In world demographics, the world population is the total number of humans currently alive. It was estimated by the United Nations to have exceeded 8 billion (8,000,000,000) on November 15, 2022. It took around 300,000 years of human prehistory and history for the human population to reach a billion and only 218 more years from there to reach 8 billion. As of 2026, the world population is approximately 8.3 billion. However, this figure is only a very rough approximation (see ).
The human population experienced continuous growth following the Great Famine of 1315–1317 and the end of the Black Death in 1350, when it had reached nearly 370 million.Jean-Noël Biraben (1980), "An Essay Concerning Mankind's Evolution". Population, Selected Papers. Vol. 4. pp. 1–13. Original paper in French:(b) Jean-Noël Biraben (1979)."Essai sur l'évolution du nombre des hommes". Population. Vol. 34 (no. 1). pp. 13–25. The highest global population growth rates, with increases of over 1.8% per year, occurred between 1955 and 1975, peaking at 2.1% between 1965 and 1970. The growth rate declined to 1.1% between 2015 and 2020 and is projected to decline further in the 21st century. The global population is still increasing, but there is significant uncertainty about its long-term trajectory due to changing fertility and mortality rates. The UN Department of Economics and Social Affairs (UNDESA) has projected the world population to reach between 9 and 10 billion people by 2050, providing an 80% confidence interval of 10–12 billion by the end of the 21st century, with a growth rate by then of zero. However, other demographers predict that the human population may begin to decline in the second half of the 21st century if global fertility rates continue to fall.
The total number of births globally, as of 2024, is approximately 132 million/year, which is projected to peak during the period 2040–2045 at 141 million/year and then decline slowly to 126 million/year by 2100. The total number of deaths is currently 63 million/year and is projected to grow steadily to 122 million/year by 2100.
The global median age of human beings, as of 2026, is 31.1 years.
History
Estimates of world population by their nature are an aspect of modernity, possible only since the Age of Discovery. Early estimates for the population of the worldThe compound "world population" becomes common from c. the 1930s, adapted from early 20th-century "world's population"; pre-20th century authors use "population of the world". date to the 17th century: William Petty, in 1682, estimated the world population at 320 million (current estimates ranging close to twice this number); by the late 18th century, estimates ranged close to one billion (consistent with current estimates)."The population of the world, which Sir W. P. in 1682, stated at only 320 millions, has been estimated by some writers at about 730 million, by others, at upwards of 900 million; Mr. Wallace, of Edinburgh, conjectured it might amount to 1 billion, and this number has since generally been adopted who have noticed the subject;" The Monthly Magazine 4 (July–December 1797), p. 167. More refined estimates, broken down by continents, were published in the first half of the 19th century, at 600 million to 1 billion in the early 1800s and 800 million to 1 billion in the 1840s.600 million: Simon Gray, The Happiness of States (1818), p. 356 . 800 million: Gordon Hall, Samuel Newell, The Conversion of the World (1818), p. 10 . 800 to 1000 million: John Redman Coxe, Considerations Respecting the Recognition of Friends in Another World (1845), p. 21 (footnote with references).
It is difficult for estimates to be better than rough approximations, as even current population estimates are fraught with uncertainties from 3% to 5%.
Prehistoric patterns The history of the world's population involves a great deal of speculation. Before 9000 BC, virtually all humans were hunter-gatherers living in small bands that usually verged on the edge of extinction. Survival depended on the capture of hunted animals; if supply of animals dwindled for any reason, humans would starve; if the human population grew too large the number of surviving animals would shrink, leading to starvation the next year for the hunters (humans had not yet invented the technique of domesticating and herding animals). The hunting cultures sometimes fished, and usually gathered wild seeds and nuts, but they did not plant or grow vegetables or any other crops. One very rough estimate is 8 million hunters lived circa 9000 BC when the first of several "agricultural revolutions" occurred in the eastern hemisphere (the dates are very conjectural). Around the year 9000 BC in the Middle East, for reasons unknown, some groups began to domesticate and graze sheep. The practice of cultivating plants was invented independently in three places: in the Middle East and Europe (wheat, 6500–3500 BC), in Southeast Asia (rice, 6800–4000 BC), and in Central America and Peru (corn, about 2500 BC).Peter Bellwood, First Farmers: The Origins of Agricultural Societies (Blackwell 2004).
Agriculture provided a steady food supply that could be stored for a year or longer in order to minimize the risk of famine. Farm production could be expanded by systematic human exertion. The new technology of farming meant that the food supply was proportional to the number of workers who could plant and harvest the crops. Every new pair of hands meant more food for the community, so children were valued in agricultural societies. Later, additional workers found useful work in building irrigation canals and systems that provided a stable water supply for crops, especially in Egypt, Mesopotamia, India, China, Peru and Mexico. The population could now grow because new people paid their own way. (It would take many centuries before the arable land supply became a limiting factor.) However, death rates were high, especially for infants and children, so even with high birth rates growth was slow. The same amount of land could support either 1,000 hunters or 100,000 farmers, and thus farmers ultimately won the fight for the land. Farmers gathered in permanent villages, and through a process of warfare consolidated into much larger states, including those in China, India, Egypt and Mesopotamia. From 300 to 1400 AD large agricultural states also existed throughout the eastern United States, called the "Hopewell tradition" and "Mississippian cultures". They are most famous as Mound Builders, but their culture collapsed (for unknown reasons) by 1500. The natives encountered by the English and French were nomadic hunters who supplemented their meat diet with cultivated vegetables.Fekri A. Hassan, "Population dynamics" in Companion Encyclopedia of Archaeology (Routledge, 2002), pp. 672–713.Mark Nathan Cohen, The Food Crisis in Prehistory: Overpopulation and the Origins of Agriculture (Yale University Press, 1977).
Ancient and post-classical history
Estimates of the population of the world at the time agriculture emerged in around 10,000 BC have ranged between 1 million and 15 million.Ralph Thomlinson, 1975, Demographic Problems: Controversy over population control, 2nd Ed., Dickenson Publishing Company, Ecino, California, . Even earlier, genetic evidence suggests humans may have gone through a population bottleneck of between 1,000 and 10,000 people about 70,000 BC, according to the now largely discredited Toba catastrophe theory. By contrast, it is estimated that around 50–60 million people lived in the combined eastern and western Roman Empire in the 4th century AD.
The Plague of Justinian caused Europe's population to drop by around 50% between the 6th and 8th centuries AD. The population of Europe was more than 70 million in 1340. From 1340 to 1400, the world's population fell from an estimated 443 million to 350–375 million, with the Indian subcontinent suffering the most tremendous loss and Europe suffering the Black Death pandemic; it took 200 years for European population figures to recover. The population of China decreased from 123 million in 1200 to 65 million in 1393, presumably from a combination of Mongol invasions, famine, and plague.
Starting in AD 2, the Han dynasty of ancient China kept consistent family registers to properly assess the poll taxes and labor service duties of each household.Nishijima, Sadao (1986), "The economic and social history of Former Han", in Twitchett, Denis; Loewe, Michael, Cambridge History of China: Volume I: the Ch'in and Han Empires, 221 B.C. – A.D. 220, Cambridge: Cambridge University Press, pp 595–96. In that year, the population of Western Han was recorded as 57,671,400 individuals in 12,366,470 households, decreasing to 47,566,772 individuals in 9,348,227 households by AD 146, towards the end of the Han dynasty. From 200 to 400, the world population fell from an estimated 257 million to 206 million, with China suffering the greatest loss. At the founding of the Ming dynasty in 1368, China's population was reported to be close to 60 million; toward the end of the dynasty in 1644, it may have approached 150 million. England's population reached an estimated 5.6 million in 1650, up from an estimated 2.6 million in 1500. New crops that were brought to Asia and Europe from the Americas by Portuguese and Spanish colonists in the 16th century are believed to have contributed to population growth. Since their introduction to Africa by Portuguese traders in the 16th century, maize and cassava have similarly replaced traditional African crops as the most important staple food crops grown on the continent.
The pre-Columbian population of the Americas is uncertain; historian David Henige called it "the most unanswerable question in the world." By the end of the 20th century, scholarly consensus favored an estimate of roughly 55 million people, but numbers from various sources have ranged from 10 million to 100 million. Encounters between European explorers and populations in the rest of the world often introduced local epidemics of extraordinary virulence. According to the most extreme scholarly claims, as many as 90% of the Native American population of the New World died of Old World diseases such as smallpox, measles, and influenza. Over the centuries, the Europeans had developed high degrees of immunity to these diseases, while the indigenous peoples had no such immunity.
Modern history
During the European Agricultural and Industrial Revolutions, the life expectancy of children increased dramatically. The percentage of the children born in London who died before the age of five decreased from 74.5% in 1730–1749 to 31.8% in 1810–1829. Between 1700 and 1900, Europe's population increased from about 100 million to over 400 million. Altogether, the areas populated by people of European descent comprised 36% of the world's population in 1900.
Population growth in the Western world became more rapid after the introduction of vaccination and other improvements in medicine and sanitation. Improved material conditions led to the population of Britain increasing from 10 million to 40 million in the 19th century. The population of the United Kingdom reached 60 million in 2006. The United States saw its population grow from around 5.3 million in 1800 to 106 million in 1920, exceeding 307 million in 2010.
20th century
The first half of the 20th century in Imperial Russia and the Soviet Union was marked by a succession of major wars, famines and other disasters which caused large-scale population losses (approximately 60 million excess deaths). After the collapse of the Soviet Union, Russia's population declined significantly – from 150 million in 1991 to 143 million in 2012 – but by 2013 this decline appeared to have halted.