World Population

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World population

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Population density (people per km²) by country, 2006 Population by region as a percentage of world population (1750–2005) The world population is the total number of living humans on Earth at a given time. As of 29 November 2009, the Earth's population is estimated by the United States Census Bureau to be 6.8 billion.^[1]The world population has been growing continuously since the end of the Black Death around 1400.^[2]The fastest rates of world population growth (above 1.8%) were seen briefly during the 1950s then for a longer period during the 1960s and 1970s (see graph ). According to population projections, world population will continue to grow until at least 2050. The 2008 rate of growth has almost halved since its peak of 2.2% per year, which was reached in 1963. World births have levelled off at about 134 million per year, since their peak at 163- million in the late 1990s, and are expected to remain constant. However, deaths are only around 57 million per year, and are expected to increase to 90 million by the year 2050. Because births outnumber deaths, the world's population is expected to reach about 9 billion by the year

2040.^[3][4]

Contents

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1 Population figures 2 Rate of increase

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2.1 Models 2.2 Milestones 2.3 Years for population to double

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3 Distribution 4 Most populous nations 5 Ethnicity 6 Demographics of youth 7 Forecast 8 Predictions based on population growth 9 Number of humans who have ever lived 10 See also 11 Further resources 12 References 13 External links

[edit] Population figures

Further information: World population estimates

A dramatic population bottleneck is theorized for the period around 70,000 BC (see Toba catastrophe theory ). After this time and until the development of agriculture, 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. It is estimated that over 55 million people lived in the combined eastern and western Roman Empire (AD 300– 400).^[5]The Plague of Justinian caused Europe's population to drop by around 50% between 541 and the 700s.^[6]The population of the world was more than 440 million in 1340. The Black Death pandemic in the 14th century may have reduced the world's population from an estimated 450 million to between 350 and 375 million in 1400.^[7]It took roughly 200 years for Europe's population to regain its 1340 level.^[8]

At the founding of the Ming dynasty in 1368, China 's population was reported to be close to 60 million, and toward the end of the dynasty in 1644 it might have approached 150 million.^[9]England 's population reached an estimated 5.6 million in 1650, up from an estimated 2.6 million in 1500.^[10]New crops that had come to Asia and Europe from the Americas via the Spanish colonizers in the 16th century contributed to the population growth.^[11][12]Since being introduced by Portuguese traders in the 16th century,^[13]maize and manioc have replaced traditional African

crops as the continent’s most important staple food crops.^[14]Alfred W. Crosby speculated that

increased production of maize, manioc, and other American crops "enabled the slave traders drew many, perhaps most, of their cargoes from the rain forest areas, precisely those areas where American crops enabled heavier settlement than before."^[15]

Scholars estimate that between 900,000 and 18 million people inhabited North America north of present-day Mexico at the time of European contact.^[16]

Cities with at least one million inhabitants in 2006. In 1800, only 3% of the world's population lived in cities, a figure that has risen to 47% by the end of the twentieth century.

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

90 to 95% of the Native American population of the New World was caused by Old World

diseases such as smallpox , measles, and influenza.^[17]Over the centuries, the Europeans had developed high degrees of immunity to these diseases, while the indigenous peoples had no such immunity.^[18]

During the Agricultural and Industrial Revolutions , the life expectancy of children increased

dramatically.^[19]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.^[20][21]Europe’s population doubled during the 18th century, from roughly 100 million to almost 200 million, and doubled again during the 19th century.^[22]The population growth became more rapid after the introduction of compulsory vaccination and improvements in medicine and sanitation.^[23][24][25]As living conditions and health care improved during the 19th century, Britain's population doubled every 50 years.^[26]By 1801 the population of England had grown to 8.3 million, and by 1901 had grown to 30.5 million.^[27]

The population of the Indian subcontinent , which stood at about 125 million in 1750, had reached 389 million by 1941.^[28]The region is currently home to 1.5 billion people.^[29]The total number of inhabitants of Java increased from about 5 million in 1815 to more than 130 million in the early 21st century.^[30]Mexico's population has grown from 13.6 million in 1900 to about 112 million in 2009.^[31]

Below is a table with historical and predicted population figures shown in millions.^{[32][33][34][35]}The availability of historical population figures varies by region.

World historical and predicted populations (in millions)^[36]

Region World Africa Asia
1750

791

1800

1850

1900

1950

1999

2008

2050

2150

978 1,262 1,650 2,521 5,978 6,707 8,909 9,746
106 502 163