Introduction

The Greenhouse Gas (GHG) Emission Inventory Program was established as a means to combat climate change by tracking the historical progress of reducing GHG emissions in the state of California.

Background

In 2006, California passed Assembly Bill 1803, which tasks the California Air Resources Board (CARB) with creating an inventory of the state’s GHG emissions from economic sector sources including agriculture, commercial, forestry, electrical, industrial, residential, and transportation. This program works in concert with various initiatives under the California Global Warming Solutions Act to show progress toward meeting the state’s GHG reduction goals and mitigation, with a plan to achieve carbon neutrality by 2045 or earlier.

Key foundational legislation

AB 32 — California Global Warming Solutions Act: The act tasks CARB with numerous responsibilities to help address the threat of climate change.

AB 1803 — Committee on Budget: The bill puts responsibility on CARB for the development and maintenance of a GHG emissions inventory.

Applicable laws & regulations

AB 32 — California Global Warming Solutions Act

AB 1803 — Committee on Budget

Related definitions

The “California Air Resources Board (CARB)” is the regulatory agency that oversees all efforts to control air pollution and conserve air quality standards in the state.

“Carbon neutrality” is the result of all GHG emissions being counterbalanced by carbon sequestration.

The “California Global Warming Solutions Act” requires CARB to develop statewide initiatives that will reduce GHG emissions to 40 percent below the 1990 level by 2030.

A “greenhouse gas (GHG)” is any gas that absorbs infrared radiation in the atmosphere. This includes, but isn’t limited to, carbon dioxide, hydrochlorofluorocarbons, hydrofluorocarbons, methane, nitrous oxide, ozone, perfluorocarbons, and sulfur hexafluoride.

Key to remember

To achieve statewide GHG goals, including carbon neutrality by 2045, CARB tracks GHG emissions released into the atmosphere across different economic sectors.

Real-world example

Compared to 2019 pre-pandemic levels, GHG inventory data shows an overall downward trend in reported emissions. Data did show a 3 percent increase in 2021 as the pandemic ended and the economy opened back up, but it’s projected to decrease again when 2022 data is finalized and released in late 2024.

Emissions decreased from 2020 to 2021 in the agriculture sector, driven by the use of digesters to remove methane from the air. CARB regulations also resulted in refrigerant emissions leveling out for the first time in 20 years.

Similarly, emissions rose in the transportation sector, which is directly related to pandemic stay-at-home orders being lifted. The energy sector saw an increase in demand, which resulted in higher emissions. The industrial sector also saw elevated emissions due to more demand for refineries and petroleum extraction.