What does it do?
Circular food systems aim to optimally use the available biomass and agricultural lands to guarantee a healthy diet for humans while avoiding the transgression of planetary boundaries. The CiFoS model is a quantitative tool used to explore optimal uses of the available biomass and agricultural lands as well as the consequences that these uses will have for human nutrition and planetary health (especially land use, greenhouse gas emissions, water use, phosphorus use, and nitrogen use). With the CiFoS model, we can tackle key questions such as “Which crops should we produce where?”, “Which and how many animals are needed?”, “On what scale should we close nutrient cycles?”, “What will our diet look like if we transition towards a circular food system?”, “How would circular diets differ around the world?”, and “What is the impact of a circular diet in our planet’s boundaries?”.
How does it work?
The CiFoS model is coded in GAMS (General Algebraic Modelling System) and R. The model consists of different modules: human-nutrition systems, cropping systems, farmed animal systems, fisheries, processing, transportation, and GHG emissions. Each module can be fed with input data specific to the context of analysis (e.g., the World, the European Union, or a specific country). The CiFoS model ingeniously ties all modules together to provide a healthy diet with the minimum environmental impact. We usually model a baseline scenario based on current production patterns and compare it with different circular food system redesigns to better understand the transformative potential of adopting circular practices in our food systems.
The human nutrition system module accounts for the macro and micro-nutrient dietary requirements of a given population (e.g., protein, calcium, vitamin B-12) and the nutrient composition of the various food items consumed (e.g., bread, lentils, yogurt). The cropping systems module accounts for the available extension of arable lands and grasslands in a given area, the types of crops that could be potentially grown based on agro-ecological zones and soil types, crop and grass yields, crop rotations, crop fertilization requirements, and fertilizer types. The farmed animal systems module accounts for different animal production systems (e.g., dairy, beef, pigs, broilers, layers, and farmed fish) of a given area, the productivity level of each animal production system (e.g., intensive, backyard), the herd structure (e.g., parent and reproduction stocks), nutrient requirements of the herd structure and the types and amount of feeds (e.g., crop residues, food waste, human-edible biomass) and their nutrient content. The fisheries module accounts for the quantity of capture fisheries for each species according to the maximum sustainable yield of a given place. The processing module accounts for the processing of crop and animal raw materials into food and by-products. The transportation module allows trade and accounts for the distance between the place of production and the place of consumption (e.g., the distance between two countries). Finally, the GHG emissions module accounts for the associated GHG emissions of crop and animal production systems (following IPCC tier 2 methodologies), composting of food losses and waste, and transportation.
What makes it unique?
The CiFoS model is unique because it embraces circularity principles due to its model structure: residual streams (by-products, manure, food waste) from one process become the input of another to estimate the environmental impact of healthy diets at a food systems level. For instance, human-inedible by-products can be used as fertilizer or feed for farmed animals. In this way, CiFoS does not have to deal with critical methodological choices that can substantially affect the direction of the results (types of allocation, functional units). Furthermore, CiFoS has been developed with a generic setup, making it applicable to different scales. For instance, it can be used at a continental level and allow trade between countries, or it can be used at a country level to account for local dietary preferences and contexts.
Prospects
We plan to expand the CiFoS model in multiple directions. For example, we want to incorporate additional environmental impact categories, such as biodiversity loss. Furthermore, we aim to expand the model to quantify the environmental potential of diverse food systems innovations, including farmed insects, single-cell foods, seaweed farming, strip cropping, etc. Lastly, we want to incorporate a constraint for model diets with reduced risk for non-communicable diseases such as diabetes and cardiovascular disease.
