World population milestones

Estimated (to 2011) and projected (from 2012) populations of the world and its inhabited continents. The shaded regions correspond to range of projections by the United Nations Department of Economic and Social Affairs;^[1]

World population milestones went unnoticed until the 20th century, since there was no reliable data on global population dynamics.^[2]

The population of the world reached

one billion in 1804
two billion in 1927
three billion in 1960
four billion in 1974
five billion in 1987
six billion in 1999
seven billion in 2011
eight billion in 2023

^[3]^[4]

Old estimates put the global population at 9 billion by 2037–2046, 15 years after 8 billion, and 10 billion by 2054–2071, 17 years after 9 billion; however these milestones are likely to be reached far sooner.^[5]^{[needs update]} Projected figures vary depending on underlying statistical assumptions and which variables are manipulated 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 scenario predicts a massive increase to 256 billion by 2150, assuming fertility remains at 1995 levels.^[6]

World population milestones in billions (UN estimates)^[7]
Population	1	2	3	4	5	6	7	8	9	10
Year	1804	1927	1960	1974	1987	1999	2011	2023	2037	2054
Years elapsed	260,000 to 350,000	123	33	14	13	12	12	12	14	17

World population milestones in billions (USCB estimates)
Population	1	2	3	4	5	6	7	8	9	10
Year	1804	1927	1960	1974	1987	1999	2011	2023	2046	2071
Years elapsed	260,000 to 350,000	123	33	14	13	12	12	12	23	25

^ "World Population Prospects, the 2010 Revision". Archived from the original on 1 July 2014. Retrieved 7 November 2011.
^ Vaclav Smil, "Global Population: Milestones, Hopes, and Concerns" Archived 3 February 2023 at the Wayback Machine, Medicine & Global Survival, October 1998; Vol. 5, No. 2, 105–108
^ "The babies born as world population hits 8bn". BBC. 16 November 2022. Archived from the original on 3 February 2023. Retrieved 17 November 2022.
^ World Population 3000 (Top 25 Countries by Population 1000 A.D - 3000 A.D), archived from the original on 3 February 2023, retrieved 31 January 2023
^
*"Ch. 5: Population Size and Composition". World Population Prospects, the 2000 Revision (PDF). Vol. III. United Nations Population Division. p. 171. Retrieved 3 July 2010.
- "Executive Summary". World Population Prospects: The 2002 Revision Volume III: Analytical Report (PDF). 2002. Retrieved 3 July 2010.
- "World Population to 2300" (PDF). New York: United Nations Department of Economic and Social Affairs: Population Division. 2004: 3, 14. Archived (PDF) from the original on 15 January 2012. Retrieved 3 July 2010. {{cite journal}}: Cite journal requires |journal= (help)
- "World Population: 1950–2050". U.S. Census Bureau, Population Division. June 2010. Archived from the original on 29 May 2010. Retrieved 3 July 2010. {{cite journal}}: Cite journal requires |journal= (help)
- "2009 World Population Data Sheet" (PDF). Washington, DC: Population Reference Bureau. 2009. Archived (PDF) from the original on 22 April 2010. Retrieved 3 July 2010. {{cite journal}}: Cite journal requires |journal= (help)
^ "Key Findings". Long-Range Population Projections (PDF). New York: United Nations: Department of Economic and Social Affairs. 2003. Archived from the original (PDF) on 16 October 2018. Retrieved 16 October 2018. {{cite book}}: |work= ignored (help)
^ "United Nations Population Division World Population Prospects: The 2022 Revision" (PDF). Archived (PDF) from the original on 19 July 2022. Retrieved 14 August 2022.

[1] "World Population Prospects, the 2010 Revision". Archived from the original on 1 July 2014. Retrieved 7 November 2011.

[2] Vaclav Smil, "Global Population: Milestones, Hopes, and Concerns" Archived 3 February 2023 at the Wayback Machine, Medicine & Global Survival, October 1998; Vol. 5, No. 2, 105–108

[UN8bn-3] "The babies born as world population hits 8bn". BBC. 16 November 2022. Archived from the original on 3 February 2023. Retrieved 17 November 2022.

[4] World Population 3000 (Top 25 Countries by Population 1000 A.D - 3000 A.D), archived from the original on 3 February 2023, retrieved 31 January 2023

[WorldPopProspects-5] *"Ch. 5: Population Size and Composition". World Population Prospects, the 2000 Revision (PDF). Vol. III. United Nations Population Division. p. 171. Retrieved 3 July 2010.
"Executive Summary". World Population Prospects: The 2002 Revision Volume III: Analytical Report (PDF). 2002. Retrieved 3 July 2010.

"World Population to 2300" (PDF). New York: United Nations Department of Economic and Social Affairs: Population Division. 2004: 3, 14. Archived (PDF) from the original on 15 January 2012. Retrieved 3 July 2010. {{cite journal}}: Cite journal requires |journal= (help)

"World Population: 1950–2050". U.S. Census Bureau, Population Division. June 2010. Archived from the original on 29 May 2010. Retrieved 3 July 2010. {{cite journal}}: Cite journal requires |journal= (help)

"2009 World Population Data Sheet" (PDF). Washington, DC: Population Reference Bureau. 2009. Archived (PDF) from the original on 22 April 2010. Retrieved 3 July 2010. {{cite journal}}: Cite journal requires |journal= (help)

[6] "Executive Summary". World Population Prospects: The 2002 Revision Volume III: Analytical Report (PDF). 2002. Retrieved 3 July 2010.

[7] "World Population to 2300" (PDF). New York: United Nations Department of Economic and Social Affairs: Population Division. 2004: 3, 14. Archived (PDF) from the original on 15 January 2012. Retrieved 3 July 2010. {{cite journal}}: Cite journal requires |journal= (help)

[8] "World Population: 1950–2050". U.S. Census Bureau, Population Division. June 2010. Archived from the original on 29 May 2010. Retrieved 3 July 2010. {{cite journal}}: Cite journal requires |journal= (help)

[9] "2009 World Population Data Sheet" (PDF). Washington, DC: Population Reference Bureau. 2009. Archived (PDF) from the original on 22 April 2010. Retrieved 3 July 2010. {{cite journal}}: Cite journal requires |journal= (help)

[LongRangeProjections2003KeyFindings-6] "Key Findings". Long-Range Population Projections (PDF). New York: United Nations: Department of Economic and Social Affairs. 2003. Archived from the original (PDF) on 16 October 2018. Retrieved 16 October 2018. {{cite book}}: |work= ignored (help)

[7] "United Nations Population Division World Population Prospects: The 2022 Revision" (PDF). Archived (PDF) from the original on 19 July 2022. Retrieved 14 August 2022.

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