Chapter 06 · Governance & regulationRegulation & International Instruments
California AB 1305 (Voluntary Carbon Market Disclosures Act)
Definition
California's Voluntary Carbon Market Disclosures Act, enacted 2023 and effective 1 January 2024. It imposes website disclosure duties on three groups: entities marketing or selling voluntary carbon offsets in California (§44475); entities purchasing or using offsets and making associated claims (§44475.1); and any entity operating in the state that makes net-zero, carbon-neutral or significant emissions-reduction claims (§44475.2). Disclosures must be updated at least annually.
References
Effective 1 January 2024; annual website disclosures; covered groups (sellers, buyers making claims, claim-making entities); penalties up to $2,500/day capped at $500,000.
Three statutory prongs (§44475, §44475.1, §44475.2); six disclosure factors; author's letter on 1 January 2025 first disclosures; AB 2331 failure; AG/public-prosecutor enforcement; no private right of action.
This reference provides supporting context for how “California AB 1305 (Voluntary Carbon Market Disclosures Act)” is defined and used.
Overview
What it means
AB 1305 is the first US law to regulate voluntary-carbon-market claims by disclosure rather than prohibition. Required content spans, among other factors, the offset project's identity, registry, protocol, durability, and whether emissions data or claims were independently verified; claim-makers must disclose how progress is measured and whether interim targets exist.
Penalties reach $2,500 per day per violation, capped at $500,000, enforceable by the Attorney General and public prosecutors; there is no private right of action.
The author's published intent letter signalled that the first annual disclosures were expected from 1 January 2025; a cleanup bill (AB 2331) to clarify scope failed, leaving interpretive ambiguities — including how far "operating in California" reaches — to enforcement practice.
How it is used
Companies selling offsets or making carbon-neutral claims in California publish annual website disclosures; compliance teams map claims against the three prongs; the law is a reference model in global debates on regulating green claims and offset integrity.
Why it matters
AB 1305 converts offset and net-zero claims from marketing into a regulated disclosure regime — an early statutory answer to greenwashing in voluntary carbon markets, watched worldwide as claims regulation spreads.