Time taken for each billion people to
be added to the world's population (including future
estimates).
In
biology, a
population is
the collection of
inter-breeding
organisms of a particular
species; in
sociology, a collection of human beings.
Individuals within a population share a factor may be reduced by
statistical means, but such a generalization may be too vague to
imply anything.
Demography is used extensively in
marketing, which relates to economic units, such
as retailers, to potential customers. For example, a
coffee shop that wants to sell to a younger audience
looks at the demographics of an area to be able to appeal to this
young audience.
World population
As of , the world population is estimated by the
United States Census Bureau to
be billion.
According to papers published by the
United States Census Bureau, the
world population hit 6.5 billion (6,500,000,000) on 24 February
2006. The
United Nations
Population Fund designated 12 October 1999 as the approximate
day on which world population reached 6 billion. This was about 12
years after world population reached 5 billion in 1987, and 6 years
after world population reached 5.5 billion in 1993.
However, the
population of some countries, such as Nigeria
and China is
not even known to the nearest million, so there is a considerable
margin of error in such estimates.
Population growth increased
significantly as the
Industrial
Revolution gathered pace from 1700 onwards. The last 50 years
have seen a yet more rapid increase in the
rate of population
growth due to
medical advances and
substantial increases in agricultural productivity, particularly
beginning in the 1960s, made by the
Green Revolution. In 2007 the United
Nations Population Division projected that the world's population
will likely surpass 10 billion in 2055.In the future, world
population has been expected to reach a peak of growth, from there
it will decline due to economic reasons, health concerns, land
exhaustion and environmental hazards. There is around an 85% chance
that the world's population will stop growing before the end of the
century. There is a 60% probability that the world's population
will not exceed 10 billion people before 2100, and around a 15%
probability that the world's population at the end of the century
will be lower than it is today. For different regions, the date and
size of the peak population will vary considerably.
Population control
Population control is the practice of curtailing population
increase, usually by reducing the
birth
rate. Surviving records from
Ancient
Greece document the first known examples of population control.
These
include the colonization movement, which saw Greek outposts being built across the
Mediterranean
and Black
Sea
basins to accommodate the excess population of
individual states. Infanticide
and abortion were encouraged in some
Greek city states in order to keep population
down.
An important example of mandated population control is People's
Republic of China's
one-child
policy, in which having more than one child is made extremely
unattractive. This has led to allegations that practices like
forced abortions, forced sterilization, and infanticide are used as
a result of the policy. The country's
sex
ratio at birth of 114 boys to 100 girls may be evidence that
the latter is often
sex-selective.
It is helpful to distinguish between
fertility control as individual
decision-making and population control as a governmental or
state-level policy of regulating population growth. Fertility
control may occur when individuals or couples or families take
steps to decrease or to regulate the timing of their own
child-bearing. In
Ansley Coale's
oft-cited formulation, three preconditions for a sustained decline
in fertility are: (1) acceptance of calculated choice (as opposed
to fate or chance or divine will) as a valid element in fertility,
(2) perceived advantages from reduced fertility, and (3) knowledge
and mastery of effective techniques of control. In contrast to a
society with
natural fertility, a
society that desires to limit fertility and has the means to do so
may use those means to delay childbearing, space childbearing, or
stop childbearing. Delaying sexual intercourse (or marriage), or
the adoption of natural or artificial means of contraception are
most often an individual or family decision, not a matter of a
state policy or societal-wide sanctions. On the other hand,
individuals who assume some sense of control over their own
fertility can also accelerate the frequency or success of
child-bearing through planning.
At the societal level, declining fertility is almost an inevitable
result of growing secular education of women. However, the exercise
of moderate to high levels of fertility control does not
necessarily imply low fertility rates. Even among societies that
exercise substantial fertility control, societies with an equal
ability to exercise fertility control (to determine how
many children to have and when to bear them) may display widely
different
levels of fertility (numbers of children borne)
associated with individual and cultural preferences for the number
of children or size of families.
In contrast to
fertility control, which is mainly an
individual-level decision, governments may attempt to exercise
population control by increasing access to means of
contraception or by other population policies and programs. The
idea of "population control" as a governmental or societal-level
regulation of population growth does not require "fertility
control" in the sense that it has been defined above, since a state
can affect the growth of a society's population even if that
society practices little fertility control. It's also important to
embrace policies favoring population
increase as an aspect
of population control, and not to assume that states want to
control population only by limiting its growth. To stimulate
population growth, governments may support not only
immigration but also pronatalist policies such
as tax benefits, financial awards, paid work leaves, and childcare
to encourage the bearing of additional children. Such policies have
been pursued in recent years in France and Sweden, for example.
With the same goal of increasing population growth, on occasion
governments have sought to limit the use of abortion or modern
means of birth control. An example was
Romania's 1966 ban on access to
contraception and abortion on demand.
In ecology, population control is on occasions considered to be
done solely by
predators,
diseases,
parasites, and
environmental factors. In a constant environment, population
control is regulated by the availability of food, water, and
safety. The maximum number of a species or individuals that can be
supported in a certain area is called the
carrying capacity. At many times human
effects on animal and plant populations are also considered.
Migrations of animals may be seen as a natural way of population
control, for the food on land is more abundant on some
seasons. The area of the migrations' start is left
to reproduce the food supply for large mass of animals next time
around. See also
immigration.
India is another example where the government has taken measures to
reduce the country’s population. Concerns that the rapidly growing
population would adversely affect economic growth and living
standards caused India to implement an official family planning
program in the late 1950s and early 1960s; it was the first country
in the world to do so.
See also
Notes
- U.S. Census Bureau - World POPClock
Projection
- As graphically illustrated by population since 10,000BC and population since 1000AD
- Food First/Institute for Food and Development
Policy
- Ansley
J. Coale, "The Demographic Transition," Proceedings of the
International Population Conference, Liège, 1973, Volume 1, pp.
53-72.
- For illustrations of the distinction between fertility control
and fertility levels, see Barbara A. Anderson and Brian D. Silver,
"A Simple Measure of Fertility Control," Demography 29,
No. 3 (1992): 343-356, and B. A. Anderson and B. D. Silver, "Ethnic
Differences in Fertility and Sex Ratios at Birth: Evidence from
Xinjiang," Population Studies 49 (1995): 211-226. The
fundamental work on models of fertility control was that by Coale
and his colleagues. See, e.g., Ansley J. Coale and James T.
Trussell, “Model Fertility Schedules: Variations in the Age
Structure of Childbearing in Human Populations.” Population
Index 40 (1974): 185 – 258.
- For a discussion of the range of "population policy" options
available to governments, see Paul Demeny, "Population Policy: A
Concise Summary," Population Council, Policy Research Division,
Working Paper No. 173 (2003)[1].
- Charlotte Höhn, "Population policies in advanced societies:
Pronatalist and migration strategies," European Journal of
Population/Revue européenne de Démographie 3, Nos. 3-4 (July,
1988): 459-481.
- See
http://en.wikipedia.org/wiki/Hunting#Wildlife_management.
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