I’m reading a fantastic book right now called From Malthus to the Club of Rome and Back, a collection of essays on demography and resource consumption by Paul Neurath. There have been lots of quotable lines, but this one in particular caught my eye:
I have no quarrel with those who expect that some day we shall be able to irrigate the Sahara desert and farm the Amazon basin or the Congo basin (except to ask what effect cutting down the rain forests may have on man’s ability to survive on this earth), or that we shall be able some day to dig minerals out of the earth through shafts three and four times as deep as the deepest today. But I do have some quarrel, or at least some serious questions, with those who take it for granted that we shall be able to accomplish all of this within the short time left, some 100 to 120 or maybe 130 or so years, while mankind grows at current rates from its present size of 4 billion to some 30 to 50 billion – that is, unless we heed the warning of the model makers and others, that mankind simply cannot keep up for long its current 2 percent per year rate of growth, and its current ever-growing rate of consumption of irreplaceable materials. My quarrel is with those who take all of this for granted on no better basis than their own optimism and the fact that so far mankind has indeed managed – neglecting to heed the fact that through most of its history mankind managed with very small growth rates, that even as recently as 300 years ago, the growth rate amounted to only some 3 to 5 per 1,000 per year, compared with our current 20 per 1,000, and in fact in wide regions of Africa, 30 and 35 and more per 1,000 per year. (p. 81, 1975)
The numbers have of course shifted since this was originally written over 35 years ago (current global population growth is approximately 1.16% per year). But the main point is that the pace of change is the key factor, not whether hard limits to growth exist but whether we can adapt and innovate in time.