title: Contribution of milk production to global greenhouse gas emissions. An estimation based on typical farms.
abstract: OBJECTIVE
  Studies on the contribution of milk production to global greenhouse gas (GHG) emissions are rare (FAO 2010) and often based on crude data which do not appropriately reflect the heterogeneity of farming systems. This article estimates GHG emissions from milk production in different dairy regions of the world based on a harmonised farm data and assesses the contribution of milk production to global GHG emissions.
  
  
  RESULTS
  The methodology comprises three elements: (1) the International Farm Comparison Network (IFCN) concept of typical farms and the related globally standardised dairy model farms representing 45 dairy regions in 38 countries; (2) a partial life cycle assessment model for estimating GHG emissions of the typical dairy farms; and (3) standard regression analysis to estimate GHG emissions from milk production in countries for which no typical farms are available in the IFCN database. Across the 117 typical farms in the 38 countries analysed, the average emission rate is 1.50 kg CO(2) equivalents (CO(2)-eq.)/kg milk. The contribution of milk production to the global anthropogenic emissions is estimated at 1.3 Gt CO(2)-eq./year, accounting for 2.65% of total global anthropogenic emissions (49 Gt; IPCC, Synthesis Report for Policy Maker, Valencia, Spain, 2007).
  
  
  CONCLUSIONS
  We emphasise that our estimates of the contribution of milk production to global GHG emissions are subject to uncertainty. Part of the uncertainty stems from the choice of the appropriate methods for estimating emissions at the level of the individual animal.
authors.affiliation: IFCN Dairy Research Center, Schauenburgerstraße 116, 24118 Kiel, Germany. martin.hagemann@ifcndairy.org
authors.forename: Martin
authors.initials: M
authors.lastname: Hagemann
authors.forename: Asaah
authors.initials: A
authors.lastname: Ndambi
authors.forename: Torsten
authors.initials: T
authors.lastname: Hemme
authors.forename: Uwe
authors.initials: U
authors.lastname: Latacz-Lohmann
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis / Q000378:metabolism; D003612:Dairying / Q000379:methods*; D004784:Environmental Monitoring / Q000379:methods*; D005511:Food Handling; D017752:Greenhouse Effect; D008697:Methane / Q000032:analysis / Q000378:metabolism; D008954:Models, Biological; D009609:Nitrous Oxide / Q000032:analysis / Q000378:metabolism; D012044:Regression Analysis; D035501:Uncertainty
chemical_list: D002245:Carbon Dioxide; D009609:Nitrous Oxide; D008697:Methane