Even more absurd were the predictions based on Malthusian theory widely published by Paul Ehrlich, both alone and together with his protégé John Holdren (currently President Obama’s science adviser) as well as the Club of Rome during the 1968–1972 timeframe.
Writing circa 1970 in works such as The Population Bomb (1968), Population, Resources, Environment (1970), and The Limits to Growth (1972), all of these theorists predicted that the “population explosion” would cause a catastrophic collapse of human well-being by the turn of the century, exactly the opposite of what actually happened. If Ehrlich et al. had been right, average world GDP per capita would have fallen from $3,200 in 1970 to less than $2,000 today. Instead, it rose to over $8,000 by 2010.
This four-fold error in predicting the future was really unforgivable, because Ehrlich et al. had the advantage of hindsight in knowing about the wild inaccuracy of Malthus’s original prediction, which by 1970 had already been shown to be off by a factor of 50 (an actual 18-fold increase in GDP per capita instead of a predicted threefold drop.) But even worse, it is evident that Ehrlich, Holdren, and the Club of Rome studiously ignored data readily available to them about the economic history of the recent past. That is, if one takes the trouble of extending their predictive theory backwards in time (as shown by the thin line marked with exes in Fig. 2), we see that it predicts an average global GDP per capita of over $7,300 for the year 1900 instead of the $670 that it was in reality. Now, Ehrlich was born in the year 1932 (for which his theory predicts an average GDP of $5,700, instead of the $1,060 that it really was). If a wealthy world had actually existed in the less populated 1930s, he should have been able to witness it himself. Instead, within his own lifetime (by 1970), he had seen the world population double and the global standard of living more than triple at the same time. He didn’t even have to open an almanac to know he was wrong. Instead, the data that disproved his theory were readily available to him by direct observation. The same can be said of Aurelio Peccei and his band at the Club of Rome. The first task of any scientist is to compare the predictions of their theory to known data. The fact that Ehrlich, Holdren, and the Club of Rome refused to do this shows that their publications were not science at all, but mere fakery — or less charitably, but perhaps more accurately, pure bunk costumed in pseudo-scientific gibberish for the purpose of justifying an anti-capitalist, anti-development — and ultimately, anti-human — ideology.
So what do the data actually suggest concerning the real relationship between human well-being and population size?
One of the first things any real scientist would do in trying to discover how one variable within a system changes with respect to another is to graph the first variable against the second and see if a clear relationship emerges. Figure 3 follows this tried-and-true technique and graphs world population size and per capita GDP against each other, using the data of the five hundred years of human history.
Fig. 3: How per capita GDP has changed as population has grown, 1500–2010
Well, there certainly seems to be a pattern here, which obviously is not the Malthusian claim that living standards decrease as population grows. Rather, what we see is GDP per capita increasing with population, with a nearly straight-line, direct proportionality holding for the past century. Put another way, the total GDP has risen, not in proportion to the population size, but in proportion to the size of the population squared.