Estimates of historical world population


This article lists current estimates of the world population in history. In summary, estimates for the progression of world population since the Late Middle Ages are in the following ranges:
Year14001500160017001800190020002100
population
350M–400M430M–500M500M–580M600M–680M890M–980M1,560M–1,710M6,060M–6,150M 10,000M–13,000M
average annual growth<0.1%<0.12%0.15%–0.3%0.1%–0.15%0.3%–0.5%0.5%–0.6%1.3%–1.4%0.7%–0.8%

Estimates for pre-modern times are necessarily fraught with great uncertainties, and few of the published estimates have confidence intervals; in the absence of a straightforward means to assess the error of such estimates, a rough idea of expert consensus can be gained by comparing the values given in independent publications. Population estimates cannot be considered accurate to more than two decimal digits; for example, the world population for the year 2012 was estimated at 7.02, 7.06, and 7.08 billion by the United States Census Bureau, the Population Reference Bureau, and the United Nations Department of Economic and Social Affairs, respectively, corresponding to a spread of estimates of the order of 0.8%.

Deep prehistory

As a general rule, the confidence of estimates on historical world population decreases for the more distant past. Robust population data exist only for the last two or three centuries. Until the late 18th century, few governments had ever performed an accurate census. In many early attempts, such as in Ancient Egypt and the Persian Empire, the focus was on counting merely a subset of the population for purposes of taxation or military service. Published estimates for the 1st century suggest uncertainty of the order of 50%. Some estimates extend their timeline into deep prehistory, to "10,000 BCE", i.e., the early Holocene, when world population estimates range roughly between 1 and 10 million.
Estimates for yet deeper prehistory, into the Paleolithic, are of a different nature. At this time, human populations consisted entirely of non-sedentary hunter-gatherer populations, with anatomically modern humans existing alongside archaic human varieties, some of which are still ancestral to the modern human population due to interbreeding with modern humans during the Upper Paleolithic. Estimates of the size of these populations are a topic of paleoanthropology. A late human population bottleneck is postulated by some scholars at approximately 70,000 years ago, during the Toba catastrophe, when Homo sapiens population may have dropped to as low as between 1,000 and 10,000 individuals. For the time of speciation of Homo sapiens, some 200,000 years ago, an effective population size of the order of 10,000 to 30,000 individuals has been estimated, with an actual "census population" of early Homo sapiens of roughly 100,000 to 300,000 individuals.
Estimates regarding the questions of "how many people have ever lived?" or "what percentage of people who have ever lived are alive today?" can be traced to the 1970s. The more dramatic phrasing of "the living outnumber the dead" also dates to the 1970s, a time of population explosion and growing fears of human overpopulation in the wake of decolonization and before the adoption of China's one-child policy. The claim that "the living outnumber the dead" was never accurate. Arthur C. Clarke in 2001: A Space Odyssey has the claim that "Behind every man now alive stand 30 ghosts, for that is the ratio by which the dead outnumber the living", which was roughly accurate at the time of writing.
Recent estimates of the "total number of people who have ever lived" are in the order of 100 billion. The answer depends on the definition of "people", i.e., whether only Homo sapiens are to be counted, or all of the genus Homo; due to the small population sizes in the Lower Paleolithic, however, the order of magnitude of the estimate is not affected by the choice of cut-off date substantially more than by the uncertainty of estimates throughout the Neolithic to Iron Age. Importantly, the estimate is also affected by the estimate of infant mortalities vs. stillborn infants, due to the very high rate of infant mortality throughout the pre-modern period. An estimate on the "total number of people who have ever lived" as of 1995 was calculated by Haub at "about 105 billion births since the dawn of the human race" with a cut-off date at 50,000 BC, and inclusion of a high infant mortality rate throughout pre-modern history.

Historical population

Before 1950

The following table uses astronomical year numbering for dates, negative numbers corresponding roughly to the corresponding year BCE. The table starts counting approximately 10,000 years before present, or around 8,000 BCE, during the middle Greenlandian, about 1,700 years after the end of the Younger Dryas and 1,800 years before the 8.2-kiloyear event.
From the beginning of the early modern period until the 20th century, world population has been characterized by a rapid growth. For the period of Classical antiquity to the Middle Ages, roughly 500 BCE to CE 1500, there was also a general tendency of growth, but not strictly monotonic: A noticeable dip in world population is assumed due to the Black Death in the mid-14th century.
YearPRB
UN
Maddison
HYDE
Biraben
McEvedy &
Jones 		Thomlinson
Durand
Clark
Gapminder
−100002M4M1–10M4M
−90004M
−80005M5M5–10M
−70007M8M
−600014M11M
−500027M18M5M5–20M5M
−400050M28M7M7M
−3000100M45M14M14M
−200072M27M27M
−1000100M115M50M50M
−500150M
−200227M150M150M
1300M300M226M188M255M170M226270–330M256M170M
100195M
200202M256M190M190M
300205M
350254M
400209M206M190M190M
500280M210M206M190M190M
600213M206M200M237M200M
700226M207M210M207M
800240M224M220M261M224M
900269M226M240M226M
1000400M310M267M295M254M265M275–345M280M254M
1100450M353M301M320M301M
1200500M393M400M360M384M400M
1250400M416M416M
1300500M392M432M360M400M432M
1340443M378M443M
1400500M390M374M350M374M
1500600M500M438M461M425M440–540M427M460M
1600600M556M554M579M545M498M579M
1650545M500M516M579M
1700660M603M603M1079M1010M1000M1041M1079M
1750791M814M700M770M
18001,000M978M989M900M985M
18201,042M1,093M
18501,265M1,262M1,189M1,263M1,241M1,200M1,200M1,278M
18701,272M1,347M
18751,325M1,383M
19001,656M1,650M1,547M1,654M1,633M1,625M1,600M1,650–1,710M1,668M1,645M
19101,750M1,777M1,790M
19131,793M1,829M
19201,860M1,935M1,912M1,968M1,924M
19252,000M2,000M2,007M
19302,070M2,092M2,145M2,100M
19402,300M2,240M2,307M2,340M2,324M