121 The GHG inventory was developed in accordance with the Intergovernmental Panel on Climate Change (IPCC) Guidelines for National GHG Inventories, the internationally recognized standard for developing national GHG inventories. Other categories exist besides included emissions: excluded emissions, carbon dioxide from biogenic materials, emissions and removals from forest lands and wood products, and other emissions. Excluded emissions are discussed elsewhere in this chapter. Since the 2021 edition of the inventory (2000 – 2019 emissions), CARB staff have made improvements to emissions estimation methods and incorporated new data sources. More information is available here: https://ww2.arb.ca.gov/sites/default/files/classic/cc/inventory/ghg_inventory_00-20_method_update_document.pdf