numbers, not adjectives — D. J. C. MacKay
by Carl Edward Rasmussen, 2016-05-23.
The term sustainable growth sounds pretty cool and is frequently referred to in relation to the economy in today's politics. It is interesting to examine what it might actually mean?
Imagine a man living in the year 01. Let's say he was rather poor, and had a total of 1 kg of possessions, some clothes, a pair of sandals and maybe some tools. Let's also assume that he was industrious and diligent, and that his possessions increased by 3% per year. This means that in the first year he would accumulate a further 30 grams, maybe some buttons, or a couple of sheets of paper. The following year it would be 31 grams (because of the effect of compound interest). When he dies, he passes his possessions on to one of his children, and she continues the same pattern. For simplicity, we ignore siblings and such. How many possessions would his descendant have today, in 2016? The answer is a lot, an awful lot, in fact more than 10 times the total mass of the entire earth2. Clearly, this growth is absolutely absurd to even contemplate.
You could claim that the example is irrelevant because the time span is too long. And indeed, it is true that 67 generations is quite a while, yet not unimaginably long. But at which generation did it become absurd? At which generation was it no-longer reasonable for that descendant to expect growth? And don't forget, we were only assuming a 3% growth, quite modest by the standards of many modern economists and politicians. And finally, in reality we are 7 billion people, not 1 person, who expect growth. The example shows clearly that growth can not be sustainable, at least not if it requires anything physical, such as stuff, energy or land (either directly or indirectly). But I am not sure what kind of growth it could be if it doesn't require any resources?3 Historically at least, growth has been accompanied by increased use of resources, which come from a limited (although possibly large) supply.
So what do politicians really mean when they say 'sustainable growth'? There are only two options which could possibly be meant, because there are only two interpretations which could actually exist in reality, and they are either 'temporary growth followed by stagnation' or 'temporary growth followed by decline'. I do not know which one is really meant. The point here is that it is usually not specified for how long the temporary growth is desired?
So how long is probably meant? Well, the problem with 'sustainable growth' is that it can't really be sustainable because it will eventually run out of resources (stuff, energy, land etc) which is finite in supply. So, sustainable growth must simply mean growth until the effects of shortages of resources prohibit further growth.
How would we know when we reach the point where it would be advisable to stop growth? I think we need to carefully look around for clues as to when this might happen. Clues could include scarcity of natural resources such a clean air and clean water, scarcity of land, or sources of food, agricultural land, forestry and fisheries. It could also be increased pressures on ecosystems, and habitats, and the resulting loss of biodiversity. Or the depletion of the ability of the natural environment to absorb waste, such as the atmospheres accumulation of Carbon Dioxide. These are all simple examples to look out for. If you ever see any of these happening, and you hear the term 'sustainable growth', then I think it would be reasonable to ask for a clarification 'how much' growth is meant, at what further cost to already depleted resources?
Our careful examination of the term 'sustainable growth' has established that it doesn't actually correspond to anything in the real world. It could be that people who use it are just a bit sloppy, and what they really mean is 'for 10 years or so' or something like that. Or it could be that they are incredibly short sighted, to a degree which warrants caution as to the intactness of their faculties. Or it may be that they use the term in a malicious way to cover up the fact that what they are advocating doesn't actually make sense. Either way, there seems reason to be deeply suspicious about any use of the term.