Generic model for calculating carbon footprint of milk using four different life cycle assessment modelling approaches

The aim of the study is to develop a tool, which can be used for calculation of carbon footprint (using a life cycle assessment (LCA) approach) of milk both at a farm level and at a national level. The functional unit is ‘1 kg energy corrected milk (ECM) at farm gate’ and the applied methodology is LCA. The model includes switches that enables for, within the same scope, transforming the results to comply with 1) consequential LCA, 2) allocation/average modelling (or ‘attributional LCA’), 3) PAS 2050 and 4) The International Dairy Federations (IDF) guide to standard life cycle assessment methodology for the dairy sector. The key elements of consequential LCA and the IDF guide are presented and explained by examples. The national carbon footprints (CF) for milk produced in Denmark and Sweden in 2005 are presented. •The model can calculate carbon footprint of milk at both national and farm level.•Four different modelling assumptions in life cycle inventory are used (e.g. IDF).•Effects related to land use changes can be included or excluded in the CF.•Results are presented for Danish and Swedish milk produced in 2005.