It is curious how at least three prominent entomologists strayed into human affairs in the twentieth century, as if the world of insects were too narrow for them. Alfred Kinsey, who studied gall-wasps, became the most famous sexologist of his time; Edward Wilson, who knew more about ants than anyone in history, founded sociobiology, the theory that evolution explained social organization which in turn explained human behavior; and Paul Ehrlich, the lepidopterist who became the Cassandra of population growth.
It is true that man shares 60 percent of his DNA with the fruit-fly, Drosophila, but that does not mean that man is largely insect, despite how he might appear seen in the street below from the top of a very tall building.
Ehrlich, who died recently aged 93, was the object of much pent-up mockery in his obituaries. In 1968, he wrote that there would be mass famine in the 1970s and it was too late to avoid it. Hundreds of millions would definitely die of hunger.
At least no one could accuse Ehrlich of having been mealy-mouthed. He did not merely project into the future, claiming that if x continued, y would happen, not being able to say whether x would continue; he said that because of x, y had become inevitable. He stuck his neck out and predicted events within a timeframe; he was not like one of those economists who tells us that the stock market will either go up or go down.
Apart from having read his famous book, The Population Bomb, soon after it first came out, and what I have since read in his obituaries, I know little of Ehrlich, and therefore cannot speculate as to whether he was pleased or sorry that his dire predictions turned out to be (so far) mistaken. I know from experience that there is a pleasure to be had from contemplating future catastrophe, and moreover everyone likes to be proved right (“I told you so”). Let the heavens fall, so long as my warnings prove to have been correct.
There are, perhaps, good reasons why an entomologist should have been a predictor of population disaster. Everyone knows what the expression “a plague of locusts” means, and for certain worshippers of Nature, man is little more than a plague of locusts. Destructive population explosions of insects, particularly in larval form, are by no means rare. I sit in my garden as I write this, where, a few years ago, an explosion of the population of the caterpillars of a moth newly introduced into Europe from China, the box tree moth (Cydalima perspectalis), decimated and left for dead all the box trees. Very shortly afterwards, untold numbers of the moth, rather pretty individually (being cream colored with gold edging, a bit like the Oval Office), but like something out of a Hitchcock film when in such quantities, invaded the house and covered the walls of our bedroom. I cannot say why, exactly, but the sensation of moths fluttering about your face while you try to get to sleep is not merely unpleasant, but sinister.
Anyhow, we thought that our box trees were done for, but in fact they have recovered excellently, ready for the next explosion of the population of the box tree month. (We in Europe have also recently imported a species of stink bug, the tiger mosquito, and the Asiatic hornet from China, but that is a small price to pay for cheap goods.) I am not sure what is the lesson for humanity to be drawn from the box tree moth; the Bible does not say, “Go to the box tree moth, thou sluggard, consider her ways and be wise.”
Perhaps going to insects like this is precisely what Ehrlich did, and there are no facts or data from which it is impossible to draw the wrong conclusions.
Ehrlich was a Malthusian. The Reverend Thomas Malthus was a Church of England clergyman (by all accounts a very nice man) who was unfitted for survival, or at any rate advancement, in the Church because he was born with a hare lip and cleft palate—only the former was reparable in those days—which limited his capacity for public speaking. He became a professor of political economy instead.
His basic idea was that population tended to grow geometrically while the means of subsistence grew only arithmetically. As Gertrude put it in her account of Ophelia’s death, “long it could not be.” Either epidemic, war, or famine, or just possibly a restraint in human behavior would check population growth, as the absence of box trees would inhibit the population of the box tree moth. This seemed a compelling argument.
Karl Marx detested Malthus, seeing in him an apologist of inescapable mass poverty, but he was much influenced by him nevertheless (as was Darwin), and made precisely the same mistake that Malthus made. Malthus thought that only one variable, the size of population, would change, and did not realize that the productive capacity of the land and industry could more than compensate for the growth in population. Marx did not see this either: He thought the majority of the population was destined for immiseration, leading eventually to a cataclysm, after which everything would be all right.
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Ehrlich was a Malthusian; and the problem with Malthusianism is that, however many times you expel it from your thoughts, it returns. True, the catastrophe has not happened yet; but still, one thinks, it will happen at some unspecified time in the future. Even if the population fails to grow, each person will consume ever more resources which, being finite, will run out. This thought returns to one’s mind even as one resists it; it will never be finally refuted.
When, in 1986, I travelled through Niger, in the Sahel, it was very poor; its population was 6 million. It is now 26 million, so clearly famine, epidemic, and war, let alone restraint, have not kept the population in check. Except for Africa, the panic about population is now about its decline, not its increase. Whether this panic is more justified than was the one about overpopulation, I leave to people of the future to decide.
Two things are certain, however. The first is that mankind cannot get anything just right. The second is that man is the only species that derives pleasure from contemplating its own extinction.
