In one of the earliest known works of literature, “The Epic of Gilgamesh,” the goddess Ishtar threatens her father Anu: “I will break in the doors of hell and smash the bolts; there will be confusion of people, those above with those from the lower depths. I shall bring up the dead to eat food like the living; and the hosts of dead will outnumber the living.”
Can this be true? Do the dead really outnumber the living? The United Nations’ Population Division tells us that, as of 2017, there were 7.6 billion people living on earth, but how many preceded them?
First, a disclaimer: The number of the dead – however interesting intellectually – should be a matter of very little public concern. While political decisions are too often based on both historical fact and myth, they are seldom based on prehistory.
Yet the history of the numbering of the dead is a political one. Environmentalists use the tally of the dead to support their claim that the number of those living is fast approaching an unsustainable level. Their opponents employ different numbers to demonstrate the plentiful capacity of Mother Earth.
Because of unknown variables such as life expectancy during prehistoric times, and even the way we define “people,” their estimates vary by the billions. Nevertheless, the dozen or so scientists who have tried to calculate the number of those who preceded those of us currently alive all believed that their estimates carried with them a political message, a lesson to be learned regarding the limits of what the planet can support.
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It’s not hard to show how the very premise of these arguments is dead wrong. Whether the threat of overpopulation is very real or much exaggerated, the issue revolves around the correlation between the numbers of the living and the resources available to them – not with the ratio between the living and the dead. The dead have no more needs. They don’t eat food and don’t drive cars.
As far as we know, the first attempt to calculate the number of the dead was made in 17th-century England. Seemingly, it’s surprising that it took so long. One would assume that the question of how many people have ever lived would go hand-in-hand with other basic intellectual questions that have long engaged thinkers, such as the age of the world or its distance from the sun.
It is even more surprising given the fact that the regimes of the ancient world were very much aware of demographic questions. Consider, for example, 1 Chronicles 21: “Satan arose against Israel and incited David to number Israel. David said to Joab and to the commanders of the army, ‘Go and count Israel from Beer-sheba to Dan and bring me information as to their number.’ ... Joab reported to David the number of the people that had been recorded.... God was displeased about this matter and He struck Israel” (21:1-7).
Fortunately, not all censuses ended with a plague, and population counts were regularly undertaken in ancient Egypt, Babylonia, China, India, and Rome – usually for tax and military purposes.
Overpopulation was also a concern for classical thinkers. Aristotle, for example, was worried that city-states would grow beyond their means. In his Politics, he advocated limiting childbirth by law, and supported abortion of any excess pregnancies.
So counting the living is as old as written history itself. This is not the case, however, with counting the dead – though it’s not for a lack of interest.
The number of the dead was, and still is, a worldly concern for many believers. Most religions promise some sort of resurrection or reincarnation. In early Christianity, for instance, fierce discussions were held over such questions as whether the dead would clothed or naked when they returned to life, whether dead babies will be resurrected as adults, and whether there would be enough fertile land to feed everyone. Somehow, however, the technical question of just how many dead there were never came up.
How can we explain the absence of such considerations among the ancients? The obvious answer would be that the dead cannot be counted – their numbers must be estimated. And because statistics is a modern science, pre-modern scholars just couldn’t do the math.
Aristotle actually complained about the lack of such figures in his time, writing in Politics that, “One would have thought that it was even more necessary to limit population than property; and that the limit should be fixed by calculating the chances of mortality in the children, and of sterility in married persons. The neglect of this subject, which in existing states is so common, is a never-failing cause of poverty” (translation by Benjamin Jowett).
Nearly 2,000 years later, an English haberdasher and science buff would finally fulfil Aristotle’s wishes – by using the gloomy records known as the “bills of mortality.”
Starting in the era of Elizabeth I, in 1592, and then regularly from October 29, 1603, onward, British authorities began compiling a weekly record of the number of deaths collected by parish clerks around the kingdom. The bills were used by officials to monitor recurrences of bubonic plague, thus giving them the option of knowing when it was prudent to evacuate London.
Oddly enough, the bills, which included names of the deceased, and, beginning in 1629, the specific causes of death as well, were also sold to the public. A single copy cost a penny, and a yearly subscription cost four shillings. The rich, who could afford it (and who were more likely to be literate), wanted to know in advance when the time to leave for the countryside was approaching, and, in between plagues, simply to see which friends had passed away.
Back to Eden
But there was one man who saw in the bills more than just a collection of trivia. John Graunt wanted to prove that “A true Accompt of the Plague cannot be kept, without the Accompt of other Diseases” – and, more generally, “That a true Accompt of people is necessary for the Government.”
On February 5, 1662, the London-born Graunt presented his book, “Natural and Political Observations Made upon the Bills of Mortality,” to the Royal Society. It became the founding work of modern statistics, demography and epidemiology. It was Graunt who first discovered the numerical regularity, and hence the numerical predictability, of human fertility and mortality.
Mining the bills of mortality for their data, Graunt was able to make numerous observations, including “That two parts of nine die of Acute, and seventy of two hundred twenty nine of Chronical Diseases, and four of two hundred twenty nine of outward Griefs,” “That Autumn, or the Fall, is the most unhealthfull season”, “That every Wedding one with another produces four Children,” and that “More Men die then Women.”
But one section of Graunt’s index of insights immediately stands out. It reads: “Adam and Eve in 5,160 years might have, by the ordinary proportion of Procreation, begotten more people, then are now probably upon the face of the earth.”
Graunt didn’t prove that hypothesis, and for a good reason: If you assume, as he did, that humanity has always doubled its numbers every 64 years – the rate at which 17th-century London was doubling its population, according to Graunt – then by his day, there should have been 18,446,744,073,709,551,614, or 18 quintillion, descendants of Eden’s lovebirds.
The numbers simply didn’t make sense, but Graunt made some sense of them anyway, concluding that, “the World is not above 100 thousand years old, as some vainly Imagine, nor above what the Scripture makes it.”
Graunt’s friend and colleague Sir William Petty was also tempted to calculate the number of all people ever born – and encountered the same problem. It was Petty, a prominent economist, philosopher and scientist, who coined the term “political arithmetic” to describe what we now call statistics. Petty’s approach was a novelty: In 17th-century England, using numbers to make informed political decisions was considered utterly vulgar. And Petty tried to put a number on everything – from fields per acre of fertile land in Ireland to Holland’s financial advantage over England.
In his 1682 “Essay on the Growth of London,” Petty tried to prove – with numbers – that London was the most populated city in Europe, a claim made by the British at the time and disputed by foreigners.
By sampling the Bills of Mortality over regular intervals that were “neither remarkable for extraordinary healthfulness or sickliness,” Petty came to the conclusion that London’s population was doubling every 40 years, while Britain’s population doubled in size every 360 years. And, from vague figures given to him by the collectors of the chimney tax (a sort of property tax), he calculated that London’s population was then 669,930, with the population of England and Wales being 7,369,000.
Extrapolating these growth rates, Petty predicted a local population explosion in London by 1842: “It appears that in A.D. 1840 the people of the city will be 10,718,880, and those of the [rest of the] country but 10,917,389, which is but inconsiderably more. Wherefore it is certain and necessary that the growth of the city must stop before the said year 1840.”
Logistics aside, Petty argued that when the urban population of London exceeds that of rural England and Wales combined, then the city dwellers must surely starve, because there won’t be enough farmers to “perform the tillage, pasturage, and other rural works necessary to be done without the said city.”
Stretching the numbers out even further in time, Petty then predicted a global Malthusian catastrophe by the year 3682: “That if the people double in 360 years, that the present 320,000,000 computed by some learned men to be now upon the face of the earth, will within the next 2,000 years so increase as to give one head for every two acres of land in the habitable part of the earth. And then, according to the prediction of the Scriptures, there must be wars, and great slaughter, &c.”
However, this new science of population projection was not only a powerful tool for predicting the future – it was also a way to peek into the past. By extrapolating population growth backward, Petty tried to estimate the total number of people ever born. But whatever doubling period Petty used to try to chart population through the ages seemed to contradict both biblical and classical accounts: “For if we pitch upon any one number throughout for this purpose, 150 years is the fittest of all round numbers; according to which… there would have been about 8,000 in David’s time, when were found 1,100,000, of above twenty years old (besides others) in Israel, upon the survey instigated by Satan… And there would have been but a quarter of a million about the birth of Christ, when Rome and the Roman Empire were so great…On the other hand, if we pitch upon a less number, as 100 years, the world would have been over-peopled 700 years since. Wherefore no one number will solve the phenomena, and therefore we have supposed several.”
So Petty rightfully assumed that the pace of population growth varies over time. He did assume, however, that the global rate had decreased – from a population doubling every 10 years, in the years following Noah’s Flood, to every 1,200 years in his lifetime. This is how Petty arrived at his estimate of 20.32 billion having lived since the beginning of time. Why 20.32 billion? To prove his prediction of a global population explosion by 3682, when the living will not only outnumber earth’s capacity, but will also outnumber the dead, “from all which it is plain, how madly they were mistaken, who did so petulantly vilifie what the Holy Scriptures have delivered.”
Hence the idea of a population explosion was always perceived as a sin against the dead, with no connection to the question of the resources at the disposal of the living. But when the population explosion became a central political concern, in the second half of the 20th century, the precise number of those who came before turned into a confused battlefield dividing those who supported limiting birth rates and their opponents.
Between 1945 and 1954, and with political pressure and financial and technical assistance from the Population and Statistical Commissions of the newly formed United Nations, 150 of the world’s 214 nations and countries held censuses. Based on these censuses – and on additional, independent research from those countries that refused to take part in the UN’s undertaking – in 1951 the organization published its first projections – low, medium and high – of future world population.
Historian Matthew Connelly writes in his 2008 book “Fatal Misconception: The Struggle to Control World Population”: “As recently as 1945, informed observers had not expected the 3 billion mark to be reached before the millennium. Now it was the low projection for 1980… In fact, even the maximum expected growth – to 3.6 billion – would fall far short of the actual increase.”
Along with rational concerns of food security, the UN’s figures, which surprised many, also gave birth to a powerful myth, one that persists to this very day: the belief that the number of people currently alive exceeds the total number of all those who have ever existed.
Passing a milestone
Shortly after the publication of the UN’s projections, German physicist and amateur demographer Wilhelm Fucks published a paper titled ”How Many People Have Ever Lived.” It was published in a German-language journal of political science, yet the paper begins with an unusual footnote: “The above calculation was provoked by occasional statements voiced by F. Gummert in numerous conversations, according to which the number of the living was to be higher than the number of the dead.”
Unlike his 17th-century predecessors, the unfortunately named Fucks understood that population growth rates were rising, not declining or stagnating. He used local and global historical censuses and estimates, such as the Roman censuses and the Norman Domesday Book, and then assigned varied growth rates to different epochs, starting from a modest 0.3 percent annual growth among prehistoric hunter-gatherer societies and ending with the rapid 4.9 percent rate of the Industrial Age.
All in all, Fucks estimated that a total of 55.8 billion had lived on earth throughout the ages. Deducting from that number the UN’s then-current population estimate of 3 billion, Fucks resolved his quarrel with Gummert victoriously by stating that “the total number of people who ever lived on Earth is between 20 and 35 times higher from the number of those living on earth today.”
However, the UN would soon change its projections, and dramatically, leading to new fears – and to a new wave of fascinating, though completely irrelevant, calculations. Beginning with the Chinese census of 1953, the UN regularly updated its already shocking estimates, resulting in the surprise announcement in 1959 that humanity had already passed the 3 billion milestone – some 20 years ahead of the UN’s own prediction.
Connelly notes that, “It had taken almost all of human history to reach 1 billion people around 1800, and 130 years to grow from 1 to 2 billion; from 1930 to about 1960 world population grew by another billion. This was the first time anyone really noticed, because previously there was no United Nations office to mark the moment, much less offer projections for the future.”
One of the officials marking the historic landmark was the prominent statistician Wilhelm Winkler. A professor of statistics at the University of Vienna, Winkler was also head of the state population statistics office in postwar Austria, and he spearheaded the 1959 Vienna International Population Congress, during which the UN made its dramatic announcement.
Winkler presented a calculation of the total number of people ever born as a way of reassuring the public regarding the news. In a paper published in the official proceedings of the International Population Congress, Winkler attempted to dispel fears of an imminent population explosion by proving that the number of those then alive was a negligible proportion of the total that had ever lived. His calculation is striking for its intentionally high estimates for the dead. Like Fucks before him, Winkler must have known that growth rates had increased with time. Yet he chose to prove his point by applying the record-high growth rates of 1959 to the entirety of human history.
Winkler also broke with tradition by being the first – and the last – to partly abandon the “Adam and Eve” scenario in favor of three separate calculations based on three different scenarios for the origins of the human race: one original couple, an initial cohort of 50 couples, and a third option positing 1,000 pairs of human males and females. Winkler then went on to proclaim that the total number of people ever born ranged between 3.39 and 5.260 trillion people. And he makes his motivation for doing so very clear.
Estimating that the habitable surface of the earth was at the time 100 million square kilometers, Winkler writes: “If all people ever being born were still alive… every person would be allotted about 20 to 30 square meters, meaning roughly the size of a rather big room, therefore we are not dealing yet with the life threatening squeezing of a sardine can – which some overly frightened population politics are already painting on the wall for the imminent future.”
By overstating the number of people ever born, and thus underplaying the number then alive, Winkler was hoping to sweeten the UN’s bitter pill. But Canadian demographer Nathan Keyfitz soon picked up on Winkler’s trick. In his 1960 paper “How Many People Have Lived on the Earth?,” he reached an “estimate of 69 billion… the present world population is about 4 percent of this number.”
Keyfitz ended his paper by stating the obvious: “If, for instance, we do not divide the interval at all but simply take it that two people living a million years ago have now increased to 3 billion, then the number of man-years is… about 80 times as many as we found. In reading Professor Winkler’s article, I do not believe that he was aware of this.”
Keyfitz was not alone. Using 12 different time periods, each with its own growth rate, American ecologist Edward Smith Deevey, Jr., calculated, in a 1960 article, “The Human Population,” published in in Scientific American, that “about 110 billion individuals seem to have passed their days, and left their bones, if not their marks, on this crowded planet.”
Finally, in 1962, Annabelle Desmond, from the Population Reference Bureau, published a detailed history of world population estimates, and offered her own calculation regarding the number of the dead, while alluding back to Winkler – and acknowledging the growing popularity of the subject. Asked Desmond: “How many people have ever been born since the beginning of the human race? What percentage does the present world population of three billion represent of the total number of people who have ever lived?
“These questions are frequently asked the Population Reference Bureau’s Information Service.”
Her organization decided to do its own calculation, Desmond asserted, “because of the perennial interest and because of the credence sometimes given to what would seem to be unrealistic appraisals.” The number she arrived at was about the same as that of Keyfitz: “about 77 billion babies have been born.”
But her bureau’s response to Winkler wasn’t purely scientific either. Desmond emphasized that, “Rapid population growth cannot be maintained indefinitely in any part of the world. If birth rates to not decline in overcrowded lands, death rates eventually will rise to check growth… If the demographic transition to a balance between low birth and death rates could be hastened in the less developed countries, this gulf might yet be bridged in time to avert a Malthusian disaster.”
But despite the many scientific and popular papers and textbooks that have cited their calculations, the myth that there are now more people alive than all those living throughout human history proved resilient. It was repeated and reprinted in various forms, by both professional ecologists and laymen, usually as a rhetorical tool to emphasize the dangers of a global population explosion.
‘It can’t be good’
Consider, for example, the introductory words of political scientist Lester W. Milbrath to his 1996 book “Learning To Think and Act Environmentally: While There Is Still Time”: “Human population took 10,000 generations to grow to two billion; now, in one lifetime, it will grow another five billion. We currently add over 90 million people to the planet every year. That’s about the size of Mexico or Germany. There are more people alive today than have ever died. If other creatures could speak, they would call us an epidemic.”
In a 1979 poem, American poet William Matthews wrote how, “There are now more of us / Alive than ever have been dead, / I don’t know what this means, but it can’t be good.” Upon reading the poem, a fellow poet decided to ask Arthur H. Westing, an Amherst College ecologist, if it was true. Westing’s calculation, first published in 1981, estimates that 46.4 billion people had been born since the dawn of humanity some 300,000 years ago, meaning that the 1981 world population of 4.4 billion was about 9 percent of all people who ever lived.
Westing’s calculation is interesting for two reasons. First, he rejects the estimates provided by Deevey, Keyfitz and Desmond. By disregarding precursor species such as Homo erectus and Homo habilis, he starts the clock at two Homo sapiens in 298,000 B.C.E. Demographer Carl Haub would soon set the clock much later, at 50,000 B.C.E.
But what is more intriguing about Westing’s paper appears in a 2010 updated version in the journal BioScience, in which he uses the changing ratio between the living and the dead as a warning for the future: “Updating the above 1980 values to 2010, the number of people worldwide to have ever been born rises to approximately 49.2 billion. With the United Nations global population estimate for mid-2010 being about 6.9 billion, those of us living today thus now represent the somewhat higher fraction of about 14 percent of all those who have ever lived. Sad to say, we continue to ignore the ever-growing multiplicity of indications that Earth’s capacity to sustain a healthy biosphere is being increasingly overwhelmed by our relentlessly expanding human numbers, needs, and desires.”
Of course, “Earth’s capacity to sustain a healthy biosphere” has nothing to do with the number of people who lived in the Neolithic period, or in Aboriginal Australia. Nonetheless, measuring the changing ratio between the people living right now and those long gone had become, by the turn of the millennium, something of a touchstone for both overpopulation devotees and skeptics.
In 1995, Haub, a senior demographer at the Population Reference Bureau, published his paper “How Many People Have Ever Lived?,” updating it periodically, as recently as this year. Haub writes in his original paper, echoing his colleague Annabelle Desmond: “The question of how many people have ever lived on Earth is a perennial one among information calls to PRB. One reason the question keeps coming up is that somewhere, at some time back in the 1970s, a writer made the statement that 75 percent of the people who had ever been born were alive at that moment.”
Haub calculated that 106 billion people had lived up to 1995, “So, our estimate here is that about 6.5 percent of all people ever born are alive today. That’s actually a fairly large percentage when you think about it.”
The PRB’s 2018 update places today’s population of 7.5 billion at 6.9 percent of the total number of people ever born, and offers projections based on the UN’s current forecasts, placing the living at 7.8 percent by 2030 and 8.7 percent by 2050. Mathematical biologist Joel E. Cohen has argued against these calculations. In a 2014 paper, Cohen reviews previous estimates, starting with Petty and ending with Haub, noting that “It is curious that nearly all empirical estimates of the number of people ever born assume exponential population growth.”
Cohen thought that was a mistake, explaining that, “If the world’s human population reaches stationarity or declines, as many people expect within a century, the presently rising fraction of people ever born who are now alive will begin to fall.”
In other words, because of the dramatic drop in natural-growth rates – from 2.1 percent in the mid-20th century down to 1.09 percent at the start of the 21st, and up to the estimate of a rate of zero growth by the end of the century – when we, the readers of this newspaper, die, fewer people will be born to replace us. And so, future generations will continue to be but a small and ever-shrinking fraction of the total of humanity that ever lived.