article

The world population is the total number of humans alive on the planet Earth at a given time. According to estimates published by the United States Census BureauUnited States Census Bureau, the Earth's population reached 6.5 billion on Saturday, February 25,2006.Leonard, David. "World Population to reach 6.5 Billion on Saturday". February 24,2006. MSNBC In line with population projections, this figure continues to grow at rates that are unprecedented prior to the 20th century. Approximately one fifth of all humans that have existed in the last six thousand years are currently alive. By some estimates, there are now one billion people in the world between the ages of fifteen and twenty-four.

Rate of population increase

The 20th century saw the biggest increase in the world's population in human history. The following table shows estimates of when each billion milestone was met:

  • 1 billion was reached in 1802.
  • 2 billion was reached 125 years later in 1927.
  • 3 billion was reached 34 years later in 1961.
  • 4 billion was reached 13 years later in 1974.
  • 5 billion was reached 13 years later in 1987.
  • 6 billion was reached 12 years later in 1999.

These numbers show that the world's population has tripled in 72 years, and doubled in 38 years up to the year 1999.

Some estimates say that the human population around AD 950 was 250 million and in 2027 will be 8 billion, and the world population doubled (or will double) in the following years (doubling times in parentheses):

  • AD 950 (650) 1600 (202) 1802 (125) 1927 (47) 1974 (50) 2027.
Yet other estimates (beginning with 375 million around year 1420) say:
  • 1420 (300) 1720 (155) 1875 (86) 1961 (38) 1999.
Note how, during the 2nd millennium, each doubling has taken roughly half as long as the previous doubling.

The UN estimated in 2000 that the world's population was then growing at the rate of 1.4 percent (or 91 million people) per year. This represents a decrease in the growth rate from its level in 1990, mostly due to decreasing birth rates.

The first five years of the 21st century saw something of a decline in the overall population growth, with the world's population increasing at a rate of about 76 million people per year as of 2005.

Forecast of world population

The future growth of population 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 World population prospects: the 2004 revision population database, are as follows.

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

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 10 billion, due to gradually decreasing birth rates.

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

Doomsayers

In 1798, Thomas Malthus predicted that population growth would eventually outrun food supply, 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: The Death of the West: How Dying Populations and Immigrant Invasions Imperil Our Country and Civilization (ISBN 0312302592), by Patrick Buchanan, The Empty Cradle: How Falling Birthrates Threaten World Prosperity (ISBN 0465050506), by Longman, and Fewer: How the New Demography of Depopulation Will Shape Our Future (ISBN 156663606X), by Wattenberg.

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 (toxic waste rather than food shortages).

Population distribution

The vertical axis of the chart above is in billions. The population figures in the table below are in thousands.World population prospects: the 2004 revision population databaseThe World at Six Billion

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

The Day of Six Billion

The United Nations Population Fund designated October 12 1999 as the approximate day on which world population reached six billion. It was officially designated "The Day of Six Billion".

This was about twelve years after the world population reached five billion, in 1987. The child that has been proclaimed by the United Nations Population Fund and welcomed by the U.N. Secretary-General Kofi Annan as the six billionth baby, was born on the designated day two minutes after midnight, not in India or China, as might be expected, but to Fatima Nevic and her husband Jasminko in Sarajevo, Bosnia.

See also

References

External links

Population

`

Població mundial | Weltbevölkerung | Población humana | Population mondiale | 세계 인구 | Populasi dunia | Wereldbevolking | 世界人口 | Ludność świata | População mundial | Svjetsko stanovništvo | Dünya nüfusu

 

This article is licensed under the GNU Free Documentation License. It uses material from the "World population".

Home Page • arts • business • computers • games • health • hospitals • home • kids & teens • news • physicians • recreation• reference • regional • science • shopping • society • sports • world