Among life-forms found on the surface of our planet, all food energy originates in the green plants and nowhere else. The energy that originates in green plants is passed on to creatures who feed on the plants, and is passed on again to predators who feed on plant eaters, and is passed on again to predators who feed on those predators, and is passed on again to scavengers who return to the soil nutrients that green plants need to keep the cycle going. All this can be said to be the A of the ABCs of ecology. The various feeding and feeder populations of the community maintain a dynamic balance, by feeding and being fed upon. Imbalances within the community -- caused, for example, by disease or natural disasters -- tend to be damped down and eradicated as the various populations of the community go about their usual business of feeding and being fed upon, generation after generation. Viewed in systems terms, the dynamic of population growth and decline in the biological community is a negative feedback system. If you've got too many deer in the forest, they're going to gobble up their food base -- and this reduction in their food base will cause their population to decline. And as their population declines, their food base replenishes itself -- and since the replenishment makes more food available to the deer, the deer population grows. In turn, the growth of the deer population depletes the availability of food, which in turn causes a decline in the deer population. Within the community, food populations and feeder populations control each other. As food populations increase, feeder populations increase. As feeder populations increase, food populations decrease. As food populations decrease, feeder populations decrease. As feeder populations decrease, food populations increase. And so on. This is the B of the ABCs of ecology. For systems thinkers, the natural community provides a perfect model of negative feedback. A simpler model is the thermostat that controls your furnace. Conditions at the thermostat convey the information "Too cold," and the thermostat turns the furnace on. After a while, conditions at the thermostat convey the information "Too hot," and thermostat turns the furnace off. Negative feedback. Great stuff. The A of the ABCs of ecology is food. The community of life is nothing else. It's flying food, running food, swimming food, crawling food, and of course just sitting-there-and-growing-food. The B of the ABCs of ecology is this, that the ebb and flow of all populations is a function of food availability. An increase in food availability for a species means growth. A reduction in food availability means decline. Always. Invariably. More food, growth. Less food, decline. Every time. Without exception. There is no species that dwindles in the midst of abundance, no species that thrives on nothing. This is the B of the ABCs of ecology. Defeating the system's controls For a 190,000 years our species grew at an infinitesimal rate from a few thousand to 10,000,000. Then about 10,000 years ago we began to grow rapidly. This was not a miraculous event or an accidental event or even a mysterious event. We began to grow more rapidly because we'd found a way to defeat the negative feedback controls of the community. We'd become food producers -- agriculturists. In other words, we'd found a way to increase food availability at will. This ability to make food available at will is the blessing on which our civilization is founded. The ability to produce food at will is an undoubted blessing, but its very blessedness can make it dangerous -- and dangerously addictive. "At will" is the operative expression here. Because we could now produce food at will, our population was no longer subject to control by food availability on a random basis. Anytime we wanted more food, we could grow it. After 190,000 years of being limited by what was available, we began to control what was available -- and invariably we began to increase what was available. You don't become a farmer in order to reduce food availability, you become a farmer to increase food availability. And so do he folks next door. And so do the folks farming throughout your region. You are all involved in increasing food availability for your species. And here comes the B in the ABCs of ecology: An increase in food availability for a species means growth for that species. In other words, ecology predicts that the blessing of agriculture will bring us growth -- and history confirms ecology's prediction. As soon as we began to increase the availability of our own food, our population began to grow -- not glacially, as before, when we were subject to the community's negative feedback controls -- but rapidly. Population expansion among agriculturists was followed by territorial expansion among agriculturists. Territorial expansion made more land available for food production -- and no one goes into farming to reduce food production. More land, more food production, more population growth. With more people, we need more food. With more food available, we soon have more people -- as predicted by the laws of ecology. With more people, we need more food. With more food, we soon have more people. With more people, we need more food. With more food, we soon have more people. Positive feedback, this is called, in systems terminology. Another example: When conditions at the thermostat convey the information "Too hot," the thermostat turns the furnace ON instead of OFF. That's positive feedback. Negative feedback checks an increasing effect. Positive feedback reinforces an increasing effect. Positive feedback is what we see at work in this agricultural revolution of ours. Increased population stimulates increased food production, which increases the population. More food, more people. More people, more food. More food, more people. More people, more food. More food, more people. Positive feedback. Bad stuff. Dangerous stuff. A demonstration Let me now outline a demonstration that will clarify the issues I've raised here. Into a nice roomy cage we introduce two young, healthy mice. The cage has a built-in feeder that enables us to make food available to the mice in any quantity we like. We start by putting in a certain amount of food and we increase it daily. However much the pair of mice eat the first day, we put in 50% more the second day. However much they eat the second day, we put in 50% more the third day. Before long there are 4 mice. No matter, we follow our procedure. Whatever they eat in a day, we put in 50% more the next. Before long there are 8 mice, 16 mice, 32 mice. No matter, whatever they eat in one day, we put in 50% more the next. 64 mice, 128, 250, 500, 1000. Whatever the mice eat in one day, we put in 50% more the next, carefully extending the sides of the cage as needed to avoid stressful overcrowding. 2000, 4000, 8000, 16,000, 32,000, 64,000. At this point, someone runs in and yells, "Stop! Stop! This is a population explosion!" What shall we do? I have a suggestion. Let's start by answering this question: How much did the 64,00 mice eat yesterday? Answer: 500 kilos of food. Okay. Well, ordinarily, we'd put 750 kilos of food into the cage tomorrow, but let's abandon that procedure now. Our new procedure will be based on this theory: Yesterday 500 kilos was enough for them, so why shouldn't 500 kilos be enough for them today?

So today we put just 500 kilos of food into the cage, same as yesterday. Now watch closely. There are no food riots. Why should there be? The mice have just as much to eat today as they did yesterday. Now watch closely again. No mice are starving. Why would there be? Now its tomorrow, and again we put just 500 kilos of food into the cage. Again, watch closely. There are still no food riots. Still no mice starving. We do it again on day three. Again, no food riots, no mice starving. But aren't new mice being born? Of course -- and old mice are dying. Day four, day five, day six. I'm waiting for the food riots, but there are no food riots. I'm waiting for the famine, but there is no famine. There are 64,000 mice, and 500 kilos of food will feed 64,000 mice. Why should there be riots? Why should there be famine? And the population explosion stopped overnight. What else could it do? Population growth has to be supported by increased food availability. Always. Without exception. Less food -- decline. More food -- growth. Same food -- stability. That's what we've got here: Stability. Now the head of the department charges in and says, "Who needs 64,000 mice? These mice are eating us out of house and home. What's special about 64,000 mice anyhow? Why not 8,000? Why not 4,000?" You know what to do because you understand the B in the ABCs of ecology. We don't need birth control. All we need is food control. Someone says, here's what we do. Yesterday 500 kilos of food went into the cage. Today we'll reduce that by a kilo. Oh no, another objects. A kilo is too much. Let's reduce it by a quarter of a kilo. So that's what they do. 499.75 kilos of food go into the cage. Tension in the lab as everyone waits for food riots and famine -- but of course there are no food riots and no famine. Among 64,000 mice, a quarter of a kilo of food is like a flake of dandruff apiece. Tomorrow 499.5 kilos of food go into the cage. Still no food riots and no famine. This procedure is followed for 1000 days -- and not once is there a food riot or a famine. After 1000 days only 250 kilos of food are going into the cage -- and guess what? There are no longer 64,000 mice in the cage. There are only 32,000. Not a miracle -- just a demonstration of the laws of ecology. A decline in food availability has been answered by a decline in population. As always. Nothing to do with riots. Nothing to do with famine. Just the normal response of a feeder population to the availability of food. Objections I've been surprised by how challenging people find these ideas. They feel menaced by them. They get angry. They feel I'm attacking the foundation of their lives. They feel I'm calling into question the blessedness of the greatest blessing of civilized life. They somehow feel I'm questioning the sacredness of human life itself. I've been told that it doesn't have to be this way. I've been told that it's possible for us to increase food production and simultaneously reduce our population. This is basically the position taken by birth-control advocates. This is basically the position taken by well-intentioned organizations that undertake to improve indigenous agricultural techniques in Third World countries. They want to give technologically undeveloped peoples the means of increasing their population with one hand and birth-control aids with the other hand. They're certain that we can go on increasing food production while ending population growth through birth control. This represents a denial of the B in the ABCs of ecology. History -- and not just 30 years of history but 10,000 years of history -- offers no support whatever for the idea that we can simultaneously increase food production and end population growth. On the contrary, history resoundingly confirms what ecology teaches: If you make more food available, there will be more people to consume it. Obviously the matter is different at the individual level. Old Macdonald on his farm can increase food production and simultaneously hold his family's growth to zero, but this clearly isn't the end of the story. What's he going to do with that increase he produced on his farm? Is he going to soak it in gasoline and burn it? If so, then he hasn't actually produced an increase at all. Is he going to sell it? Presumably that is what he's going to do with it, and if he does sell it, then that increase enters the annual agricultural increase that serves to support our global population growth. I'm often told that even if we stop increasing food production, our population will continue to grow. This represents a denial of both the A and the B of the ABCs of ecology. The A in the ABCs of ecology is this: We are food. We are food because we are what we eat -- and what we eat is food. To put it plainly, each and every one of us is made from food. When people tell me that our population will continue to add new millions even if we stop increasing food production, then I have to ask what these additional millions of people will be made of, since no additional food is being produced for them. And of course I have to deal with the starving millions. Don't we have to continue to increase food production in order to feed the starving millions? There are two things to understand here. The first is that the excess that we produce each year does not go to feed the starving millions. It didn't go to feed the starving millions in 2002, it didn't go to feed the starving millions in 2001, it didn't go to feed the starving millions in 2000, it didn't go to feed the starving millions in 1999 -- and it won't go to feed the starving millions in 2003. Where did it go? It went to fuel our population explosion. That's the first thing. The second thing is that everyone involved in the problem of world hunger knows that the problem is not a shortage of food. Producing more food does not solve the problem, because that's simply not the problem. Producing more food just produces more people. Our population explosion can no more continue without food than a fire can continue without fuel. The fact that our population continues to grow year after year is proof that we're producing more food year after year. When all else fails, it will be objected that the people of the world will not tolerate a limit on food. That may be, but it has nothing to do with the facts I've presented here. What do I have against birth control? I don't have a thing against birth control as such. It just represents very poor problem-solving strategy. The rule in crisis management is, Don't make it your goal to control effects, make it your goal to control causes. If you control causes, then you don't have to control effects. Birth control is a strategy aimed at effects. Food-production control is a strategy aimed at causes. We'd better have a look at it.