Life Cycle Assessment of greenhouse gas emissions from agricultural enterprises

Life Cycle Assessment (LCA) is an internationally agreed approach which is used to assess environmental impacts from production systems. It was originally developed for manufacturing industries but has been increasingly applied to other sectors of the economy. LCA involves analysis of each stage in the production process of a system or enterprise.

When initiating a LCA, it is important to clarify the goal, scope and functional unit of the study. The functional unit is the product or service for which all impacts are to be assessed, such as a tonne of wheat or a kilogram of beef. Comparative LCAs can be developed, such as for a tonne of wheat using nitrogen fixed by a legume crop versus a tonne of wheat using only synthetic nitrogen fertiliser.

NSW DPI has initially focussed on LCA activities on greenhouse gas emissions, with the option of later considering other impacts, such as water use and eutrophication. NSW DPI has also decided to develop cradle-to-farm-gate LCAs for agricultural systems, to which post-farm impacts could be added. This means that we will assess both pre-farm and on-farm emissions.

Beyond this agricultural focus, NSW DPI has been developing LCAs for forest products for some time (e.g. Ximenes & Grant 2009; Ximenes 2001) and work has occurred in the biofuels area.

In the future NSW DPI will build LCAs for specific enterprises, which will then be used to create LCAs for agricultural systems. System-based LCAs will be important in developing understanding of how enterprises and practices can influence emissions profiles, including those in subsequent enterprises.