Population growth

Population growth is the change in a population over time, and can be quantified as the change in the number of individuals of any species in a population using "per unit time" for measurement. In biology, the term population growth is likely to refer to any known organism, but this article deals mostly with the application of the term to human populations in demography.

In demography, population growth is used informally for the more specific term population growth rate (see below), and is often used to refer specifically to the growth of the human population of the world.

Simple models of population growth include the Malthusian Growth Model and the logistic model.

Population growth 1800-2011: from 1 billion to 7 billion estimated in 31.10.2011. During the year 2011 according to estimates: [1]

Population[1]
Year Billion
1800 1
1927 2
1960 3
1974 4
1987 5
1999 6
2011* 7
UNFPA
United Nations Population Fund
estimate 31.10.2011

Contents

Determinants of population growth

Population growth is determined by four factors, births(B), deaths(D), immigrants(I), and emigrants(E). Using a formula expressed as

∆P≡(B-D)+(I-E)

In other words, the population growth of a period can be calculated in two parts, natural growth of population (B-D) and mechanical growth of population (I-E),in which Mechanical growth of population is mainly affected by social factors, e.g. the advanced economies are growing faster while the backward economies are growing slowly even with negative growth.

Population growth rate

In demographics and ecology, population growth rate (PGR) 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. Specifically, PGR ordinarily 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:[2]

PGR = \frac{ \ln(P(t_2)) - \ln(P(t_1))} {(t_2-t_1)}

The most common way to express population growth is as a percentage, not as a rate. The change in population over a unit time period is expressed as a percentage of the population at the beginning of the time period. That is:

\mathrm{Percentage\ Growth} = \mathrm{Growth\ rate} \times 100%.

For small time periods and growth rates, the added population is the growth rate multiplied by the time period.

A positive growth ratio (or rate) indicates that the population is increasing, while a negative growth ratio indicates the population is decreasing. A growth ratio of zero indicates that there were the same number of people at the two times -- net difference between births, deaths 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] Equivalently, percent death rate = the average number of deaths in a year for every 100 people in the total population.

If the length of the time is taken smaller and smaller, the PGR approaches the logarithmic derivative of the population function P. If the population as a function of time is exponential, say P(t) = Ceat, the logarithmic derivative is a. Thus, the PGR approximates the exponent a for populations with exponential growth.

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

Excessive growth and decline

Main articles: Overpopulation and population decline

Population exceeding the carrying capacity of an area or environment is called overpopulation. It may be caused by growth in population or by reduction in capacity. Spikes in human population can cause problems such as pollution and traffic congestion, these might be resolved or worsened by technological and economic changes. Conversely, such areas may be considered "underpopulated" if the population is not large enough to maintain an economic system (see population decline). Between these two extremes sits the notion of the optimum population.

Human population growth rate

Globally, the growth rate of the human population has been declining since peaking in 1962 and 1963 at 2.20% per annum. In 2009, the estimated annual growth rate was 1.1%.[5] The CIA World Factbook gives the world annual birthrate, mortality rate, and growth rate as 1.915%, 0.812%, and 1.092% respectively[6] The last one hundred years have seen a rapid increase in population due to medical advances and massive increase in agricultural productivity[7] made possible by the Green Revolution.[8][9][10]

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.[11] 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.[12]

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 HIV-related deaths. Some Western Europe countries might also encounter negative population growth.[13] Japan's population began decreasing in 2005.[14]

Growth by country

The growth by country in the world increased from 1990 to 2008 with 1,423 million and 27 % growth. As persons the increase was among highest in India 290 million and China 192 million. Population growth was among highest in Qatar 174 % and United Arab Emirates 140 %.[15]

Rank Country Population (thousands)
2010		 Population (thousands)
1990		 Growth (%)
1990-2010
  World 6,895,889 5,306,425 30.0%
1  China 1,341,335 1,145,195 17.1%
2  India 1,224,614 873,785 40.2%
3  United States 310,384 253,339 22.5%
4  Indonesia 239,871 184,346 30.1%
5  Brazil 194,946 149,650 30.3%
6  Pakistan 173,593 111,845 55.3%
7  Nigeria 158,423 97,552 62.4%
8  Bangladesh 148,692 105,256 41.3%
9  Russia 142,958 148,244 -3.6%
10  Japan 126,536 122,251 3.5%

1960s to 2010 table of population growth

Population growth 1990-2008 (%)[16]
Africa 55 %
Middle East 51 %
Asia 35 %
Latin America 30 %
OECD North America 24 %
OECD Europe 9 %
OECD Pacific 8 %
Former Soviet Union -1 %
Non-OECD Europe -11 %

Many of the world's countries, including many in Sub-Saharan Africa, the Middle East, South Asia and South East Asia, have seen a sharp rise in population since the end of the Cold War. The fear is that high population numbers are putting further strain on natural resources, food supplies, fuel supplies, employment, housing, etc.; in some the less fortunate countries. The population of Chad has, for example, ultimately grown from 6,279,921 in 1993 to 10,329,208 in 2009,[17] further straining its resources. Vietnam, Mexico, Nigeria, Egypt, Ethiopia and the DRC are witnessing a similar growth in population, strained resources and a possible overpopulation problem in the near future.

The situation was most acute in northern, western and central Africa. Refugees from places like the Sudan have helped further strain the resources of neighbouring states like Chad and Egypt. The nation is also host to roughly 255,000 refugees from Sudan’s Darfur region, and about 77,000 refugees from the Central African Republic, whilst approximately 188,000 Chadians have been displaced by their own civil war and famines, have either fled to either the Sudan, the Niger or, more recently, Libya.

Example nation 1st Population total. 2nd Population total. 3rd Population total. 4th Population total. 5th Population total. Life expectancy in years. Total population growth from 1st Pop. Total to 5th Pop. Total.
Eritrea* N/A* N/A* 3,437,000(1994)[18] 4,298,269 (2002) 5,673,520 (2008)[19] 61 (2008)[20] 2,236,520 (since independence)
Ethiopia* 23,457,000(1967)*[21] 50,974,000(1990)* [22] 54,939,000(1994) [18] 67,673,031(2003) 79,221,000(2008)[23] 55(2008)[20] 55,764,000
Sudan** 14,355,000(1967)**[21] 25,204,000(1990)** [22] 27,361,000 (1994)**[18] 38,114,160 (2003)** 42,272,000(2008)**[24] 50(2008)**[20] 27,917,000
Chad 3,410,000(1967)[21] 5,679,000(1990) [22] 6,183,000 (1994)[18] 9,253,493(2003) 10,329,208 (2009)[17] 47(2008)[20] 6,919,205
Niger 3,546,000(1967)[21] 7,732,000(1990) [22] 8,846,000(1994)[18] 10,790,352 (2001) 15,306,252 (2009)[25] 44 (2008)[20] 11,760,252
Nigeria 61,450,000(1967)[21] 88,500,000(1990) [22] 108,467,000 (1994)[18] 129,934,911 (2002) 158,259,000 (2008)[26] 47(2008)[20] 96,809,000
Mali 4,745,000(1967)[21] 8,156,000(1990),[22] 10,462,000(1994)[18] 11,340,480(2002) 14,517,176(2010).[27] 50(2008)[20] 9,772,176
Mauritania 1,050,000(1967)[21] 2,025,000(1990) [22] 2,211,000 (1994)[18] 2,667,859 (2003) 3,291,000 (2009)[17] 54(2008)[20] 2,241,000
Senegal 3,607,000(1967)[21] 7,327,000(1990) [22] 8,102,000 (1994) [18] 9,967,215(2002) 13,711,597 (2009)[28] 57(2008)[20] 10,104,597
Gambia 343,000(1967)[21] 861,000(1990) [22] 1,081,000 (1994)[18] 1,367,124 (2000) 1,705,000(2008)[26] 55(2008)[20] 1,362,000
Algeria 11,833,126 (1966)[21] 25,012,000 (1990) [22] 27,325,000 (1994) [18] 32,818,500 (2003) 34,895,000[23][29](2008) 74 (2008)[20] 23,061,874
The DRC/Zaire 16,353,000(1967)[21] 35,562,000 (1990) [22] 42,552,000 (1994) [18] 55,225,478 (2003) 70,916,439 (2008) [23][30] 54(2008)[20] 54,563,439
Egypt 30,083,419 (1966)[21] 53,153,000 (1990) [22] 58,326,000 (1994) [18] 70,712,345 (2003) 79,089,650 [31][31] (2008) [23] 72 (2008)[20] 49,006,231
Réunion (French colony) 418,000 (1967)[21] N/A(1990) [22] N/A (1994)[18] 720,934 (2003) 827,000 (2009) [29] N/A (2008)[20] 409,000
The Falkland Islands (UK colony) 2,500(1967)[21] N/A(1990) [22] N/A(1994)[18] 2,967 (2003) 3,140(2010)[17] N/A(2008)[20] 640
Chile 8,935,500(1967)[21] 13,173,000 (1990) [22] 13,994,000(1994)[18] 15,116,435 (2002) 17,224,200 (2011) 77 (2008)[20] 8,288,700
Colombia 19,191,000(1967)[21] 32,987,000(1990) [22] 34,520,000(1994)[18] 41,088,227 (2002) 45,925,397(2010)[32] 73 (2008)[20] 26,734,397
Brazil 85,655,000(1967)[21] 150,368,000 (1990) [22] 153,725,000 (1994)[18] 174,468,575 (2000) 190,732,694(2010) [33] 72(2008)[20] 105,077,694
Mexico 45,671,000(1967)[21] 86,154,000(1990) [22] 93,008,000(1994)[18] 103,400,165 (2000) 112,322,757(2010)[34] 76(2008)[20] 66,651,757
Fiji 476,727 (1966)[21] 765,000(1990) [22] 771,000 (1994)[18] 844,330 (2001) 849,000[29] (2010) 70 (2008)[20] 372,273
Nauru 6,050(1966)[21] 10,000(1990) [22] N/A (1994)[18] 12,329 (2002) 9,322 (2011)[35] N/A (2008)[20] 3,272
Jamaican 1,876,000 (1967)[21] 2,420,000 (1990) [22] 2,429,000 (1994)[18] 2,695,867 (2003) 2,847,232[36](2010) 74 (2008)[20] 971,232
Australia 11,540,764 (1964)[21] 17,086,000 (1990) [22] 17,843,000 (1994)[18] 19,546,792 (2003) 22,858,456[37] (2010) 82 (2008)[20] 11,066,508
Albania 1,965,500(1964)[21] 3,250,000 (1990) [22] 3,414,000 (1994)[18] 3,510,484 (2002) 2,986,952 (July 2010 est.)[17][38] (2010) 78 (2008)[20] 1,021,452
Poland 31,944,000(1967)[21] 38,180,000 (1990) [22] 38,554,000 (1994)[18] 38,626,349 (2001) 38,192,000(2010)[39] 75 (2008)[20] 6,248,000
Hungary 10,212,000(1967)[21] 10,553,000 (1990) [22] 10,261,000 (1994)[18] 10,106,017 (2002) 9,979,000(2010)[40] 73 (2008)[20] -142,000
Bulgaria 8,226,564(1965)[21] 8,980,000 (1990) [22] 8,443,000 (1994)[18] 7,707,495(2000) 7,351,234 (2011)[41] 73 (2008)[20] -875,330
UK 55,068,000 (1966)[21] 57,411,000 (1990) [22] 58,091,000 (1994) [18] 58,789,194 (2002) 62,008,048 (2010)[42] 79(2008)[20] 7,020,048
Ireland/Éire 2,884,002(1966)[21] 3,503,000(1990) [22] 3,571,000 (1994)[18] 3,840,838 (2000) 4,470,700 [43] (2010) 78 (2008)[20] 1,586,698
The PRC/China 720,000,000(1967)[21] 1,139,060,000(1990) [22] 1,208,841,000 (1994)[18] 1,286,975,468 (2004) 1,339,724,852(2010)[44] 73 (2008)[20] 619,724,852
Japan*** 98,274,961(1965)[21] 123,537,000(1990) [22] 124,961,000 (1994)[18] 127,333,002 (2002) 127,420,000 (2010)[45] 82(2008)[20] 28,123,865
Ryukyu Islands (Once occupied by America)*** 934,176(1965)[21] — — — — — —
India# 511,115,000 (1967)[21] 843,931,000 (1990) [22] 918,570,000 (1994)[18] 1,028,610,328 (2001) 1,210,193,422(2011)[46] 69 (2008)[20] 699,078,422
Population (1000 million) and growth 1990-2008 (%)
1990 2008  %
Eritrea* (1992) 3184 5674 78 %
Ethiopia* 50974 79221 55 %
Sudan** 25204 42272 68 %
Chad (2009) 5679 10329 82 %
Niger (2009) 7732 15306 98 %
Nigeria 88500 158259 79 %
Mali (2010) 8156 14517 78 %
Mauritania (2009) 2025 3291 63 %
Senegal (2009) 7327 13712 87 %
Gambia 861000 1705000 98 %
Algeria 25012 34895 40 %
Zaire 35562 70916 99 %
Egypt 53153 79090 49 %
Chile (2011) 13173 17224 31 %
Colombia (2010) 32987 45925 39 %
Brazil (2010) 150368 190733 27 %
Mexico (2010) 86154 112323 30 %
Fiji (2010) 765 849 11 %
Nauru (2011) 10000 9322 -7 %
Jamaican (2010) 2420 2847 18 %
Australia (2010) 17086 22687 33 %
Albania (2010) 3250 2987 -8 %
Poland(2010) 38180 38192 0 %
Hungary (2010) 10553 9979 -5 %
Bulgaria (2011) 8980 7351 -18 %
UK (2010) 57411 62008 8 %
Ireland/Éire (2010) 3503 4471 28 %
China(2010) 1139060 1339725 18 %
Japan (2010) 123537 127420 3 %
India (2011) 843931 1210193 43 %
Year after country if different, refs as in the previous table
Population growth 1990-2008 (%)[16]
Qatar 174 %
UAE 140 %
Jordan 86 %
Benin 81 %
Congo 69 %
Angola 69 %
Tanzania 67 %
Syria 67 %
Togo 65 %
Kenya 64 %
Côte d'Ivoire 63 %
Senegal 62 %
Mozambique 61 %
Nigeria 60 %
Zambia 60 %
Singapore 59 %
Eritrea 57 %
Ethiopia 57 %
Gabon 56 %
Israel 56 %
Ghana 56 %
Iraq 56 %
Bahrain 56 %
Brunei 54 %
Cameroon 54 %
Pakistan 54 %
Guatemala 54 %
Sudan 53 %
Oman 51 %
Notes
* Eritrea left Ethiopia in 1991.
** Split in to the nations of Sudan and Southern Sudan during 2011.
*** Merged in 1972.
# Merged in 1975.

Into the future

Main article: Projections of population growth

According to projections, the world population will continue to grow until at least 2050, with the population reaching 9.1 billion in 2050.[47]

See also

References

  1. ^ a b 7. miljardis ihminen, Helsingin Sanomat editor Mr Timo Paukku 5.9.2011 D1 (Finnish)
  2. ^ Enns, Richard. It's a Nonlinear World. Springer, 2010, p. 4.
  3. ^ Association of Public Health Epidemiologists in Ontario
  4. ^ Population growth rate
  5. ^ U.S. Census Bureau, January 2010
  6. ^ World Factbook
  7. ^ BBC NEWS | The end of India's green revolution?
  8. ^ Food First/Institute for Food and Development Policy
  9. ^ Rising food prices curb aid to global poor
  10. ^ Record rise in wheat price prompts UN official to warn that surge in food prices may trigger social unrest in developing countries
  11. ^ U.S. Census Bureau, January 2010
  12. ^ U.S. Census Bureau, June 2009
  13. ^ UN population projections
  14. ^ Japan sees biggest population fall
  15. ^ CO2 Emissions from Fuel Combustion Population 1971-2008 IEA (pdf pages 83-85)
  16. ^ a b CO2 Emissions from Fuel Combustion Population 1971-2008 IEA
  17. ^ a b c d e "Falkland Islands (Islas Malvinas)". CIA. https://www.cia.gov/library/publications/the-world-factbook/geos/fk.html. Retrieved 5 March 2010. 
  18. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af The British Collins Longman Student Atlas, the 1996 and in 1998 publications, ISBN 978-0004488790 for the 1998 edition, ISBN 0-00-448365-0 for the 1996 edition
  19. ^ url=http://www.un.org/esa/population/publications/wpp2008/wpp2008_text_tables.pdf
  20. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af 'Modern School Atlas (96th edition)', ISBN 978-1-84907-013-3.
  21. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af The British Oxford economic atlas of the World 4th edition, ISBN 019 8941072
  22. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae The British Collins Atlas of the World, the 1993 edition, ISBN 0-0044-8038-4
  23. ^ a b c d Ethiopia Central Statistics Office -- Population Projection for mid-2008
  24. ^ Department of Economic and Social Affairs (PDF). World Population Prospects, Table A.1. 2008 revision. United Nations. http://www.un.org/esa/population/publications/wpp2008/wpp2008_text_tables.pdf. 
  25. ^ Central Intelligence Agency (2009). "Niger". The World Factbook. https://www.cia.gov/library/publications/the-world-factbook/geos/ng.html. Retrieved January 10, 2010. 
  26. ^ a b Department of Economic and Social Affairs Population Division (2009) (PDF). World Population Prospects, Table A.1. 2008 revision. United Nations. http://www.un.org/esa/population/publications/wpp2008/wpp2008_text_tables.pdf. Retrieved 2009-03-12. 
  27. ^ "Mali preliminary 2009 census". Institut National de la Statistique. http://instat.gov.ml/voir_actu.aspx?lactu=44. Retrieved January 12, 2010. 
  28. ^ Central Intelligence Agency (2009). "Senegal". The World Factbook. https://www.cia.gov/library/publications/the-world-factbook/geos/sg.html. Retrieved January 10, 2010. 
  29. ^ a b c Department of Economic and Social Affairs Population Division (2010) (PDF). World Population Prospects, Table A.1. 2008 revision. United Nations. http://www.un.org/esa/population/publications/wpp2010/wpp2010_text_tables.pdf. Retrieved 2009-03-12. 
  30. ^ The World Factbook- Congo, Democratic Republic of the. Central Intelligence Agency.
  31. ^ a b "Central Agency for Population Mobilisation and Statistics — Population Clock (July 2008)". Msrintranet.capmas.gov.eg. http://www.msrintranet.capmas.gov.eg/pls/fdl/tst12e?action=&lname=. Retrieved 2010-08-25. 
  32. ^ "Departamento Administrativo Nacional de Estadística". Dane.gov.co. http://www.dane.gov.co/reloj/reloj_animado.php. Retrieved 2010-08-22. 
  33. ^ IBGE. Censo 2010: população do Brasil é de 190.732.694 pessoas.
  34. ^ "INEGI 2010 Census Statistics". inegi.org.mx. http://www.inegi.org.mx/inegi/contenidos/espanol/prensa/comunicados/rpcpyv10.asp. Retrieved 2010-11-25. 
  35. ^ Central Intelligence Agency (2011). "Nauru". The World Factbook. https://www.cia.gov/library/publications/the-world-factbook/geos/nr.html. Retrieved 12 February 2011. 
  36. ^ https://www.cia.gov/library/publications/the-world-factbook/geos/jm.html
  37. ^ "Population clock". Australian Bureau of Statistics website. Commonwealth of Australia. http://www.abs.gov.au/ausstats/abs@.nsf/94713ad445ff1425ca25682000192af2/1647509ef7e25faaca2568a900154b63?OpenDocument. Retrieved 12 April 2011.  The population estimate shown is automatically calculated daily at 00:00 UTC and is based on data obtained from the population clock on the date shown in the citation.
  38. ^ Population Forecast to 2060 by International Futures hosted by Google Public Data Explorer
  39. ^ "Wzrasta liczba ludności Polski - Wiadomości - WP.PL". Wiadomosci.wp.pl. 2010-07-23. http://wiadomosci.wp.pl/kat,1347,title,Wzrasta-liczba-ludnosci-Polski,wid,12502858,wiadomosc.html. Retrieved 2010-07-27. 
  40. ^ Hungarian Central Statistical Office. Retrieved 25 July 2010.
  41. ^ http://www.nsi.bg/EPDOCS/Census2011pr.pdf
  42. ^ "Total population at 1 January". Eurostat. 11 March 2011. http://epp.eurostat.ec.europa.eu/tgm/table.do?tab=table&language=en&pcode=tps00001&tableSelection=1&footnotes=yes&labeling=labels&plugin=1. Retrieved 29 April 2011. 
  43. ^ "CSO – Population and Migration Estimates April 2010" (PDF). September 2010. http://www.cso.ie/releasespublications/documents/population/current/popmig.pdf. Retrieved 21 September 2010. 
  44. ^ Communiqué of the National Bureau of Statistics of People's Republic of China on Major Figures of the 2010 Population Census
  45. ^ Official Japan Statistics Bureau estimate
  46. ^ "Provisional Population Totals - Census 2011". Indian Census Bureau 2011. http://www.censusindia.gov.in/2011-prov-results/indiaatglance.html. Retrieved 2011-03-29. 
  47. ^ "U.N.: Population to top 9 billion by 2050. CNN. February 25, 2005

External links

Major articles
Biological topics
Population ecology
Literary works
Lists
Events and
organizations
Related articles