Greenhouse Gas Inventory –
2022 Inventory Results

Sonoma County is committed to measuring, tracking, and reporting our greenhouse gas (GHG) emissions to communicate progress and focus our actions.

The information below is specific to 2022 Inventory Results.

For access to RCPA’s full archive of greenhouse gas inventories, please see our main page here.

While our ambitious GHG reduction goals take into account the critical role both regional and state entities play, our GHG inventory reflects the sectors and emissions sources that can be reduced through the actions of local governments and regional entities.

The Sonoma County Regional Climate Protection Authority (RCPA) established a baseline communitywide GHG inventory for calendar year 2010 and a backcast inventory for 1990 as part of the Climate Action 2020 and Beyond (CA2020) development process. The RCPA has since completed inventory updates for 2015, 2018, 2020, and 2022 to help track progress towards achieving the short and long-term emissions reduction goals established in CA2020 and in the Sonoma Climate Mobilization Strategy.


RCPA has recently published its fifth inventory of communitywide greenhouse gas (GHG) emissions, bringing the report up to date through 2022. This article explores the details of the current inventory and provides RCPA’s initial analysis of emission reduction trends and future mobilization opportunities. In short, Sonoma County emissions in 2022 were 3.11 million metric tons of CO2e (MTCO2e), which is over a 10 percent reduction from 2018 emissions of 3.46 million MTCO2e, but a slight 0.6 percent increase from 2020 emissions of 3.09 million MTCO2e.

RCPA believes this small increase is because 2020 emissions were artificially low due to the impacts of the COVID-19 pandemic and the extended economic shutdown. Therefore, 2022 emissions should be viewed not as an increase from 2020 levels, but as a continued decrease from 1990-2018 levels, with 2020 being an outlier year that produced artificially low emission levels.


In 2016,  RCPA led the Climate Action 2020 initiative and created the county’s first community GHG inventory using 2010 data. This effort also created a historical backcast using 1990 data to provide a benchmark from which to track the impacts of local climate protection campaigns. As part of Climate Action 2020, an ambitious set of goals was adopted by the RCPA Board, including the target of reducing GHG emissions to 25% below 1990 levels by 2020.

Following the initial inventory in 2016, RCPA completed updates in 2018 using 2015 data, in 2020 using 2018 data, and now in 2022 with 2020 data. All of these inventories follow the U.S. Community Protocol for Accounting and Reporting of Greenhouse Gas Emissions produced by ICLEI and last updated in July 2019.

Finally, as part of the Sonoma Climate Mobilization Strategy adopted by the RCPA Board in March 2021, the countywide GHG goals have been further strengthened. The updated goals call for Sonoma County to become carbon neutral by 2030, working toward even deeper emissions reductions of 80% below 1990 levels by 2030. RCPA is also working with agency partners to expand local carbon sequestration efforts to balance the remaining emissions and ensure carbon neutrality.

2022 Inventory Overview

Sonoma County emissions in 2022 were 3.11 million metric tons of CO2e (MTCO2e), which is over a 10 percent reduction from 2018 emissions of 3.46 million MTCO2e, but a slight 0.6 percent increase from 2020 emissions of 3.09 million MTCO2e. RCPA believes this small increase is because 2020 emissions were artificially low due to the impacts of the COVID-19 pandemic and the extended economic shutdown. Therefore, 2022 emissions should be viewed not as an increase from 2020 levels, but as a continued decrease from 1990-2018 levels, with 2020 being an outlier year that produced artificially low emission levels.

As outlined in the original Climate Action 2020 effort, Sonoma County’s regional approach to reducing GHG emissions recognizes the challenge’s shared nature and that each community has a different capacity to achieve emission reductions. Additionally, statewide policies and programs to reduce GHG emissions related to building energy and transportation play a critical role. 

This 2022 inventory report is an essential milestone in our work to reduce countywide emissions. RCPA will use the results from the 2022 GHG Inventory Update to inform the implementation of the Sonoma Climate Mobilization Strategy and work with its member and partner agencies to develop new climate policies and programs to achieve reductions at the speed and scale needed to respond to the climate crisis. 

2022 Inventory Results by Sector

Building Energy

Countywide emissions from energy used in buildings decreased over 45 percent from 1990 to 2022, although emissions in this sector rose just slightly from 2020. In 2022, Sonoma Clean Power provided approximately 76 percent of the total electricity used by Sonoma County residents, PG&E provide approximately 21 percent, and Healdsburg Electric–an independent utility operated by the City of Healdsburg–provided 3 percent. 

As the electricity fuel mix for each of these utilities becomes cleaner over time, Sonoma County will continue to see emissions reductions in the electricity sub-sector. One opportunity to further reduce emissions is to increase the percentage of local customers choosing to voluntarily adopt 100% renewable service plans, such as Sonoma Clean Power’s Evergreen rate plan, PG&E’s Green Saver plan, or Healdsburg Electric’s Green Rate. The extra cost of these more renewable energy products allows each utility to fund additional emission reduction strategies to further reduce emissions of their entire portfolio.

Another critical step is transitioning from natural gas appliances for space heating, water heating, and cooking to all electric appliances. Emissions from natural gas have become the predominant source of emissions in the building energy sector as our emissions from electricity have declined due to cleaner sources. Additionally, the pipelines that deliver natural gas to our homes leak methane, a greenhouse gas 84 times more potent than CO2 over the first 10 years of release. Finally, cooking with natural gas can increase indoor air pollution, which has been shown to have numerous adverse health impacts.

In pursuit of lower emissions, the Sonoma Climate Mobilization Strategy includes two strategies designed to address these opportunities and achieve the necessary emission reductions in this sector: 

  • All-Electric Buildings Campaign – accelerate the electrification of existing buildings and electrify all new buildings 
  • Carbon-Free Electricity – accelerate the transition to 100 percent carbon-free electricity 

RCPA works in close partnership with both Sonoma Clean Power (SCP) and the Bay Area Regional Energy Network (BayREN) to implement these efforts.

First, the significant reduction in emissions from electricity consumption is a key result from the 2014 inception of Sonoma Clean Power – a community choice energy provider which offers Sonoma County communities the option of purchasing lower-carbon and zero-carbon electricity delivered through PG&E power lines. SCP also offers multiple programs to encourage local residents and businesses to upgrade their buildings to be more energy efficient. Many of these programs are spotlighted at SCP’s Customer Center in Santa Rosa.

Additionally, the Bay Area Regional Energy Network (BayREN) is a regional collaborative that is led by the Association of Bay Area Governments (ABAG) and serves the Bay Area’s nine counties with outreach, training, technical assistance, funding, and resources to make the Bay Area and California a greener, more resilient, more equitable and more energy efficient place to live. BayREN administers 10 programs to support local government efforts to reduce greenhouse gas emissions, including technical assistance and incentive programs for single-family residential homeowners, multifamily residential property owners, commercial businesses, and public government buildings.


The transportation sector accounts for approximately 1.8 million MT CO2e, or 57.7 percent of 2022 emissions, and is the largest source of emissions for the County. This sector includes emissions from on-road driving, off-road equipment, and diesel used for passenger rail service in Sonoma County. Countywide emissions from the transportation sector have increased 1.4 percent from 1990, showing how imperative efforts are to transition to zero-emission vehicles and reduce the total vehicle miles travelled by local residents. 

On the positive side, RCPA expects that on-road transportation emissions will continue to rise at a lower rate than vehicle miles traveled due to improvements in fuel efficiency and as the shift from fossil fuel vehicles to hybrid and electric vehicles becomes even more widespread. The State of California’s recently announced requirement for 100 percent zero-emission vehicle sales by 2035 is a major step in this direction. 

The Sonoma Climate Mobilization includes three strategies that build on the Shift Plan and are designed to achieve the necessary emission reductions in this sector: 

  • Drive Less Sonoma County Campaign – make it easier to get around Sonoma County without a car 
  • EV Access for All Partnership – accelerate the transition to 100 percent electric vehicles for all transportation needs not otherwise met by biking or walking 
  • Sonoma County Vehicle Miles Traveled Mitigation Bank – develop new funding sources for transportation projects that reduce VMT

Currently, RCPA is working in partnership with SCTA staff on development of the Countywide Active Transportation Plan (ATP) to enhance mobility and create a more responsive and efficient transportation network in Sonoma County. Local residents are encouraged to voice their transportation needs through an interactive webmapping platform that enables city planners and government officials to improve transportation infrastructure based on community input. SCTA is currently working with several jurisdictions to update the ATP with the latest information and needs.

Countywide emissions from Water and Wastewater did not change significantly from 2020 to 2022 but have been reduced by nearly 69 percent from 1990 levels. Emissions in this sector result from electricity used to convey water across the county, as well as from the breakdown of organic waste during the wastewater treatment process. Most emissions in this sector result from wastewater treatment, including various processes that release methane and nitrous oxide.

Much of the the long-term reduction in water-related emissions can be attributed to Sonoma Water, the local agency that manages most of the water conveyance within the county. Since 2015, Sonoma Water has had contracts to procure 100 percent of its electricity needs through renewable and carbon-free resources, thus achieving a carbon-neutral electricity supply to power Sonoma Water’s water conveyance and wastewater processing systems. This initiative has been the leading cause of the dramatic reductions in water-related emissions since 1990.

RCPA is also leading the development and implementation of the Water Upgrades $ave Program in partnership with the Bay Area Regional Energy Network (BayREN). Water Upgrades $ave program, an innovative new program that provides utility on-bill financing for water and energy-saving improvements in single-family and multifamily residences. The program currently operates in Sebastopol and Cloverdale and anticipates serving more Sonoma County and greater Bay Area jurisdictions soon.

Solid Waste
The 2022 emissions from solid waste were a 6.7 percent decrease from 2020 and a 53.9 percent decrease from 1990. Local jurisdictional efforts to comply with new state waste reduction laws over the past few years have contributed to this decline in emissions. AB 1826 (Chesbro, 2014) requires businesses that generate a specified amount of organic waste per week to arrange for recycling services for that waste and for jurisdictions to implement a recycling program to divert organic waste from businesses subject to the law. Additionally, SB 1383 (Lara, 2016) sets requirements for jurisdictions to coordinate efforts to reduce organic waste disposal by 75 percent by 2025 and to rescue at least 20 percent of currently disposed surplus food by 2025 for people to eat instead of being throw away. Between these two efforts, almost all businesses in the county producing over four cubic yards of waste per week have access to a blue and green bin for recycling and composting. Between the newly adopted requirements at the State level and better local access to waste-related resources, these efforts significantly reduce overall solid waste and waste-related emissions. 

The Sonoma Climate Mobilization includes one strategy in the solid waste sector: 

  • Zero Waste by 2030 — develop policies, programs, and education campaigns to eliminate waste sent to landfills 

RCPA works in partnership with Zero Waste Sonoma (ZWS) on countywide solid waste reduction efforts. In 2022, ZWS established a requirement for Tier 1 Generators, primarily consisting of local operations, to start recovering excess whole foods. ZWS also helps enforce both AB 1826: Mandatory Commercial Organics, which was eclipsed by SB 1383: Short-lived Climate Pollutants in January 2022. SB 1383 is a Senate Bill in California law that establishes statewide greenhouse gas emission reduction goals. Due to the fastmoving progress of ZWS, in 2024, Tier 2 Generators, such as larger food entities, will be required to donate excess foods.

Livestock and fertilizer emissions are the third largest source of emissions in Sonoma County. The primary emissions are generated by enteric (digestive) fermentation and manure management. Emissions from this sector were a very slight decrease from 2020, and also only a slight decrease from 1990 levels. Emissions from this sector are included in the countywide inventory but not allocated to any specific jurisdiction.

Several strategies in the Sonoma Climate Mobilization Strategy are related to carbon sequestration and climate resilience that will impact this sector: 

  • Protect Existing Carbon Stocks — maintain the carbon that is currently held in soil and plants 
  • Increase Carbon Stocks — capture more carbon in soils and plants 
  • Scale Up the Infrastructure for Sequestration — build the physical, social, and economic capacity for successful carbon sequestration

Much of this work locally is being implemented though the Sonoma-Marin Ag and County Climate Coalition (SMACCC). This effort aims to promote carbon farming and establish a regional supply chain for climate-smart agricultural products by developing a tracking system and marketing campaign for commodities produced using methods that reduce greenhouse gas emissions or sequester carbon. Over five years, the initiative will support numerous farms and ranches, significantly reducing emissions and building on existing partnerships and data systems to monitor impacts. With potential funding up to $10 million, this scalable model could support up to 100 farms and sequester hundreds of thousands of metric tons of CO2 over 20 years.

Forest Land and Trees

The Sonoma Climate Mobilization Strategy sets a goal of reaching carbon neutrality by 2030. To meet this end, Sonoma County must reduce its greenhouse gas emissions by at least 80 percent below 1990 levels and achieve an increase in carbon sequestration that is large enough to remove the remaining CO2 from the atmosphere. There are multiple existing efforts on rural lands to increase sequestration, and the potential exists to increase sequestration in the urban parts of the county as well. Sonoma County’s forestlands and wetlands, especially the Sonoma Baylands, provide additional capacity to sequester carbon. 

Sonoma County’s natural resources play a pivotal role in our fight against rapid climate change. RCPA recognizes the prime importance of promoting conservation and restoration efforts to maximize the region’s carbon sequestration potential. By safeguarding and enhancing these resources, we can significantly contribute to mitigating the impacts of climate change and fostering a more sustainable future. Two recent reports are being used to guide our efforts in this arena: the Sonoma County Climate Resilient Lands Strategy (August 2022) and the County of Sonoma Carbon Inventory and Sequestration Potential Study (October 2023). 

Forest land and trees in Sonoma County serve as significant areas for carbon sequestration, capturing and storing atmospheric carbon dioxide. Natural and working lands encompass a variety of landscapes that aid in carbon sequestration, including diverse natural ecosystems, agricultural areas, and urban green spaces. The total carbon storage across all lands regardless of ownership amounts to 101,355,691 MTCO2e, with publicly owned lands contributing 12,513,728 MTCO2e, representing approximately 12% of the naturally stored carbon in 2022. A majority of the carbon stock in Sonoma County is held within forests (48.52%), grassland (20.63%), and vineyards (7.49%). The Carbon Inventory and Sequestration Potential Study offers a number of strategies to increase these carbon stocks over time. RCPA will continue to work with the County of Sonoma and other jurisdictional partners to implement projects and track progress over the upcoming years.


In conclusion, here are the key findings from the most recent 2022 GHG inventory:

  • Overall emissions have decreased 21% from 1990, but have risen just slightly above 2020 values
  • Building energy emissions have decreased 45% between 1990 and 2022
  • Solid waste emissions have decreased 54% between 1990 and 2022
  • Transportation continues to be the largest source of emissions for the county at nearly 58% of total
  • 2020 emission values appear to be artificially low due to impacts of COVID-19 economic slowdown

Finally, to meet RCPA’s carbon neutrality goals for 2030, dramatic decreases in emissions and large-scale increases in sequestration are both needed.