World population

World population 1950-2000

Increase rate 1950-2000

The world population is the total number of humans alive at a given time. According to estimates published by the United States Census Bureau, the world population in June 2005 was ~6,556,773,622. 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 in the last six thousand years are currently alive. By some estimates, there are now one billion (thousand million) young people in the world between the ages of 15 and 24.

Contents

1 When was six billion reached? 2 Rate of population increase 3 Forecast of world population 4 Doomsayers 5 Different continents 6 External links

When was six billion reached?

The United Nations Population Fund designated October 12, 1999 as the approximate day on which world population reached six billion. This was about 12 years after 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.

Rate of population increase

The last 70 years of the 20th century saw the biggest increase in the world's population in human history. The following table shows when each billion milestone was met:

• 1 billion reached in 1802.
• 2 billion reached in 1927.
• 3 billion reached in 1961.
• 4 billion reached in 1974.
• 5 billion reached in 1987.
• 6 billion reached in 1999.

From the figures above, the world's population has tripled in 72 years, and doubled in 38 years up to the year of 1999.

Including a few more estimates (beginning with 250 million in 950 and ending with 8 billion in 2027), the world population was doubled by the following years (doubling times in parentheses):

• 950 (650) 1600 (202) 1802 (125) 1927 (44) 1971 (56) 2027,

or (beginning with 375 million in 1420):

• 1420 (300) 1720 (155) 1875 (86) 1961 (38) 1999.

The UN estimated in 2000 that the world's population was then growing at the rate of 1.2 percent (or 77 million people) per year. This represents a decrease in the growth rate from its level in 1990, mostly due to decreasing birth rates.

As of 2004, the world's population is increasing at a rate of 75 million people per year.

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 its world population projections downward.

The current projections from the UN's Population Division, from their 2004 revision of the World Population Prospects database [1] (http://esa.un.org/unpp/), are:

Year	Population (billions)
2010	6.8
2020	7.6
2030	8.2
2040	8.7
2050	9.1

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 less optimistic scenarios, disasters triggered by a growing population's demand for scarce resources will cause a sudden population crash, or even a Malthusian catastrophe. (See overpopulation for more details.)

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 mindshare throughout the 1960s and 1970s. The dire predictions of Ehrlich and other neo-Malthusians were vigourously challenged by a number of economists, notably Julian Simon. 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).

Different continents

The vertical axis of the chart above is in thousands. Likewise, the population figures in the table below are in thousands.

Year	World	Africa	Asia	Europe	Latin-America	North America	Oceania
1750	791000	106000	502000	163000	16000	2000	2000
1800	978000	107000	635000	203000	24000	7000	2000
1850	1262000	111000	809000	276000	38000	26000	2000
1900	1650000	133000	947000	408000	74000	82000	6000
1950	2518629	221214	1398488	547403	167097	171616	12812
1955	2755823	246746	1541947	575184	190797	186884	14265
1960	3021475	277398	1701336	604401	218300	204152	15888
1965	3334874	313744	1899424	634026	250452	219570	17657
1970	3692492	357283	2143118	655855	284856	231937	19443
1975	4068109	408160	2397512	675542	321906	243425	21564
1980	4434682	469618	2632335	692431	361401	256068	22828
1985	4830979	541814	2887552	706009	401469	269456	24678
1990	5263593	622443	3167807	721582	441525	283549	26687
1995	5674380	707462	3430052	727405	481099	299438	28924
2000	6070581	795671	3679737	727986	520229	315915	31043
2005	6453628	887964	3917508	724722	558281	332156	32998
2010	6830283	984225	4148948	719714	594436	348139	34821
2015	7197247	1084540	4370522	713402	628260	363953	36569
2020	7540237	1187584	4570131	705410	659248	379589	38275
2025	7851455	1292085	4742232	696036	686857	394312	39933
2030	8130149	1398004	4886647	685440	711058	407532	41468
2035	8378184	1504179	5006700	673638	731591	419273	42803
2040	8593591	1608329	5103021	660645	747953	429706	43938
2045	8774394	1708407	5175311	646630	759955	439163	44929
2050	8918724	1803298	5222058	631938	767685	447931	45815

External links

• World Population Prospects (http://esa.un.org/unpp/). Retrieved April 7, 2005.
• The World in Balance (http://www.pbs.org/wgbh/nova/transcripts/3108_worldbal.html) Transcript of two-part PBS' Nova on World Population
• BBC (1999). UN chief welcomes six billionth baby (http://news.bbc.co.uk/2/hi/in_depth/472704.stm). Retrieved March 6, 2005.
• Central Intelligence Agency (2004). CIA The World Factbook 2004 (http://www.cia.gov/cia/publications/factbook/geos/xx.html). Retrieved February 13, 2005.
• United Nations (2001). United Nations Population Information Network (http://www.un.org/popin/). Retrieved February 13, 2005.
• United States Census Bureau (2004). Historical Estimates of World Population (http://www.census.gov/ipc/www/worldhis.html). Retrieved February 13, 2005.
• PopulationData.net (2005). PopulationData.net - Informations and maps about populations around the world (http://www.populationdata.net).
• Population Reference Bureau www.prb.org - News and issues related to population (http://www.prb.org).
• World Population Clock (2005). WorldPopClock.com - World population clock (http://www.worldpopclock.com).
• Population Counter. See estimates of populations in various countries around the world and watch them get updated! China is the most active, so if you want to see what happens, just head straight for that densely populated country. (http://rumkin.com/tools/population/).

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