Food systems are complex because many interacting processes and stakeholders are involved. They are dynamic because their outcomes unfold over time.
I’ll start with a brief definition of system dynamics as well as of food systems:
- System dynamics is a computer-aided approach to policy analysis and design. It applies to dynamic problems arising in complex social, managerial, economic, or ecological systems — literally any dynamic systems characterized by interdependence, mutual interaction, information feedback, and circular causality (for a more complete introduction to system dynamics, check out the System Dynamics Society webpage. Conceptually, the feedback concept is at the heart of the system dynamics approach. A feedback loop exists when information resulting from some action travels through a system and eventually returns in some form to its point of origin, potentially influencing future action. If the tendency in the loop is to reinforce the initial action, the loop is called a reinforcing feedback loop; if the tendency is to oppose the initial action, the loop is called a balancing feedback loop. Balancing loops can be variously characterized as goal-seeking, equilibrating, or stabilizing processes. Reinforcing loops are sources of growth or accelerating collapse; they are disequilibrating and destabilizing. Combined, reinforcing and balancing circular causal feedback processes can generate all manner of dynamic patterns. Stocks (levels) and the flows (rates) that affect them are essential components of feedback loops. Stocks (accumulations, state variables) are the memory of a dynamic system and are the sources of its disequilibrium and dynamic behavior.
- Food systems, at a minimum, comprise the sets of activities involved in food production; processing and packaging; distribution and retail; and consumption (Ericksen, 2008). These activities lead to a number of social, environmental and food security outcomes such as food availability, access and utilization, but also the provision of ecosystem services or the accumulation of human, financial and social capital. Food system activities and outcomes eventually result in processes that feed back to environmental and socioeconomic drivers (Ericksen, 2008; FAO, 2008). The drivers, in turn, describe the bio-geophysical as well as the social, economic and political environments that determine how food system activities are performed.
This brief definition of food systems contains many of the elements that characterize the system dynamics approach, most notably the concepts of feedback loops and stocks or accumulations.
Feedback loops, for example, link food system activities with their environmental as well as their health drivers. Although growing empirical evidence points at the importance of the links and feedbacks between food system activities, the environment and the health system, they have not been extensively modeled (Hammond & Dubé, 2012).
An essential aspect of feedback loops is the notion of accumulation and delays for entities that can be stocked up or depleted. Accumulation is central to food systems. Environmental resources needed for food sector activities include but are not limited to stocks of land, water, and nutrients. The condition of these resources affects their productivity and thus the outcome of food system activities. Food system activities involve inventories of food that is produced, food that is processed and distributed, and food that is available for consumption. Managing accumulations is thus relevant not only in natural resource management situations such as soil nutrient management (Saysel, 2014) but also in the operation of value chains (e.g., Sterman, 1989a, 1989b) and in commodity cycles (Arango & Moxnes, 2012).
In two recent publications, we used system dynamics structural thinking tools, that is, causal loop as well as stock and flow diagrams, to study the vulnerability of food systems and the effectiveness of possible ways to alleviate it.
In Stave & Kopainsky (2015), we develop diagrams that demonstrate that vulnerability of a national food system does not only or automatically result from exogenous shocks that might affect a country. Rather, vulnerability can be either intensified or reduced by the interaction of feedback loops in the food system, and buffered or amplified by the structure of stocks and flows. For example, any addition of stocks in a supply chain increases the amplitude of potential oscillations in food availability by increasing the difference between actual and desired production and thus creates more potential instability in the food system. Additions of stocks in a food supply line arise from increasing specialization and the resulting additional processing steps, which is typical for modern food systems (Sundkvist et al. 2005).
In Brzezina, Kopainsky & Mathijs (2016), we evaluate whether organic farming can reduce some of the vulnerabilities in the European food system. We end up arguing that organic farming has some potential to bring resilience to the European food system, but it has to be carefully designed and implemented to overcome the contradictions between the dominant socio-economic organization of food production and the ability to enact all organic farming’s principles—health, ecology, fairness and care—on a broader scale. This is partly because organic food producers compete with each other based solely on price, which does not internalize all externalities of food production. In other words, many of the socially and ecologically progressive attributes of organic produce are neglected in the price of organic food. Such a price-based competition disincentives the organic food producers from continuous improvement of their practices and involves them into the productivity paradigm and the reinforcing spiral of efficiency maximization. This is evident in the organic ‘conventionalization’ and ‘supermarketization’ debate (Darnhofer, 2014; Guthman, 2004).
Another reason why I find system dynamics useful to reflect on food system issues is the mass balance inherent in stocks and flows. Let’s take the example of the targets operationalizing the Sustainable Development Goal 2.
- Target 2.3 talks about incomes of small-scale food producers. Income is a flow that accumulates into a stock of financial capital, which can subsequently be spent or invested in various ways. Simply measuring the flow of income, however, is not sufficient for assessing whether financial capital can be accumulated. Such assessments are only possible if indicators about the financial capital stock and/or the outflows of the stock accompany indicators about income.
- Target 2.4 talks about the progressive improvement of land and soil quality. Land and soil quality are natural resources. The condition of the resource is a stock that increases with regeneration and decreases with utilization/degradation. If land and soil quality are to be improved, it is not enough to lower utilization/degradation. A stock only increases if the inflow exceeds the outflow. Restoring stocks to a desired value that is higher than the current value requires a period of time during which the inflow exceeds the outflow. A reduction in the outflow thus needs to be sufficiently big to decrease below the inflow. Measures of land or soil quality thus would have to be complemented by information about the rates of change in land or soil quality.
Literature cited here:
This blog post was first an initial draft for and now is an adapted version of the following paper:
- Kopainsky, B., Tribaldos, T., & Ledermann, S. T. (2017). A food systems perspective for food and nutrition security beyond the post-2015 development agenda. Systems Research and Behavioral Science, n/a-n/a. doi: 10.1002/sres.2458
Further cited literature:
- Arango, S., & Moxnes, E. (2012). Commodity cycles, a function of market complexity? Extending the cobweb experiment. Journal of Economic Behavior & Organization, 84(1), 321-334.
- Darnhofer, I. (2014). Contributing to a transition to sustainability of agri-food systems: Potentials and pitfalls for organic farming. In Organic Farming, Prototype for Sustainable Agricultures; Bellon, S., Penvern, S., Eds.; Springer: Dordrecht, The Netherlands; Heidelberg, Germany; New York, NY, USA; London, UK, 2014; pp. 439–452.
- Ericksen, P. J. (2008). Conceptualizing food systems for global environmental change research. Global Environmental Change, 18(1), 234-245.
- FAO. (2008). Climate Change and Food Security: A Framework Document. Rome: Food and Agriculture Organization of the United Nations (FAO).
- Guthman, J. (2004). Agrarian Dreams: The Paradox of Organic Farming in California; University of California Press: Berkeley, CA, USA; Los Angeles, CA, USA; London, UK.
- Hammond, R. A., & Dubé, L. (2012). A systems science perspective and transdisciplinary models for food and nutrition security. Proceedings of the National Academy of Sciences, 109(31), 12356-12363. doi: 10.1073/pnas.0913003109
- Saysel, A. K. (2014, July 20 – 24). Analyzing soil nitrogen management with dynamic simulation experiments. Paper presented at the 32nd International Conference of the System Dynamics Society, Delft, The Netherlands.
- Sterman, J. D. (1989a). Misperceptions of feedback in dynamic decision making. Organizational Behavior and Human Decision Processes, 43(3), 301-335.
- Sterman, J. D. (1989b). Modeling managerial behavior: Misperceptions of feedback in a dynamic decision making experiment. Management Science, 35(3), 321-339.