Carbon Sequestration through Compost Application Pilot Project

Moving towards climate resilience

The completion of the first project initiated by Sonoma County’s Climate Resilience Fund, the “Carbon Sequestration through Compost Application Pilot Project”, marks a significant milestone in Sonoma County’s journey toward climate resilience. This initiative showcases the impact of investing in local partnerships to fulfill the county’s commitment to combating climate change and promoting environmental stewardship.

The initiative is the first to be completed with support from the County’s $10 million settlement from PG&E related to the 2017 wildfires. It has demonstrated the power of carbon cycle solutions in addressing the pressing climate challenges of our time. By increasing the pace and scale of compost application throughout Sonoma County, we have not only enhanced soil health and water retention, but also contributed to the drawdown of atmospheric carbon, also known as carbon sequestration. The goal of the “Carbon Sequestration through Compost Application Pilot Project” was to increase carbon sequestration through the application of compost on multiple properties in both agricultural and community settings throughout the county.

Here in Sonoma County, the Regional Climate Protection Authority (RCPA), established in 2009, has made carbon sequestration a cornerstone of its strategy to protect our climate. This initiative is perfectly aligned with the County’s ambitious five-year Strategic Plan to achieve carbon neutrality by 2030.

But what is Carbon Sequestration exactly, and what does it take to put carbon back in the ground?

When we compost, we keep organic materials out of landfills, which reduces the release of methane—a greenhouse gas much more potent than carbon dioxide. Instead of creating methane, composting allows food waste to decompose slowly. This process helps plants grow by providing them with nutrient-rich compost. Additionally, these plants absorb carbon dioxide from the atmosphere, further benefiting the environment.

Composting also enhances the resilience of our landscapes, inherently making natural areas more resilient and less prone to natural disaster threats. It helps soil retain water during droughts and reduces erosion during extreme storms. In other words, composting not only tackles greenhouse gases but also strengthens our environment against the impacts of climate change.

“This project is a great example of what we can achieve when we bring together the significant climate and agricultural expertise in Sonoma County,” said Sonoma County Transportation Authority/Regional Climate Protection Authority Chair Lynda Hopkins. “Not only does this carbon sequestration effort remove a significant amount of carbon from our atmosphere using composting techniques that farmers are familiar with, it also serves as an inspiration for other agricultural sectors and can generate new ideas to combat the local effects of climate change. Carbon sequestration is an important component in the RCPA Climate Mobilization Strategy and aligns perfectly with the County of Sonoma’s Strategic Plan.”

The project has yielded meaningful outcomes in both education and practical application. One of the primary achievements includes the establishment of a compost rebate program designed to incentivize agriculturalists to utilize compost on their lands. This rebate has played a crucial role in financially supporting local farmers and landowners in adopting sustainable agricultural practices and supporting ecosystem services that benefit our communities and environment. Access to high quality compost at lower prices enables farmers to access this sustainable resource.

Project Results

Sixteen farms and ranches participated in the program during 2023, collectively sequestering an impressive 6,070 metric tons of CO2 equivalent over 15 years. To put this into perspective, sequestering this amount of carbon is equivalent to taking approximately 1,500 passenger commuter vehicles off the road for one year. Another compelling comparison is the amount of carbon sequestered by 7,087 acres of U.S. forests in a single year.

Furthermore, the project facilitated educational programming to the public, with seven events throughout the county focusing on composting, the carbon cycle, and soil health. Over 380 participants attended the events and learned valuable techniques about composting at home, the importance of utilizing municipal green bins, and the detrimental effects of sending organic waste to landfills. These events have not only raised awareness but have also empowered individuals to take meaningful actions to connect proactively with the carbon cycle.

The success of the Carbon Sequestration through Compost Application Pilot Project would not have been possible without the collaboration of key partners, including Sonoma County Ag + Open Space, Daily Acts, Sonoma Resource Conservation District, Gold Ridge Resource Conservation District, Carbon Cycle Institute, and Zero Waste Sonoma. Together with RCPA, these agencies and organizations have played a pivotal role in advancing Sonoma’s efforts to achieve the goals outlined in the Short-Lived Climate Pollutants Act (SB1383) and pave the way towards a more resilient Sonoma County. The project exemplifies our community’s commitment to environmental stewardship and innovation, laying the groundwork for future rebate and educational projects aimed at promoting sustainability and resilience through the power of compost.