Regulation & International Instruments
California AB 1305 (Voluntary Carbon Market Disclosures Act)
A California law, effective 1 January 2024, requiring detailed public disclosures from carbon-offset sellers, offset buyers making claims, and any entity making net-zero or carbon-neutral claims.
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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.
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.
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