Zero population growthZero population growth, sometimes abbreviated ZPG, is a condition of demographic balance where the number of people in a specified population neither grows nor declines; that is, the number of births plus in-migrants equals the number of deaths plus out-migrants. ZPG has been a prominent political movement since the 1960s. As part of the concept of optimum population, the movement considers zero population growth to be an objective towards which countries and the whole world should strive in the interests of accomplishing long-term optimal standards and conditions of living.
Population growthPopulation growth is the increase in the number of people in a population or dispersed group. Actual global human population growth amounts to around 83 million annually, or 1.1% per year. The global population has grown from 1 billion in 1800 to 7.9 billion in 2020. The UN projected population to keep growing, and estimates have put the total population at 8.6 billion by mid-2030, 9.8 billion by mid-2050 and 11.2 billion by 2100.
Population dynamicsPopulation dynamics is the type of mathematics used to model and study the size and age composition of populations as dynamical systems. Population dynamics has traditionally been the dominant branch of mathematical biology, which has a history of more than 220 years, although over the last century the scope of mathematical biology has greatly expanded. The beginning of population dynamics is widely regarded as the work of Malthus, formulated as the Malthusian growth model.
Financial crisisA financial crisis is any of a broad variety of situations in which some financial assets suddenly lose a large part of their nominal value. In the 19th and early 20th centuries, many financial crises were associated with banking panics, and many recessions coincided with these panics. Other situations that are often called financial crises include stock market crashes and the bursting of other financial bubbles, currency crises, and sovereign defaults.
Population ageingPopulation ageing is an increasing median age in a population because of declining fertility rates and rising life expectancy. Most countries have rising life expectancy and an ageing population, trends that emerged first in developed countries but are now seen in virtually all developing countries. That is the case for every country in the world except the 18 countries designated as "demographic outliers" by the United Nations. The aged population is currently at its highest level in human history.
Aging of JapanJapan has the highest proportion of elderly citizens of any country in the world. 2014 estimates showed that about 38% of the Japanese population was above the age of 60, and 25.9% was above the age of 65, a figure that increased to 29.1% by 2022. By 2050, an estimated one-third of the population in Japan is expected be 65 and older. The aging of Japanese society, characterized by sub-replacement fertility rates and high life expectancy, is expected to continue.
Population pyramidA population pyramid (age structure diagram) or "age-sex pyramid" is a graphical illustration of the distribution of a population (typically that of a country or region of the world) by age groups and sex; it typically takes the shape of a pyramid when the population is growing. Males are usually shown on the left and females on the right, and they may be measured in absolute numbers or as a percentage of the total population. The pyramid can be used to visualize the age of a particular population.
Population declinePopulation decline, also known as depopulation, is a reduction in a human population size. Over the long term, stretching from prehistory to the present, Earth's total human population has continued to grow; however, current projections suggest that this long-term trend of steady population growth may be coming to an end. Until the beginning of the Industrial Revolution, the global population grew very slowly, at about 0.04% per year. After about 1800, the growth rate accelerated to a peak of 2.
Human population planningHuman population planning is the practice of managing the growth rate of a human population. The practice, traditionally referred to as population control, had historically been implemented mainly with the goal of increasing population growth, though from the 1950s to the 1980s, concerns about overpopulation and its effects on poverty, the environment and political stability led to efforts to reduce population growth rates in many countries.
Population ecologyPopulation ecology is a sub-field of ecology that deals with the dynamics of species populations and how these populations interact with the environment, such as birth and death rates, and by immigration and emigration. The discipline is important in conservation biology, especially in the development of population viability analysis which makes it possible to predict the long-term probability of a species persisting in a given patch of habitat.
DemographyDemography () is the statistical study of populations, especially human beings. Demographic analysis examines and measures the dimensions and dynamics of populations; it can cover whole societies or groups defined by criteria such as education, nationality, religion, and ethnicity. Educational institutions usually treat demography as a field of sociology, though there are a number of independent demography departments.
List of economic crisesThis is a list of economic crises and depressions. Financial crisis of 33 The result of the mass issuance of unsecured loans by main Roman banking houses. Crisis of the Third Century Coin exchange crisis of 692. Byzantine emperor Justinian II refuses to accept tribute from the Umayyad Caliphate with new Arab gold coins for fear of exposing double counting in the Byzantine financial system (actual weight less, than nominal quantity), which leads to the Battle of Sebastopolis and the revolt of taxpayers who burned financial officials in a copper bull.
Economic growthEconomic growth can be defined as the increase or improvement in the inflation-adjusted market value of the goods and services produced by an economy in a financial year. Statisticians conventionally measure such growth as the percent rate of increase in the real and nominal gross domestic product (GDP). Growth is usually calculated in real terms – i.e., inflation-adjusted terms – to eliminate the distorting effect of inflation on the prices of goods produced. Measurement of economic growth uses national income accounting.
Economic depressionAn economic depression is a period of carried long-term economic dow that is the result of lowered economic activity in one major or more national economies. Economic depression maybe related to one specific country were there is some economic crisis that has worsened but most often reflexes historically the American Great Depression and similar economic status that may be recognized as existing at some country, several countries or even in many countries.
ChinaChina (), officially the People's Republic of China (PRC), is a country in East Asia. It is the world's second-most populous country with a population exceeding 1.4 billion. China spans the equivalent of five time zones and borders fourteen countries by land, tied with Russia as having the most of any country in the world. With an area of nearly , it is the world's third largest country by total land area. The country consists of 22 provinces, five autonomous regions, four municipalities, and two semi-autonomous special administrative regions.
GlobalizationGlobalization, or globalisation (Commonwealth English; see spelling differences), is the process of interaction and integration among people, companies, and governments worldwide. The term globalization first appeared in the early 20th century (supplanting an earlier French term mondialization), developed its current meaning some time in the second half of the 20th century, and came into popular use in the 1990s to describe the unprecedented international connectivity of the post-Cold War world.
Post-growthPost-growth is a stance on economic growth concerning the limits-to-growth dilemma — recognition that, on a planet of finite material resources, extractive economies and populations cannot grow infinitely. The term "post-growth" acknowledges that economic growth can generate beneficial effects up to a point, but beyond that point (cited as $25,000 GDP/capita by Richard Wilkinson and Kate Pickett in their book The Spirit Level) it is necessary to look for other indicators and techniques to increase human wellbeing.
Economic collapseEconomic collapse, also called economic meltdown, is any of a broad range of bad economic conditions, ranging from a severe, prolonged depression with high bankruptcy rates and high unemployment (such as the Great Depression of the 1930s), to a breakdown in normal commerce caused by hyperinflation (such as in Weimar Germany in the 1920s), or even an economically caused sharp rise in the death rate and perhaps even a decline in population (such as in countries of the former USSR in the 1990s).
Population dynamics of fisheriesA fishery is an area with an associated fish or aquatic population which is harvested for its commercial or recreational value. Fisheries can be wild or farmed. Population dynamics describes the ways in which a given population grows and shrinks over time, as controlled by birth, death, and migration. It is the basis for understanding changing fishery patterns and issues such as habitat destruction, predation and optimal harvesting rates. The population dynamics of fisheries is used by fisheries scientists to determine sustainable yields.
Stability theoryIn mathematics, stability theory addresses the stability of solutions of differential equations and of trajectories of dynamical systems under small perturbations of initial conditions. The heat equation, for example, is a stable partial differential equation because small perturbations of initial data lead to small variations in temperature at a later time as a result of the maximum principle. In partial differential equations one may measure the distances between functions using Lp norms or the sup norm, while in differential geometry one may measure the distance between spaces using the Gromov–Hausdorff distance.
