California Air Resources Board

The Assembly Bill 32 Greenhouse Gas Emissions Inventory (Inventory) uses several data sources to calculate California's GHG emissions. Methods differ by edition of the Inventory and by sector. The methods used for the 2026 edition Inventory are described in detail in the Method Report below.

The Inventory's primary data source is the reports submitted to CARB through the Regulation for the Mandatory Reporting of GHG Emissions. The Inventory also relies on data from other California State and federal agencies. National parties to the United Nations Framework Convention on Climate Change have developed GHG inventories using guidance from the Intergovernmental Panel on Climate Change's Task Force on National GHG Inventories since the 1990s. The calculation methods used in California's GHG Inventory are generally consistent with these guidelines.

2026 Edition Inventory Comprehensive Method Report [pdf] (Coming Soon)