The provision of food causes environmental impacts that range from local through to global in scale. Organic farming, used in general here to mean farming practices with a greater emphasis on long-term sustainability, is one general approach to reduce these impacts. Whilst organic farming may be argued to be superior to conventional farming on the basis of local impacts, it is not often clear how organic farming performs relative to conventional farming in terms of wider, global impacts. In this paper we present a comparative assessment of on-farm and indirect energy consumption, land disturbance, water use, employment, and emissions of greenhouse gases, NOx, and SO2 of organic and conventional farming in Australia. A hybrid input–output-based life-cycle technique is employed in order to ensure a complete coverage of indirect requirements originating from all upstream production stages. Using data from a detailed survey of organic farms, the results show that direct energy use, energy related emissions, and greenhouse gas emissions are higher for the organic farming sample than for a comparable conventional farm sample. Direct water use and employment are significantly lower for the organic farms than for the conventional farms. However, the indirect contributions for all factors are much higher for the conventional farms, leading to their total impacts being substantially higher. This shows that indirect effects must be taken into account in the consideration of the environmental consequences of farming, in particular for energy use and greenhouse gas emissions, where the majority of impacts usually occur off-farm. Subject to yield uncertainties for organic versus conventional farming, from the sample here we can conclude that in addition to their local benefits, organic farming approaches can reduce the total water, energy and greenhouse gases involved in food production.
