What you need to know: CARB released an updated inventory calculating carbon stored in California’s natural and working lands using design principles established by the Intergovernmental Panel on Climate Change (IPCC). The data show plants have absorbed twice the carbon lost to wildfires, demonstrating the important role of nature as the state works toward carbon neutrality.

SACRAMENTO – Today the California Air Resources Board (CARB) released the second edition of California’s Natural and Working Lands Carbon Inventory (https://ww2.arb.ca.gov/our-work/programs/nature-based-strategies/natural-and-working-lands-carbon-inventory/2025-natural-0). The inventory shows that even with catastrophic wildfires occurring more recently, the state’s natural and working lands have absorbed more carbon than they released since 2001, helping counterbalance emissions from those fires.

“California’s natural and working lands are proving to be powerful allies in our effort to address climate change,” said CARB Chair Lauren Sanchez (https://ww2.arb.ca.gov/about/leadership/lauren-sanchez). “Even in the face of devastating wildfires, California's ecosystems continue to grow and absorb carbon dioxide, helping us move toward carbon neutrality. This inventory shows the incredible power of nature and is yet another example of how California continues to stand up for science with innovative programs and policies.”

The inventory is developed to identify how lands can help California achieve carbon neutrality by measuring annual gains and losses year over year. It complements the state’s annual greenhouse gas emissions (GHG) inventory (https://ww2.arb.ca.gov/news/clean-transportation-drove-californias-emissions-drop-2023) which counts emissions and reductions from about 80 percent of California’s sources of human-caused climate emissions. 

The inventory released today (https://ww2.arb.ca.gov/our-work/programs/nature-based-strategies/natural-and-working-lands-carbon-inventory/2025-natural-0) shows that California lands store nearly five billion metric tons of carbon with over 70% of all carbon in forests and shrublands. The inventory accounts for all organic carbon stored in living and dead biomass, near-surface soils, and wood products harvested from within the state.

CARB produced the inventory using design principles established by the IPCC and a combination of remote sensing data and ground-based measurement data.

Why it matters

While the report shows that nature has helped counterbalance wildfire emissions since 2001, California’s lands have more recently lost more carbon than they absorbed because of record-breaking wildfires driven by climate change. 

This demonstrates how climate change and other human-induced factors continue to impact the carbon balance of our ecosystems and the importance of California’s efforts to reach carbon neutrality to avoid even worse impacts in the future. It also shows the important role of prescribed fires, which help reduce overgrown vegetation and keep ecosystems healthy, helping prevent destructive wildfires and protect communities.

The inventory underscores the massive amount of carbon in California’s vegetation and soils and the importance of achieving state’s Nature-Based Solutions Climate Targets.

This work is further supported by Governor Newsom’s commitment to conserve 30% of the state’s lands and coastal waters by 2030 (known as 30x30) (https://www.californianature.ca.gov) to help protect natural systems and combat biodiversity loss.

Highlights from the report

• In 2022, almost 5 billion metric tons of carbon were contained within California’s lands, with 53% of this carbon stored below ground in soils across all land cover types.
• Despite a longer-term storage increase, during the final eight years of the inventory (2014-2022), California’s lands acted as a net source of carbon, with total stocks decreasing by about 4%..
• Increased wildfire activity and resulting landcover change were the main drivers for the loss of carbon stocks after 2014.
• Despite increasing wildfire activity, average annual GHG emissions from wildfires are about half of the carbon dioxide absorbed by plants and soil, though emissions exceeded storage in severe fire years like 2008, 2020, and 2021.
• The carbon impacted by prescribed fire is more than ten times lower than that from wildfires, while processing harvested wood products emits about 60% as much as wildfires emissions on average.
• New features include better alignment with targets and goals, more carbon and ecosystems categories than before, better post wildfire accounting and improved soil carbon estimates. 

Measuring wildfire emissions

In addition to releasing the inventory which tracks carbon gains and losses on California’s lands, CARB also released a new wildfire emission inventory that integrates satellite data and advanced scientific methodology to provide more detailed, day-by-day info about air pollutants generated by wildfires. Visit CARB's website (https://ww2.arb.ca.gov/wildfire-emissions) to learn more and explore the new wildfire emission data.

What’s next

California continues to stand for science and advance nature-based climate solutions. The results of the inventory will help inform the next update to the state’s plan to achieve carbon neutrality.

In addition, CARB, the California Natural Resources Agency (CNRA) and CALFIRE are now operating the first Redwood Flux Observatory. The observatory helps to link satellite data and computer models to evaluate the health and resilience of California’s coastal redwood forest.

CARB, CNRA, the NASA Ames Research Center and Wildfire and Forest Resilience Task Force are also using the first wall-to-wall statewide LiDAR maps. Data from this project are used to map 100 million acres of terrain and vegetation in the state to monitor forest and wildland health.