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Roger Payne on the R/V Odyssey in the Seychelles.
Photo: Chris Johnson

September 17, 2002
"Exponential Growth"
  Real Audio

This is Roger Payne speaking to you from our research vessel Odyssey in the waters of the Seychelle Islands of the Indian Ocean.

A recent report published by the National Academy of Sciences, indicates that at some time back in the late 1970s our ecological demands on the Earth exceeded the Earths ability to support us sustainably. In other words: the total area of biologically productive land, and sea, and fresh water that produces all of the resources humanity consumes, and assimilates the wastes we generate was, as of then, no longer sufficient to keep up with human demands sustainably. The authors of this paper conclude that in the 25 to 30 years since then, the area needed to support humans sustainably has become 1.2 Earth equivalents-that is to say, we now need all of the arable land and productive ocean and fresh-water fisheries of this entire planet plus a further area roughly equal to the arable areas of Europe and Australia. We need to ask ourselves where we are going to get two more continents the size of Europe and Australia so that we can raise sustainably the resources and detoxify the waste products that we are currently producing. Because we have no such area we are eating into our children's inheritance and making the problem worse at an ever-increasing rate. Many people feel that technology will save us. But because the human population is increasing exponentially it is not amenable to a technological fix since such a fix would have to violate mathematical law. There is simply no possible solution that can ever enable any exponential increase of anything, anywhere, to keep on going indefinitely if it takes place within a finite system.

The rule is simple: in any finite system all exponential increases must come to an end. The only question concerns how violent that end will be. The rule is that the longer it takes to apply the brakes, the more sweeping and disruptive the end becomes. That is the nature of exponential increases in population. As long as you are dealing with a finite system, the consequences represent an unrepealable natural law. The earth is a finite system.

At the end of the above report the authors emphasized the need to keep human demands on Nature within the amount that Nature can supply - it seems a reasonable request.

David Suzuki and Holly Dressel in their book "From Naked Ape to Superspecies" quote a graphic example put forward by University of Colorado physicist Arthur Bartlett that shows some of the unexpected consequences of exponential population growth. He suggested that we imagine a test tube full of the food for bacteria, and to imagine that we introduce a single bacterium into it of a species that that will divide once each minute. The test tube starts with one cell. A minute later, there are two bacteria; in two minutes, four; in three minutes, eight and so on. Because the population is doubling every minute it is an example of exponential population growth. At 60 minutes in this example, the test tube is full of bacteria and all the food has been eaten.

So here's the big question: when was the test tube half full? The answer, of course, is at 59 minutes. We have to remember that the population is doubling each minute. This means that at 58 minutes, it was a quarter full; at 57 minutes, an eight full; and so on.

At 55 minutes, the test tube was only 3 percent full, so if at 55 minutes, some bacterial scientist spoke up and said, 'I think we have a population problem here!' the less astute majority would probably reply 'What are you talking about? Ninety-seven percent of the test tube is empty, and we've been around for 55 minutes!' They might even point out that the test tube was already supporting billions of bacteria yet 97% of the food in it was still uneaten. But if no one did anything and the population doubling was allowed to continue, then at 59 minutes most bacteria would probably realize that they were in trouble. Suppose they then threw money and equipment at their scientists and begged them to find a solution. And suppose that, in less than a minute, those bacterial scientists somehow created three more test tubes full of food! The bacteria would be saved! Or would they? At 60 minutes the first test tube would have no more food in it but would be full of bacteria. At 61 minutes, the second test tube's food would be gone and it would be full of bacteria, and at 62 minutes all four test tubes would be full of bacteria and every bit of food would be gone. So even by quadrupling the amount of food and space available, the bacteria would have gained only two extra minutes. If they wanted to subsidize their population explosion for just one minute beyond that they would have to raise another four test tubes of food… instantaneously.

Most scientists now believe that the human population is well into its 59th minute, yet we are still not doing anything with a significant chance of helping us avoid the fate our species faces unless we move quickly to defuse our population explosion, or to produce even more food.

If we apply this example more directly to the human condition we must substitute for the one-minute doubling time of the bacteria, the current doubling time for the human population-about 32 years. We now know that our population is already using more than our planet can supply sustainably. And we know that we are therefore dependent on deficit spending of our natural resources. But suppose our scientists could somehow create the same kind of miracle the bacterial scientists created in the above example. We would have to face a consequence not mentioned in the bacterial example: for once our scientists improved food productivity that would, from the point of view of most people, remove the pressure and cause them to think we have plenty to eat-the crisis is therefore past. In that sense, the solution to this kind of problem can sometimes make the problem harder to solve. But also, since the kinds of remedial steps that are necessary to avoid exponentially increasing catastrophes like population growth are painful in all ways, including economically, the majority or our population can be expected to oppose the necessary solutions.

But let us assume that by mass education we could educate people enough to the problems brought on by exponential population growth so that they realized the necessity of continuing to change their ways even when food and other resources were still comfortably available. How much time would that give our scientists to quadruple our food supply? Well, if as compared to the bacterial example we are well into the 59th minute, we must be well into our 32 year doubling time. So let us be generous and guess we still have 20 years to quadruple our food supply. Twenty years is the length of time since 1982. Given that in 1982 we had far more options available than we do now, but that the same threats of overpopulation were with us, how well have we done in quadrupling our food supply since 1982? The answer is not well at all. Some people might wish to blame environmentalists for having dragged their feet so much about the dangers of genetic engineering that they have slowed down the application of that promising way of making the earth produce more. However, given that we are already about 25 years into deficit spending of our sustainable environmental inheritance and are reducing our capital at an accelerating rate by eroding our top soil, draining our aquifers, and increasing the rate of desertification exponentially, even the most optimistic forecasts re genetic engineering don't predict that it can quadruple the human food supply in the 20 years.

But let us ignore that fact for a moment and assume that we will be able to wave some magic wand of technofixing and make the earth produce the resources to support four times the human population it can now support. Once we have that magic technofix in place how long will the earth be able to support a continuation of the present rate of population increase? The answer is about 50 more years-in other words, before this century is out. Or, viewed in another way: if you are less than 25 years old now-before you reach your full life expectancy. That also means that we cannot expect that children being born now will have the kind of world surrounding them in the future that we would like to see them have, and that the only way they can possibly hope to see dignity at the ends of their lives is to work as hard as they can to put family planning at the top of the world's agenda.

Of course, it is important not to forget that the picture I have painted is probably a best-case scenario. If you are inclined to accept the assumptions of other scientists-many of whom are at least as well qualified as those I have quoted to hold the opinions that they do-you will have to be prepared to see the earth fail to produce enough resources for our exponentially increasing population in as little as thirty years, meaning that anyone born after 1957 must face the real possibility of having to contend with massive disruptions of their lives long before they reach their full life expectancies-and in most cases well before they have reached retirement age. This raises an interesting question: Is it not time to invest all or our efforts to change this world? After all, just what are we saving ourselves and our resources for? Unless we unite to use all of our efforts to bring the human population under control, we may ourselves live long enough to see our children living in a world we never dreamed they would have to face.

This is Roger Payne suggesting that the time has come-it really has. We are at war with the consequences of our past actions and it is time for us to rise up and act.

© 2002 Written by Roger Payne
Research by Genevieve Johnson

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