The world’s food supply could lose $600 billion when climate shocks collide with war
Global food shocks were already piling up before Russia fired a single shot into Ukraine. Fertilizer and diesel had been getting pricier for months. By the time ships were blocked from Odesa, food prices were climbing fast.
That sequence proved decisive. A new study set out to test which crises hurt grain supplies the most. The energy price spike, it turns out, did more damage than the war itself.
The bigger lesson lies in the timing. None of these shocks turns catastrophic on its own. The real damage arrives when one lands in a bad harvest year.
A fragile balance
About a fifth of the calories the world eats crosses a border before reaching a plate. Trade in farm goods has more than doubled in recent decades.
That web moves food from surplus regions to places that fall short, smoothing out good years and bad. The same connections that share abundance, though, can also spread strain.
A drought in one region, an export ban in another, a jump in the cost of running a tractor – each ripples outward through the network. When several food shocks land in the same year, they can stack.
Jasper Verschuur, a researcher at the University of Oxford and Delft University of Technology, led a team that built a model to test that kind of pile-up. The researchers wanted to know which jolts hurt the most, and whether trade softens the blow or spreads it.
Testing global food shocks
The team rebuilt the world’s grain trade inside a computer. The model tracks 177 countries and four staples that feed much of the planet: maize, wheat, rice, and soybeans.
Each country could buy, sell, draw down reserves, or strike up new trading partners at a price.
Onto that baseline the researchers layered shocks drawn from recent history. One mimicked the loss of Ukrainian exports and the disruption of Black Sea shipping. Another raised the cost of fertilizer, diesel, and pesticide, echoing the energy crisis.
A third shock copied the real export bans placed on grain between 2022 and 2023. Then came the part that earlier studies had mostly skipped. The researchers ran all three at once, against 54 years of real weather.
Those years ranged from bumper harvests to widespread crop failure. That let the team watch how the shocks interacted rather than treating each as a separate problem.
Fuel prices hit hardest
Most people would point to the war as the biggest threat to the world’s grain supply. The model says otherwise. The jump in energy prices did the most damage and dominated the combined scenario across most regions and crops.
The likely reason is reach. A blockade or an export ban bites hard in specific places, and countries can often route around it by buying elsewhere.
Pricier fuel and fertilizer touch nearly every farm on Earth at once, so there is nowhere to substitute toward.
That broad hit echoes an earlier study that found fuel and fertilizer costs more damaging than lost exports.
Under the combined shock, prices rose by roughly a quarter for soybeans and about half for wheat. Consumer welfare – the value buyers get beyond what they pay – fell by around 16% for wheat in a typical year.
When the weather turns
The standout finding sits in what happens when a rough harvest and the human-made shocks arrive together.
In an average year, the world’s grain system shrugs off a lot. Trade adjustments reabsorb the damage, and prices wobble without breaking.
Push the weather toward a bad year, though, and the floor gives way. The team found that the swing between the worst weather year and a normal one often outweighed the added effect of war, bans, and fuel costs combined. The buffer simply ran out.
A bad harvest does more than add to the other shocks – it removes the slack that lets trade do its job. When the crises land in a poor-weather year, the global drop in consumer welfare can top $600 billion in a single year.
That is a synchronized loss touching almost every country at once. Earlier single-shock models had no way to capture this kind of pile-up.
Which countries fare worse
Not every nation feels these jolts the same way. The team tested five traits that shape how well a country copes. These included import dependence, the number of suppliers, and the size of grain reserves.
No single trait explained resilience on its own. For wheat, thin reserves left countries like Zambia and Mongolia badly exposed. For rice, leaning on a narrow set of suppliers was the weak point, which hurt nations such as Rwanda and Burundi.
What held across the board was the value of variety. Countries drawing from many suppliers weathered the shocks better, especially for rice. Low-income nations get squeezed hardest when several trade disruptions hit at once.
Resilience is not a fixed national trait. It bends with the crop and the severity of the year.
Building resilience now
Before this work, most models fed grain supply through a single global market and waved away short-term shocks. Models that tracked real trade routes could handle only one disruption at a time.
This study put trade flows, storage, and stacked disruptions in one frame – and showed that a bad harvest can erase the cushion trade normally provides.
The result gives governments something concrete to act on. The danger is not any single crisis but the unlucky overlap of several. The payoff comes from preparing before the bad year arrives.
That preparation means building reserves, supporting home-grown supply, and widening the roster of trading partners. Scrambling once prices are already climbing comes too late.
The math also flips a common instinct. Focusing only on the conflict in the headlines leaves the bigger lever – the cost of fuel and fertilizer on every farm – untouched.
The risk of simultaneous breadbasket failure is rising, which makes the case for readiness now, not after the shelves thin.
The study is published in the journal PLOS Climate.
—–
Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates.
Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.
—–