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The world population is the sum total of all living humans on Earth. As of today, it is estimated to number 7.025 billion by the United States Census Bureau (USCB). The USCB estimates that the world population exceeded 7 billion on March 12, 2012. According to a separate estimate by the United Nations Population Fund, it reached this milestone on October 31, 2011.
The world population has experienced continuous growth since the end of the Great Famine and the Black Death in 1350, when it stood at around 370 million. The highest rates of growth – global population increases above 1.8% per year – were seen briefly during the 1950s, and for a longer period during the 1960s and 1970s. The growth rate peaked at 2.2% in 1963, and had declined to 1.1% by 2011. Total annual births were highest in the late 1980s at about 138 million, and are now expected to remain essentially constant at their 2011 level of 134 million, while deaths number 56 million per year, and are expected to increase to 80 million per year by 2040. Current projections show a continued increase in population (but a steady decline in the population growth rate), with the global population expected to reach between 7.5 and 10.5 billion by 2050.
|World population (millions)|
|#||Top ten most populous countries||1990||2008||2025*|
|Top ten most populous (%)||60.0 %||58.9 %||57.5 %|
|+ OECD Pacific*||187||202||210|
|+ ex-Soviet Union*||133||136||146|
|European Union – 27 states||473||499||539|
|US + Canada||278||338||392|
| Geographical definitions as in IEA Key Stats 2010 p.66|
Six of Earth's seven continents are permanently inhabited on a large scale. Asia is the most populous continent, with its 4.2 billion inhabitants accounting for over 60% of the world population. The world's two most-populated countries alone, China and India, together constitute about 37% of the world's population. Africa is the second-most-populated continent, with around 1 billion people, or 15% of the world's population. Europe's 733 million people make up 11% of the world's population, while the Latin American and Caribbean regions are home to around 600 million (9%). Northern America, primarily consisting of the United States and Canada, has a population of around 352 million (5%), and Oceania, the least-populated region, has about 35 million inhabitants (0.5%). Though it is not permanently inhabited by any fixed population, Antarctica has a small, fluctuating international population, based mainly in polar science stations. This population tends to rise in the summer months and decrease significantly in winter, as visiting researchers return to their home countries.
|Continent name||Density (inhabitants/km2)||Population (2011)||Most populous country||Most populous city|
|Asia||86.7||4,140,336,501||China (1,341,403,687)||Tokyo (35,676,000)|
|Africa||32.7||994,527,534||Nigeria (152,217,341)||Cairo (19,439,541)|
|Europe||70||738,523,843||Russia (142,905,200)||Moscow (14,837,510)|
|North America||22.9||528,720,588||United States (313,485,438)||Mexico City/Metro Area (8,851,080 / 21,163,226)|
|South America||21.4||385,742,554||Brazil (190,732,694)||São Paulo (19,672,582)|
|Oceania||4.25||36,102,071||Australia (22,612,355)||Sydney (4,575,532)|
|Antarctica||0.0003 (varies)||4,490 (non-permanent, varies)||N/A||McMurdo Station (955)|
It is estimated that the world population reached one billion for the first time in 1804. It would be another 123 years before it reached two billion in 1927, but it took only 33 years to reach three billion in 1960. Thereafter, the global population reached four billion in 1974, five billion in 1987, six billion in 1999 and, according to the United States Census Bureau, seven billion in March 2012. The United Nations, however, estimated that the world population reached seven billion in October 2011.
According to current projections, the global population will reach eight billion by 2030, and will likely reach around nine billion by 2050. Alternative scenarios for 2050 range from a low of 7.4 billion to a high of more than 10.6 billion. Projected figures vary depending on underlying statistical assumptions and the variables used in projection calculations, especially the fertility variable. Long-range predictions to 2150 range from a population decline to 3.2 billion in the 'low scenario', to 'high scenarios' of 24.8 billion. One extreme scenario predicted a massive increase to 256 billion by 2150, assuming the global fertility rate remained at its 1995 level of 3.04 children per woman; however, by 2010 the global fertility rate had declined to 2.52.
There is no estimation for the exact day or month the world's population surpassed the one or two billion marks. The days of three and four billion were not officially noted, but the International Database of the United States Census Bureau places them in July 1959 and April 1974. The United Nations did determine, and celebrate, the "Day of 5 Billion" on July 11, 1987, and the "Day of 6 Billion" on October 12, 1999. The "Day of 7 Billion" was declared by the Population Division of the United Nations to be October 31, 2011.
A dramatic population bottleneck is theorized for the period around 70,000 BC as a result of the Toba supervolcano eruption. From this time until the development of agriculture around the 11th millennium BC, it is estimated that the world population stabilized at about one million people, whose subsistence entailed hunting and foraging – a lifestyle that by its nature ensured a low population density. The total world population probably never exceeded 15 million inhabitants before the invention of agriculture. By contrast, it is estimated that more than 50–60 million people lived in the combined eastern and western Roman Empire (AD 300–400).
The plague which first emerged during the reign of Justinian caused Europe's population to drop by around 50% between 541 and the 8th century. The population of Europe was more than 70 million in 1340. The Black Death pandemic of the 14th century may have reduced the world's population from an estimated 450 million in 1340 to between 350 and 375 million in 1400; it took roughly 200 years for Europe's population to regain its 1340 level. China experienced a population decline from an estimated 123 million around 1200 to an estimated 65 million in 1393, which was presumably due to a combination of Mongol invasions and plague.
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 had come to Asia and Europe from the Americas via the Spanish colonizers in the 16th century are believed to have contributed to population growth. Since being introduced by Portuguese traders in the 16th century, maize and cassava have replaced traditional African crops as that continent’s most important staple food crops. Alfred W. Crosby speculated that increased production of maize, cassava, and other American crops "...enabled the slave traders [who] drew many, perhaps most, of their cargoes from the rain forest areas, precisely those areas where American crops enabled heavier settlement than before."
The population of the Americas in 1500 may have been between 50 and 100 million. The pre-Columbian North American population probably numbered somewhere between 2 million and 18 million. Encounters between European explorers and populations in the rest of the world often introduced local epidemics of extraordinary virulence. Archaeological evidence indicates that the death of around 90% of the Native American population of the New World was caused by 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.
During the 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 of European settlement comprised 36% of the world's population in 1900.
Population growth in the West became more rapid after the introduction of compulsory vaccination and improvements in medicine and sanitation. As living conditions and health care improved during the 19th century, the United Kingdom's population doubled every fifty years. By 1801, the population of England had grown to 8.3 million, and by 1901 it had reached 30.5 million; 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.
The first half of the 20th century in Russia and the Soviet Union was marked by a succession of wars, famines and other disasters, each accompanied by large-scale population losses. By the end of World War II in 1945, the Russian population was about 90 million fewer than it could have been otherwise. In recent decades, Russia's population has declined significantly – from 148 million in 1991 to 143 million in 2012 – and may sink as low as 107 million by 2050, if current demographic trends continue.
Many countries in the developing world have experienced rapid population growth over the past century. China's population rose from approximately 430 million in 1850 to 580 million in 1953, and now stands at over 1.3 billion. The population of the Indian subcontinent, which stood at about 125 million in 1750, reached 389 million in 1941; today, the region is home to over 1.22 billion people. The population of Java increased from about five million in 1815 to more than 130 million in the early 21st century. Mexico's population grew from 13.6 million in 1900 to about 112 million in 2009. Between the 1920s and 2000s, Kenya's population grew from 2.9 million to 37 million.
As of 2012, the global sex ratio is approximately 1.01 males to 1 female – the greater number of men is possibly due to the significant gender imbalances evident in the Indian and Chinese populations. Approximately 26.3% of the global population is aged under 15, while 65.9% is aged 15–64 and 7.9% is aged 65 or over. The global average life expectancy is 67.07 years, with women living an average of 69 years and men approximately 65 years. 83% of the world's over-15s are considered literate. In June 2012, British researchers calculated the total weight of Earth's human population as 287 million tonnes, with the average person weighing 62 kilograms (140 lb).
The nominal 2011 gross world product was estimated at US$$70.16 trillion, giving an annual global per capita figure of around US$10,000. Around 1.29 billion people (18.4% of the world population) live in extreme poverty, subsisting on less than US$1.25 per day; approximately 925 million people (13.2%) are malnourished. In December 2011, there were around 2.26 billion global Internet users, constituting 32.7% of the world population.
The Han Chinese are the world's largest single ethnic group, constituting over 19% of the global population, while the second-largest single ethnicity, the Bengali people, account for around 4.8%. By comparison, people of white European descent constitute between 12% and 13% of the world population. The world's most-spoken first languages are Mandarin Chinese (spoken by 12.44% of the world's population), Spanish (4.85%), English (4.83%), Arabic (3.25%) and Hindi-Urdu (2.68%). The world's largest religion is Christianity, whose adherents account for 33.35% of the global population; Islam is the second-largest religion, accounting for 22.43%, and Hinduism the third, accounting for 13.78%. In 2005, around 16% of the global population were reported to be non-religious.
|Rank||Country / Territory||Population||Date|| % of world
|1||China||1,351,820,000||July 7, 2012||19.2%|||
|3||United States||313,869,000||July 7, 2012||4.47%|||
|5||Brazil||196,656,000||July 7, 2012||2.8%|||
|6||Pakistan||180,036,000||July 7, 2012||2.56%|||
|9||Russia||141,927,297||January 1, 2010||2.02%|||
|10||Japan||127,610,000||May 1, 2012||1.82%|||
Approximately 4.06 billion people live in these ten countries, representing around 58% of the world's population as of April 2012.
The tables below list the world's most densely populated countries, both in absolute terms and in comparison to their total populations.
|Rank||Country/Region||Population||Area (km2)|| Density |
(Pop. per km2)
|Country||Population||Area (km2)|| Density
(Pop. per km2)
|Japan||127,170,110||377,873||337||Declining in population|
|United Kingdom||62,041,708||243,610||255||Growing country|
|South Korea||49,354,980||99,538||493||Steady in population|
|Taiwan||22,955,395||35,980||640||Declining in population|
|Sri Lanka||20,238,000||65,610||309||Growing country|
|Netherlands||16,790,000||41,526||404||Steady in population|
Different geographical regions have different rates of population growth. According to the United Nations, the growth in population of the different regions of the world from 2000 to 2005 totalled:
During the 20th century, the global population saw its greatest increase in known history, rising from about 1.6 billion in 1900 to over 6 billion in 2000. This increase was due to a number of factors, including the lessening of the mortality rate in many countries by improved sanitation and medical advances, and a massive increase in agricultural productivity attributed to the Green Revolution.
In 2000, the United Nations estimated that the world's population was growing at an annual rate of 1.14% (equivalent to around 75 million people), down from a peak of 88 million per year in 1989. By 2000, there were approximately ten times as many people on Earth as there had been in 1700. According to data from the CIA's 2005–2006 World Factbooks, the world population increased by an average of 203,800 people every day in the mid-2000s. The World Factbook increased this estimate to 211,090 people every day in 2007, and again to 220,980 people every day in 2009.
In some countries, there is negative population growth (i.e. net decrease in population over time), especially in Central and Eastern Europe – this is mainly due to low fertility rates. During the 2010s, Japan and some countries in Western Europe are also expected to encounter negative population growth, due to sub-replacement fertility rates.
In 2006, the United Nations stated that the rate of population growth was visibly diminishing due to the ongoing global demographic transition. If this trend continues, the rate of growth may diminish to zero by 2050, concurrent with a world population plateau of 9.2 billion. However, this is only one of many estimates published by the UN. In 2009, UN population projections for 2050 ranged from about 8 billion to 10.5 billion.
Estimated world population figures, 10,000 BC–2000 AD.
Estimated world population figures, 10,000 BC–2000 AD (in log y scale).
World population forecast to 2050 from International Futures.
|Year|| UN est.
|Difference|| US est.
In the long run, the future population growth of the world is difficult to predict. The United Nations and the US Census Bureau both give different estimates. According to the latter, the world population reached seven billion in March 2012, while the UN asserted that this occurred in late 2011.
Average global birth rates are declining slightly, but vary greatly between developed countries (where birth rates are often at or below replacement levels) and developing countries (where birth rates typically remain high). Different ethnicities also display varying birth rates. Death rates can change unexpectedly due to disease, wars and other mass catastrophes, or advances in medicine.
The UN has issued multiple projections of future world population, based on different assumptions. From 2000 to 2005, the UN consistently revised these projections downward, until the 2006 revision, issued on March 14, 2007, revised the 2050 mid-range estimate upwards by 273 million.
|Year||World||Asia||Africa||Europe||Latin America||Northern America||Oceania|
|2000||6,115||3,698 (60.5%)||819 (13.4%)||727 (11.9%)||521 (8.5%)||319 (5.2%)||31 (0.5%)|
|2005||6,512||3,937 (60.5%)||921 (14.1%)||729 (11.2%)||557 (8.6%)||335 (5.1%)||34 (0.5%)|
|2010||6,909||4,167 (60.3%)||1,033 (15.0%)||733 (10.6%)||589 (8.5%)||352 (5.1%)||36 (0.5%)|
|2015||7,302||4,391 (60.1%)||1,153 (15.8%)||734 (10.1%)||618 (8.5%)||368 (5.0%)||38 (0.5%)|
|2020||7,675||4,596 (59.9%)||1,276 (16.6%)||733 (9.6%)||646 (8.4%)||383 (5.0%)||40 (0.5%)|
|2025||8,012||4,773 (59.6%)||1,400 (17.5%)||729 (9.1%)||670 (8.4%)||398 (5.0%)||43 (0.5%)|
|2030||8,309||4,917 (59.2%)||1,524 (18.3%)||723 (8.7%)||690 (8.3%)||410 (4.9%)||45 (0.5%)|
|2035||8,571||5,032 (58.7%)||1,647 (19.2%)||716 (8.4%)||706 (8.2%)||421 (4.9%)||46 (0.5%)|
|2040||8,801||5,125 (58.2%)||1,770 (20.1%)||708 (8.0%)||718 (8.2%)||431 (4.9%)||48 (0.5%)|
|2045||8,996||5,193 (57.7%)||1,887 (21.0%)||700 (7.8%)||726 (8.1%)||440 (4.9%)||50 (0.6%)|
|2050||9,150||5,231 (57.2%)||1,998 (21.8%)||691 (7.6%)||729 (8.0%)||448 (4.9%)||51 (0.6%)|
|Latin America and the Caribbean[Note 1]||39||10||10||16||24||38||74||167||511||577||809||912|
|Northern America[Note 1]||3||3||2||2||7||26||82||172||307||337||392||398|
|Latin America and the Caribbean[Note 1]||8.5||1.7||1.5||2.0||2.5||3.0||4.5||6.6||8.5||8.6||9.1||9.4|
|Northern America[Note 1]||0.7||0.5||0.3||0.3||0.7||2.1||5.0||6.8||5.1||5.0||4.4||4.1|
In the table below, the figures for North America only refer to post-European contact settlers, and not native populations from before European settlement.
|Year||World||Africa||Asia||Europe||Latin America[Note 1]||Northern America||Oceania||Notes|
|70,000 BC||< 0.015|||
|Year||World||Africa||Asia||Europe||Latin America||Northern America||Oceania||Notes|
Hoerner (1975) proposed a formula for population growth which represented hyperbolic growth with an infinite population in 2025. The hyperbolic growth of the world population observed until the 1970s has recently been correlated to a non-linear second order positive feedback between demographic growth and technological development. This feedback can be described as follows: technological growth → increase in the carrying capacity of land for people →demographic growth → more people → more potential inventors → acceleration of technological growth →accelerating growth of the carrying capacity - faster population growth →accelerating growth of the number of potential inventors →faster technological growth → hence, the faster growth of the Earth's carrying capacity for people, and so on.
The transition from hyperbolic growth to slower rates of growth is related to the demographic transition.
Using linear interpolation and extrapolation of UNDESA population estimates, the world population has doubled, or will double, in the following years (with two different starting points). Note how, during the 2nd millennium, each doubling took roughly half as long as the previous doubling, fitting the hyperbolic growth model mentioned above. However, after 2025 it is unlikely that there will be another doubling of the global population in the 21st century.
The scientific consensus is that the current population expansion and accompanying increase in usage of resources is linked to threats to the global ecosystem. The InterAcademy Panel Statement on Population Growth, which was ratified by 58 member national academies in 1994, called the growth in human numbers "unprecedented", and stated that many environmental problems, such as rising levels of atmospheric carbon dioxide, global warming, and pollution, were aggravated by the population expansion. At the time, the world population stood at 5.5 billion, and lower-bound scenarios predicted a peak of 7.8 billion by 2050, a number that current estimates state will be reached in the late 2020s.
In 1798, the economist Thomas Malthus incorrectly predicted that continued population growth would exhaust the global food supply by the mid-19th century. In 1968, Paul R. Ehrlich reprised this argument in The Population Bomb, predicting mass global famine in the 1970s and 1980s. The dire predictions of Ehrlich and other neo-Malthusians were vigorously challenged by a number of economists, notably Julian Lincoln Simon. Agricultural research already under way, such as the Green Revolution, led to dramatic improvements in crop yields. Food production has so far kept pace with population growth, but neo-Malthusians point out that the Green Revolution relies heavily on petroleum-based fertilizers, and that many crops have become so genetically uniform that a crop failure could potentially have global repercussions. Food prices in the early 21st century are rising sharply on a global scale, and causing serious malnutrition to spread widely.
From 1950 to 1984, as the Green Revolution transformed agriculture around the world, grain production increased by over 250%. The world population has grown by about four billion since the beginning of the Green Revolution, and most scholars believe that, without the Revolution, there would be greater levels of famine and malnutrition than the UN presently documents. The energy for the Green Revolution was provided by fossil fuels, in the form of natural gas-derived fertilizers, oil-derived pesticides, and hydrocarbon-fueled irrigation.
The potential peaking of world oil production may test the critics of Malthus and Ehrlich, as oil is of crucial importance to global transportation, power generation and agriculture. In May 2008, the price of grain was pushed up severely by the increased cultivation of biofuels, the increase of world oil prices to over $140 per barrel ($880/m3), global population growth, the effects of climate change, the loss of agricultural land to residential and industrial development, and growing consumer demand in the population centres of China and India. Food riots subsequently occurred in some countries across the world. However, oil prices then fell sharply, and remaining below $100/barrel until around 2010. Resource demands are expected to ease as population growth declines, but it is unclear whether rising living standards in developing countries will once again create resource shortages.
Richard C. Duncan claims the that the world population will decline to about 2 billion around 2050. David Pimentel, professor of ecology and agriculture at Cornell University, estimates that the sustainable agricultural carrying capacity for the United States is about 200 million people; its population as of 2011 is over 310 million. In 2009, the UK government's chief scientific advisor, Professor John Beddington, warned that growing populations, falling energy reserves and food shortages would create a "perfect storm" by 2030. Beddington claimed that food reserves were at a fifty-year low, and that the world would require 50% more energy, food and water by 2030. According to a 2009 report by the United Nations Food and Agriculture Organisation (FAO), the world will have to produce 70% more food by 2050 to feed a projected extra 2.3 billion people.
The observed figures for 2007 showed an actual increase in absolute numbers of undernourished people in the world, with 923 million undernourished in 2007, versus 832 million in 1995. The 2009 FAO estimates showed an even more dramatic increase, to 1.02 billion.
Human population control is the practice of artificially altering the rate of growth of a human population. Historically, human population control has been implemented by limiting the population's birth rate, by contraception or by government mandate, and has been undertaken as a response to factors including high or increasing levels of poverty, environmental concerns, religious reasons, and overpopulation. The use of abortion in some population control strategies has caused controversy, with organizations such as the Roman Catholic Church explicitly opposing any intervention in the human reproductive process.
An estimate of the total number of humans who have ever lived was prepared by Carl Haub of the nonprofit Population Reference Bureau in 1995, and was subsequently updated in 2002; the updated figure totalled approximately 106 billion. Haub characterized this figure as an estimate that required "selecting population sizes for different points from antiquity to the present and applying assumed birth rates to each period". Given an estimated global population of 6.2 billion in 2002, it could be inferred that about 6% of all people who had ever existed were alive in 2002. Various estimates published in the first decade of the 21st century give figures ranging from approximately 100 billion to 115 billion. In the 1970s, claims emerged alleging that 75% of all the people who had ever lived were alive at that time. This view was eventually debunked as unscientific.
An accurate estimate of the number of humans who have ever lived is difficult to produce for numerous reasons. Firstly, the set of specific characteristics that define a "human" is a matter of definition, and it is open to debate which members of early Homo sapiens and earlier or related species of Homo to include in the estimate (see also Sorites paradox). Even if the scientific community reached a broad consensus regarding which characteristics distinguished human beings, it would be nearly impossible to pinpoint the time of their first appearance to even the nearest millennium, due to the scarcity of fossil evidence. However, the very limited size of the world population in prehistoric times (as compared to its current size) makes this source of uncertainty of limited importance.
More importantly, robust population data only exist 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 Ancient Egypt and in the Persian Empire, the focus was on counting merely a subset of the people for purposes of taxation or military service. All claims of population sizes preceding the 18th century are imprecise estimates, and thus the margin of error for the total number of humans who have ever lived should be in the billions, or even tens of billions of people.
Another critical factor for such an estimate is life expectancy. Using an average figure of twenty years and the population estimates above, one can compute a total of about 58 billion. Using a figure of forty yields around 30 billion. However, life expectancy varies greatly when taking into account children who died before their first birthday, a number very difficult to estimate for earlier times. Haub states that "life expectancy at birth probably averaged only about ten years for most of human history". His estimates for infant mortality suggest that around 40% of those who have ever lived did not survive beyond their first birthday.
The United Nations operates several organisations with various population-related competencies, including the Commission on Population and Development, the United Nations Population Division, and the United Nations Population Fund.
|Wikimedia Commons has media related to: World population statistics|
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