Introduction

Global agricultural systems are highly interconnected, with traded food accounting for 20% of globally consumed calories. Recent extreme weather events and geopolitical conflicts, such as the war in Ukraine, have highlighted vulnerabilities in this network. These compounding climatic and non-climatic shocks can disrupt supply chains, causing significant price fluctuations and acute food insecurity.

Materials and methods

The study introduces a spatial price equilibrium model representing 177 countries and four major staple crops: maize, wheat, rice, and soybeans. This model evaluates the short-term impacts of single and compound shocks on global grain supplies. Scenarios included weather-driven yield variability, reductions in Ukrainian grain exports, energy price spikes, and trade bans. A compound scenario combined all these disruptions to assess global consumer surplus and price impacts, using 54 years of historical weather data to model baseline yield fluctuations.

Results

Weather variability alone causes substantial price volatility, particularly in regions relying heavily on domestic production or facing high transport costs, such as Sub-Saharan Africa. When non-climatic shocks are introduced, energy price spikes dominate consumer surplus losses across most crops, primarily due to agriculture’s widespread reliance on fuel. Trade bans significantly impact specific regions, such as rice in Sub-Saharan Africa and wheat in Central Asia. Under a compound shock scenario coinciding with poor weather, global consumer surplus losses can escalate dramatically. The worst episodic losses are projected at USD 246.4 billion for maize and USD 145.6 billion for wheat, equating to reductions of 10–15% in consumer surplus.

Discussion

The analysis demonstrates that trade adjustments can buffer the effects of mild shocks by allowing countries to substitute import sources. However, the indirect effects of the Ukraine war via energy prices cause more widespread harm than the direct supply constraints, as energy costs affect all nations regardless of their trade network position. A country’s resilience depends on a combination of factors, including supply diversification, import dependency, and storage capacities.

Limitations

The model assumes inelastic short-term supply, meaning farmers cannot adjust crop choices or inputs within a single growing season. It also excludes certain market dynamics, such as speculation, derivatives trading, and government interventions like tariff adjustments or price subsidies, which could exacerbate or mitigate real-world price spikes.

Conclusion

A globalised food system is essential for food security, enabling surplus regions to supply areas with limited agricultural capacity. However, this interconnectedness necessitates rigorous stress testing against plausible compounding shocks. The developed modelling approach can help identify systemic vulnerabilities and inform targeted resilience strategies, such as strategic stockpiling, domestic production support, and establishing new trade agreements.