ABSTRACT
This chapter discusses the systems analysis and life cycle assessment modelling approaches and will go on from there to look at a range of model applications. The applications include use within the national inventories of various countries across species, including discussions around the use of different emission factors. The Swiss and French methods to estimate enteric methane emission factors for dairy cows aligned better with inventories like the Irish one rather than the complex tier 3 approaches applied by the Netherlands and Germany. France used a more advanced method to calculate enteric methane emission factors for sheep and New Zealand reported applying a country-specific tier 2 method. Of these nations, 13 used tier 2 methane emission factors for manure for all species within this category. Life cycle assessment considers the environmental effects of a product, service system. The method adopts a systems approach, but in contrast to systems analysis, general step and principles of the LCA methodology are internationally standardized.
