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: 3A1aii - Livestock - Enteric Fermentation - Cattle - Other Cattle
Sector: Agriculture & Forestry : Enteric Fermentation : Cattle

♦ Activity: Livestock population - Bulls

♦ Greenhouse gas: Methane ( CH4 )

► Year 2005 —

● Greenhouse gas emission estimate —

Amount: 6,404 tonnes of CH4 Emitted (160,089 tonnes CO2 Eq.)
Basis: Calculation
Calculation: Cattle enteric fermentation model
Reference: USEPA (2013). Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2011 U.S. Environmental Protection Agency. Annex 3.10: Methodology for Estimating CH4 Emissions from Enteric Fermentation. ttps://

● Activity level used in calculations —

Activity: Livestock population = 70,000 head of Bulls
Basis: Data
Reference: Wirth, T. (2015). Data request between CARB and Tom Wirth, US Environmental Protection Agency, December 2015.

● Parameters and Constants used in calculations —

Parameter: Not applicable
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.).

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

Amount: 91,480 g (i.e. 91.48 kg) of CH4 per head of Bulls
2,286,991 g (i.e. 2.29 tonnes) of CO2eq. per head of Bulls