Sustainable growth is an impossibility
Most thinking people support the concept of a sustainable future. After all, given the possible harms involved, it seems only rational to try to avoid potentially disastrous ecological overshoot. But a big part of rationality is numeracy, which is the mathematical equivalent of literacy, and this kind of numeracy seems to be absent from our policy decisions.
Bacteria grow by doubling. One bacterium divides to become two, the two divide to become four, the four become eight, sixteen, and so on. Suppose we had bacteria that doubled in number this way every minute. Suppose we put one of these bacteria in an empty bottle at 11:00 in the morning and then observe that the bottle becomes full at precisely noon. […]
Here are three questions. First: at what time was the bottle half full? Answer: at 11:59, one minute before 12:00, because with steady growth the bacteria double in number every minute.
Second: if you were an average bacterium in that bottle, at what time would you first realize you were running out of space? Well, consider the last few minutes in the bottle. At 12:00, it’s full; one minute before noon, it’s half full; two minutes before noon, it’s a quarter full; before that, an eighth; then a sixteenth. At five minutes before noon, when the bottle is only 3% full and is 97% open space, just yearning for development, would you realize there might be a looming problem?
Now suppose that at two minutes before noon some of the bacteria realize they are running out of space, and they launch a great search for new bottles. They search offshore on the outer continental shelf and in the overthrust belt and in the Arctic, and they find three new bottles. That is an incredible discovery; it’s three times the total amount of resource they had ever known about. They now have four bottles, where before their discovery there was only one. Surely this will help them create a sustainable society, won’t it?
Now for my third question: how long can growth continue as a result of this magnificent discovery? Well, look at the score; at 12:00, one bottle is filled, there are three to go; 12:01, two bottles are filled, there are two to go; and at 12:02, all four are filled, and that’s the end of the line.
You do not need any more arithmetic than this to evaluate the absolutely contradictory statements that we have all heard from politicians, who tell us in one breath that we can go on increasing our populations, our effluents, our rates of consumption of fossil fuels or water, and in the next breath they say, “Don’t worry, we will always be able to discover the new resources and technologies that we will need to meet the requirements of that growth.”
A little arithmetic is all that is needed to show that “sustainable growth” is an impossibility. But this seems beyond most politicians and most sustainability “experts,” who advocate all manner of efficiency improvements which, taken together, cannot achieve sustainability, because they do not include stopping growth in population and rates of consumption.
The earth is but one country and mankind its citizens.
Sustainable growth, a phrase beloved by politicians, is an oxymoron. In a world of finite size, with limited resources, sustained growth of any material thing, such as a population or an economy, is not possible. Physical objects or processes cannot grow forever in a finite world. Understanding this simple fact is central to any understanding of sustainability.