL in September. The approval ends that extended rulemaking journey.

CARB's formal approval marks another significant step toward implementation of California's climate disclosure program, notwithstanding legal challenges to SB 253 and 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 and finalize Scope 1 and Scope 2 emissions data. The regulation also codifies first-year enforcement relief for entities that were not collecting Scope 1 and Scope 2 information as of December 5, 2024.

ISSB Goes Live at COP17 With Nature Disclosure Exposure Draft

On the global standard-setting front, the International Sustainability Standards Board is launching a major new consultation this week. The ISSB is hosting a webinar on Thursday, October 22, 2026 to mark the launch of an Exposure Draft proposing a Practice Statement on nature-related disclosures, which will be open for a 120-day consultation ending February 19, 2027. The launch is timed to coincide with the UN Convention on Biological Diversity's COP17 conference.

The ISSB aims to give stakeholders the opportunity to provide feedback on the proposed requirements, including on whether an IFRS Practice Statement is the right form of standard-setting for nature-related disclosures. The webinar will explain how the proposed Practice Statement is intended to support companies in applying IFRS S1 to nature-related risks and opportunities, and will cover how the proposals draw on the extensive efforts of the Taskforce on Nature-related Financial Disclosures (TNFD).

EU's Revised ESRS Poised to Enter Force in November

In Europe, the regulatory calendar is also advancing. The European Commission published the finalized revised European Sustainability Reporting Standards in the Official Journal of the EU on September 22, 2026, with the new regulation set to enter into force on November 10, 2026. The revised ESRS will apply to financial years beginning on or after January 1, 2027, although companies already subject to CSRD reporting in FY2026 can choose to use the existing standards or the revised ESRS, provided they disclose which framework they have applied.

Separately, EFRAG released a draft XBRL Taxonomy for the revised ESRS on September 17, 2026, and launched a public consultation open until November 11, 2026; the taxonomy sets out the technical framework needed to produce ESRS disclosures in machine-readable form. EFRAG intends to hand over the final XBRL Taxonomy to ESMA and the Commission in November 2026, with a view to formal submission by the end of the year.

The Divergence That Defines 2026

The contrast between U.S. federal and sub-national trajectories could not be sharper. The SEC's climate disclosure rule was adopted in March 2024, stayed immediately, and has never taken effect; the SEC has formally proposed to rescind it in its entirety, with a final vote expected in late 2026 or early 2027. Meanwhile, California's mandatory regime is operational, and the ISSB's global framework continues to gain adherents. More than 45 jurisdictions are using or taking steps to introduce the ISSB Standards, and by 2027, companies in 18 jurisdictions will be issuing ISSB-based reports, underscoring that the global direction of travel toward mandatory climate disclosure remains intact.