Water foot printing of livestock products: impact assessment of beef production systems

Summary

This study provides new strategic insight into the environmental impacts of beef cattle production in southern Australia. Firstly, for beef cattle raised in a diverse selection of case study production systems in New South Wales, water footprints were calculated using a life cycle assessment (LCA)-based approach, which takes into account the environmental relevance of the water being used. This approach contrasts markedly with volumetric approaches based on the concept of virtual or embedded water. 
Secondly, environmental impacts associated with greenhouse gas (GHG) emissions and water-use were aggregated to enable their relative importance to be quantitatively compared. Thirdly, for each case study production system, an inventory of land use was compiled. This will enable an integrated assessment of GHG emissions, water and land use when LCA impact assessment models for land use become sufficiently developed. 
Six geographically-defined beef cattle production systems were compared which were diverse in farm practice (grass and feedlot finishing), product (yearling to heavy steers), environment (high-rainfall coastal to semi-arid inland) and local water stress (Table 1). As such, the results are intended to be broadly indicative of the likely range of beef cattle produced in NSW. Geographical definition of the production systems was necessary because the water footprint calculations took into account the local water stress where operations occurred. 
Consumptive water use ranged from 24.7 to 234 L/kg live weight (LW) and the water footprint ranged from 3.3 to 221 L H2Oe/kg LW at the point of marketing (Table 2). For explanation, a product with a water footprint of 1 L H2Oe exerts equivalent pressure on freshwater systems (from water use in its production life cycle) as the direct consumption of 1 L H2O at the global average water stress index (WSI). Due to variation in local water stress, the water footprint and water use results were not correlated. The large range in water footprint indicates that generalisations about the industry should be avoided. That said, many low input, predominantly non-irrigated, pasture-based systems have little impact on freshwater resources from consumptive water use and the livestock have a water footprint similar to many broad acre cereals. The general assertion, that cattle production is a driver of water scarcity, is not supported.