Last reviewed on May 13, 2014

California Greenhouse Gas Emission Inventory

Main sources (electricity generation, transportation, manufacturing) and sinks (forestry) of carbon dioxide
Main sources and sinks of carbon dioxide

2014 Edition Released

bullet A new edition of California's greenhouse gas emission inventory has been released. It includes emissions estimates for years 2000 to 2012. The report summarizing GHG emissions is available on the Publications page, and emissions data are available for download on the GHG inventory data page.
Please note that, starting with this edition of the inventory, CO2 equivalent values are now calculated using the IPCC's Fourth Assessment Report (AR4) Global Warming Potential (GWP) values.


The greenhouse gas (GHG) emissions inventory provides estimates of the amount of GHGs emitted to the atmosphere by human activities within California. The Air Resources Board is responsible for maintaining and updating California's GHG Inventory per H&SC §39607.4.

The inventory includes estimates for carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), sulfur hexafluoride (SF6), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs), which are often referred to as the "six Kyoto gases", plus nitrogen trifluoride (NF3). The current GHG inventory covers years 2000 to 2012. The emission estimates are statewide estimates that rely both on state, regional or national data sources, and on aggregated facility-specific emissions reports. In particular, 2009 through 2012 facility level data from the GHG Mandatory Reporting Program were used for compiling statewide emissions from electricity generation, refineries, cement plants, lime and nitric acid production.

As estimates are refined to include additional years and improved estimation methods, new editions of the inventory are released. GHG emissions for the years 1990 through 1999 are included in the archived 1990-2004 GHG inventory published in November 2007 (available in the archive section of this site), which provided the basis for developing the 1990 statewide emissions level and 2020 emissions limit required by AB 32.

The State's emission reduction program under the Global Warming Solutions Act of 2006 (AB 32) utilizes the GHG inventory estimates. The difference between the 2020 emissions limit and the 2020 business-as-usual forecast is the amount of emission reductions that must be achieved by the State through measures detailed in the Scoping Plan.

For general questions regarding California's Greenhouse Gas Emission Inventory, please contact:Anny Huang, Manager, Emission Inventory Analysis Section, Phone: (916) 323-8475