California Wildfire Emission Estimates

November 18: Draft Report Available: California’s Historical Wildfire Activity before Modern Wildfire Suppression

CARB staff has made the following report available for informal public comment and review. Please email your comments or questions to Anny Huang, Manager of the Emission Inventory Analysis Section, by January 31, 2022.

Draft Report: California's Historical Wildfire Activity before Modern Wildfire Suppression

CARB's Role in Addressing Wildfire and Prescribed Fire Emissions

As California continues to see extensive impacts due to wildfires every year, CARB has prepared a FAQ document that discusses the agency's role in addressing emissions due to wildfires and prescribed fire.

Frequently Asked Questions: Wildfire Emissions

December 31, 2020: Draft Report Available: Greenhouse Gas Emissions of Contemporary Wildfire and Forest Management Activities

Pursuant to Senate Bill 901 - Wildfire, CARB staff has made the following report available for informal public comment and review. Please email your comments or questions to Anny Huang, Manager of the Emission Inventory Analysis Section, by February 28, 2021.

A Report on Greenhouse Gas Emissions of Contemporary Wildfire, Prescribed Fire, and Forest Management Activities

Public Comments Received

Public Webinar: Estimation of Greenhouse Gas Emissions from Forest Management Activities, Contemporary Wildfire, and Historical Fire

The California Air Resources Board (CARB) staff hosted a public webinar on staff’s estimation of greenhouse gas (GHG) emissions from contemporary wildfire and forest management activities, and a presentation on historical fire activity before modern fire suppression. In the first part of the webinar, staff presented the methodology and estimation results of GHG emissions from wildfire and prescribed burn, as well as the amount of ecosystem carbon transformed by forest management activities (which may include tree harvest, removals, and planting; prescribed burn; and other vegetation fuels management to reduce fire risk). In the second part of the webinar, staff presented a scientific literature review of quantitative historical fire data that are needed for modeling fire emissions. The data and literature review focuses on the 1,400 years before modern fire suppression began in 1910.

Date: Tuesday, December 1, 2020

Time: 2:00 p.m. to 4:00 p.m. (Pacific Time)

Hour 1, staff presented GHG Emissions of Wildfire and Forest Management Activities.

Hour 2, staff presented Summary of Scientific Literature Review of Historical Fire Activity.

Webinar Materials

Program Information

Fire has served a natural function in California's diverse ecosystems for millennia, such as facilitating germination of seeds for certain tree species, replenishing soil nutrients, clearing dead biomass to make room for living trees to grow, and reducing accumulation of fuel that lead to high-intensity wildfires. However, fire also impacts human health and safety, and releases greenhouse gas (GHG) emissions and other air pollutants. The GHGs emitted by fire are carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). Fire releases biomass carbon into the atmosphere in the form of CO₂. Methane is emitted due to incomplete combustion of biomass, and N₂O is a product of combustion. In recent years the magnitude and intensity of wildfires have increased across California. In an effort to contextualize the GHG emissions from wildfires, the documents below present an estimate of the emissions since 2000.

Estimates of Fire Emissions, 2000-2020

Greenhouse gas emissions from wildfires are tracked separately when compared to anthropogenic sources due, in large part, to carbon cycling. Anthropogenic emissions from fossil fuels come from geological sources, which are part of the slow carbon cycle, where carbon pools change over the course of many millennia (e.g., fossil fuel formation). In contrast, the fast carbon cycle, in which carbon moves between pools over months to centuries, includes natural emission sources, such as wildfires and plant decomposition and respiration. The acceleration of fossil fuel burning has led to an increase in ambient CO₂ concentrations not seen in over 100,000 years; however, wildfire emissions are part of a fast carbon cycle that is balanced by vegetation growth.

Wildfire Emissions & Burned Area Estimates 2000–2022 (published in 2023)

Wildfire Emissions & Burned Area Estimates 2000–2021 (published in 2022)

Wildfire Emissions & Burned Area Estimates 2000–2020 (published in 2021)