Fear and the Three-Day Food Supply


One of the scary factoids in circulation these days is the revelation that grocery stores hold only a three- or four-day supply of food. People wield this statistic to argue that our food system is appallingly insecure and in grave danger of failure. We’re only a few days from starvation, goes the frightening story, and we’re liable one day to find our supermarket shelves empty and the populace in panic.

To accept this forecast uncritically, though, means ignoring how complex systems work. We can scare ourselves by selectively focusing on a small piece of a larger picture and behaving as if that tiny bit were the whole story. It’s a natural tendency: Any organism interested in surviving needs to focus on what’s going wrong much more than what’s going right. But in this case, believing the tale of empty shelves may distract us from more urgent problems.

Storing large amounts of grains and other foods in cities is an ancient strategy, and it hasn’t protected against famine. Many European cities and walled towns kept grain supplies designed to carry them through hard times, yet, according to historian Fernand Braudel, famine remained a regular visitor. Continent-wide, famines that killed 10% or more of the population struck Europe 13 times in the 16th century, 11 times in the 17th, and 16 times in the 18th century. Local famines were far more common, yet most towns had large granaries. With a little thought, we can see why storing food in public granaries isn’t an effective strategy. How much food would a city of 50,000 need to store to get through months of utter crop failure? The math is brutal: the town would be almost knee deep in grain. And, more urgently, during a food panic, how many pounds of grain being handed to you by the state would make you calm down? Five? Ten? That’s only a couple of day’s supply for a small family. During a food panic, I suspect the government would need to hand out 20 to 50 pounds of grain per family every few days to calm a frightened populace. And during a panic, even the largest food storages are emptied quickly. The enemy here is fear, not the food system. In my book, anyone shouting “Run to the stores and buy as much food as you can!” deserves a special place in hell.

Storing more than a few days supply of food within a city makes little sense for a number of reasons. It requires dedicated storage buildings in cities—where space is most expensive. We’d need security forces to protect the food, a bureaucracy to run the logistics, and all that food must be cycled in and out for freshness. Plus, imagine a half million or more hungry people all converging on central granaries expecting to be fed. The logistical problems are enormous: think FEMA or TSA, and you can see why it’s the wrong level to operate at. A much more sensible place for emergency food storage is at the household level. If you are worried about food shortages, get your own stash and store as much as makes you comfortable. In designing a solution to a problem, it’s critical to intervene at the proper level, and here, the household is a far more effective level than the state.

Another reason for not instituting centralized food warehouses is that food systems are based much more on flow than they are on storage, and they usually have been. Claiming that our strategy for food delivery is precarious is not thinking in terms of dynamic whole systems, in which flows are far greater than storage—though both are important. Imagine someone panicking because they suddenly realized that their yard’s soil only contains enough water for four days of plant growth. That may be true, but we know also that water is constantly flowing in—storage is only one bit of the picture. Moisture is being pulled upward through the soil, rain is likely before long, plus we have the water line from the street, household graywater, and all the other ways that the tiny bit of water on that land is being renewed continuously. Yes, it’s possible that all the water delivery systems could break down simultaneously, just as the whole food system could, but that entails large-scale network failures—the utterly perfect storm—that would likely send signals well in advance and affect much more than water or food.

If we don’t look at flows, and don’t think in terms of whole systems, we can make ourselves very scared about the complex systems surrounding us. I call this tendency “drawing the box too small.” If we draw a boundary at, say, the city limits of Chicago and measure how much food is available within it, we can get frightened at how little there is: a few days supply. But that’s not really Chicago’s whole food supply, is it? If we enlarge the boundary to, say, what can be delivered to the city within an hour’s drive, suddenly that food supply contains all the farms and gardens, warehouses, cold-storage units, processing plants, feedlots, ships anchored in Lake Michigan full of grain, distribution centers, rail depots, and other sources of food within a 50-mile radius. That’s a lot more than a four-day supply. Then, enlarge the box to a day’s drive and the food supply will last for weeks. And if we increase the box to include the entire nation or continent—which is still only a part of our food system—we now have an essentially infinite supply of food, renewed every growing season, since the US is still a net food producer.

What makes think that something as unnatural as city limits is the boundary of a city’s food supply? And what kind of catastrophe would limit a city to the food within it? Obviously, a local disaster such as a hurricane or earthquake could do this, but it also could destroy any food grown or stored there, or start a panic that depletes even the largest supply. (Or takes martial law to protect it and draconian rules to distribute it. I’d rather store my own.) Even Hurricane Katrina didn’t prevent food from reaching New Orleans before many people went hungry. Perhaps a rupture of the transportation system would do it. But what would cause this? Rapid destruction of large parts of the highway or rail system is unlikely except in war or national strike (and striking workers and their families need to eat, too). These networks are highly distributed and redundant: There are many routes to any city. A major and sudden fuel shortage might do it, but I suspect that we’d quickly see rationing and redistribution of fuel away from many non-food uses, since governments know that hungry people start revolts. And actual transportation of food only uses 4% of the total energy in the food system (Weber and Matthews, Env. Sci. Technology, 2008, 42: 3508), so a fuel shortage would have less effect on moving food into cities, and more on the production and processing of food, which is a slower process that would unwind over weeks and months, not days.

There’s a lot wrong with our food system, but its “just in time” nature is not one of the flaws. We need to ask why the idea of four days of food on grocery shelves scares us, and why it makes us believe we have a precarious food system. Cities have always drawn from the surrounding countryside for their food. Why is it hard to trust that the current food system will continue to deliver food into cities? I suspect that part of our fear is that the size and number of components of the food systems is so vast that we can’t easily grasp how it works or believe that something that complex can continue to function long. It’s like worrying that your circulatory system—with its billions of red blood cells, pulsing lung tissue, ornately branching veins and arteries, and complicated gas exchange network—will fail and you won’t be able to get oxygen into your blood. It makes me dizzy just to think about it. Fortunately, complex adaptive systems such as our bodies and our food supply continue to function without our conscious control; they are highly networked and on many levels.

The long-term storage for our food supply is on the land, widely distributed, where it belongs. The food system has many tiers, and the “food stored in cities” level is a minor component. The system encompasses many levels of intermediate food storage components such as farms, cooperative grain-storage towers, processing plants, warehouses, shipping in transit, and distribution centers, each holding or supplying a significant percentage of our food supply and operating over a timeframe of weeks and months. It is a system in which flow makes up more of the capacity than storage. With a perishable good such as food, that’s as it should be. Having more than a few day’s supply of food stored at the end of the chain, in cities, would be a misallocation of resources away from the sources that generate the food and direct its constant stream toward the user. It’s smart for residents to store emergency food in their home, in whatever quantity makes them feel safe. But an expensive revamping of our food system to build collective infrastructure for urban food storage makes little sense when flow is the key element of any food system.

Our food system has many flaws. We need more locally grown food. The current system is far too dependent on fossil fuels, is concentrated in too few seed varieties and a handful of corporations, is subsidized toward unhealthy and unwise products, and wastes prodigious quantities of water and nutrients. But an absence of giant state-run granaries is not one of its failings. In a complex system, flows are at least as important as storages, and is the appropriate place to focus. A secure food system stems far more from the flow of food and the existence of many levels of nearby and faraway storages than from the amount of food on grocery shelves. To claim that our just-in-time system is precarious is drawing the box far too small, and ignores the flow-based nature of the complex, constantly readjusting systems that we depend on.

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