Last reviewed on 06-22-2018

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

♦ Category: Waste

IPCC: 4B - Biological Treatment of Solid Waste
Sector: Industrial : Solid Waste Treatment : Composting

♦ Activity: Feedstock processed -

♦ Greenhouse gas: Methane ( CH4 )

► Year 2017 —

● Greenhouse gas emission estimate —

Amount: 9,654 tonnes of CH4 Emitted (241,338 tonnes CO2 Eq.)
Basis: Calculation
Calculation: [Feedstock Processed]*[Composting CH4 emission factor]*[Short ton to kilogram conversion]
Reference: IPCC (2006). 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Eggleston H.S., Buendia L., Miwa K., Ngara T., and Tanabe K. (eds). Vol.5, Chap. 4: Biological Treatment of Solid Waste. Published: IGES, Japan. Accessed online at:

● Activity level used in calculations —

Activity: Feedstock processed = 4,925,271 ton
Basis: Compilation
Reference: ARB (2016). Technical support document on GHG inventory methodologies for the 2000-2014 inventory. See Discussion of emissions from composting of greenwaste available at: ttps://

● Parameters and Constants used in calculations —

Parameter: Composting CH4 emission factor = 1.96 g / kg
Reference: ARB (2017). Method for estimating greenhouse gas emission reductions from diversion of organic waste from landfills to compost facilities. California Air Resources Board. Available online at:
Constant: Short ton to kilogram conversion = 907.1847 kg / ton
Reference: NIST (2008). Guide for the Use of the International System of Units (SI). Ambler Thompson & Barry N. Taylor (Ed.). NIST Special Publication 811, 2008 edition. National Institute of Standards and Technology, Gaithersburg, MD.
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: 1,960 g (i.e. 1.96 kg) of CH4 per ton
49,000 g (i.e. 49 kg) of CO2eq. per ton