Overpopulation is a generally undesirable condition where an organism’s numbers exceed the carrying capacity of its habitat. The term often refers to the relationship between the human population and its environment, the Earth, or smaller geographical areas such as countries.
The population has been growing continuously since the end of the Black Death, around the year 1400, although the most significant increase has been in the last 50 years, mainly due to medical advancements and increases in agricultural productivity.
The recent rapid increase in human population over the past two centuries has raised concerns that the planet may not be able to sustain present or larger numbers of inhabitants. Steve Jones, head of the biology department at University College London, has said, “Humans are 10,000 times more common than we should be”. Many environmental problems, such as rising levels of atmospheric carbon dioxide, global warming, and pollution, are aggravated by the population expansion. Other problems associated with overpopulation include the increased demand for resources such as fresh water and food, starvation and malnutrition, consumption of natural resources faster than the rate of regeneration (such as fossil fuels), and a decrease in living conditions. However, some believe that waste and over-consumption, especially by wealthy nations, is putting more strain on the environment than overpopulation.
Limiting birth rates through legal regulations, educating people about family planning, increasing access to birth control and contraception, and extraterrestrial settlement have been suggested as ways to mitigate overpopulation in the future. China and other nations already have regulations limiting the birth rate, with China using the one child policy. Contraception is a response to the fact that nearly 40% of pregnancies are unintended and that in the poorest regions mothers often lack information and the means to control the size of their families.
History of concern
Concern about overpopulation is relatively recent in origin. Throughout history, populations have grown slowly despite high birth rates, due to the population-reducing effects of war, plagues and high infant mortality. During the 750 years before the Industrial Revolution, the world’s population increased very slowly, remaining under 250 million. By the beginning of the 19th century, the world population had grown to a billion individuals, and intellectuals such as Thomas Malthus and physiocratic economists predicted that mankind would outgrow its available resources, since a finite amount of land was incapable of supporting an endlessly increasing population. Mercantillists argued that a large population was a form of wealth, which made it possible to create bigger markets and armies.
Demographic transition and Sub-replacement fertility
The theory of demographic transition held that, after the standard of living and life expectancy increase, family sizes and birth rates decline. However, as new data has become available, it has been observed that after a certain level of development the fertility increases again. This means that both the worry the theory generated about aging populations and the complacency it bred regarding the future environmental impact of population growth are misguided. Factors cited in the old theory included such social factors as later ages of marriage, the growing desire of many women in such settings to seek careers outside child rearing and domestic work, and the decreased need of children in industrialized settings.
The latter factor stems from the fact that children perform a great deal of work in small-scale agricultural societies, and work less in industrial ones; it has been cited to explain the decline in birth rates in industrializing regions. Another version of demographic transition is proposed by anthropologist Virginia Abernethy in her book Population Politics, where she claims that the demographic transition occurs primarily in nations where women enjoy a special status (see Fertility-opportunity theory). In strongly patriarchal nations, where she claims women enjoy few special rights, a high standard of living tends to result in population growth.
Fresh water. Water crisis
Fresh water supplies, on which agriculture depends, are running low worldwide.This water crisis is only expected to worsen as the population increases. Potential problems with dependence on desalination are reviewed below, however, the majority of the world’s freshwater supply is contained in the polar icecaps, and underground river systems accessible through springs and wells. Fresh water can be obtained from salt water by desalination. For example, Malta derives two thirds of its freshwater by desalination. A number of nuclear powered desalination plants exist; However, the high costs of desalination, especially for poor countries, make impractical the transport of large amounts of desalinated seawater to interiors of large countries.
Some scientists argue that there is enough food to support the world population, but critics dispute this, particularly if sustainability is taken into account. Africa
In Africa, if current trends of soil degradation and population growth continue, the continent might be able to feed just 25% of its population by 2025. Hunger and malnutrition kill nearly 6 million children a year. In 2001, 46.4% of people in sub-Saharan Africa were living in extreme poverty.
… During a remarkably short period of time, we have lost a quarter of the world’s topsoil and a fifth of its agricultural land, altered the
composition of the atmosphere profoundly, and destroyed a major proportion of our forests and other natural habitats without replacing them. Worst of all, we have driven the rate of biological extinction, the permanent loss of species, up several hundred times beyond its historical levels, and are threatened with the loss of a majority of all species by the end of the 21st century.
Effects of human overpopulation
Some problems associated with or exacerbated by human overpopulation:
* Inadequate fresh water for drinking water use as well as sewage treatment and effluent discharge. Some countries, like Saudi Arabia, use energy-expensive desalination to solve the problem of water shortages. *Depletion of natural resources, especially fossil fuels. * Increased levels of air pollution, water pollution, soil contamination and noise pollution. *Deforestation and loss of ecosystems that sustain global atmospheric oxygen and carbon dioxide balance; *Changes in atmospheric composition and consequent global warming. *Irreversible loss of arable land and increases in desertification. *Mass species extinctions
*High infant and child mortality. High rates of infant mortality are caused by poverty. Rich countries with high population densities have low rates of infant mortality. *Bacteria diseases, excessive air and water pollution, and new viruses that infect humans. *Increased chance of the emergence of new epidemics and pandemics. *Starvation, malnutrition or poor diet with ill health and diet-deficiency diseases *Low life expectancy in countries with fastest growing populations. *Unhygienic living conditions for many based upon water resource depletion, discharge of raw sewage and solid waste disposal. *Conflict over scarce resources and crowding, leading to increased levels of warfare.
Overpopulation is related to the issue of birth control; some nations, like the People’s Republic of China, use strict measures to reduce birth rates. Religious and ideological opposition to birth control has been cited as a factor contributing to overpopulation and poverty. Some leaders and environmentalists have suggested that there is an urgent need to strictly implement a China-like one-child policy globally by the United Nations, because this would help control and reduce population gradually. Indira Gandhi, late Prime Minister of India, implemented a forced sterilization programme in the 1970s. Officially, men with two children or more had to submit to sterilization, but many unmarried young men, political opponents and ignorant men were also believed to have been sterilized. This program is still remembered and criticized in India.