Food Security/Insecurity 101:

Part 2 - Food and Energy

By Ken Ross

In Part 1 of this ‘story’, we examined the (UN) definition of ‘food security’. In this part of the food security/insecurity story, we will dig a little deeper, and explore the nature of food itself, our modern methods of food production, and their relationships with ‘energy’.

Humans, along with every other food consuming organism on the planet, ingest ‘food’ for the energy it can provide the body of the consumer organism. Sure, food contains much more than just energy (e.g. building blocks for cells, water, vitamins and minerals, fibre and probiotic organisms), but it is its energy component that tends to make clear, the more common issues we encounter in the food security or insecurity story, so that’s where we will focus attention for the moment.

You will probably recall, from your High School Science, that producer organisms use an external energy source to make complex molecules that have high energy chemical bonds within them. These molecules are like ‘energy batteries’ for the producer organisms, for when they need to, they can break the molecules down and release the energy in a form that can be used to ‘power’ the life processes of the producer organisms. Consumer organisms aren’t able to create molecules like that, but what consumer organisms (and decomposer organisms also) have ‘learnt’ to do is piggy back on the work of the producers, and utilise those energy packages to power their own bodies, by consuming parts of, or the whole bodies of, producers. Those high energy molecules and the materials they are packed in, we call ‘food’.


The chemical energy encapsulated in food ‘flows’ from its source (most often, the light energy of the sun), through the organisms in ecosystems and finally out into the atmosphere and space where it is lost from the earth as low-grade energy. Although it is a unidirectional flow, it is described as a food ‘chain’, because it has distinct stages or interconnected ‘links’ in it. Food chains begin with producer organisms capturing an external energy source (e.g. incoming solar
energy captured by photosynthetic green plants), move onto the level that consumes the producer organisms (e.g. herbivores, such as sheep), then a further level of organisms that consume the herbivore organisms (e.g. the carnivore level, such as humans), then occasionally, a higher ‘top carnivore’ level. Therefore, food chains, and the ‘food webs’ they culminate in, describe the passage of
energy through the organisms in an ecosystem (or ‘food system’). In general, the step from one level in a foodchain to the next (e.g., from producers to herbivores, or from herbivores to carnivores) involves a large reduction in available energy – usually approximating 90%, because every organism in a level of the food chain is expending a lot of the energy it obtained, to maintain itself, reproduce and grow. This being the case, the amount of food energy available to organisms feeding at the herbivore level in any food chain, is usually 10X (approx.) the amount of energy available to carnivores in the same food systeIt will be obvious to you that consumer organisms, would not be able to live for long periods, if they were constantly using more energy to power their bodies, and seek food, than they were able to obtain from their food, on a regular basis. Consumers in that position, gradually lose condition, start to break down their own tissues, then die (of 'starvation’). Over the Millenia we have been ‘human’, this has been a general rule for us also. Even when humans used draft animals to assist with food production, those animals still had to be fed, to power their bodies and provide the extra energy expended in the agriculture work. We weren’t getting something (work from animals), for nothing (the cost of their food). Throughout our history the number of humans in a group or society was regulated by the amount of food (energy) that could be collected or grown, and over the long period, humans had to ensure they expended (gathering food) much less energy than the food provided – otherwise they were going backwards, and people would die. Humans, therefore had to take care that they didn’t exceed the ‘carrying capacity’ of their lands or 'place’.



It also follows that, throughout human evolutionary history, humans have had to be mindful of the levels within an ecosystem they are drawing their energy from. Generally, the producer level contains 10x the amount of energy to be found at the herbivore level, though if much of that is tied up in inedible (to humans) grasses, that energy can only be tapped by eating the herbivores that can eat grasses – hence we hunted and also domesticated, grazing animals. For most human societies, it meant that a balance of plant and meat products were eaten, and a lot of the energy requirement for humans came to rely on high energy carbohydrate molecules in plants – especially those found in grains and nuts. Of course, another factor to bemindful of, was the hunting, gathering and growing of food, had to ‘cost’ less (in the energy sense) than the energy realised when the food was eaten. These were ecological ‘truisms’ until the advent of fossil fuels. Before fossil fuels, human food production had to be mindful of the energy in / energy out relationship (even draft animals or human slaves had to eat). Once humans started to use fossil fuels to power food production, processing and transportation, these considerations went out the window. Fossil fuels are much higher in energy per unit (of weight) than foods are, and their utilisation has enabled much greater amounts of food materials to be produced than human and animal power could ever accomplish. Fossil fuels have also enabled the expansion of human population numbers which again puts pressure on food production.


Today, in industrialised agriculture, approximately 10 kilojoules of fossil fuel energy are expended to produce 1 kilojoule of food energy that reaches the consumer) this figure varies between crops, localities, terrain and soil types, and the nature/efficiency of the machinery being used). That this method of producing food energy with fossil fuel energy is grossly inefficient from an ‘energy’ perspective (10 units in for 1 unit out), will be obvious to most. What is less obvious at the surface level (in spite of what you are paying at the pump), is that fossil fuel is a ‘cheap’ form of energy (compared with the cost of ‘human energy’), and its use enables the production of large volumes of food at low prices – and if you are reacting to that statement, do a little research into the relationship between the energy content and work capacity of a barrel of oil, and the work output of one human in a year.


In most advanced, first world societies, humans have high expectations of plentiful and varied food availability at relatively low price. While this seems perfectly ‘normal’, it is a reasonably, recent phenomena and one that is extremely artificial and fragile. For any country or region, this situation (and the food it creates or enables) is called its ‘phantom carrying capacity’. Phantom Carrying Capacity is a consideration/measure of the food that only reaches the consumer because its production, processing and/or transport was enabled or aided by fossil fuel. For most industrialised countries, the phantom carrying capacity of their entire food system approximates 90% of all the food consumed in that country. If that hasn’t hit you between the eyes, take a moment to consider what would happen when a country or region’s fossil fuel supply is seriously disrupted, or runs dry? Cuba, post the collapse of the USSR, provides a very real example for the curious.


So, while we are banging on about the fragility of food systems almost entirely reliant on fossil fuels, let’s take a sideways glance at another aspect of food insecurity – the ‘Ghost Acreage’ of a food system. Ghost Acreage, is a measure that takes account of the required food imported to a country or region, plus that which comes from the sea. Ghost acreage is therefore a description of the land area (and sea equivalent) required to produce the food a region/country isn’t currently producing (or can’t produce) for itself. Aotearoa/NZ produces more food than it consumes (remember, we are a net exporter of food), but the UK produces only 40% of the food it needs and Japan, only 30%. The ghost acreages for those two countries are therefore, 60% and 70% respectively.

It isn’t rocket science, is it? Even if absolutely everyone in the UK (all 65 million of them) were currently ‘food secure’, according to the UN definition (which they patently aren’t), the food system is still in a highly fragile (precarious) state, because:

1        Approximately 90% of the food being consumed is entirely reliant on fossil fuels for its production, processing and transport, and, as you may have noticed, the production, transport, marketing and pricing of fossil fuels, is highly volatile.

2        The UK only has direct control (grown in the UK) over approx. 40% of its food requirements. That means it is highly reliant on other countries to behave in a collaborative manner for the other, 60% of its food needs. Have you noticed how difficult ‘collaboration’ is becoming? Do really hungry people behave rationally, and collaboratively?


Food for thought, anyone?