Population decline can refer to the decline in population of any organism, but this article refers to population decline in humans. It is a term usually used to describe any great reduction in a human population. It can be used to refer to long-term demographic trends, as in urban decay or rural flight, but it is also commonly employed to describe large reductions in population due to violence, disease, or other catastrophes.
Sometimes known as depopulation, population decline is the reduction over time in a region's population. The decline can be caused by several factors including sub-replacement fertility (along with limited immigration), heavy emigration, disease, famine, and war. History is replete with examples of large scale depopulations. Many wars, for example, have been accompanied by significant depopulations. Before the 20th century, population decline was mostly observed due to disease, starvation and/or emigration. The Black Death in Europe, the arrival of Old World diseases to the Americas, the tsetse fly invasion of the Waterberg Massif in South Africa, and the Great Irish Famine all caused sizable population declines. In modern times, the AIDS epidemic caused declines in the population of some African countries. Less frequently, population declines are caused by genocide or mass execution; for example, in the 1970s, the population of Cambodia declined because of wide-scale executions by the Khmer Rouge.
Sometimes the term underpopulation is applied to a specific economic system. It does not refer to carrying capacity, and is not a term in opposition to overpopulation, which deals with the total possible population that can be sustained by available food, water, sanitation and other infrastructure. "Underpopulation" is usually defined as a state in which a country's population has declined too much to support its current economic system. Thus the term has nothing to do with the biological aspects of carrying capacity, but is an economic term employed to imply that the transfer payment schemes of some developed countries might fail once the population declines to a certain point. An example would be if retirees were supported through a social security system which does not invest savings, and then a large emigration movement occurred. In this case, the younger generation may not be able to support the older generation.
Changing trends 
Today, emigration, sub-replacement fertility and high death rates in the former Soviet Union and its former allies are the principal reasons for that region's population decline. However, governments can influence the speed of the decline, including measures to halt, slow or suspend decline. Such measures include pro-birth policies and subsidies, media influence, immigration, bolstering healthcare and laws aimed at reducing death rates. Such is the case in Russia, Armenia, and many Western European nations who have used immigration and other policies to suspend or slow population decline. Therefore although the long term trend may be for greater population decline, short term trends may slow the decline or even reverse it, creating seemingly conflicting statistical data. A great example of changing trends occurring over a century is Ireland.
Statistical misreadings 
Statistical data, especially comparing only two sets of figures, can show an incorrect population trend. A nation's population could be increasing, but a one-off event could have resulted in decline and vice-versa. Nations can acquire territory or lose territory and people, consider people citizens they previously denied citizenship to, e.g. stateless persons, indigenous people, and undocumented immigrants or long stay foreign residents. Political instability can render an area within a nation's count unreliable for comparison.
A common misreading is due to time. Populations on the verge of decline could rise in summer and decline in winter as deaths increase in winter in cold regions, similarly, census dates over too long a time range could show a rise when a country has already tipped into decline. Therefore, numerous sets of statistics should be interpreted to get an idea of a trend.
Decline by nation or territory 
A number of nations today, stretching from North Asia (Japan) through Eastern Europe, Kazakhstan, Ukraine, Belarus, Moldova, Estonia, Latvia, Lithuania, Bulgaria, Georgia, Armenia, and into Central and Western Europe, including Bosnia, Croatia, Slovenia, Germany, Hungary, and now Italy now face long term population decline. Countries rapidly approaching long term population declines (but currently still growing, albeit slowly) include Greece, Spain, Cuba, Uruguay, Denmark, Finland, Portugal, Austria and Lesotho.
Many nations in Western Europe (and the EU as a whole) today would have declining populations if it were not for international immigration. The total population of the continent of Europe (including Russia and other non-EU countries) already peaked around the year 2000 and as of 2004 is falling.
AIDS had played a mild some role in temporary population decline; however, at the time, data available suggests that, even with high AIDS mortality, fertility rates in Africa are sufficiently high, so that overpopulation trends continue. AIDS has contributed to a population explosion in Africa as money from fertility reduction programs was redirected into the HIV/AIDS crisis; African fertility rates have actually increased in the past two decades while population grew by over 50%.
|Country||Year||Population||Rate of natural decrease
|Main reason for decrease|
|Belarus||2012||9,542,883||0.362||low birth rate|
|Bulgaria||2012||7,037,935||0.796||low birth rate, high death rate, high rate of abortions, a relatively high level of emigration of young people and a low level of immigration|
|Croatia||2012||4,480,043||0.092||low birth rate|
|Czech Republic||2012||10,577,300||0.134||low birth rate|
|Cuba||2012||11,075,244||0.115||emigration, low birth rate|
|Estonia||2012||1,274,709||0.65||low birth rate|
|Germany||2012||81,305,856||0.2||low birth rate|
|Hungary||2012||9,958,453||0.184||low birth rate|
|Italy||2012||60, 813, 326||0.09||low birth rate|
|Japan||2012||127,368,088||0.077||low birth rate and a low level of immigration|
|Latvia||2012||2,191,580||0.598||low birth rate|
|Lithuania||2012||3,525,761||0.278||low birth rate|
|Netherlands||2011 December||16,725,902||0.008||Low birth rate|
|Northern Mariana Islands||2012||44,582||2.449||?|
|Federated States of Micronesia||2012||106,487||0.343||emigration|
|Moldova||2012||3,656,843||1.014||low birth rate|
|Poland||2012||38,415,284||0.075||low birth rate|
|Portugal||2011||10,561,614||0.07||political crisis, economic crisis|
|Romania||2012||21,848,504||0.26||low birth rate, emigration|
|Russia||2012||143,200,000||0.48||high death rate, low birth rate, high rate of abortions, and a low level of immigration|
|Serbia||2012||7,276,604||0.464||Low birth rate|
|South Africa||2012||48,810,427||0.412||white flight, high incidence of disease (HIV/AIDS)|
Long term population decline 
A long-term population decline is typically caused by sub-replacement fertility, coupled with a net immigration rate that fails to compensate the excess of deaths over births. A long-term decline is accompanied by population aging and creates an increase in the ratio of retirees to workers and children. When a sub-replacement fertility rate remains constant, population decline accelerates over the long term, short term often create flip-flops of trends. No nation in the world has a net population loss since 1950, though Bulgaria has increased the least at less than 1%, and half of all nations have more than quadrupled their populations.
Eastern Europe and Former Soviet Republics 
Population is falling due to health factors and low replacement, as well as emigration of ethnic Russians to Russia. Exceptions to this rule is in those ex-Soviet states which have a Muslim majority (Uzbekistan, Turkmenistan, Tajikistan, Kyrgyzstan, Azerbaijan) as high birth rates are traditional. Much of Eastern Europe has lost population due to migration to Western Europe. In Eastern Europe and Russia, natality fell abruptly after the end of the Soviet Union, and death rates generally rose. Together these nations occupy over 8,000,000 square miles (21,000,000 km2) and are home to over 400 million people (less than six percent of the world population), but if current trends continue, more of the developed world and some of the developing world could join this trend.
Albania's population in 1989 recorded 3,182,417 people, the largest for any census. Since then, its population declined to 2,831,741 in the October 2011 census figures. This represents a decrease of 12.4% in total population since the peak census figure.
Belarus' population peaked at 10,151,806 in 1989 Census, and declined to 9,457,500 in July 1, 2012. This represents a 7.3% decline since the peak census figure.
Bulgaria's population declined from a peak of 9,009,018 in 1989 and since 2001, has lost yet another 600,000 people, according to 2011 census preliminary figures to no more than 7.3 million. This represents a 23.4% decrease in total population since the peak, and a -0.82% annual rate in the last 10 years. Bulgaria is the country with the smallest population growth since 1950, at 0.5%.
When Latvia split from the Soviet Union, it had a population of 2,666,567, which was close to its peak population. The latest census recorded a population of 2,067,887 in 2011. This represents a 22.5% decline since the peak census figure. The decline is caused by both a negative population growth rate and a negative net migration rate.
When Lithuania split from the Soviet Union, it had a population of 3.7 million, which was close to its peak population. The latest census recorded a population of 3.05 million in 2011, down from 3.4 million in 2001., further falling to 2,988,000 in September 1, 2012. This represents a 23.8% decline since the peak census figure, and some 13.7% since 2001.
Ukraine census in 1989 resulted in 51,452,034 people, the closest known data to the peak, however than number has plummeted to 45,539,000 as of Feb 1, 2013. This represents a 12.9% decrease in total population since the peak census figure, but 23.9% above the 1950 population.
Croatia's peak census population was 4,784,265 in 1991 and has since shrunk to 4,290,612 as of 2011. This represents a 11.5% decrease since the peak census figure.
Greece's latest census reported its population fell to 10,787,690 in 2011 from 10,934,097 in 2001 census.
Though Japan's population has been predicted to decline for years, and its monthly and even annual estimates have shown a decline in the past, the 2010 census result figure was slightly higher, at just above 128 million than the 2005 census and its population has yet to register a decline between census periods. Factors implicated in the higher figures were more Japanese returnees than expected as well as changes to the methodology of data collection. Population estimate as of December 2012 is 127,520,000, or a return to 2004 levels. This is still 53% above 1950 levels.
Hungary's population peaked in 1980 at 10,709,000, far earlier than its Soviet cousins, and has continued its decline to under 10 million as of August 2010. This represents a decline of 7.1% since its peak, however, compared to neighbors situated to the East, the rate has been far more modest, averaging -0.23% a year over the period.
Romania's 1992 census showed 22,810,035 people, by the October 2011 census it had recorded only 19,042,936 people, a decline of over 2.6 million from the 21.68 million in 2002. It represents a decline of nearly 19.8% from the peak census figure, and a total population loss only exceeded by Russia and Ukraine. It is only 16.7% above 1950 population.
Serbia recorded a peak census population of 7,576,837 in 1991, falling to 7,120,666 in the latest October 2011 census. That represents a decline of 6.4% since its peak census figure.
Halted Declines 
Russia's total population is among the largest drops in numbers (but not in percentage). Its peak was 148,689,000 in 1991, while it dropped to 141,909,000 in 2009. This represents a 4.6% decrease in total population since the peak census figure. Still, the Russian government estimates an increase in the population to 143,030,106 in 2011, an increase of 0.8% in just two years. This recent trend can be attributed to a lower death rate, higher birth rate, and continued immigration. It is some 40% above the 1950 population.
Germany has encountered population decline and increase off and on for decades. German population was expected to decline in 2012, but increased due to immigration. The nation's population at 2012 end was 82.0 million, up by 200,000. This represents almost 20% increase over 1950, the lowest among OECD nations.
In the current area of the Republic of Ireland, the population has fluctuated dramatically. The population of Ireland was 6.53 million in 1851, but it dropped due to the Irish famine. The population of the Irish Republic was less than 3 million in the 1930s, but it then rose and in 2011 it was 4.58 million.
Declines within race or ethnicity 
Some large and even majority groups within a population have shown an overall decline in numbers while the total population increases. Such is the case in California, where the Non-Hispanic Whites population declined from 15.8 million to 14.95 million, meanwhile the total population increased from 33 million to over 37 million from 2000 to 2010 censuses. In Western Europe, the population of people of local origins have been in absolute decline for a number of years while total populations have shown increases.
Populations of certain ethnic groups worldwide has slowed down considerably while others have increased. In particular, 5 groups: Non-Hispanic European North Americans (~230 million), European Brazilians (~90 million), Native Europeans (~700 million), Japanese (~128 million), Chinese (~1380 million), and Koreans (~73 million) population growth rates have declined sharply to very modest growth, and all these groups are expected to see population declines in the next 20–30 years, if they aren't seeing them already. Ethnic Thais (~65 million) are also expected to follow not far behind, although their cousins the ethnic Lao birth rates still in the high range.
Economic consequences 
The effects of a declining population can be adverse for an economy which has borrowed extensively for repayment by younger generations. Economically declining populations are thought to lead to deflation, which has a number of effects. However, Russia, whose economy has been rapidly growing (8.1% in 2007) even as its population is shrinking, currently has high inflation (12% as of late 2007). For an agricultural or mining economy the average standard of living in a declining population, at least in terms of material possessions, will tend to rise as the amount of land and resources per person will be higher.
But for many industrial economies, the opposite might be true as those economies often thrive on mortgaging the future by way of debt and retirement transfer payments that originally assumed rising tax revenues from a continually expanding population base (i.e. there would be fewer taxpayers in a declining population). However, standard of living does not necessarily correlate with quality of life, which may increase as the population declines due to presumably reduced pollution and consumption of natural resources, and the decline of social pressures and overutilization of resources that can be linked to overpopulation. There may also be reduced pressure on infrastructure, education, and other services as well.
The period immediately after the Black Death, for instance, was one of great prosperity, as people had inheritances from many different family members. However, that situation was not comparable, as it did not have a continually declining population, but rather a sudden shock, followed by population increase. Predictions of the net economic (and other) effects from a slow and continuous population decline (e.g. due to low fertility rates) are mainly theoretical since such a phenomenon is a relatively new and unprecedented one.
A declining population due to low fertility rates will also be accompanied by population ageing which can contribute problems for a society. This can adversely affect the quality of life for the young as an increased social and economic pressure in the sense that they have to increase per-capita output in order to support an infrastructure with costly, intensive care for the oldest among their population. The focus shifts away from the planning of future families and therefore further degrades the rate of procreation. The decade-long economic malaise of Japan and Germany in the 1990s and early 2000s is often linked to these demographic problems, though there were also several other causes. The worst case scenario is a situation where the population falls too low a level to support a current social welfare economic system, which is more likely to occur with a rapid decline than with a more gradual one.
The economies of both Japan and Germany both went into recovery around the time their populations just began to decline (2003–2006). In other words, both the total and per capita GDP in both countries grew more rapidly after 2005 than before. Russia's economy also began to grow rapidly from 1999 onward, even though its population has been shrinking since 1992-93 (the decline is now decelerating). In addition, many Eastern European countries have been experiencing similar effects to Russia. Such renewed growth calls into question the conventional wisdom that economic growth requires population growth, or that economic growth is impossible during a population decline. However, it may be argued that this renewed growth is in spite of population decline rather than because of it, and economic growth in these countries would potentially be greater if they were not undergoing such demographic decline. For example, Russia has become quite wealthy selling fossil fuels such as oil, which are now high-priced, and in addition, its economy has expanded from a very low nadir due to the economic crisis of the late 1990s. And although Japan and Germany have recovered somewhat from having been in a deflationary recession and stagnation, respectively, for the past decade, their recoveries seem to have been quite tepid. Both countries fell into the global recession of 2008-2009, but are now recovering once again, being among the first countries to recover.
In a country with a declining population, the growth of GDP per capita is higher than the growth of GDP. For example, Japan has a higher growth per capita than the United States, even though the US GDP growth is higher than Japan's. Even when GDP growth is zero or negative, the GDP growth per capita can still be positive (by definition) if the population is shrinking faster than the GDP.
A declining population (regardless of the cause) can also create a labor shortage, which can have a number of positive and negative effects. While some labor-intensive sectors of the economy may be hurt if the shortage is severe enough, others may adequately compensate by increased outsourcing and/or automation. Initially, the labor participation rates (which are low in many countries) can also be increased to temporarily reduce or delay the shortage. On the positive side, such a shortage increases the demand for labor, which can potentially result in a reduced unemployment rate as well as higher wages. Conversely, a high population means labor is in plentiful supply, which usually means wages will be lower. This is seen in countries like China and India.
A smaller national population can also have geo-strategic effects, but the correlation between population and power is a tenuous one. Technology and resources often play more significant roles.
National efforts to reverse declining populations 
Russian President Vladimir Putin directed Parliament to adopt a 10-year program to stop the sharp decline in Russia's population, principally by offering financial incentives and subsidies to encourage women to have children. Australia currently offers a $5,000 bonus for every baby plus additional fortnightly payments, a free immunisation scheme and recently proposed to pay all child care costs for women who want to work. Many European countries, including France, Italy, Germany and Poland, have offered some combination of bonuses and monthly payments to families. Some Japanese localities, facing significant population loss, are offering economic incentives. Yamatsuri, a town of 7,000 just north of Tokyo, offers parents $4,600 for the birth of a child and $460 a year for 10 years. The Republic of Singapore has similar plans: $3,000 for the first child, $9,000 in cash and savings for the second; and up to $18,000 each for the third and fourth. The effectiveness of these policies is currently the subject of debate.
Paid maternity and paternity leave policies can also be used as an incentive. Sweden built up an extensive welfare state from the 1930s and onward, partly as a consequence of the debate following Crisis in the Population Question, published in 1934. Today, Sweden has generous parental leave where parents are entitled to share 16 months paid leave per child, the cost divided between both employer and State.
Alternative concept relative to skills 
Sometimes the concept of population decline is applied where there has been considerable ex-migration of skilled professionals. In such a case, the government may have ceased to reward or value certain skills (e.g. science, medicine and engineering), and sectors of the economy such as health care and technology may go into decline. Such characterizations have been made of Italy, Bulgaria and Russia in the period starting about 1990.
See also 
- Birth dearth
- Societal collapse
- Negative Population Growth
- Human population control
- Political demography
- Rural flight
- Sub-replacement fertility
- Zero population growth
- Church of Euthanasia
- Collapse: How Societies Choose to Fail or Succeed by Jared Diamond
- Russian Cross
- Aging of Europe
- Aging of Japan
- List of sovereign states and dependent territories by fertility rate
- Depopulate - Webster's Online Dictionary
- Depopulate - yourdictionary.com.
- "2006 World Population Datasheet" (PDF). Population Reference Bureau.
- 2007 World Population Data Sheet
- http://www.nsi.bg/census2011/pagebg2.php?p2=36&sp2=37&SSPP2=4 2011 National Demographic Census, Age Structure
- Cuban Population still on the Decrease
- Rosenberg, Matt Population Decline in Russia
- Bonin, Holger (2001). Generational accounting: theory and application. Springer. ISBN 3-540-42266-8.
- http://www.ukrstat.gov.ua/operativ/operativ2013/fin/ds/kn/kn_e/kn0213_e.html Statistical Table Feb 2013
- Gulyas, Veronika (October 28, 2010). "Hungarian Population Falls Below 10 Million". The Wall Street Journal.
- CIA World Factbook—Russia [CIA World Factbook] Retrieved on November 14, 2008
- Nicholas Eberstadt. 2005. "Russia, the Sick Man of Europe". Public Interest, Winter 2005 
- Wheatley, Alan (August 18, 2009). "Japan Could Defy the Skeptics". The New York Times. Retrieved March 27, 2010.
- Gilmore, Grainne; Walsh, Dominic (August 13, 2009). "France and Germany emerge from recession". The Times (London). Retrieved March 27, 2010.
- Economist.com Grossly distorted picture
- C. J. Chivers (May 11, 2006). "Putin Urges Plan to Reverse Slide in the Birth Rate". New York Times.
- Population Research Institute
- BBC Report 2004: World population growth 'falling'
- 2002 Revision of the official United Nations population estimates and projections
- The Global Baby Bust
- Symptoms of the Global Demographic Decline