(It’s Spring Break here this week, so I am taking the week off from blogging to work to revise a few articles and begin working on new research projects. As a result, I am re-posting old posts that some new readers might have missed but which were very popular the first time I posted them. The following was initially posted on October 31, 2011.)
The seven billionth person on Earth will be born today according to the United Nations. To mark occasion, the BBC has developed an application that allows calculating your own number. I learned that, of all the people now alive, I was born 4,133,669,462nd.
As is inevitably the case when talking about the world’s population, the birth of the seven billionth person has caused a rash of newspaper articles, newscasts, and blog posts about how this really is a sign that at least two of the Four Horsemen of the Apocalypse — famine and death — will soon be here.
For a perfect example of that type of fear mongering, see this presentation, by Australian journalist Julian Cribb.
The Reverend’s New(est) Clothes
But really, Cribb is merely serving us the reheated leftovers of Reverend Thomas Malthus‘ Essay on the Principle of Population. In this book, first published in 1798, Malthus asserted that disease and famine would naturally arise to limit the size of any population.
Thus, because population growth would outpace agricultural growth (after all, there is only a limited amount of arable land in the world), disease and famine would take care of keeping the size of the population in check. Malthus actually estimated that the upper bound was equal to about one billion.
Malthus’ argument was brought up again by Paul Ehrlich in 1968, when he published The Population Bomb which, according to Wikipedia, “warned of the mass starvation of humans in the 1970s and 1980s due to overpopulation, as well as other major societal upheavals, and advocated immediate action to limit population growth” (the emphasis is mine).
For an example of how Malthus’ arguments are still very much in fashion, you can read this article in The Guardian, or listen to the following newscast by Public Radio International (click on the arrow to begin playing; a transcript is available here):PRI's The World - Global Population to Reach Seven Billion
Keep Calm and Carry On
Obviously, neither Malthus’ nor Ehrlich’s doomsday predictions have come true. This is all thanks to technological innovation. That is, increases in agricultural productivity have consistently outpaced the rate at which the world’s population continues to increases.
This has been true since the beginning of time, so why worry now?
It is true that food prices are high and that there is a famine in the Horn of Africa. But as far as I can tell, food prices are high mostly as a result of misguided policies (e.g., ethanol mandates). Not only that, but economists are confident that famine is the result of human action, and not of a lack of food to go around.
Moreover, there are several untapped technological innovations which could be used to feed the world. One obvious example is biotechnology, which some argue is being kept out of the regions that most need it. Another example is urban or peri-urban agriculture. Vertical farming is yet another example. And Nathan Yaffe recently discussed some low-hanging fruit for agricultural productivity.
Likewise, population bomb-type arguments conveniently dismiss the idea of a demographic transition, i.e., the transition from high to low birth and death rates as countries grow richer.
Concretely, the demographic transition means that the size of any population eventually tapers off and hits an upper bound. In the limit, the demographic transition could even mean that the size of a country’s population actually decreases when fewer than 2.1 children are born per woman in a given country. Western Europe and Japan are both good examples of this.
Ultimately, I find the rhetoric surrounding the birth of the seven billionth person to be irresponsible, because it can easily lead to misguided population control policies. History is rife with stories of governments trying to impose a limit on the number of children a couple can have, which leads to abandoned children, unsafe abortions, and so on.
Very often, the rhetoric surrounding population debates reminds me of the rhetoric surrounding immigration, which discusses the costs of immigration while ignoring its benefits. In both cases, people seem to be unable to see further than the end of their noses as they conveniently ignore the general equilibrium consequences of both population and immigration to focus purely on the partial equilibrium consequences.
Maybe I am being stupidly optimistic. In order to oppose my views, I suppose some would resort to the four most dangerous words in the English language and claim that “This time it’s different,” that technology will not save us this time around. Maybe. But I’ll go with the last 2.5 million years and say “Maybe not.”