CA AB2331

Requires business entities marketing or selling voluntary carbon offsets in California to disclose detailed project information on their websites, including project identification, location, protocol, crediting period, and carbon storage monitoring requirements, with initial disclosures due July 1, 2025.

Defines "voluntary carbon offset" as a tradable instrument (rather than a product) sold or marketed in the state that claims to represent greenhouse gas emission reductions or removals, excluding legally or regulatory-mandated reductions and certain compliance-based credits.

Allows resellers of voluntary carbon offsets to satisfy disclosure requirements by directing buyers to the original generator's disclosures, providing information at settlement for eligible contract participants, or directing buyers to registry-published project disclosures.

Requires entities making net zero, carbon neutral, or similar emissions claims to disclose how such claims were determined, verified, and measured, including science-based targets and third-party verification information on their websites by July 1, 2025.

Establishes civil penalties of up to $2,500 per day for violations (maximum $500,000 total) and requires annual updates to all disclosures posted on business websites.