Biophysical Analysis of Agri-Food Systems: Scales, Energy Efficiency, Power and Metabolism of Society

In this chapter, I discuss some important theoretical issues that should be addressed when attempting a sustainability assessment of the biophysical performance of agri-food systems. Assessing the sustainability of an agri-food system is a complex matter due to the multi-functional nature of agriculture and the multi-scale nature of the relations between agroecosystems and socio-economic systems. The complexification of the agri-food system makes it difficult to clearly establish what is local, and what can be described as a short food chain, and we might be confronted with cases where, according to certain environmental criteria, products imported from a long distance can perform better than locally produced ones. I argue that a fund/flow analysis is a very useful approach when assessing the pressure on biophysical systems and monitoring their health (stock/flow, and flow/flow may also be useful approaches). Energy is the cornerstone of any living system, including societies. I discuss how energy efficiency and energy flow (power) need to be understood as mutually dependent factors, and how they play a key role in interfacing with the performance of the agri-food and socio-economic systems. If we address societies as living systems, we adopt the concept of metabolism as a useful approach to study the functioning of the biophysical characteristics of agri-food systems and societies alike. In this chapter, I review the history of the concept of metabolism in this context and the approaches taken by the two main schools of thought on the topic. As many definitions are found in literature on the subject, I try to suggest two possible definitions, taking into account the specific approaches. The Vienna school, led by Marina Fischer-Kowalski, embraces a stock/flow and flow/flow approach, considering society as a black box. I would suggest naming this approach “steady-state social metabolism”, or, for short, “social metabolism”. The Barcelona school, led by Mario Giampietro, addresses the relation between fund/flow patterns taking place in a society (its internal organisation), and the fund/flow patterns taking place in its environment as a co-evolutionary, self-organising process. I would suggest naming this approach “co-evolutionary societal-ecological metabolism”, or, for short, “societal metabolism”. Finally, I stress that a biophysical analysis has to be carried out in parallel with an analysis of the socio-economic dimension of a society, as the two dimensions are strictly correlated. I point out that in order to develop a more sustainable agri-food system, we have to intervene in the very functioning of society, and that the complex nature of society’s metabolism has to be carefully addressed.