World population

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Map of countries by population —showing the population of the People's Republic of China and India, the only two countries to have a population greater than a billion. (See List of countries by population.)
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Map of countries by population —showing the population of the People's Republic of China and India, the only two countries to have a population greater than a billion. (See List of countries by population.)

The world population is the total number of human beings alive on the planet Earth at a given time. As of late 2006, the world population reached 6.5 billion.[1] In line with population projections, this figure continues to grow at rates that were unprecedented prior to the 20th century, although the rate of increase has almost halved since growth rates reached their peak in 1963.

Contents

[edit] Historical figures

Below is a table of historical population figures shown in thousands.[2][3][4] The availability of historical population figures varies by region. Please see World population estimates for more figures.

Year World Africa Asia Europe Central & South America Northern America* Oceania notes
8000 BC 5 000 [5]
1000 BC 50 000 [5]
500 BC 100 000 [5]
1 AD 300 000 [6]
1000 310 000
1750 791 000 106 000 502 000 163 000 16 000 2 000 2 000
1800 978 000 107 000 635 000 203 000 24 000 7 000 2 000
1850 1 262 000 111 000 809 000 276 000 38 000 26 000 2 000
1900 1 650 000 133 000 947 000 408 000 74 000 82 000 6 000
1950 2 518 629 221 214 1 398 488 547 403 167 097 171 616 12 812
1955 2 755 823 246 746 1 541 947 575 184 190 797 186 884 14 265
1960 3 021 475 277 398 1 701 336 604 401 218 300 204 152 15 888
1965 3 334 874 313 744 1 899 424 634 026 250 452 219 570 17 657
1970 3 692 492 357 283 2 143 118 655 855 284 856 231 937 19 443
1975 4 068 109 408 160 2 397 512 675 542 321 906 243 425 21 564
1980 4 434 682 469 618 2 632 335 692 431 361 401 256 068 22 828
1985 4 830 979 541 814 2 887 552 706 009 401 469 269 456 24 678
1990 5 263 593 622 443 3 167 807 721 582 441 525 283 549 26 687
1995 5 674 380 707 462 3 430 052 727 405 481 099 299 438 28 924
2000 6 070 581 795 671 3 679 737 727 986 520 229 315 915 31 043
2005 6 453 628 887 964 3 917 508 724 722 558 281 332 156 32 998**

* Northern America indicates the United States and Canada.

** This figure is disputed. Please see the talk page or update the figure and cite your source.

[edit] Rate of increase

Main article: Population growth
Population evolution in different continents. The vertical axis is logarithmic and is billions of people.
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Population evolution in different continents. The vertical axis is logarithmic and is billions of people.

Different regions have different rates of population growth. The 20th century saw the biggest increase in the world's population in human history.

In 2000, the United Nations estimated that the world's population was then growing at the rate of 1.14% (or about 75 million people) per year[7]. According to data from the CIA's 2005-2006 World Factbooks, the world human population currently increases by 203,800 every day.[8]

Globally, the population growth rate has been steadily declining from its peak of 2.19% in 1963, but growth remains high in the Middle East and Sub-Saharan Africa.[9] In some countries there is negative population growth (ie. net decrease in population over time), especially in Central and Eastern Europe (mainly due to low fertility rates) and Southern Africa (due to the high number of HIV-related deaths). Within the next decade, Japan and Western Europe are also expected to encounter negative population growth due to sub-replacement fertility rates.

Population growth which exceeds the carrying capacity of an area or environment results in overpopulation. Conversely, such areas may be considered "underpopulated" if the population is not large enough to maintain an economic system (see population decline).

Population (est.) 10,000 BC - 2000 AD.

World population 1950–2000

Increase rate 1950–2000

[edit] Milestones

The following shows estimates of when each billion milestone was met:

Population 1 billion 2 billion 3 billion 4 billion 5 billion 6 billion
Year 1802 1928 1961 1974 1987 1999
Years till next billion 126 33 13 13 12

These numbers show that the world's population has tripled in 72 years, and doubled in 38 years up to the year 1999. Including some more estimates, the world population has been doubled or will double in the following years (with two different starting points). Note how, during the 2nd millennium, each doubling has taken roughly half as long as the previous doubling.

Population 250 million 500 million 1 billion 2 billion 4 billion 8 billion
Year AD 950 1600 1802 1928 1974 2028
Years till next doubling 650 202 126 46 51
Population 375 million 750 million 1.5 billion 3 billion 6 billion
Year 1420 1720 1875 1961 1999
Years till next doubling 300 155 86 38

[edit] Population distribution

Population density map of the world in 1994; Observe the very high concentration along the Ganges, Yangtze and Yellow river basins, Western Europe, the Indonesian island of Java, the United States' BosWash megalopolis, and Southern California.
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Population density map of the world in 1994; Observe the very high concentration along the Ganges, Yangtze and Yellow river basins, Western Europe, the Indonesian island of Java, the United States' BosWash megalopolis, and Southern California.
Population by region, 2005
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Population by region, 2005

Asia accounts for over 60% of the world population with almost 3.8 billion people. China and India alone comprise 20% and 16% respectively. Africa follows with 840 million people, 12% of the world population. Europe's 710 million people make up 11% of the world's population. North America is home to 514 million (8%), South America to 371 million (5.3%) and Oceania to roughly 60 million** (.9%).

** This figure is disputed. Please see the talk page or update the figure and cite your source.

[edit] Demographics

According to the 2006 CIA World Factbook, 27.4% of the world's population is below 15 years of age.[10]. By some estimates[citation needed], there are now one billion people in the world between the ages of 15 and 24.

[edit] Forecast of world population

The future population growth of the world is difficult to predict. Birth rates are declining slightly on average, but vary greatly between developed countries (where birth rates are often at or below replacement levels) and developing countries. Death rates can change unexpectedly due to disease, wars and catastrophes, or advances in medicine. The UN itself has issued multiple projections of future world population, based on different assumptions. Over the last 10 years, the UN has consistently revised these projections downward.


Current projections by the UN's Population Division, based on the 2004 revision of the World Population Prospects database [11], are as follows.

Year Population (billions)
2010 6.8
2020 7.6
2030 8.2
2040 8.7
2050 8.9


Alternately, the United States Census Bureau issued a revised forecast for world population that increased its projection for the year 2050 to above 9.4 billion people, up from 9.1 billion people. The latest Census Bureau estimates for the same upcoming years are as follows:

2010 6.8

2020 7.6

2030 8.3

2040 8.9

2050 9.4

Link for these figures is here http://www.census.gov/ipc/www/worldpop.html


Other projections of population growth predict that the world's population will eventually crest, though it is uncertain exactly when or how. In some scenarios, the population will crest as early as the mid-21st century at under 9 billion, due to gradually decreasing birth rates.[citation needed]

In other scenarios, disasters triggered by the growing population's demand for scarce resources will eventually lead to a sudden population crash, or even a Malthusian catastrophe (also see overpopulation).

Below is a table of predicted population figures.[12][13][14] Please see World population estimates for more figures.

Year World Africa Asia Europe Latin America Northern America* Oceania
2010 6 830 283 000 984 225 000 4 148 948 000 719 714 000 594 436 000 348 139 000 34 821 000
2015 7 197 247 000 1 084 540 000 4 370 522 000 713 402 000 628 260 000 363 953 000 36 569 000
2020 7 540 237 000 1 187 584 000 4 570 131 000 705 410 000 659 248 000 379 589 000 38 275 000
2025 7 851 455 000 1 292 085 000 4 742 232 000 696 036 000 686 857 000 394 312 000 39 933 000
2030 8 130 149 000 1 398 004 000 4 886 647 000 685 440 000 711 058 000 407 532 000 41 468 000
2035 8 378 184 000 1 504 179 000 5 006 700 000 673 638 000 731 591 000 419 273 000 42 803 000
2040 8 593 591 000 1 608 329 000 5 103 021 000 660 645 000 747 953 000 429 706 000 43 938 000
2045 8 774 394 000 1 708 407 000 5 175 311 000 646 630 000 759 955 000 439 163 000 44 929 000
2050 8 918 724 000 1 803 298 000 5 217 202 000 653 323 000 767 685 000 447 931 000 45 815 000

* Northern America indicates the United States and Canada

[edit] Predictions based on our growing population

In 1798, Thomas Malthus predicted that population growth would eventually outrun food supply in the middle of the 19th century, resulting in catastrophe. In 1968, Paul R. Ehrlich reignited this argument with his book The Population Bomb, which helped give the issue significant attention throughout the 1960s and 1970s. The dire predictions of Ehrlich and other neo-Malthusians were vigorously challenged by a number of economists, notably Julian Simon.

On the opposite end of the spectrum there are a number of doomsayers who argue that today's low fertility rates will have severe negative consequences.[15]

Child poverty has been linked to people having children before they have the means to care for them.

More recently, some scholars have put forward the Doomsday argument applying Bayesian probability to world population to argue that the end of humanity will come sooner than we usually think (owing to toxic waste rather than to food shortages).[citation needed]

[edit] Number of humans that have ever lived

Estimates of the number of human beings who have ever lived on Earth constitute an extremely large range, with low estimates around 45 billion, and the highest estimates topping out around 125 billion. Many of the more robust estimates fall into the range of 90 to 110 billion humans.

However, it is important to understand that it is impossible to make anything close to a preceise count of the number of human beings who have every lived for the following reasons:

  • The specific range of characteristics; physiological, psychological, and cultural, which define a modern human being continue to be a subject of intense scholoarly research and debate. Until such debates are completely resolved, it is impossible to know just when in human history one might begin the count. Resolving these debates would require drawing a thin line between early humans and pre-humans, and in the lack of anthropological evidence, the placing of such a line is shaped by the personal interpretation of experts, and remains arbitrary at best.
  • Even if the scientific community reached wide consensus regarding what characteristics defined the very first human beings, it would be nearly impossible to pin point the exact decade, century, or millenium which they first appeared. The fossil record is simply too scarce. Only a few thousand fossils of early humans have ever been found, many no bigger than a tooth or a knucklebone. While that may sound like a large number, it is truly miniscule when you consider that these few thousand bone fragments must be used to extrapolate the population distribution of millions of early human beings spread thinly across the face of the Earth.
  • Until the late 1700's, exceedingly few nation, kingdoms, or empires had ever performed a census that was considered to be anything more than an rough estimate. In many of these early attempts, the focus was not even on counting people, but merely a subset of the people for purposes of taxation or military service. Even with the advent of agencies like the United States Bureau of the Census, reliable census methods and technologies continued to evolve right into the twentieth century. Even today, these reliable methods and technologies are not applied uniformly in all parts of the world. In short is has been less than two centuries that we have had anything that remotely resembles the robust statistical data that would be needed to perform a calculation regarding the total number of humans that have ever lived.

Any such precise population count offered by any source is simply the numeric result of populations statistics, which necessarily used estimates and rough averages as their basis. While they may, if done astutely, provide us with a remote idea about the number of humans who have ever lived on the Earth, the margin of error should always be regarded as being in the billions, or even the tens of billions of people.

"Guesstimating the number of people ever born... requires selecting population sizes for different points from antiquity to the present and applying assumed birth rates to each period..."[16]

Also, the number may depend on the definition of "human"; does it extend to homo erectus? The australopithecine? Pre-Cretaceous mammals? Or only the modern homo sapiens? A relative lack of fossils makes the dividing line hard to draw.

According to 2002 data:[16]

  • The number who have ever been born is 106,456,367,669
  • The world population in mid-2002 was 6,215,000,000
  • The percentage of those ever born who were living in 2002 was 5.8%

[edit] References

  1. ^ Leonard, David. "World Population to reach 6.5 Billion on Saturday". February 24, 2006. MSNBC
  2. ^ World population prospects: the 2004 revision population database
  3. ^ The World at Six Billion
  4. ^ Population Growth over Human History
  5. ^ a b c an average of figures from different sources as listed at the US Census Bureau's Historical Estimates of World Population
  6. ^ The range of figures from different sources as listed at the US Census Bureau's Historical Estimates of World Population put the population at 1 AD between 170 million to 400 million.
  7. ^ census.gov
  8. ^ Current world population (ranked)
  9. ^ Ron Nielsen, The little green handbook, Picador, New York (2006) ISBN 0-312-42581-4
  10. ^ Age structure of the world -- 2006 CIA World Factbook
  11. ^ World population prospects: the 2004 revision population database
  12. ^ World population prospects: the 2004 revision population database
  13. ^ The World at Six Billion
  14. ^ Population Growth over Human History
  15. ^ The Death of the West: How Dying Populations and Immigrant Invasions Imperil Our Country and Civilization (ISBN 0-312-30259-2), by Patrick Buchanan, The Empty Cradle: How Falling Birthrates Threaten World Prosperity (ISBN 0-465-05050-6), by Longman, and Fewer: How the New Demography of Depopulation Will Shape Our Future (ISBN 1-56663-606-X), by Wattenberg
  16. ^ a b How Many People Have Ever Lived on Earth? by Carl Haub, 2002; calculated from a cut-off date of 50,000 years ago.

[edit] See also

[edit] External links

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