Trade Wars Make It Challenging to Feed the World Within Environmental Limits

Growing geopolitical tensions, trade disputes, and export restrictions have renewed concerns about the resilience of globally integrated food systems. While previous studies have examined the implications of agricultural trade for food security and environmental outcomes, little is known about how trade restrictions reshape production, resource use, and food access at the spatial scales where agricultural decisions occur. Existing approaches either lack endogenous behavioral responses or rely on highly aggregated representations of land and production systems. We address this gap using a multi-crop version of SIMPLE-G, a global gridded equilibrium model that integrates economic decision-making with high-resolution data on crop yields, land availability, water constraints, and production systems. We use the model to evaluate the consequences of global crop import tariffs and to quantify the land-use and productivity adjustments required to maintain food security under reduced trade integration. Our results show that trade restrictions increase crop prices, reorganize production across landscapes, and worsen food insecurity, with the largest impacts concentrated in import-dependent regions. Major exporters such as the United States and Brazil reduce production of internationally traded crops, while food-importing regions expand domestic production through import substitution. However, these market adjustments are insufficient to maintain baseline food security. Restoring pre-tariff levels of undernourishment would require substantial additional cropland expansion or accelerated productivity growth. In North Africa, for example, maintaining baseline food security requires either a 62.7% increase in cropland extent or a 24.9% increase in total factor productivity. Similar but smaller adjustment requirements emerge across the Middle East, Central America, and China. Iso-nutrition frontiers reveal the trade-offs between land conversion and productivity enhancement needed to offset the food-security consequences of trade fragmentation. Beyond the policy implications of trade restrictions, this study demonstrates the value of high-resolution economic modeling for understanding how global market shocks propagate through local agricultural landscapes. By resolving market-mediated responses at the grid-cell level, the framework provides a foundation for evaluating interactions among trade, food security, agricultural productivity, and environmental sustainability in the next generation of global gridded economic models.