Projections of population growth

World population estimates from 1800 to 2100, based on "high", "medium" and "low" United Nations projections in 2010 (colored red, orange and green) and US Census Bureau historical estimates (in black). Actual recorded population figures are colored in blue. According to the highest estimate, the world population may rise to 16 billion by 2100; according to the lowest estimate, it may decline to 6 billion.

According to current projections of population growth, the world population of humans will continue to grow until at least 2050, with the estimated population, based on current growth trends, to reach 9 billion in 2040,[1][2] and some predictions putting the population in 2050 as high as 11 billion.[3] World population passed the 7 billion mark on October 31, 2011.[1]

According to the United Nations' World Population Prospects report,[4] the world population is currently growing by approximately 74 million people per year. Current United Nations predictions estimate that the world population will reach 9.0 billion around 2050, assuming a decrease in average fertility rate from 2.5 down to 2.0.[5][6]

Almost all growth will take place in the less developed regions, where today's 5.3 billion (circa 2010) population of underdeveloped countries is expected to increase to 7.8 billion in 2050. By contrast, the population of the more developed regions will remain mostly unchanged, at 1.2 billion. An exception is the United States population, which is expected to increase 31% from 305 million in 2008 to 400 million in 2050 due to projected net international migration.[7] In 2000–2005, the average world fertility was 2.65 children per woman, about half the level in 1950–1955 (5 children per woman). In the medium variant, global fertility is projected to decline further to 2.05 children per woman.

Growth regions

A world map showing global variations in fertility rate per woman, according to the CIA World Factbook's 2015 data.

  7–8 children
  6–7 children
  5–6 children
  4–5 children
  3–4 children
  2–3 children
  1–2 children
  0–1 children

During 2005–2050, twelve countries are expected to account for half of the world's projected population increase: India, China, United States, Indonesia, Nigeria, Pakistan, Brazil, Democratic Republic of the Congo, Ethiopia, Philippines, Mexico and Egypt, listed according to the size of their contribution to population growth.

Global life expectancy at birth, which is estimated to have risen from 46 years in 1950–1955 to 65 years in 2000–2005, is expected to keep rising to reach 75 years in 2045–2050. In the more developed regions, the projected increase is from 75 years today to 82 years by mid-century. Among the least developed countries, where life expectancy today is just under 50 years, it is expected to be 66 years in 2045–2050. The population of 31 countries or areas, including Ukraine, Romania, Japan and most of the successor States of the former Soviet Union, is expected to be lower in 2050 than in 2005.

Projected migration to Western countries

According to the United Nations, during 2005–2050 the net number of international migrants to more developed regions is projected to be 98 million. Because deaths are projected to exceed births in the more developed regions by 73 million during 2005–2050, population growth in those regions will largely be due to international migration. In 2000–2005, net migration in 28 countries either prevented population decline or doubled at least the contribution of natural increase (births minus deaths) to population growth. These countries include Austria, Canada, Croatia, Denmark, Germany, Italy, Portugal, Qatar, Singapore, Spain, Sweden, the United Arab Emirates and the United Kingdom.[8] Birth rates are low in a small percentage of developing countries.[5]

By 2050 (Medium variant), India will have 1.70 billion people, China 1.34 billion, Nigeria 398 million, United States 388 million, Indonesia 322 million, Pakistan 309 million, Brazil 238 million, Bangladesh 202 million, Democratic Republic of Congo 195 million, Ethiopia 188 million, Mexico 163 million, Egypt 151 million, Philippines 148 million, Tanzania 137 million, Russia 128 million, Vietnam 112 million, Japan 107 million, Uganda 101 million, Turkey 95 million, Kenya 95 million, Iran 92 million, Iraq 83 million, Sudan 80 million and the United Kingdom 75 million, .

World population in 2050

Estimates of population levels in different continents between 1950 and 2050, according to the United Nations. The vertical axis is logarithmic and is in millions of people.

Walter Greiling projected in the 1950s that world population would reach a peak of about nine billion, in the 21st century, and then stop growing after a readjustment of the Third World and a sanitation of the tropics.[10] Recent extrapolations from available figures for population growth show that the population of Earth will stop increasing around 2070.[11]

The United Nations Department of Economic and Social Affairs report (2004) projects the world population to peak at 9.22 billion in 2075. After reaching this maximum the world population is projected to decline slightly and then resume increasing slowly, to reach a level of 8.97 billion by 2300, about the same as the projected 2050 figure.[12] A 2014 paper by demographers from several universities and the United Nations Population Division forecast that the world's population will reach about 10.9 billion in 2100 and continue growing thereafter.[13] An alternative scenario is given by Jorgen Randers, who argues that traditional projections insufficiently take into account the downward impact of global urbanization on fertility. Randers' "most likely scenario" reveals a peak in the world population in the early 2040s at about 8.1 billion people, followed by decline.[14]

These projected growth patterns depend on assumptions about vital rates. Total fertility is assumed to continue to decline, at varying paces depending on circumstances in individual countries, to a below-replacement level of 1.85 children per woman by mid century. Countries already at this level or below, and other countries when they reach it, will eventually return to replacement over a period of a century and stay at replacement going forward. All countries are projected to have reached replacement fertility by 2175.

Some of the authors of the report say that life expectancy is assumed to rise slowly and continuously. The projections in the report assume this with no upper limit, though at a slowing pace depending on circumstances in individual countries. By 2100, the report assumes life expectancy to be from 66 to 97 years, and by 2300 from 87 to 106 years, depending on the country. Based on that assumption, they said that rising life expectancy will produce small but continuing population growth by the end of the projections, ranging from 0.03 to 0.07 percent annually.

However, based on recent research, many expect that life expectancy will leap ahead and indefinite human lifespans are not necessarily unfeasible.[15][16][17] This could significantly raise the estimates. In an essay within the U.N. report, Tim Dyson said,

"A rapid increase in life expectancy, which would raise the population pyramids, seems within reach, since it responds to an old and powerful demand for longevity."[12]

Most populous nations by 2030

The United Nations Population Fund has calculated, based on current trends, the future population of the world's countries. These figures can easily change as events such as wars, diseases, breakthroughs in life extension technologies, or dramatic demographic changes would all greatly affect the results. The study projected the world population in 2030 to be 8.321 billion.[18]

Projected
rank
2030 		Current
rank
2014 		Change Country Projected
population (2030) 		Population (2010) Population
change
(percent)
— — —  World 8,321,380,000 6,895,889,000 +20.7%
01 02 +1  India (demographics) 1,523,482,000 1,224,614,000 +24.4%
02 01 −1  China (demographics) 1,393,076,000 1,341,335,000 +3.9%
03 03 =  United States (demographics) 361,680,000 310,384,000 +16.5%
04 04 =  Indonesia (demographics) 279,659,000 239,871,000 +16.6%
05 07 +2  Nigeria (demographics) 257,815,000 158,423,000 +62.7%
06 06 =  Pakistan (demographics) 234,432,000 173,593,000 +35.0%
07 05 −2  Brazil (demographics) 220,492,000 194,946,000 +13.1%
08 08 =  Bangladesh (demographics) 181,863,000 148,692,000 +22.3%
09 09 =  Russia (demographics) 136,429,000 142,958,000 −4.6%
10 11 +1  Mexico (demographics) 135,398,000 113,423,011 +19.4%

After 2050

Projections for after 2050 have usually assumed that fertility rates will have declined by then and the population will be stable or will decrease. However, a study in 2014 found that fertility rates in Africa have leveled off at around 4.6 instead of continuing to decline, and that consequently world population may be as high as 12 billion by 2100. Reasons for the continuing high fertility rate include better survival rates with respect to HIV, and lack of availability of contraception.[19][20] Another study on the other hand concludes that education of women will lead to low fertility rates even in Africa.[19] Evolutionary biology also suggests the demographic transition may reverse itself; in addition, recent evidence suggests birth rates may be rising in the 21st century in the developed world.[21]

Population projections of the 101 largest cities in the 21st century

Large urban areas are hubs of economic development and innovation, with larger cities underpinning regional economies and local and global sustainability initiatives. Currently, 757 million humans live in the 101 largest cities;[22] these cities are home to 11% of the world’s population.[22] By the end of the century, the world population is projected to grow, with estimates ranging from 6.9 billion to 13.1 billion;[22] the percentage of people living in the 101 larger cities is estimated to be 15% to 23%.[22]

The following 101 cities with the largest population projections for the years 2025, 2050, 2075, and 2100 are listed below.[22]

Rank City Projected Population (millions) 2025 City Projected Population (millions) 2050 City Projected Population (millions) 2075 City Projected Population (millions) 2100
1 Tokyo 36.40 Mumbai 42.40 Mumbai 57.86 Lagos 76.60
2 Mumbai 26.39 Delhi 36.16 Lagos 55.26 Dar es Salaam 73.68
3 Delhi 22.50 Dhaka 35.19 Kinshasa 54.51 Mumbai 67.24
4 Dhaka 22.02 Kinshasa 35.00 Delhi 49.34 Kinshasa 63.05
5 São Paulo 21.43 Kolkata 33.04 Kolkata 45.09 Lilongwe 57.43
6 Mexico City 21.01 Lagos 32.63 Karachi 43.37 Delhi 57.33
7 New York 20.63 Tokyo 32.62 Dhaka 42.45 Blantyre City 56.78
8 Kolkata 20.56 Karachi 31.70 Dar es Salaam 37.49 Khartoum 56.59
9 Shanghai 19.41 New York 24.77 Cairo 33.00 Niamey 55.24
10 Karachi 19.10 Mexico City 24.33 Manila 32.75 Kolkata 52.40
11 Kinshasa 16.76 Cairo 24.04 Kabul 32.67 Kabul 59.27
12 Lagos 15.80 Manila 23.55 Khartoum 30.68 Karachi 49.06
13 Cairo 15.56 São Paulo 22.83 Nairobi 28.42 Nairobi 46.66
14 Manila 14.81 Shanghai 21.32 New York 27.19 N’Djamena 41.15
15 Beijing 14.55 Lahore 17.45 Tokyo 24.64 Cairo 40.54
16 Buenos Aires 13.77 Kabul 17.09 Baghdad 24.39 Manila 39.96
17 Los Angeles 13.67 Los Angeles 16.42 Lahore 23.88 Dhaka 38.54
18 Rio de Janeiro 13.41 Chennai 16.28 Addis Ababa 23.71 Mogadishu 36.37
19 Jakarta 12.36 Khartoum 16.00 Mexico City 22.80 Addis Ababa 35.82
20 Istanbul 12.10 Dar es Salaam 15.97 Chennai 22.21 Lusaka 35.76
21 Guangzhou 11.84 Beijing 15.97 Bangalore 21.31 Baghdad 34.10
22 Osaka-Kobe 11.37 Jakarta 15.92 Niamey 20.37 Kampala 31.41
23 Moscow 10.53 Bangalore 15.62 Kampala 20.23 New York 27.25
24 Lahore 10.51 Buenos Aires 15.55 Hyderabad 19.94 Lahore 27.01
25 Shenzhen 10.20 Baghdad 15.09 São Paulo 19.73 Chennai 25.81
26 Chennai 10.13 Hyderabad 14.61 Los Angeles 18.02 Bangalore 24.77
27 Paris 10.04 Luanda 14.30 Kano 17.69 Kano 24.52
28 Chicago 9.93 Rio de Janeiro 14.29 Luanda 17.15 Hyderabad 23.17
29 Tehran 9.81 Nairobi 14.25 Ahmedabad 16.96 Dakar 21.18
30 Seoul 9.74 Istanbul 14.18 Sana'a 16.69 Ibadan 20.53
31 Bangalore 9.72 Addis Ababa 13.21 Mogadishu 15.94 Maputo 20.39
32 Lima 9.60 Guangzhou 13.00 Buenos Aires 15.55 Sana’a 19.91
33 Bogota 9.60 Ahmedabad 12.43 Lilongwe 15.23 Ahmedabad 19.71
34 Wuhan 9.34 Chittagong 12.21 Blantyre City 15.06 Kigali 18.30
35 Tianjin 9.24 Chicago 11.93 Jakarta 14.96 Los Angeles 18.06
36 Hyderabad 9.09 Ho Chi Minh City 11.86 Pune 14.91 Bamako 17.85
37 London 8.62 Lima 11.57 Ibadan 14.81 Pune 17.32
38 Bangkok 8.33 Bogota 11.56 Chittagong 14.73 Mexico City 17.25
39 Hong Kong 8.31 Shenzhen 11.20 Dakar 14.56 Abuja 16.28
40 Chongqing 8.28 Paris 11.12 Lusaka 14.52 Tokyo 15.54
41 Luanda 8.24 Bangkok 11.08 N'Djamena 14.48 Antananarivo 15.45
42 Ho Chi Minh City 8.15 Tehran 11.00 Abidjan 14.27 Conakry 14.79
43 Baghdad 8.06 Pune 10.92 Shanghai 14.17 Alexandria 14.73
44 Khartoum 7.94 Abidjan 10.71 Bamako 13.54 Phnom Penh 14.60
45 Ahmedabad 7.74 Kano 10.44 Chicago 13.09 Surat 14.53
46 Chittagong 7.64 Wuhan 10.26 Bangkok 12.55 Abidjan 14.16
47 Kabul 7.18 Moscow 10.24 Surat 12.51 Luanda 14.03
48 Santiago (BR) 7.03 Osaka-Kobe 10.19 Antananarivo 12.40 Mombasa 14.01
49 Pune 6.80 Tianjin 10.15 Rio de Janeiro 12.35 São Paulo 13.77
50 Hano 6.75 Sana'a 10.05 Ho Chi Minh City 12.32 Buenos Aires 13.75
51 Belo Horizonte 6.75 Hanoi 9.83 Alexandria 11.99 Chittagong 13.37
52 Santiago (CH) 6.31 London 9.75 Abuja 11.75 Chicago 13.12
53 Riyadh 6.28 Seoul 9.47 Ouagadougou 11.70 Ouagadougou 12.63
54 Miami 6.27 Hong Kong 9.47 Istanbul 11.56 Bangkok 12.14
55 Dongguan 6.16 Kampala 9.43 Lima 11.35 Kanpur 11.73
56 Shenyang 6.16 Surat 9.17 Bogota 11.25 Kaduna 11.45
57 Addis Ababa 6.16 Chongqing 9.09 Maputo 10.92 Lubumbashi 11.07
58 Philadelphia 6.13 Ibadan 8.75 Paris 10.87 Giza 11.01
59 Abidjan 6.03 Alexandria 8.73 Conakry 10.63 Faisalabad 11.00
60 Toronto 5.95 Dakar 8.52 Beijing 10.62 Jaipur 10.95
61 Madrid 5.94 Yangon 8.44 Tehran 10.36 Mbuji-Mayi 10.72
62 Nairobi 5.87 Riyadh 8.09 Hanoi 10.21 Jakarta 10.17
63 Yangon 5.87 Bamako 7.63 Kanpur 10.09 Monrovia 10.12
64 Surat 5.70 Miami 7.53 London 10.09 Lucknow 10.05
65 Dar es Salaam 5.69 Santiago (BR) 7.49 Kigali 9.79 Benin City 9.66
66 Alexandria 5.65 Kanpur 7.39 Faisalabad 9.73 London 9.56
67 Dallas-Fort Worth 5.42 Philadelphia 7.36 Lubumbashi 9.57 Paris 9.33
68 Tlaquepaque 5.37 Antananarivo 7.26 Moscow 9.51 Nagpur 9.13
69 Tonala 5.37 Belo Horizonte 7.19 Hong Kong 9.46 Ho Chi Minh City 9.05
70 Zapopan 5.37 Faisalabad 7.11 Jaipur 9.43 Lima 9.05
71 Chengdu 5.32 Toronto 7.04 Yangon 9.37 Mosul 8.87
72 Xi'an-Shaanxi 5.23 Abuja 6.94 Mbuji-Mayi 9.27 Bogota 8.83
73 Barcelona 5.18 Jaipur 6.91 Giza 8.96 Rio de Janeiro 8.62
74 Atlanta 5.15 Ouagadougou 6.90 Phnom Penh 8.85 Moscow 8.43
75 Guiyang 5.11 Niamey 6.79 Lucknow 8.65 Al-Hudaydah 8.42
76 Singapore 5.10 Santiago (CH) 6.77 Guangzhou 8.64 Miami 8.29
77 Kano 5.06 Dongguan 6.76 Mombasa 8.53 Lome 8.27
78 Houston 5.05 Shenyang 6.76 Miami 8.27 Hong Kong 8.27
79 Boston 5.03 Mogadishu 6.57 Kaduna 8.26 Patna 8.17
80 Guadalajara 4.97 Giza 6.52 Philadelphia 8.09 Tehran 8.17
81 Guadalupe 4.95 Madrid 6.52 Accra 7.98 Accra 8.17
82 Washington DC 4.89 Dallas-Fort Worth 6.51 Nagpur 7.86 Port Harcourt 8.15
83 Sydney 4.83 Lucknow 6.34 Riyadh 7.76 Philadelphia 8.10
84 Nanjing 4.77 Tlaquepaque 6.22 Osaka-Kobe 7.69 Tashkent 8.10
85 Haerbin 4.70 Tonala 6.22 Toronto 7.59 Yangon 8.02
86 Porto Alegre 4.63 Zapopan 6.22 Seoul 7.52 Bat Dambang 7.98
87 Detroit 4.61 Atlanta 6.19 Shenzhen 7.44 Ta’izz 7.92
88 Kanpur 4.60 Lubumbashi 6.15 Lome 7.25 Rawalpindi 7.88
89 Ankara 4.59 Conakry 6.14 Dallas-Fort Worth 7.14 Kathmandu 7.82
90 Brasilia 4.58 Houston 6.06 Monrovia 7.08 Pikine 7.87
91 Algiers 4.50 Boston 6.04 Douala 7.07 Indore 7.66
92 St. Petersburg 4.48 Mbuji-Mayi 5.95 Al-Hudaydah 7.06 Ogbomosho 7.64
93 Monterrey 4.41 Accra 5.94 Patna 7.03 Douala 7.64
94 Sana’a 4.38 Aleppo 5.90 Rawalpindi 6.97 Hanoi 7.50
95 Recife 4.35 Washington DC 5.87 Benin City 6.97 Brazzaville 7.45
96 Changchun 4.34 Chengdu 5.84 Aleppo 6.88 Toronto 7.44
97 Jaipur 4.30 Sydney 5.82 Wuhan 6.82 Al Qalyubiyah 7.24
98 Faisalabad 4.28 Guadalajara 5.76 Atlanta 6.79 Dushanbe 7.18
99 Melbourne 4.24 Nagpur 5.76 Tianjin 6.75 Maiduguri 7.17
100 Ibadan 4.23 Xi'an 5.75 Houston 6.66 Dallas-Fort Worth 7.16
101 Dakar 4.23 Guadalupe 5.73 Ta'izz 6.64 Zaria 7.13

See also

References

  1. 1 2 "World Population Clock". Worldometers. Retrieved 24 October 2011.
  2. ↑ International Data Base (IDB) — World Population
  3. ↑ http://esa.un.org/unpp/
  4. ↑ World Population Prospects
  5. 1 2 United Nations Population Division Home Page, United Nations Department of Economic and Social Affairs
  6. ↑ Microsoft Word – WorldPOP2300.doc
  7. ↑
  8. ↑ http://www.un.org/News/Press/docs/2005/pop918.doc.html
  9. ↑ http://www.geohive.com/earth/his_proj_continent.aspx
  10. ↑ Walter Greiling: Wie werden wir leben? ("How are we going to live?") Econ publishers, Munich 1954
  11. ↑ Ciro Pabón y Ciro Pabón, Manual de Urbanismo, Editorial Leyer, Bogotá, 2007, ISBN 978-958-711-296-2
  12. 1 2 United Nations Department of Economic and Social Affairs. World Population to 2300. 2004. Executive Summary, Page 2.
  13. ↑ Gerland, P.; Raftery, A. E.; Ev Ikova, H.; Li, N.; Gu, D.; Spoorenberg, T.; Alkema, L.; Fosdick, B. K.; Chunn, J.; Lalic, N.; Bay, G.; Buettner, T.; Heilig, G. K.; Wilmoth, J. (September 14, 2014). "World population stabilization unlikely this century". Science (AAAS) 346 (6206): 234–7. doi:10.1126/science.1257469. ISSN 1095-9203. PMC 4230924. PMID 25301627. Retrieved September 21, 2014.
  14. ↑ Randers, Jorgen (2012). 2052: A Global Forecast for the Next Forty Years. Vermont: Chelsea Green Publishing. p. 62.
  15. ↑ Newmark, PA; Sánchez Alvarado, A (2002). "Not your father's planarian: a classic model enters the era of functional genomics". Nat Rev Genet 3: 210–219. doi:10.1038/nrg759. PMID 11972158.
  16. ↑ Bavestrello, Giorgio; Sommer, Christian; Sarà, Michele (1992). "Bi-directional conversion in Turritopsis nutricula (Hydrozoa)". Scientia Marina 56 (2–3): 137–140.
  17. ↑ Martínez, DE (1998). "Mortality patterns suggest lack of senescence in hydra". Exp Gerontol 33 (3): 217–225. doi:10.1016/S0531-5565(97)00113-7. PMID 9615920.
  18. ↑ World Population Prospects, the 2010 Revision Archived April 19, 2012, at the Wayback Machine.
  19. 1 2 Andy Coghlan (27 Sep 2014). "Global population may boom well beyond the year 2050". New Scientist: 11.
  20. ↑ Patrick Gerland, Adrian Raftery; et al. (18 Sep 2014). "World population stabilization unlikely this century". Science 346: 234–7. doi:10.1126/science.1257469. PMC 4230924. PMID 25301627.
  21. ↑ Can we be sure the world's population will stop rising?, BBC News, 13 October 2012
  22. 1 2 3 4 5 Hoornweg, Daniel; Pope, Kevin (January 2014). "Population predictions of the 101 largest cities in the 21st century" (PDF). Global Cities Institute (Working Paper No. 4).
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