Many of us awoke this morning to learn that the world’s seven billionth citizen had supposedly been born. Or, rather, three seven-billionth babies: Because of competition among UN agencies and charities to mark this world-population milestone, we wound up with a Baby Seven Billion in the Philippines, another in India and a third in Russia.
As if the world’s odometer had turned over and displayed a long row of zeroes, these births have elicited a storm of analysis, doomsaying, counter-doomsaying and debate over the magnitude of population growth. Such a noise has not been made since the birth of Baby Six Billion (Adnan Nevic of Bosnia, in 1999) or Baby Five Billion (Matej Gaspar of Croatia, in 1987).
But did the human race really fructify itself past the seven-billion mark on Halloween morning? Well, no. Or rather, maybe. Which is to say: We have no idea.
It could, in fact, have happened a year ago. Or it could happen in 2013. Or any time in between: We really have no idea how many people are born in any country, never mind the whole world, in any given year or day; we also have little idea how many people have died, which has as much effect on population.
The United Nations Population Division, the agency that keeps track of the number of humans, decided earlier this year to declare Oct. 31, 2011 Seven Billion Day, to draw attention to their latest World Population Prospects report, which estimates and predicts world population growth.
Its officials are happy to admit that the day was completely arbitrary: “The 31st October is a symbolic date, which is based on interpolated data from the original 5-year period estimates prepared by the Population Division,” they write.
The problem is that those estimates are mainly based on the national census data of 141 countries that produce them, and “official estimates” — that is, informed guesses — for another 89. And the countries with the fastest population growth and therefore the most profound effect on the pace of change are by definition very poor countries (Afghanistan and Somaliahave among the fastest-growing populations) and therefore have the worst statistics. Many of them have not conducted a census in 10, 15 or sometimes 20 years, and a few never really have at all.
So the UN officials say publicly that their figures could be off by a margin of six months in either direction if those statistics are assumed to have a margin of error of 1 per cent.
Which sounds fine, until you realize that they don’t even know what the margin of error is — and 1 per cent is probably way too low. Britain’s last census was adjusted by more than 1 per cent, and it’s famed for being one of the world’s most advanced. India’s has been adjusted by margins of several percentage points.
So many professional population-watchers assume that the margin of error is more like two years in either direction. Several institutions, including the US Census Bureau, believe that the seven billion mark will be crossed in 2012.
A group of scholars at the Vienna Institute of Demography published a research paper this year showing that the 7-billion mark is statistically more likely to be crossed late in 2012, though there is also a high likelihood that it could be crossed in 2013 or 2014.
Most informed observers feel that the proper date is probably later rather than earlier, because one thing we do know is that population growth rates are falling fast in almost every country.
In fact, it could well be that Baby Eight Billion, wherever he or she (or they) appear, will be the last such mini-celebrity.
The world’s population will likely level out and start dropping at some point this century – and depending on education, birth control knowledge and urbanization (the three biggest factors in growth rates), it could plateau at a low estimate of 8 billion in mid-century, or at an alarming high of 15 billion around 2100. Statisticians, such as the Vienna demographers, say the peak is more likely to fall somewhere on the middle-to-low end of that estimate.
It all goes to show that the arrival of billion-milestone babies, like so many other babies, is something that comes as a complete surprise.