Projections of population growth

World population growth 1700–2100

Population projections are attempts to show how the human population living today will change in the future.[1] These projections are an important input to forecasts of the population’s impact on this planet and humanity’s future well-being.[2]

The 2019 forecast from the United Nation’s Population Division shows that world population growth peaked at 2.1% per year in 1962, has since dropped to 1.0%, and could drop even further to 0.1% by 2100, a growth rate not seen since pre-industrial revolution days.[3]

World population prospects, 2019

Based on this, the UN Population Division expects world population, currently (2020) at 7.8 billion, to level out at or soon after the end of the 21st Century at 10.9 billion (the median line),[4][5] assuming a continuing decrease in the global average fertility rate from 2.5 births per woman during the 2015–2020 period to 1.9 in 2095–2100, according to the medium-variant projection.[6]

About two thirds of the predicted growth in population between 2020 and 2050 will take place in Africa.[7]

Because of population momentum the global population will continue to grow, although at a steadily slower rate, for the remainder of this century, but the main driver of long-term future population growth will be the evolution of the global average fertility rate.[6]

Growth regionsEdit

The table below shows that from 2020 to 2050, the bulk of the world's population growth is predicted to take place in Africa: of the additional 1.9 billion people projected between 2020 and 2050, 1.2 billion will be added in Africa, 0.7 billion in Asia and zero in the rest of the world. Africa's share of global population is projected to grow from 17% in 2020 to 26% in 2050 and 39% by 2100, while the share of Asia will fall from 59% in 2020 to 55% in 2050 and 43% in 2100.[8][7]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 about 2050.[5]

Sources of Population Growth
Region Pop

2020

% of

Total

Pop

2050

% of

Total

Chg

2020–50

Pop

2100

% of

Total

Africa 1.3 17 2.5 26 1.2 4.3 39
Asia 4.6 59 5.3 55 0.7 4.7 43
Other 1.9 24 1.9 20 0.0 1.9 17
World 7.8 100 9.7 100 1.9 10.9 100

The population of the More Developed regions is slated to remain mostly unchanged, at 1.3 billion for the remainder of the 21st century.  All population growth comes from the Less Developed regions.[8][9]

Sources of Population Growth
Region Pop

2020

% of

Total

Pop

2050

% of

Total

Chg

2020–50

Pop

2100

% of

Total

More Developed 1.3 17 1.3 13 0.0 1.3 12
Less Developed 6.5 83 8.4 87 1.9 9.6 88
World 7.8 100 9.7 100 1.9 10.9 100

The table below breaks out the UN’s future population growth predictions by region[7]

Annual Percent Change of Population For Three Periods In the Future
Region 2020–25

% chg/yr

2045–50

% chg/yr

2095–2100

% chg/yr

Africa 2.4 1.8 0.6
Asia 0.8 0.1 -0.4
Europe 0.0 -0.3 -0.1
Latin America & the Caribbean 0.8 0.2 -0.5
Northern America 0.6 0.3 0.2
Oceania 1.2 0.8 0.4
World 1.0 0.5 0.0

Between 2020 and the end of this century, the UN predicts that all six regions will experience  declines in population growth, that by the end of the century three of them will be experiencing population decline, and the world will have reached zero population growth.

World population in 2050Edit

 
Estimates of population levels in different continents between 1950 and 2050, according to the United Nations (2011 edition). The vertical axis is logarithmic and is in millions of people.
 
UN estimates (as of 2017) for world population by continent in 2000 and in 2050 (pie chart size to scale).[10]
     Asia      Africa      Europe      Latin America      Northern America      Oceania
 
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 (as of 2010) 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.

The median scenario of the UN 2019 World Population Prospects[8] predicts the following populations per region in 2050 (compared to population in 2000), in billions:

2000 2050 growth %/yr
Asia 3.74 5.29 +41% +0.7%
Africa 0.81 2.49 +207% +2.3%
Europe 0.73 0.71 -3% -0.1%
South/Central America
+Caribbean
0.52 0.76 +46% +0.8%
Northern America 0.31 0.43 +39% +0.7%
Oceania 0.03 0.06 +100% +1.4%
World 6.14 9.74 +60% +0.9%


After 2050Edit

Projections of population reaching more than one generation into the future are highly speculative: Thus, the United Nations Department of Economic and Social Affairs report of 2004 projected the world population to peak at 9.22 billion in 2075 and then stabilise at a value close to 9 billion;[11] By contrast, a 2014 projection by the United Nations Population Division predicts a population close to 11 billion by 2100 without any declining trend in the foreseeable future.[12] On the other hand, a conservative scenario published in 2012 assumes that a maximum of 8 billion will be reached before 2040.[13]

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.[14][15] Evolutionary biology also suggests the demographic transition may reverse itself and global population may continue to grow in the long term.[16] In addition, recent evidence suggests birth rates may be rising in the 21st century in the developed world.[17]

UN projections published in 2019 estimate the world population in 2100 to be 10.9 billion.[8]

Year by yearEdit

The following table shows projections of world population for the 21st century.

Year United States Census Bureau

(2015)[18]

Population Reference Bureau

(1973–2015)[19]

United Nations Department of Economic and Social Affairs

(2015)[20]

2016 7,334,771,614 7,432,663,280
2017 7,412,778,971
2018 7,490,427,640
2019 7,567,402,977
2020 7,643,402,123 7,758,157,000
2021 7,718,256,830
2022 7,792,021,317
2023 7,864,725,370
2024 7,936,271,554
2025 8,006,580,553 8,000,000,000 8,141,661,000
2026 8,075,716,000
2027 8,143,729,466
2028 8,210,559,895
2029 8,276,190,519
2030 8,340,606,590 8,505,000,000 8,500,766,000
2031 8,403,880,343
2032 8,466,094,022
2033 8,527,246,205
2034 8,587,325,154
2035 8,646,304,704 8,838,908,000
2036 8,704,239,274
2037 8,761,189,197
2038 8,817,138,785
2039 8,872,066,537
2040 8,925,949,679 9,157,234,000
2041 8,978,822,945
2042 9,030,723,366
2043 9,081,617,002
2044 9,131,462,326
2045 9,180,225,214 9,453,892,000
2046 9,227,935,007
2047 9,274,616,811
2048 9,320,232,984
2049 9,364,750,182
2050 9,408,141,302 9,804,000,000 9,725,148,000
2055 9,968,809,000
2060 10,184,290,000
2065 10,375,719,000
2070 10,547,989,000
2075 10,701,653,000
2080 10,836,635,000
2085 10,953,525,000
2090 11,055,270,000
2095 11,142,461,000
2100 11,213,317,000

Drivers of population changeEdit

The population of a country or area grows or declines through the interaction of three demographic drivers: fertility, mortality, and migration.[2]

FertilityEdit

Fertility is expressed as the total fertility rate (TFR), a measure of the number of children on average that a woman will bear in her lifetime. With longevity trending towards uniform and stable values worldwide, the main driver of future population growth will be the evolution of the fertility rate.[6]

 
Map of countries by fertility rate (2018), according to CIA World Factbook

Where fertility is high, demographers generally assume that fertility will decline and eventually stabilize at about two children per woman.[2]

From 2015 to 2020, the average world fertility rate was 2.5 children per woman,[6] about half the level in 1950–1955 (5 children per woman). In the medium variant, global fertility is projected to decline further to 2.2 in 2045 to 2050 and to 1.9 in 2095–2100.[6]

MortalityEdit

If the mortality rate is relatively high and the resulting life expectancy is therefore relatively low, changes in mortality can have a material impact on population growth.  Where the mortality rate is low and life expectancy has therefore risen, a change in  mortality will have much less an effect.[2]

Because child mortality has declined substantially over the last several decades,[2] Global life expectancy at birth, which is estimated to have risen from 47 years in 1950–1955 to 67 years in 2000–2005,[21] is expected to keep rising to reach 77 years in 2045–2050.[22] In the More Developed regions, the projected increase is from 79 years today[21] to 83 years by mid-century.[22] Among the Least Developed countries, where life expectancy today is just under 65 years,[21] it is expected to be 71 years in 2045–2050.[22]

The population of 31 countries or areas, including Ukraine, Romania, Japan and most of the successor states of the Soviet Union, is expected to be lower in 2050 than in 2005.

MigrationEdit

Migration can have a significant effect on population change. To this, Global South-South migration accounts for 38% of total migration, as opposed to only 34% for Global South-North.[23] For example, the United Nations reports that during the period 2010–2020, fourteen countries will have seen a net inflow of more than one million migrants, while ten countries will have seen a net outflow of similar proportions.  The largest migratory outflows have been in response to demand for workers in other countries (Bangladesh, Nepal and the Philippines) or to insecurity in the home country (Myanmar, Syria and Venezuela).  Belarus, Estonia, Germany, Hungary, Italy, Japan, the Russian Federation, Serbia and Ukraine have experienced a net inflow of migrants over the decade, helping to offset population losses caused by a negative natural increase (births minus deaths).[24]

History of population projectionsEdit

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.[25]

Estimates published in the 2000s tended to predict that the population of Earth would stop increasing around 2070;[26]In a 2004 long-term prospective report, the United Nations Population Division projected the world population would 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.[27]

This prediction was revised in the 2010s, to the effect that no maximum will likely be reached in the 21st century.[28] The main reason for the revision was that the ongoing rapid population growth in Africa had been underestimated. A 2014 paper by demographers from several universities and the United Nations Population Division forecast that the world's population would reach about 10.9 billion in 2100 and continue growing thereafter.[12] In 2017 the UN predicted a decline of global population growth rate from +1.0% in 2020 to +0.5% in 2050 and to +0.1% in 2100.[10]

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.[29]

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 assumed 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. The hypothetical feasibility (and wide availability) of life extension by technological means would further exacerbate the overpopulation problem.[30][31][32]

Most populous nations by 2050 and 2100Edit

The UN Population Division has calculated the future population of the world's countries, based on current demographic trends. Current population is around 7.7-7.8 billion people living in the world so far. The 2019 report projects the world population in 2050 to be 9.7 billion people, and possibly as high to 11 billion by the next century, with the following estimates for the top 14 countries in 2020, 2050,and 2100:[8]

Population Growth of the Top 14 Countries in 2020, 2050, and 2100
Country Pop

2020

(mil)

Pop

2050

(mil)

Pop

2100

(mil)

2020

Rank

2050

Rank

2100

Rank

China 1,439 1,402 1,065 1 2 2
India 1,380 1,639 1,447 2 1 1
United States 331 379 434 3 4 4
Indonesia 273 331 321 4 6 7
Pakistan 221 338 403 5 5 5
Brazil 212 229 181 6 7 12
Nigeria 206 401 733 7 3 3
Bangladesh 165 192 151 8 10 14
Russian Federation 146 136 126 9 14 19
Mexico 129 155 141 10 12 17
Japan 126 106 75 11 17 36
Ethiopia 115 205 294 12 8 8
Philippines 110 144 146 13 13 15
Egypt 102 160 225 14 11 10
Dem Republic of Congo 90 194 362 16 9 6
Tanzania 60 129 286 24 15 9
Angola 33 77 188 44 24 11
Niger 24 66 165 56 30 13
World 7,795 9,735 10,875

From 2017 to 2050, the nine highlighted countries are expected to account for half of the world's projected population increase: India, Nigeria, the Democratic Republic of the Congo, Pakistan, Ethiopia, Tanzania, the United States, Uganda, and Indonesia, listed according to the expected size of their contribution to that projected population growth.[24]

Population projections of the 101 largest metropolitan areas in the 21st centuryEdit

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;[33] these cities are home to 11% of the world's population.[33] By the end of the century, the world population is projected to grow, with estimates ranging from 6.9 billion to 13.1 billion;[33] the percentage of people living in the 101 largest cities is estimated to be 15% to 23%.[33]

The following 101 metropolitan areas with the largest population projections for the years 2025, 2050, 2075, and 2100 are listed below.[33]

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   Kinshasa 58.42   Lagos 88.30
2   Mumbai 26.39   Delhi 36.16   Mumbai 57.86   Kinshasa 83.53
3   Delhi 22.50   Dhaka 35.19   Lagos 57.20   Dar es Salaam 73.68
4   Dhaka 22.02   Kinshasa 35.00   Delhi 49.34   Mumbai 67.24
5   São Paulo 21.43   Kolkata 33.04   Dhaka 46.22   Delhi 57.33
6   Mexico City 21.01   Lagos 32.63   Kolkata 45.09   Khartoum 56.59
7   New York City 20.63   Tokyo 32.62   Karachi 43.37   Niamey 56.15
8   Kolkata 20.56   Karachi 31.70   Dar es Salaam 37.49   Dhaka 54.25
9   Shanghai 19.41   New York City 24.77   Cairo 33.00   Kolkata 52.40
10   Karachi 19.10   Mexico City 24.33   Manila 32.75   Kabul 50.30
11   Kinshasa 16.76   Cairo 24.03   Kabul 32.67   Karachi 49.06
12   Lagos 15.80   Manila 23.55   Khartoum 30.68   Nairobi 46.66
13   Cairo 15.56   São Paulo 22.82   Tokyo 28.92   Lilongwe 41.38
14   Manila 14.81   Shanghai 21.32   Nairobi 28.42   Blantyre 40.91
15   Beijing 14.55   Lahore 17.45   New York City 27.92   Cairo 40.54
16   Buenos Aires 13.77   Kabul 17.09   Baghdad 24.39   Kampala 40.14
17   Los Angeles 13.67   Los Angeles 16.42   Mexico City 24.18   Manila 39.96
18   Rio de Janeiro 13.41   Chennai 16.28   Lahore 23.88   Lusaka 37.74
19   Jakarta 12.36   Khartoum 16.00   Addis Ababa 23.81   Mogadishu 36.37
20   Istanbul 12.10   Dar es Salaam 15.97   Chennai 22.21   Addis Ababa 35.82
21   Guangzhou 11.84   Beijing 15.97   Bangalore 21.31   Baghdad 34.10
22   Osaka-Kobe 11.37   Jakarta 15.92   São Paulo 21.28   New York City 30.19
23   Moscow 10.53   Bangalore 15.62   Shanghai 21.05   N'Djamena 28.81
24   Lahore 11.37   Buenos Aires 15.55   Niamey 20.37   Kano 28.28
25   Shenzhen 10.20   Baghdad 15.09   Kampala 20.23   Sana'a 27.21
26   Chennai 10.13   Hyderabad 14.61   Hyderabad 19.94   Lahore 27.05
27   Paris 10.04   Luanda 14.30   Luanda 19.65   Chennai 25.81
28   Chicago 9.93   Rio de Janeiro 14.29   Los Angeles 18.51   Tokyo 25.63
29   Tehran 9.81   Nairobi 14.25   Kano 17.69   Bangalore 24.77
30   Seoul 9.74   Istanbul 14.18   Jakarta 17.55   Ibadan 23.68
31   Bangalore 9.72   Addis Ababa 13.21   Ahmedabad 16.93   Luanda 23.55
32   Lima 9.60   Guangzhou 13.00   Sana'a 16.69   Hyderabad 23.17
33   Bogotá 9.60   Ahmedabad 12.43   Rio de Janeiro 16.56   Bamako 22.95
34   Wuhan 9.34   Chittagong 12.21   Buenos Aires 16.40   Mexico City 22.22
35   Tianjin 9.24   Chicago 11.93   Chittagong 16.04   Dakar 21.18
36   Hyderabad 9.09   Ho Chi Minh City 11.86   Mogadishu 15.94   Maputo 21.07
37   London 8.62   Lima 11.57   Beijing 15.78   Shanghai 20.79
38   Bangkok 8.33   Bogotá 11.56   Abidjan 15.52   Ouagadougou 20.63
39   Hong Kong 8.31   Shenzhen 11.20   Lilongwe 15.32   Antananarivo 20.53
40   Chongqing 8.28   Paris 11.12   Blantyre 15.06   Los Angeles 20.01
41   Luanda 8.24   Bangkok 11.08   Pune 14.91   Rio de Janeiro 19.84
42   Ho Chi Minh City 8.15   Tehran 11.00   Ibadan 14.81   Ahmedabad 19.71
43   Baghdad 8.06   Pune 10.92   Istanbul 14.68   Abidjan 19.70
44   Khartoum 7.94   Abidjan 10.71   Dakar 14.56   São Paulo 19.12
45   Ahmedabad 7.74   Kano 10.44   Lusaka 14.52   Chittagong 18.82
46   Chittagong 7.64   Wuhan 10.26   N'djamena 14.48   Abuja 18.58
47   Kabul 7.18   Moscow 10.24   Ho Chi Minh City 14.22   Kigali 18.30
48   Santiago 7.03   Osaka-Kobe 10.19   Bamako 13.54   Jakarta 18.22
49   Pune 6.80   Tianjin 10.15   Chicago 13.44   Pune 17.32
50   Hanoi 6.75   Sana'a 10.05   Guangzhou 12.84   Conakry 17.32
51   Belo Horizonte 6.75   Hanoi 9.83   Bangkok 12.55   Buenos Aires 16.99
52   Santiago 6.31   London 9.75   Surat 12.51   Beijing 15.58
53   Riyadh 6.28   Seoul 9.47   Lima 12.44   Ho Chi Minh City 15.53
54   Miami 6.27   Hong Kong 9.47   Antananarivo 12.40   Istanbul 14.79
55   Dongguan 6.16   Kampala 9.43   Alexandria 11.99   Alexandria 14.72
56   Shenyang 6.16   Surat 9.17   Bogota 11.89   Lubumbashi 14.66
57   Addis Ababa 6.16   Chongqing 9.09   Hanoi 11.79   Chicago 14.54
58   Philadelphia 6.13   Ibadan 8.75   Abuja 11.75   Surat 14.53
59   Abidjan 6.03   Alexandria 8.73   Ouagadougou 11.70   Mbuji-Mayi 14.20
60   Toronto 5.95   Dakar 8.52   Paris 11.64   Mombasa 14.01
61   Madrid 5.94   Yangon 8.44   Shenzhen 11.06   Phnom Penh 13.88
62   Nairobi 5.87   Riyadh 8.09   Maputo 10.92   Kaduna 13.20
63   Yangon 5.87   Bamako 7.63   Conakry 10.63   Hanoi 12.87
64   Surat 5.70   Miami 7.53   Hong Kong 10.41   Lima 12.81
65   Dar es Salaam 5.69   Santiago 7.49   Tehran 10.36   Guangzhou 12.68
66   Alexandria 5.65   Kanpur 7.39   Yangon 10.26   Bangkok 12.14
67   DallasFort Worth 5.42   Philadelphia 7.36   Wuhan 10.13   Paris 11.86
68   Tlaquepaque 5.37   Antananarivo 7.26   Kanpur 10.09   Kanpur 11.73
69   Tonalá 5.37   Belo Horizonte 7.19   London 10.09   Al Hudaydah 11.51
70   Zapopan 5.37   Faisalabad 7.11   Tianjin 10.03   Hong Kong 11.46
71   Chengdu 5.32   Toronto 7.04   Kigali 9.79   Yangon 11.42
72   Xi'an 5.23   Abuja 6.94   Faisalabad 9.73   Monrovia 11.21
73   Barcelona 5.18   Jaipur 6.91   Lubumbashi 9.57   Bogotá 11.20
74   Atlanta 5.15   Ouagadougou 6.90   Moscow 9.51   Benin City 11.14
75   Guiyang 5.11   Niamey 6.79   Jaipur 9.43   Giza 11.00
76   Singapore 5.10   Santiago 6.77   Mbuji-Mayi 9.27   Faisalabad 11.00
77   Kano 5.06   Dongguan 6.76   Osaka-Kobe 9.03   Accra 10.99
78   Houston 5.05   Shenyang 6.76   Riyadh 9.00   Jaipur 10.95
79   Boston 5.03   Mogadishu 6.57   Chongqing 8.98   Shenzhen 10.92
80   Guadalajara 4.97   Giza 6.52   Giza 8.96   Taiz 10.82
81   Guadalupe 4.95   Madrid 6.52   Phnom Penh 8.85   Lomé 10.21
82   Washington, D.C. 4.89   Dallas-Fort Worth 6.51   Lucknow 8.65   Lucknow 10.05
83   Sydney 4.83   Lucknow 6.34   Mombasa 8.53   Wuhan 10.00
84   Nanjing 4.77   Tlaquepaque 6.22   Miami 8.49   Tianjin 9.90
85   Harbin 4.70   Tonalá 6.22   Philadelphia 8.30   Douala 9.68
86   Porto Alegre 4.63   Zapopan 6.22   Kaduna 8.26   London 9.56
87   Detroit 4.61   Atlanta 6.19   Accra 7.98   Riyadh 9.40
88   Kanpur 4.60   Lubumbashi 6.15   Nagpur 7.86   Port Harcourt 9.40
89   Ankara 4.59   Conakry 6.14   Toronto 7.81   Miami 9.18
90   Brasilia 4.58   Houston 6.06   Seoul 7.67   Nagpur 9.13
91   Algiers 4.50   Boston 6.04   Aleppo 7.37   Philadelphia 8.98
92   St. Petersburg 4.48   Mbuji-Mayi 5.95   DallasFort Worth 7.34   Mosul 8.87
93   Monterrey 4.41   Accra 5.94   Lomé 7.25   Chongqing 8.87
94   Sana'a 4.38   Aleppo 5.90   Monrovia 7.08   Moscow 8.42
95   Recife 4.35   Washington, D.C. 5.87   Douala 7.07   Aleppo 8.37
96   Changchun 4.34   Chengdu 5.84   Al-Hudaydah 7.06   Toronto 8.33
97   Jaipur 4.30   Sydney 5.82   Patna 7.03   Patna 8.17
98   Faisalabad 4.28   Guadalajara 5.76   Santiago 6.98   Tehran 8.17
99   Melbourne 4.24   Nagpur 5.76   Atlanta 6.97   Osaka-Kobe 8.00
100   Ibadan 4.23   Xi'an 5.75   Rawalpindi 6.97   Dallas-Fort Worth 7.93
101   Dakar 4.23   Guadalupe 5.73   Benin City 6.96   Rawalpindi 7.88

See alsoEdit

ReferencesEdit

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  3. ^ Roser, Max (June 18, 2019). "Two centuries of rapid global population growth will come to an end". Our World in Data.
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  12. ^ a b 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.
  13. ^ Randers, Jorgen (2012). 2052: A Global Forecast for the Next Forty Years. Vermont: Chelsea Green Publishing. p. 62.
  14. ^ Andy Coghlan (27 Sep 2014). "Global population may boom well beyond the year 2050". New Scientist: 11.
  15. ^ Patrick Gerland, Adrian Raftery; et al. (18 Sep 2014). "World population stabilization unlikely this century". Science. 346 (6206): 234–7. doi:10.1126/science.1257469. PMC 4230924. PMID 25301627.
  16. ^ Jason Collins (January 2019). "The heritability of fertility makes world population stabilization unlikely in the foreseeable future". Evolution and Human Behavior. 40 (1): 105–111. doi:10.1016/j.evolhumbehav.2018.09.001.
  17. ^ Can we be sure the world's population will stop rising?, BBC News, 13 October 2012
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  19. ^ Data from Population Reference Bureau.
  20. ^ Data from United Nations Department of Economic and Social Affairs, Population Division. Archived 2014-03-20 at the Wayback Machine
    1950–2100 estimates (only medium variants shown): (a) World Population Prospects: The 2008 Revision. Archived 2007-03-21 at the Wayback Machine
    Estimates prior to 1950: (b) "The World at Six Billion", 1999.
    Estimates from 1950 to 2100: (c) "Population of the entire world, yearly, 1950 - 2100", 2013. Archived November 19, 2016, at the Wayback Machine
    2014: (d) http://esa.un.org/unpd/wup/Highlights/WUP2014-Highlights.pdf Archived 2014-11-02 at the Wayback Machine "2014 World Urbanization Prospects", 2014.]
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