Determining emissions profiles for Australian agricultural products at a regional scale: methodological opportunities and obstacles

Abstract

Life Cycle Assessments (LCAs) of greenhouse gas emissions associated with agriculture have commonly been conducted at a farm scale (case study) or emissions are calculated at a national scale. However, there is a scarcity of regionally-focused assessments, both in Australia and internationally. This may be partly due to difficulties in obtaining representative data that account for variability in agricultural production systems. For national policies to be regionally applicable and for landholders to identify opportunities for practice change, it is essential that inter- and intra-regional differences be better understood. We contend that by accommodating variability and testing the sensitivity of calculation methods, highly robust regional LCAs can be built. This broader analysis will not only improve our understanding about the representativeness of existing case-studies but also, to some extent, overcome the problem faced by individual producers in obtaining enterprise-level seasonally-specific data. In developing regional LCAs for cropping enterprises, we found the emissions per unit of product to be particularly sensitive to the rate at which fertiliser and soil ameliorants are applied, proportion of legumes in farming systems, emissions factors and grain yields. In a wool enterprise, the emissions profile is sensitive to changes in the enterprise emphasis from wool to meat production and to market dynamics, as well as to stocking rate and live weight gain. In this paper we describe how obstacles associated with variability of production systems and data accessibility can be overcome to enable robust regional-scale LCAs to be produced.