# Population growth

(Redirected from Malthusian Growth Model)

In biology, population growth is the increase in the number of individuals in a population. The population growth rate is the rate at which the number of individuals in a population increases in a given time period as a fraction of the initial population.

Global human population growth amounts to around 75 million annually, or 1.1% per year. The global population has grown from 1 billion in 1800 to 7 billion in 2012. It is expected to keep growing, where estimates have put the total population at 8.4 billion by mid-2030, and 9.6 billion by mid-2050.[1]

Population[2]
Years Passed Year Billion
- 1800 1
127 1927 2
33 1960 3
14 1974 4
13 1987 5
12 1999 6
12 2011 7
14 2025* 8
18 2043* 9
40 2083* 10
* UNFPA
United Nations Population Fund
estimate 31.10.2011

## Population growth rate

The "population growth rate" is the rate at which the number of individuals in a population increases in a given time period, expressed as a fraction of the initial population. Specifically, population growth rate refers to the change in population over a unit time period, often expressed as a percentage of the number of individuals in the population at the beginning of that period. This can be written as the formula, valid for a sufficiently small time interval:

$Population\ growth\ rate = \frac{ P(t_2) - P(t_1)} {P(t_1)(t_2-t_1)}$

A positive growth rate indicates that the population is increasing, while a negative growth rate indicates that the population is decreasing. A growth ratio of zero indicates that there were the same number of individuals at the beginning and end of the period—a growth rate may be zero even when there are significant changes in the birth rates, death rates, immigration rates, and age distribution between the two times.[3]

A related measure is the net reproduction rate. In the absence of migration, a net reproduction rate of more than 1 indicates that the population of females is increasing, while a net reproduction rate less than one (sub-replacement fertility) indicates that the population of females is decreasing.

## Human population growth rate

Main article: Total fertility rate
A world map showing global variations in fertility rate per woman, according to the CIA World Factbook's 2015 data.
Estimates of population evolution in different continents between 1950 and 2050, according to the United Nations. The vertical axis is logarithmic and is in millions of people.
Growth rate of world population (1950–2050).

Globally, the growth rate of the human population has been declining since peaking in 1962 and 1963 at 2.2% per annum. In 2009, the estimated annual growth rate was 1.1%.[4] The CIA World Factbook gives the world annual birthrate, mortality rate, and growth rate as 1.89%, 0.79%, and 1.096% respectively.[5] The last 100 years have seen a rapid increase in population due to medical advances and massive increase in agricultural productivity[6] made possible by the Green Revolution.[7][8][9]

The actual annual growth in the number of humans fell from its peak of 88.0 million in 1989, to a low of 73.9 million in 2003, after which it rose again to 75.2 million in 2006. Since then, annual growth has declined. In 2009, the human population increased by 74.6 million, which is projected to fall steadily to about 41 million per annum in 2050, at which time the population will have increased to about 9.2 billion.[4] Each region of the globe has seen great reductions in growth rate in recent decades, though growth rates remain above 2% in some countries of the Middle East and Sub-Saharan Africa, and also in South Asia, Southeast Asia, and Latin America.[10]

Some countries experience negative population growth, especially in Eastern Europe mainly due to low fertility rates, high death rates and emigration. In Southern Africa, growth is slowing due to the high number of AIDS-related deaths. Some Western Europe countries might also encounter negative population growth.[11] Japan's population began decreasing in 2005.[12] The United Nations Population Division expects world population to peak at over 10 billion at the end of the 21st century but Sanjeev Sanyal has argued that global fertility will fall below replacement rates in the 2020s and that world population will peak below 9 billion by 2050 followed by a long decline.[13]

## Growth by country

According to United Nations population statistics, the world population grew by 30%, or 1.6 billion people, between 1990 and 2010.[14] In number of people the increase was highest in India (350 million) and China (196 million). Population growth was among highest in the United Arab Emirates (315%) and Qatar (271%).[14]

Growth rates of the world's most populous countries
Rank Country Population
2010
Population
1990
Growth (%)
1990–2010
World 6,895,889,000 5,306,425,000 30.0%
1  China 1,341,335,000 1,145,195,000 17.1%
2  India 1,224,614,000 873,785,000 40.2%
3  United States 310,384,000 253,339,000 22.5%
4  Indonesia 239,871,000 184,346,000 30.1%
5  Brazil 194,946,000 149,650,000 30.3%
6  Pakistan 173,593,000 111,845,000 55.3%
7  Nigeria 158,423,000 97,552,000 62.4%
9  Japan 128,057,000 122,251,000 4.7%

### 1960s to 2010 table of population growth

Population growth 1990–2012 (%)[15]
Africa 73.3%
Middle East 68.2%
Asia (excl. China) 42.8%
China 19.0%
OECD Americas 27.9%
Non-OECD Americas 36.6%
OECD Europe 11.5%
OECD Asia Oceania 11.1%
Non-OECD Europe and Eurasia -0.8%
Example nation 1967 population 1990 population 1994 population 2002 population 2008 population Life expectancy in years (2008) Total population growth from 1960s to 2000s
Eritrea* N/A* N/A* 3,437,000[16] 4,298,269 5,673,520[17] 61[18] 2,236,520
Ethiopia* 23,457,000*[19] 50,974,000* [20] 54,939,000[16] 67,673,031(2003) 79,221,000[21] 55[18] 55,764,000
Sudan** 14,355,000**[19] 25,204,000** [20] 27,361,000**[16] 38,114,160 (2003)** 42,272,000**[22] 50**[18] 27,917,000
Chad 3,410,000[19] 5,679,000[20] 6,183,000[16] 9,253,493(2003) 10,329,208 (2009)[23] 47[18] 6,919,205
Niger 3,546,000[19] 7,732,000[20] 8,846,000[16] 10,790,352 (2001) 15,306,252 (2009)[24] 44[18] 11,760,252
Nigeria 61,450,000[19] 88,500,000[20] 108,467,000[16] 129,934,911 158,259,000[25] 47[18] 96,809,000
Mali 4,745,000[19] 8,156,000,[20] 10,462,000[16] 11,340,480 14,517,176(2010).[26] 50[18] 9,772,176
Mauritania 1,050,000)[19] 2,025,000 [20] 2,211,000[16] 2,667,859 (2003) 3,291,000 (2009)[23] 54[18] 2,241,000
Senegal 3,607,000[19] 7,327,000[20] 8,102,000[16] 9,967,215 13,711,597 (2009)[27] 57[18] 10,104,597
Gambia 343,000[19] 861,000[20] 1,081,000[16] 1,367,124 (2000) 1,705,000[25] 55[18] 1,362,000
Algeria 11,833,126 (1966)[19] 25,012,000[20] 27,325,000 [16] 32,818,500 (2003) 34,895,000[21][28] 74[18] 23,061,874
The DRC/Zaire 16,353,000[19] 35,562,000[20] 42,552,000[16] 55,225,478 (2003) 70,916,439 [21][29] 54[18] 54,563,439
Egypt 30,083,419 (1966)[19] 53,153,000[20] 58,326,000[16] 70,712,345 (2003) 79,089,650 [30][30][21] 72[18] 49,006,231
Réunion (French overseas department) 418,000[19] N/A[20] N/A[16] 720,934 (2003) 827,000 (2009) [28] N/A[18] 409,000
The Falkland Islands (UK Territory) 2,500[19] N/A[20] N/A[16] 2,967 (2003) 3,140(2010)[23] N/A[18] 640
Chile 8,935,500[19] 13,173,000[20] 13,994,000[16] 15,116,435 17,224,200 (2011) 77[18] 8,288,700
Colombia 19,191,000[19] 32,987,000[20] 34,520,000[16] 41,088,227 45,925,397(2010)[31] 73[18] 26,734,397
Brazil 85,655,000[19] 150,368,000[20] 153,725,000[16] 174,468,575 (2000) 190,732,694(2010) [32] 72[18] 105,077,694
Mexico 45,671,000[19] 86,154,000[20] 93,008,000[16] 103,400,165 (2000) 112,322,757(2010)[33] 76[18] 66,651,757
Fiji 476,727 (1966)[19] 765,000[20] 771,000[16] 844,330 (2001) 849,000[28] (2010) 70[18] 372,273
Nauru 6,050(1966)[19] 10,000[20] N/A[16] 12,329 9,322 (2011)[34] N/A[18] 3,272
Jamaica 1,876,000[19] 2,420,000[20] 2,429,000[16] 2,695,867 (2003) 2,847,232[35](2010) 74[18] 971,232
Australia 11,540,764 (1964)[19] 17,086,000[20] 17,843,000[16] 19,546,792 (2003) 24,084,980[36] (2010) 82[18] 10,066,508
Albania 1,965,500(1964)[19] 3,250,000[20] 3,414,000[16] 3,510,484 2,986,952 (July 2010 est.)[23][37] (2010) 78[18] 1,021,452
Poland 31,944,000[19] 38,180,000[20] 38,554,000[16] 38,626,349 (2001) 38,192,000(2010)[38] 75[18] 6,248,000
Hungary 10,212,000[19] 10,553,000[20] 10,261,000[16] 10,106,017 9,979,000(2010)[39] 73[18] -142,000
Bulgaria 8,226,564(1965)[19] 8,980,000[20] 8,443,000[16] 7,707,495(2000) 7,351,234 (2011)[40] 73[18] -875,330
UK 55,068,000 (1966)[19] 57,411,000[20] 58,091,00[16] 58,789,194 62,008,048 (2010)[41] 79[18] 7,020,048
Ireland 2,884,002(1966)[19] 3,503,000[20] 3,571,000[16] 3,840,838 (2000) 4,470,700 [42] (2010) 78[18] 1,586,698
The PRC/China 720,000,000[19] 1,139,060,000[20] 1,208,841,000[16] 1,286,975,468 (2004) 1,339,724,852(2010)[43] 73[18] 619,724,852
Japan*** 98,274,961(1965)[19] 123,537,000[20] 124,961,000[16] 127,333,002 127,420,000 (2010)[44] 82[18] 28,123,865
Ryukyu Islands (Once occupied by the US)*** 934,176(1965)[19]
India# 511,115,000[19] 843,931,000[20] 918,570,000[16] 1,028,610,328 (2001) 1,210,193,422(2011)[45] 69[18] 699,078,422
Notes
* Eritrea left Ethiopia in 1991.
** Split into the nations of Sudan and Southern Sudan during 2011.
*** Merged in 1972.
# Merged in 1975.

## Into the future

The majority of world population growth today is occurring in less developed countries.

According to UN's 2010 revision to its population projections, world population will peak at 10.1bn in 2100 compared to 7bn in 2011.[46] 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.[47] However, some experts dispute the UN's forecast and have argued that birthrates will fall below replacement rate in the 2020s. According to these forecasters, population growth will be only sustained till the 2040s by rising longevity but will peak below 9bn by 2050.[48]

## References

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2. ^ 7. miljardis ihminen, Helsingin Sanomat editor Mr Timo Paukku 5.9.2011 D1 (Finnish)
3. ^ Association of Public Health Epidemiologists in Ontario
4. ^ a b U.S. Census Bureau, January 2010
5. ^ World Factbook
6. ^ BBC NEWS | The end of India's green revolution?
7. ^ Food First/Institute for Food and Development Policy
8. ^ Rising food prices curb aid to global poor
9. ^ Record rise in wheat price prompts UN official to warn that surge in food prices may trigger social unrest in developing countries
10. ^ U.S. Census Bureau, June 2009
11. ^ UN population projections
12. ^ Japan sees biggest population fall
13. ^ [1]
14. ^ a b World Population Prospects, the 2010 Revision
15. ^ CO2 Emissions from Fuel Combustion Population 1971–2014 IEA (PDF Page 74, marked page 72)
16. The British Collins Longman Student Atlas, the 1996 and in 1998 publications, ISBN 978-0-00-448879-0 for the 1998 edition, ISBN 0-00-448365-0 for the 1996 edition
17. ^
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19. The British Oxford economic atlas of the World 4th edition, ISBN 0-19-894107-2
20. The British Collins Atlas of the World, the 1993 edition, ISBN 0-00-448038-4
21. ^ a b c d Ethiopia Central Statistics Office -- Population Projection for mid-2008
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23. ^ a b c d "Falkland Islands (Islas Malvinas)". The World Factbook. CIA. Retrieved 5 March 2010.
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26. ^ "Mali preliminary 2009 census". Institut National de la Statistique. Retrieved January 12, 2010.
27. ^ Central Intelligence Agency (2009). "Senegal". The World Factbook. Retrieved January 10, 2010.
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48. ^ http://www.project-syndicate.org/commentary/the-end-of-population-growth