California Compliance Offset Program — U.S. Forest Projects Protocol

California's Compliance Offset Program was created under the Global Warming Solutions Act of 2006 (AB 32) and began operating under the state's cap-and-trade regulation on January 1, 2013. The California Air Resources Board (CARB) adopted its U.S. Forest Projects compliance offset protocol on October 20, 2011 (revised June 25, 2015), and issued its first offset credits under the programme that September.
By around 2020, roughly 74 improved forest management (IFM) projects covering more than 4 million acres had been credited under the protocol, generating over 130 million ARB offset credits (ARBOCs) — about two-thirds of every compliance offset ever issued in California, worth an estimated $1.8 billion at prevailing 2020 prices.
Each project must be verified by an independent third party through an approved registry (Climate Action Reserve or American Carbon Registry), with site visits required at least every six years and a 100-year monitoring commitment. Projects contribute a share of credits to a shared Forest Buffer Account intended to insure against reversals from wildfire, disease or pest outbreaks.
The programme's credibility has been seriously challenged by peer-reviewed research. A 2022 Global Change Biology study (Badgley et al., building on CarbonPlan analysis) found that comparing projects to overly broad regional carbon-density baselines led to systematic over-crediting: about 29.4% of credits from 65 IFM projects — roughly 30 million tCO2e, worth about $410 million — were 'phantom' tons with no real emissions benefit. A separate 2022 study found the wildfire buffer pool undercapitalized relative to actual reversal risk, and a 2023 follow-up found little evidence that credited projects changed their forest management.
Read the full analysis: https://carbonplan.org/research/forest-offsets-explainer

Read the full analysis: https://ww2.arb.ca.gov/our-work/programs/compliance-offset-program/compliance-offset-protocols/u-s-forest-projects