Food security impacts of chokepoint disruptions in global crop supply chains

The global supply chains for major food staples, including wheat, rice, soy, and maize, are significantly reliant on few chokepoints, predominantly situated within the maritime network. Grains traded at international markets are produced in a small number of breadbasket regions. This geographical production concentration has a substantial impact on the degree of reliance on these maritime chokepoints. It has been demonstrated on multiple occasions in preceding years that ports and shipping routes are susceptible to disruption as a result of extreme weather or political conflicts. 

Here, we analyse short-term risks to global and regional food security arising from chokepoint disruptions. To this end, we have developed a model to construct global supply chain networks, incorporating different types of roads, inland waterways, railways, and maritime shipping lanes, with different ship types. Additionally, the model accounts for different types of logistic infrastructure that are important for crop transportation, like ports and railway stations and borders, with their subsequent costs and waiting time. The resulting networks are validated by different explicit examples of known crop transport routes. For the impact modelling, first, a transport cost matrix is calculated within the network, from and to every global Admin-1 region, which is done with a lowest-cost Dijkstra algorithm. Secondly, a crop trade matrix from and to every Admin-1 region is calculated. This is done by aggregating real-world trade data from country-level to Admin-1 level with a cost-based gravity-model that includes different types of consumption and the transport cost matrix. Thirdly, the lowest-cost-path between all regions that trade with each other is calculated, through the same Dijkstra algorithm as in step 1, and multiplied with the amount of trade from the trade matrix.

We assess risks to food security arising from factual as well as counterfactual scenarios, including single and multi-chokepoint disruptions. The outcomes of the different scenarios are compared with the baseline scenario, in which no chokepoint is deactivated. The study quantifies (i) how many people are affected by, and (ii) how much additional transport costs arise from alternative routes due to a disruption of a chokepoint, per crop.

The implemented supply chain network model provides a basis for understanding the implications of disruptions to global food security caused by chokepoint disruptions, highlights strongly affected ‘hotspot’ countries, and establishes the foundation for dynamic modelling of food insecurities. The model is developed for a fast computation of disruption analyses in big networks and will be available freely after final development.