There are, and have been for a few decades now, competing narratives about food, hunger, and population. And supporting these narratives are a large number of divergent arguments from people with an even larger array of ideological perspectives. I’ve been puzzled for some time that these narratives not only have co-existed for as long as they have, but that it’s still unclear which is true, and more than that, which of the supporting arguments make sense and which don’t isn’t clear.
Below I’d like to attempt to break these narratives into three (oversimplified) categories and highlight a few recent and not-so-recent arguments supporting them.
We Can Feed the World, part 1.
This argument comes in a number of forms. The first, most obvious, and most prominent one is that of the agribusiness world, which says and has said for decades that new chemistry and new genetic engineering can and will continue increasing yield. The claim they often make is stronger than this, saying that only such agribusiness science and engineering can increase yields and feed the world, and that without them people will starve. (Scientific American had a recent issue dedicated to this, and it was, frankly, a bit embarrassing to see such a magazine be so narrow in what science they considered in making their judgments.)
However, often ignored in this perspective is the fact that a billion people around the world are going hungry already, and many more are food insecure. Many farmers who have switched to using these agribusiness methods have found themselves struggling to pay for them. They have also found that the techniques, when they work at all, have little staying power: artificial fertilizers only provide a boost for so long before already-depleted soil is stripped of structure, other nutrients, and soil life and can no longer produce high yields; GMO, pesticide, and herbicide manufacturers struggle to keep pace with natural adaptations against their methods. So while it’s true these systems are feeding the world, it’s not clear they can continue to.
We Can Feed the World, part 2.
A less common but still prominent argument made by Lappe and others in books such as Diet for a Small Planet and Hope’s Edge, is that scarcity of food is a matter of proper distribution of food and/or income, and a matter of not wasting food via the present-day industrial food system. That is, there is enough food being grown to feed the world, but that instead of going to feed the world, this plant-based food is either used as animal feed for heavy meat eaters in wealthy nations, is used in the production of highly-processed industrial food, or is simply wasted.
This argument is based upon a slightly shaky premise. Even if the world were short, say, enough food for 1 billion people, and there were no waste in the current food system, there are probably enough other sources of calories that could be turned to that are outside of the human economy — that is, plants and animals that are currently not viewed as food but could be. That’s not to say that it’s preferable to increase the human footprint on the planet, but rather that the argument is premised on the footprint we have today and that footprint isn’t fixed.
Turning this reasoning on its head, we find that the argument that we can feed the planet using the food that’s grown today, with today’s footprint, doesn’t squarely face the fact that humanity has already far overshot carrying capacity and has appropriated far too many ecosystems for its use. That is, for this argument to hold — making the big assumption that the economic systems that make today’s food system exist were to be radically altered — we’d need to be able to replace all of the food growing going on across the globe in a way that puts it on a sustainable footing. Maybe this is possible, and Lappe and others give plenty of examples of how it can be done better on a small scale, but as I’ll discuss later, a large question is whether we will, not whether we can.
No We Can’t, part 1.
There are some in the mainstream of this discussion who are nevertheless pessimistic about food availability. In this camp I’ve seen arguments for decreasing the birth rate in poor nations (primarily) as they view the problem as a matter of population, and that energy/resource footprints aren’t an issue in the discussion. I’ve never found mainstream “no we can’t” arguments to be particularly well thought out, as they’re often used as a bludgeon to make a political point (e.g. “people in country X are hungry not because globalization destroyed their local economic and agricultural systems but because they have too many people, and we can’t fix that”).
No We Can’t, part 2.
Many eminent, less-mainstream thinkers fall into a second category of “no we can’t feed the world” thinking, including Meadows, Catton, Diamond, and others who take a large-scale, long-term ecological view of the predicament humanity is in today. They argue that all societies and all systems that overshoot their ecological basis a) are eventually forced to return to within that basis, b) often degrade the basis itself by being in overshoot, and that c) this process happens so slowly (over many human generations) that it’s easy for these societies to believe that they have agency, d) no past societies have been able to avoid this consequence and there is little reason to believe that now is different, and e) no one subsystem (e.g. food, manufacturing, etc.) is independent and thus all subsystems rise and fall together.
Surprisingly even mainstream commentators like Thomas Friedman have gotten in on this kind of argument, though of course after making the argument that we’re in overshoot, he manages to ignore its fundamental conclusion and instead argues that we’ll find a way out.
No We Won’t, part 1.
Last year Adam wrote a nice analysis of a Toby Hemenway article on the resilience of the food system. He made the case that while Hemenway’s arguments on how the industrial food system might continue to function and feed humanity (even while fossil fuels become more expensive and scarce) make sense in the way Lappe’s arguments make sense, there’s reason to be concerned that market conditions and public policy will make entrenched actors in the food system slow to adapt to changing conditions. Thus it’s likely that people will continue to fall off the back of the truck as things decline. Beyond simply the monetary incentive to continue growing crops for non-food uses, there is also significant inertia and sunk costs in the system that are likely to make change difficult. I find myself in agreement with this part of the argument: “I’m optimistic about the proliferation of kitchen gardens in urban and suburban spaces, but transforming land currently zoned for industrial monoculture is a much more daunting task.” I’d like to consider where this leaves us next.
Energetic limits of land productivity.
To understand what sorts of physical limits might exist on food production, I did a quick calculation. While I’m sure there are many better estimates out there, this should give us a rough idea of whether it’s even reasonable to imagine that 7 billion or more humans can be fed sustainably. Let’s start with an estimate of 200 W/m^2 of sunlight, globally averaged over night and day, arriving at the Earth’s surface. Average photosynthetic efficiency is about 1-2% for normal plants (only some algae and a few rare plants like sugarcane get higher efficiency). So that’s 2-4 W/m^2 of plant energy assuming the ground is entirely covered. Then let’s allow 50% for the plant to perform its own metabolic functions, so that’s 1-2 W/m^2 of harvestable energy (edited to add: on average — if we factor in growing degree days, we might say roughly 1-2 W/m^2 is for mid-latitude/subtropical regions, with 2-4 W/m^2 in the tropics and 0.5-1 W/m^2 in high-latitude temperate regions). Given that a person requires 100 W (about 2000 kcal / day), that results in 50-100 m^2 of land requirement per person, which is about 500-1000 sq ft, which happens to be about what David Duhon and John Jeavons found is the minimum land area on which one can feed oneself growing and eating mostly potatoes in a perfectly-managed, intensively-cultivated smallholding.
So no new technology is needed, nor is new technology possible, to improve the efficiency with which we can produce food. That is, the arguments made by those in the first camp — those who argue we must increase yields through new techniques in industrial agriculture — are bunk, as techniques have already been developed to deliver the maximal yield possible given the sunshine falling on the Earth. Literally the only way out of this (energetically), I think, is to build nuclear fusion plants and then use the energy from that to produce food somehow — that’s the only possible renewable non-solar source of energy — but this remains firmly in the realm of science fiction.
However, when we look at the amount of farmland under cultivation today, we see that it’s far more than is required to feed all of humanity ten times over if such intensive cultivation were used — perhaps 500 billion people (as my friend John pointed out). The catch, I think, is twofold.
The first catch is that we must consider total human energy consumption rather than simply what humans require to stay alive. In the absence of fossil fuels, this energy will come in large part from plant sources. To begin with, intensive cultivation requires cycling back all nutrients perfectly to keep it within 100 m^2. Otherwise it requires about 3x the land area, with the remainder used for compost crops and letting the land rest (with 3x being a rule of thumb I’ve seen in a number of sustainable agricultural methods). This ignores the water cycle and other limits for simplicity. Average energy consumption globally today is 2kW / person (16 TW / 7 billion = 2285 W). So that means we need to roughly scale down the arable land by a factor of 20 (to get the portion used for just food), and that’s with perfect nutrient cycling. Take a factor of 3 on that for compost crops, and we’re at 8 billion people living at 2kW. If we had no other impact on the planet and could do perfect sustainable organic agriculture with most people living in lower-latitude temperate and tropical regions we could sustain 8 billion people on the planet.
A couple big flaws in this estimate is that a large fraction of arable land is used to feed animals for meat, and that the 2kW used per person often involves taking the products of nature and processing them, thereby consuming an outsized portion of nature relative to that energy budget (e.g. it takes much less energy to cut down a tree than it took the tree to grow). The first could be fixed by saying that we could sustain 8 billion people on a perfectly managed vegan organic diet, and with meat, somewhere between 2-4 billion. Even this ignores the possibility of getting some of the 2kW / person from photovoltaics and wind turbines. Nevertheless, the crux of this calculation is that sustainable techniques exist to produce roughly as much food as the industrial food system produces today, but also roughly as much as is possible given energetic limits.
The second catch is the one Adam identified — converting backyard gardens is one thing, but turning the farmed-out land of the American Midwest into Jeavons-style smallholdings is another thing altogether.
Premises and Conclusions.
It’s a bit odd to end on both premises and conclusions, but there are a couple of premises that are unstated in this discussion that span the categories. Specifically, this discussion is premised on the notions that feeding the people of the world is a) good and b) hard to do either now or in the future. I think both of these are true, but I’ve seen arguments that b) isn’t fundamentally true. Neoprimitivists tend to make this argument, among others: that the world is naturally abundant and that as long as societies remain uncivilized (i.e. not living in cities with high resource consumption) then the Earth will provide with little effort. Whether this was true in the distant past, it’s certainly not applicable now and won’t be for many centuries.
Pulling these strands of thought together it seems to me that there’s good evidence all these perspectives are right, but on different timescales. We have a core industrial food system that can and will feed most of (but, crucially, not all of) the world in roughly the ways it is today, with feedback loops that will keep it stable. These feedbacks include the entrenched food distribution system, political lobbying of industrial farmers and agribusiness that want to keep subsidies flowing to keep their business models viable as long as possible, and the eating habits of the world. However since this system is not on a solid foundation, it will slowly (and, perhaps in short bursts, quickly) leak people and land into the two other categories — “no we can’t” and “no we won’t” — in which people go hungry due to lack of food or because the system is imbalanced and prioritizes other things over feeding people. I do think that, like Adam wrote, that kitchen gardens are likely to pick up some of the slack and my calculations indicate that quite a lot of food can be grown that way. However, in the long run, we’re unlikely to escape the ecological fate of so many past societies; our task is make the ride down as smooth as possible.