No One Is Prepared for the Worst Day Ever | Florian Ulrich Jenn

How a Global Catastrophe Could Trigger Worldwide Food Shortages

Imagine a massive volcanic eruption in Southeast Asia. Ash clouds ground aircraft, destroy crops and force communities to evacuate, while fast-moving pyroclastic flows bury entire towns. In the weeks that follow, sulfur dioxide reaches the upper atmosphere and transforms into fine sulfuric acid droplets. These aerosols spread around the planet, reflecting sunlight back into space.

The sun appears pale, shadows become softer, sunsets turn purple and global temperatures fall. The following summer may never arrive. Harvests could fail across regions ranging from the American Midwest to the Asian monsoon belt. As food supplies decline, countries could restrict exports, disrupt international trade and leave millions of people facing hunger.

Although this scenario has not occurred in modern history, scientists and policymakers consider it a matter of when—not if—a world-changing catastrophe will happen. Governments should begin preparing now for global disasters that could disrupt food systems on an unprecedented scale.

Three Steps to Strengthen Global Food Security

Three practical steps could improve our ability to respond. First, national risk assessments should include events such as nuclear war, major volcanic eruptions and continent-wide power outages. Second, countries should agree on international trading rules for emergencies before a crisis begins. Third, governments and researchers should invest in food-production systems that can operate with limited sunlight, fertilizer and fuel.

Recent events have shown how quickly regional crises can affect the rest of the world. The coronavirus pandemic, Russia’s invasion of Ukraine and conflict involving Iran have all placed pressure on global supply chains. The possible closure of the Strait of Hormuz is another example. A significant share of the fertilizer traded internationally passes through the region, and the Food and Agriculture Organization of the United Nations warned that fertilizer shortages could affect future harvests and food supplies.

These examples demonstrate how an interconnected world allows local emergencies to create consequences far beyond their original borders. In a global catastrophe, disruptions to trade, energy, agriculture and the climate system could spread faster and become much larger in scale.

How Likely Is a Global Catastrophe?

Some critics may question the need to prepare for events that appear extremely unlikely. However, the historical record shows that global catastrophes are not as improbable as they may seem. Ice cores provide evidence of past volcanic eruptions, and volcanologists estimate that an eruption comparable to Mount Tambora’s 1815 event remains possible. Research has also examined the likelihood of a future “year without a summer.”

A repeat of the 1859 Carrington solar storm could damage power grids across continents. Studies estimate that the probability of a severe space-weather event may be between 1% and 12% over a 10-year period. Nuclear-armed states also remain involved in geopolitical conflicts, creating an ongoing risk of nuclear escalation.

Each individual threat may be unlikely. Taken together, however, volcanic eruptions, nuclear conflict, extreme solar storms, pandemics and other hazards make it highly probable that at least one major global crisis will occur during this century.

Why Global Disasters Threaten the Food Supply

Many catastrophic events can damage the food system in similar ways. Volcanic eruptions, nuclear-war firestorms and large asteroid impacts could send particles into the atmosphere and block sunlight. Temperatures would fall, growing seasons would shorten and drought could intensify. In the most severe nuclear-winter scenarios, researchers estimate that global calorie production could decline by approximately 90%.

Long-term power outages caused by extreme solar storms would create a different chain of problems with a similar result. Without electricity, fuel, fertilizer, pesticides, transportation and functioning supply chains, farmers could struggle to plant, harvest and distribute food. This would expose the vulnerabilities of modern agriculture, which depends heavily on energy-intensive inputs and international trade.

Despite these risks, relatively few countries assess the possibility of a truly global food crisis. The UK’s National Risk Register lists hazards including volcanic eruptions, severe space weather, pandemics and overseas nuclear miscalculations. However, its reasonable worst-case scenarios generally focus on disasters causing more than 1,000 deaths and tens of billions of pounds in damage. They do not fully address global famine or nuclear war, which could kill tens of millions and cost trillions.

Switzerland’s national risk analysis covers 44 hazards, including solar storms, volcanic eruptions in other countries and meteorite impacts. Even this assessment remains limited in scale. Many countries do not yet account for hazards that could affect food supplies, energy infrastructure and international trade across the entire planet.

International Cooperation Is Essential

No country can solve this problem alone. Research on national and community resilience highlights several important factors: food self-sufficiency, decentralized infrastructure, geographic isolation and effective governance. Strong institutions, low corruption and lower inequality can also help societies respond to crises. Australia ranks highly in several resilience assessments, yet it would still face serious difficulties without imported fuel, medicine and fertilizer.

Countries must cooperate internationally to manage a crisis on this scale. Export bans were a common reaction during previous food emergencies, but widespread restrictions could isolate nations and deepen shortages. Food may still exist in some regions, yet people elsewhere could go hungry if governments refuse to trade.

Governments should establish international rules for food and fertilizer trade during global emergencies before a catastrophe occurs. Clear agreements could reduce panic, discourage hoarding and help distribute essential supplies to the regions most in need.

Building Resilient Food Systems Now

Some policymakers may argue that the probability of a global catastrophe is too low to justify the expense. Money spent preparing for a hypothetical volcanic eruption, they might say, could instead support flood protection, hospitals or national defense. That argument is more persuasive when considering only one event. But a range of hazards—including volcanic eruptions, nuclear conflict, asteroid impacts, pandemics and solar storms—could produce similar global consequences.

Many preparations would also provide benefits during more common emergencies. Low-input agriculture, decentralized electricity grids, diversified food supplies, improved seed storage and stronger risk assessments could help communities withstand droughts, wars, fuel shortages and supply-chain disruptions.

Preparation must begin before a global disaster occurs. Once harvests have failed, it will be too late to establish new industries, expand alternative food production or negotiate international agreements. Prevention is preferable when possible, but some catastrophic events cannot be stopped. When they happen, the difference between prepared and unprepared societies will be measured in lives.

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