http://en.wikipedia.org/wiki/Projections_of_population_growth
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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 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.
Contents
- 1 Growth regions
- 1.1 Projected migration to Western countries
- 2 World population in 2050
- 3 Most populous nations by 2050
- 4 After 2050
- Growth regions
A world map showing global variations in fertility rate per woman, according to the CIA World Factbook‘s 2013 data.
| Purple – 7–8 childrenPink – 6–7 children | Red – 5–6 childrenOrange – 4–5 children | Yellow – 3–4 childrenGreen – 2–3 children | Light Blue – 1–2 childrenBlue – 0–1 children |
During 2005–2050, nine countries are expected to account for half of the world’s projected population increase: India, Pakistan, Nigeria, Democratic Republic of the Congo, Bangladesh, Uganda, United States, Ethiopia, and China, listed according to the size of their contribution to population growth. China would be higher still in this list were it not for its One Child Policy.
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 51 countries or areas, including Germany, Italy, Japan and most of the successor States of the former Soviet Union, is expected to be lower in 2050 than in 2005.
1.1 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, United Arab Emirates and United Kingdom.[8] Birth rates are now falling in a small percentage of developing countries, while the actual populations in many developed countries would fall without immigration.[5]
By 2050 (Medium variant), India will have 1.6 billion people, China 1.4 billion, United States 439 million, Pakistan 309 million, Indonesia 280 million, Nigeria 259 million, Bangladesh 258 million, Brazil 245 million, Democratic Republic of the Congo 189 million, Ethiopia 185 million, Philippines 141 million, Mexico 132 million, Egypt 125 million, Vietnam 120 million, Russia 109 million, Japan 103 million, Iran 100 million, Turkey 99 million, Uganda 93 million, Tanzania 85 million, Kenya 85 million, Germany 83 million and United Kingdom 80 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.
- Africa – 2.4 billion
- Asia – 5.2 billion
- Europe – 709 million
- Latin America & Caribbean – 782 million
- North America – 446 million[9]
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.”[18]
- Most populous nations by 2050
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.[19]
| Projected Rank 2050 | Current Rank 2014 | Change | Country | Projected Population (2030) | Population (2010) | Population change (per cent) |
| — | — | — | 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 12 300 million by 2100. Reasons for the continuing high fertility rate include better survival rates with respect to HIV, and lack of availability of contraception.[20][21] Another study on the other hand concludes that education of women will lead to low fertility rates even in Africa.[20]
