Last reviewed on 06-22-2018

Documentation of California's Greenhouse Gas Inventory (11th Edition - Last updated on 11-06-2019)

♦ Category: Agriculture, Forestry and Other Land Use

IPCC: 3A2ai - Livestock - Manure Management - Cattle - Dairy Cows
Sector: Agriculture & Forestry : Manure Management : Cattle : Anaerobic lagoon

♦ Activity: Livestock population - Dairy cows

♦ Greenhouse gas: Methane ( CH4 )

► Year 2016 —

● Greenhouse gas emission estimate —

Amount: 334,985 tonnes of CH4 Emitted (8,374,616 tonnes CO2 Eq.)
Basis: Calculation
Calculation: [Livestock population] * [Volatile solids production rate] * [Methane conversion factor] * [Maximum methane production capacity] * [Methane density]
Reference: USEPA (2013). Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2011. U.S. Environmental Protection Agency. Annex 3.11: Methodology for Estimating CH4 and N2O Emissions from Manure Management. ttps://www.epa.gov/sites/production/files/2015-12/documents/us-ghg-inventory-2013-annexes.pdf#https://www.epa.gov/sites/production/files/2015-12/documents/us-ghg-inventory-2013-annexes.pdf

● Activity level used in calculations —

Activity: Livestock population = 1,009,043 head of Dairy cows
Basis: Calculation
Calculation: [Total population] * [Proportion in manure management system]
Reference: ARB (2016). Technical support document on GHG inventory methodologies for the 2000-2014 inventory. See discussion of emissions from manure management available at: ttps://ww3.arb.ca.gov/cc/inventory/pubs/reports/2000_2014/ghg_inventory_00-14_technical_support_document.pdf#https://ww3.arb.ca.gov/cc/inventory/pubs/reports/2000_2014/ghg_inventory_00-14_technical_support_document.pdf
Reference: USDA and CDFA, various years. The USDA agriculturlal census provides statewide milking cow populations every five years (2002, 2007, 2012). The milking cow population for intervening years are interpolated from CDFA growth profiles for non-census years. https://www.agcensus.usda.gov/Publications/

● Parameters and Constants used in calculations —

Parameter: Maximum methane production capacity = 0.24 m3 / kg
Reference: USEPA (2013). Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2011. U.S. Environmental Protection Agency. Annex 3.11: Methodology for Estimating CH4 and N2O Emissions from Manure Management. ttps://www.epa.gov/sites/production/files/2015-12/documents/us-ghg-inventory-2013-annexes.pdf#https://www.epa.gov/sites/production/files/2015-12/documents/us-ghg-inventory-2013-annexes.pdf
Parameter: Methane conversion factor = 0.731
Reference: Wirth, T. (2015). Data request between CARB and Tom Wirth, US Environmental Protection Agency, December 2015.
Parameter: Proportion in manure management system = 0.582
Reference: Wirth, T. (2015). Data request between CARB and Tom Wirth, US Environmental Protection Agency, December 2015.
Parameter: Total population = 1,785,403 head
Reference: ARB (2016). Technical support document on GHG inventory methodologies for the 2000-2014 inventory. See discussion of emissions from manure management available at: ttps://ww3.arb.ca.gov/cc/inventory/pubs/reports/2000_2014/ghg_inventory_00-14_technical_support_document.pdf#https://ww3.arb.ca.gov/cc/inventory/pubs/reports/2000_2014/ghg_inventory_00-14_technical_support_document.pdf
Parameter: Volatile solids production rate = 2,857 kg / year
Reference: Wirth, T. (2015). Data request between CARB and Tom Wirth, US Environmental Protection Agency, December 2015.
Constant: Average number of days per year = 365.2425 day
Reference: USNO (2004). U.S. Naval Observatory, Astronomical Applications Department, Leap Years. Accessed online at: ttp://www.usno.navy.mil/USNO/astronomical-applications/astronomical-information-center/leap-years#http://www.usno.navy.mil/USNO/astronomical-applications/astronomical-information-center/leap-years
Constant: Methane density = 662 g / m3
Reference: USEPA (2013). Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2011. U.S. Environmental Protection Agency. Annex 3.11: Methodology for Estimating CH4 and N2O Emissions from Manure Management. ttps://www.epa.gov/sites/production/files/2015-12/documents/us-ghg-inventory-2013-annexes.pdf#https://www.epa.gov/sites/production/files/2015-12/documents/us-ghg-inventory-2013-annexes.pdf
Constant: Global warming potential of CH4 = 25
Reference: IPCC (2007). Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Solomon S., Qin D., Manning M., Chen Z., Marquis M., Averyt K.B., Tignor M., and Miller H.L. (eds.). http://www.ipcc.ch/publications_and_data/publications_ipcc_fourth_assessment_report_synthesis_report.htm

● Greenhouse gas emitted per unit activity (derived from values listed above) —

Amount: 331,983 g (i.e. 331.98 kg) of CH4 per head of Dairy cows
8,299,567 g (i.e. 8.3 tonnes) of CO2eq. per head of Dairy cows
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