Project at a Glance

Title: Development of the California Dairy Emissions Model

Principal Investigator / Author(s): Kebreab, Ermias

Contractor: UC Davis

Contract Number: 19RD028

Research Program Area: Climate Change

Topic Areas: Agriculture, Greenhouse Gas Emissions, Modeling

Research Summary:

In an effort to mitigate statewide methane (CH4) emissions, California's Legislature passed Senate Bill (SB) 1383 in 2016 that mandates reduction of statewide CH4 emissions from dairy and livestock sector to 40% below 2013 levels by 2030. The Dairy and Livestock Subgroup #3 organized under SB 1383 generated a document titled, "Dairy Research Prospectus to Achieve California's SB 1383 Climate Goals," which emphasized on the need to 1) refine emission inventories using California-specific data in emission estimation process, and 2) evaluate the effectiveness of various mitigation strategies. Considering the large variability and emerging technologies in dairy practices in California, there is a critical need for California government agencies to refine the estimates of dairy CH4 emissions.

While quantifying emissions from all California dairies is cost-prohibitive, some process-based dairy emission models have demonstrated their ability to accurately estimate dairy emissions under certain conditions. These models account for nutrition and dairy management factors and result in more refined predictions compared to the use of emission factors, commonly applied by the Intergovernmental Panel on Climate Change (IPCC). For example, Manure-DeNitrification-DeComposition (DNDC) model has been used to provide estimates of Greenhouse Gas (GHG) and ammonia (NH3) emissions from isolated dairy facilities. However, these models are not well parameterized for California dairies due to lack of California-specific data, and do not incorporate all California dairy components that are sources of GHG and nitrogen (N)-gas emissions (e.g., settling basin). This project will develop and parameterize a comprehensive process-based California Dairy Emission Model (CADEM) to produce refined emission estimates of CH4, carbon dioxide (CO2), nitrous oxide (N2O), NH3, and nitric oxide (NO) from all components of California dairy farms.

For questions regarding this research project, including available data and progress status, contact: Research Division staff at (916) 445-0753

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