Food supply shocks are increasing worldwide^1,2, particularly the type of shock wherein food production or distribution loss in one location propagates through the food supply chain to other locations^3,4. Analogous to biodiversity buffering ecosystems against external shocks^5,6, ecological theory suggests that food supply chain diversity is crucial for managing the risk of food shock to human populations^7,8. Here we show that boosting a city’s food supply chain diversity increases the resistance of a city to food shocks of mild to moderate severity by up to 15 per cent. We develop an intensity–duration–frequency model linking food shock risk to supply chain diversity. The empirical–statistical model is based on annual food inflow observations from all metropolitan areas in the USA during the years 2012 to 2015, years when most of the country experienced moderate to severe droughts. The model explains a city’s resistance to food shocks of a given frequency, intensity and duration as a monotonically declining function of the city’s food inflow supply chain’s Shannon diversity. This model is simple, operationally useful and addresses any kind of hazard. Using this method, cities can improve their resistance to food supply shocks with policies that increase the food supply chain’s diversity.

全球范围内的粮食供应冲击正在增加^1,2，特别是其中一个地点的粮食生产或分配损失通过粮食供应链传播到其他地点^3,4的冲击类型。类似于生物多样性缓冲生态系统抵御外部冲击^5,6，生态学理论表明，食品供应链多样性对于管理人类面临的食品冲击风险至关重要^7,8. 在这里，我们表明，提高城市食品供应链的多样性可以将城市对轻度至中度严重程度的食品冲击的抵抗力提高多达 15%。我们开发了一个强度-持续时间-频率模型，将食品冲击风险与供应链多样性联系起来。经验-统计模型基于 2012 年至 2015 年期间美国所有大都市地区的年度粮食流入观察数据，这些年美国大部分地区都经历了中度至重度干旱。该模型将城市对给定频率、强度和持续时间的食物冲击的抵抗力解释为城市食物流入供应链香农多样性的单调递减函数。该模型简单、实用且可解决任何类型的危险。使用这种方法，