Projections of population growth

World population estimates from 1800 to 2100, based on "high", "medium" and "low" United Nations projections in 2015 and UN historical estimates for pre-1950 data.

Projections of population growth established in 2015 predict that the human population will keep growing until at least 2050, reaching an estimated 8 billion people in 2024 and 9 billion by 2040, while the 7 billion milestone was reached in 2011.^[1] As the demographic transition follows its course worldwide, the population will age significantly, with most countries outside Africa trending towards a rectangular age pyramid.^[2]

According to the 2015 edition of the United Nations' World Population Prospects report, the world population is currently growing by approximately 83 million people each year.^[3]:2 The growth rate keeps slowing, having decreased from 1.55% per year in 1995 to 1.25% in 2005 and 1.18% in 2015. The median estimate for future growth sees the world population reaching 9.7 billion in 2050 and 11.2 billion in 2100,^[3]:2 assuming a continuing decrease in average fertility rate from 2.5 in 2015 to 2.25 in 2050 and 2.0 in 2100.^[3]:10 With longevity trending towards uniform and stable values worldwide, the main driver of future population growth is the evolution of the fertility rate.^[3]:8

While most scenarios still predict continued growth into the 22nd century, there is a roughly 23% chance that the total population could stabilize or begin to fall before 2100.^[3]:3 Longer-term speculative scenarios over the next two centuries can predict anything between runaway growth to radical decline (36.4 billion or 2.3 billion people in 2300), with the median projection showing a slight decrease followed by a stabilization around 9 billion people.^[4]:13

By 2050, the bulk of the world's population growth will take place in Africa: of the additional 2.4 billion people projected between 2015 and 2050, 1.3 billion will be added in Africa, 0.9 billion in Asia and only 0.2 billion in the rest of the world. Africa's share of global population is projected to grow from 16% in 2015 to 25% in 2050 and 39% by 2100, while the share of Asia will fall from 60% in 2015 to 54% in 2050 and 44% in 2100.^[3]:3 The strong growth of the African population will happen regardless of the rate of decrease of fertility, because of the exceptional proportion of young people already living today. For example, the UN projects that the population of Nigeria will surpass that of the United States by 2050.^[3]:4 The population of the more developed regions is slated to remain mostly unchanged, at 1.2 billion, as international migrations from high-growth regions compensate the fertility deficit of richer countries.^[3]:11

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.

In 2010–2015, the average world fertility was 2.5 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 2.25 children per woman in 2045–2050 and 2.0 in 2095–2100.^[3]:10

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.^[5]

By 2050 (Medium variant), India will have 1.660 billion people, China 1.425 billion, United States 440 million, Nigeria 391 million, Indonesia 327 million, Pakistan 308 million, Brazil 238.3 million, Bangladesh 201.8 million, Democratic Republic of Congo 195.3 million, Ethiopia 188.5 million, Mexico 164 million, Philippines 157.1 million, Egypt 142 million, Russia 133 million, Tanzania 129.4 million, Vietnam 112.8 million, Japan 107 million, Uganda 101 million, Turkey 96 million, Kenya 95.5 million, Iran 92.1 million, Sudan 81 million, Germany 78 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.

The median scenario of the UN 2015 world population prospects^[3]:2 predicts the following populations per continent in 2050:

• Asia and Oceania – 5.3 billion
• Africa – 2.5 billion
• Americas – 1.2 billion
• Europe – 0.7 billion
• World total – 9.7 billion

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.^[6] Recent extrapolations from available figures for population growth show that the population of Earth will stop increasing around 2070.^[7]

In a 2004 long-term prospective report, the United Nations Population Division projected the world population to peak at 9.22 billion in 2075. After reaching this maximum, it would decline slightly and then resume a slow increase, reaching a level of 8.97 billion by 2300, about the same as the projected 2050 figure.^[4]:1 However, with more recent data on hand, the same institution in 2015 predicted continued growth beyond 2100.^[3]:2 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.^[8]

Jørgen Randers, one of the authors of the seminal 1972 long-term simulations in The Limits to Growth, offered an alternative scenario in a 2012 book, arguing that traditional projections insufficiently take into account the downward impact of global urbanization on fertility. Randers' "most likely scenario" predicts a peak in the world population in the early 2040s at about 8.1 billion people, followed by decline.^[9]

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 2004 UN 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.^[10][11][12] 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."^[4]

Most populous nations by 2030

The UN Population Division has calculated the future population of the world's countries, based on current demographic trends. The 2015 study projects the world population in 2030 to be 8.5 billion people, with the following estimates for the top 10 countries:^[3]:18

2030 rank (projected)	2015 rank	Rank change	Country	2030 population (projected)	2015 population	Population change
1	2	+1	India (demographics)	1,527,658,000	1,311,051,000	+16.5%
2	1	−1	China (demographics)	1,415,545,000	1,376,049,000	+2.9%
3	3		United States (demographics)	355,765,000	321,774,000	+10.6%
4	4		Indonesia (demographics)	295,482,000	257,564,000	+14.8%
5	7	+2	Nigeria (demographics)	262,599,000	182,202,000	+44.2%
6	6		Pakistan (demographics)	244,916,000	188,925,000	+29.7%
7	5	−2	Brazil (demographics)	228,663,000	207,848,000	+10.1%
8	8		Bangladesh (demographics)	186,460,000	160,996,000	+15.9%
9	11	+2	Mexico (demographics)	148,133,000	127,017,000	+16.7%
10	9	−1	Russia (demographics)	138,652,000	143,457,000	−3.3%
—	—	—	World (demographics)	8,500,766,000	7,349,472,000	+15.7%

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 birth rate include better survival rates with respect to HIV, and contraception shortage.^[13][14] Another study on the other hand concludes that education of women will lead to low fertility rates even in Africa.^[13] 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.^[15]

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;^[16] these cities are home to 11% of the world’s population.^[16] By the end of the century, the world population is projected to grow, with estimates ranging from 6.9 billion to 13.1 billion;^[16] the percentage of people living in the 101 larger cities is estimated to be 15% to 23%.^[16]

The following 101 cities with the largest population projections for the years 2025, 2050, 2075, and 2100 are listed below.^[16]

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	Dhaka	57.86	Dhaka	76.50
2	Mumbai	26.39	Dhaka	36.16	Lagos	55.26	Dar es Salaam	73.68
3	Dhaka	22.50	Delhi	35.19	Kinshasa	54.51	Mumbai	67.24
4	Delhi	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 City	20.63	Tokyo	32.62	Mumbai	42.45	Blantyre	56.78
8	Kolkata	20.56	Karachi	31.70	Dar es Salaam	37.49	Khartoum	56.59
9	Shanghai	19.41	New York City	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	Manila	24.26	Kabul	32.67	Kabul	49.27
12	Buenos Aires	16.50	Cairo	24.04	Khartoum	30.68	Karachi	49.06
13	Lagos	15.80	Bogota	23.55	Nairobi	28.42	Nairobi	46.66
14	Cairo	15.56	São Paulo	22.83	Bogota	27.90	N’Djamena	41.15
15	Bogota	15.21	Shanghai	22.32	New York City	27.19	Cairo	40.54
16	Beijing	14.55	Buenos Aires	22.13	Buenos Aires	25.63	Manila	39.96
17	Manila	14.20	Lahore	17.45	Tokyo	24.64	Lagos	38.54
18	Los Angeles	13.67	Kabul	17.09	Baghdad	24.39	Mogadishu	36.37
19	Rio de Janeiro	13.41	Los Angeles	16.42	Lahore	23.88	Addis Ababa	35.82
20	Jakarta	12.36	Chennai	16.28	Addis Ababa	23.71	Lusaka	35.76
21	Istanbul	12.10	Khartoum	16.00	Mexico City	22.80	Baghdad	34.10
22	Guangzhou	11.84	Dar es Salaam	15.97	Chennai	22.21	Kampala	31.41
23	Osaka-Kobe	11.37	Beijing	15.97	Bangalore	21.31	Bogota	31.03
24	Moscow	10.53	Jakarta	15.92	Niamey	20.37	Buenos Aires	30.26
25	Lahore	10.51	Bangalore	15.62	Kampala	20.23	New York City	27.25
26	Shenzhen	10.20	Baghdad	15.09	Hyderabad	19.94	Lahore	27.01
27	Chennai	10.13	Hyderabad	14.61	São Paulo	19.73	Chennai	25.81
28	Paris	10.04	Luanda	14.30	Los Angeles	18.02	Bangalore	24.77
29	Chicago	9.93	Rio de Janeiro	14.29	Kano	17.69	Kano	24.52
30	Tehran	9.81	Nairobi	14.25	Luanda	17.15	Hyderabad	23.17
31	Seoul	9.74	Istanbul	14.18	Ahmedabad	16.96	Dakar	21.18
32	Bangalore	9.72	Addis Ababa	13.21	Sana'a	16.69	Ibadan	20.53
33	Lima	9.60	Guangzhou	13.00	Mogadishu	15.94	Maputo	20.39
34	Wuhan	9.34	Ahmedabad	12.43	Lilongwe	15.23	Sana’a	19.91
35	Tianjin	9.24	Chittagong	12.21	Blantyre	15.06	Ahmedabad	19.71
36	Hyderabad	9.09	Chicago	11.93	Jakarta	14.96	Kigali	18.30
37	London	8.62	Ho Chi Minh City	11.86	Pune	14.91	Los Angeles	18.06
38	Bangkok	8.33	Lima	11.57	Ibadan	14.81	Bamako	17.85
39	Hong Kong	8.31	Shenzhen	11.20	Chittagong	14.73	Pune	17.32
40	Chongqing	8.28	Paris	11.12	Dakar	14.56	Mexico City	17.25
41	Luanda	8.24	Bangkok	11.08	Lusaka	14.52	Abuja	16.28
42	Ho Chi Minh City	8.15	Tehran	11.00	N'Djamena	14.48	Tokyo	15.54
43	Baghdad	8.06	Pune	10.92	Abidjan	14.27	Antananarivo	15.45
44	Khartoum	7.94	Abidjan	10.71	Shanghai	14.17	Conakry	14.79
45	Ahmedabad	7.74	Kano	10.44	Bamako	13.54	Alexandria	14.73
46	Chittagong	7.64	Wuhan	10.26	Chicago	13.09	Phnom Penh	14.60
47	Kabul	7.18	Moscow	10.24	Bangkok	12.55	Surat	14.53
48	Salvador	7.03	Osaka-Kobe	10.19	Surat	12.51	Abidjan	14.16
49	Pune	6.80	Tianjin	10.15	Antananarivo	12.40	Luanda	14.03
50	Hanoi	6.75	Sana'a	10.05	Rio de Janeiro	12.35	Mombasa	14.01
51	Belo Horizonte	6.75	Hanoi	9.83	Ho Chi Minh City	12.32	São Paulo	13.77
52	Santiago	6.31	London	9.75	Alexandria	11.99	Chittagong	13.37
53	Riyadh	6.28	Seoul	9.47	Abuja	11.75	Chicago	13.12
54	Miami	6.27	Hong Kong	9.47	Ouagadougou	11.70	Ouagadougou	12.63
55	Dongguan	6.16	Kampala	9.43	Istanbul	11.56	Bangkok	12.14
56	Shenyang	6.16	Surat	9.17	Lima	11.35	Kanpur	11.73
57	Addis Ababa	6.16	Chongqing	9.09	Maputo	10.92	Kaduna	11.45
58	Philadelphia	6.13	Ibadan	8.75	Paris	10.87	Lubumbashi	11.07
59	Abidjan	6.03	Alexandria	8.73	Conakry	10.63	Giza	11.01
60	Toronto	5.95	Dakar	8.52	Beijing	10.62	Faisalabad	11.00
61	Madrid	5.94	Yangon	8.44	Tehran	10.36	Jaipur	10.95
62	Nairobi	5.87	Riyadh	8.09	Hanoi	10.21	Mbuji-Mayi	10.72
63	Yangon	5.87	Bamako	7.63	Kanpur	10.09	Jakarta	10.17
64	Surat	5.70	Miami	7.53	London	10.09	Monrovia	10.12
65	Dar es Salaam	5.69	Salvador	7.49	Kigali	9.79	Lucknow	10.05
66	Alexandria	5.65	Kanpur	7.39	Faisalabad	9.73	Benin City	9.66
67	Dallas-Fort Worth	5.42	Philadelphia	7.36	Lubumbashi	9.57	London	9.56
68	Tlaquepaque	5.37	Antananarivo	7.26	Moscow	9.51	Paris	9.33
69	Tonala	5.37	Belo Horizonte	7.19	Hong Kong	9.46	Nagpur	9.13
70	Zapopan	5.37	Faisalabad	7.11	Jaipur	9.43	Ho Chi Minh City	9.05
71	Chengdu	5.32	Toronto	7.04	Yangon	9.37	Lima	9.05
72	Xi'an	5.23	Abuja	6.94	Mbuji-Mayi	9.27	Mosul	8.87
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	6.77	Guangzhou	8.64	Miami	8.29
77	Kano	5.06	Dongguan	6.76	Mombasa	8.53	Lomé	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	Harbin	4.70	Tonala	6.22	Toronto	7.59	Yangon	8.02
86	Porto Alegre	4.63	Zapopan	6.22	Seoul	7.52	Battambang	7.98
87	Detroit	4.61	Atlanta	6.19	Shenzhen	7.44	Taiz	7.92
88	Kanpur	4.60	Lubumbashi	6.15	Lomé	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

See also

• Population growth
• World population estimates
• Human overpopulation
• Pledge two or fewer (campaign for smaller families)
• List of countries and territories by fertility rate

References

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5. http://www.un.org/News/Press/docs/2005/pop918.doc.html
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11. Bavestrello, Giorgio; Sommer, Christian; Sarà, Michele (1992). "Bi-directional conversion in Turritopsis nutricula (Hydrozoa)". Scientia Marina. 56 (2–3): 137–140.
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13. Andy Coghlan (27 Sep 2014). "Global population may boom well beyond the year 2050". New Scientist: 11.
14. 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.
15. Can we be sure the world's population will stop rising?, BBC News, 13 October 2012
16. 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).