Global food shock model reveals self-sufficiency alone may not prevent crises

Oxford researchers have upended a popular assumption about food security: that countries can protect themselves by growing more food at home. Their new study, published in PLOS Climate, reveals that self-sufficiency alone may actually leave nations more vulnerable when global crises hit.

The research team, led by Jasper Verschuur at the Environmental Change Institute, analyzed how shocks ripple through the world's grain systems. Recent disruptions—the closure of the Strait of Hormuz, Russia's invasion of Ukraine—showed how quickly price spikes can spread. But the Oxford findings go deeper: they explain why producing everything domestically isn't the answer, especially for countries like the UK, where food-security debates have increasingly focused on boosting self-sufficiency.

The model tested multiple simultaneous shocks: poor harvests colliding with wars, trade disruptions, and energy crises. In the most severe scenarios, almost every country experienced food-security losses at once. But the impacts were far from equal. Countries reliant on a narrow group of suppliers and holding low grain reserves were hit hardest, with food prices spiking by 50 to 100 percent depending on how exposed their food systems were.

The mechanism is straightforward but often overlooked. Modern agriculture depends heavily on fuel, fertilizer, and transport. When energy prices spike—as they did after the Ukraine invasion—those costs ripple through global supply chains instantly. Export bans and transport disruptions have similarly severe regional effects. No country can isolate itself from these shocks, no matter how much domestic grain it produces.

The real resilience, the study suggests, comes from diversity and flexibility. Countries with multiple suppliers, strategic grain reserves, and the ability to switch trade partners weathered the same shocks far better. They could pivot when one supplier failed, absorbing the impact rather than absorbing the full price shock. This finding directly challenges the "produce everything locally" approach that appeals to policymakers nervous about food security.

"No country can build a fortress against global food shocks," said Verschuur. "And producing all food within your own borders is unfeasible for many countries, and leaves them exposed to the vagaries of their weather."

Jim Hall, director of the Oxford Martin Systemic Resilience Initiative, framed the danger differently: compound shocks are what matter. A poor harvest alone might be manageable. A war alone might not devastate food prices. But when they arrive together—a failed crop, a fertilizer shortage, a trade war, an energy crisis—the cascading effects can destabilize global systems. "What matters is not just how much food a country produces, but how prepared it is for instability."

The implications are significant for policy. Countries should focus less on maximizing self-sufficiency and more on building redundancy: diversifying suppliers, maintaining adequate reserves, and keeping trade relationships flexible enough to adapt. Rather than a fortress model, resilience looks more like a network—interconnected, adaptable, and able to absorb shocks by redistributing them.

For nations currently pursuing self-sufficiency-focused strategies, the message is clear: that approach may feel safer, but the data suggests it leaves you more exposed when crisis comes.