Implications of population change

Implications of population change

  • overpopulation, underpopulation and optimum population
  • an optimistic approach to population change
  • a pessimistic approach to population change
  • population change and sustainable developement
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Overpopulation, Underpopulation and Optimum popula

Overpopulation exists when there are too many people in an area relative to the amount of resources and the level of technology available locally to maintain a high standard of living. It implies that, with no change in the level of technology or natural resources, a reduction in the population would result in a rise in lving standards. The absolute number or density of people need not to be high if the level of technology or natural resources is low. Overpopulation is characterised by low per capita income, high unemployment and underemployment, and outward migration.

Underpopulation occurs when there are too few people in an area to use the resources efficiently for a given level of technology. In these circumstances an increase in population would mean a more effective use of resources and increased living standards for all people. Underpopulation is characterised by high per capita incomes (but but not maximum incomes), low underemployment and inward migration.

Optimum population is the theoretical population, which working with all the avialable resources, will produce the highest standard of living for the people of that area. The concept is dynamic - when technology improves, new resources become available which means that more people can be supported.

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An optimistic approach to population change

Ester Boserup, in the 'Conditions of Agricultral Change: The Economics of Agarian Change Under Population Pressure (1965)' stated that environments have limits that restrict activity. However, these limits can be altered by the use of appropriate technologies which offer the possibility of resource development or creation. People have been underlying freedom to make a difference to thier lives.

Boserup stated that food resources are created by population pressure. With demand, food systems become more intensive, for example, by making use of shorter fallow periods. She cited certain groups in tropical areas of Africa who reduced the fallow period from 20 years, to annual cropping with only 2-3 months fallow, to a system of multi-cropping in which the same plot bore two or three crops in the same year.

The pressure to change comes from the demand for increased food production. As the fallow period contracts, the farmer is compelled to adopt new startergies to maintain yeilds. Thus necessity is the mother of invention.

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Evidence to support this approach

The following two changes in agricultural practice support this view:

  • The intensity of shifting cultivation systems in various parts of the world. These move from 'slash and burn' systems in areas of very low rural population density, to systems making use of irrigation in areas of higher rural population density. People are adapting to thier changing circumstances by adopting more intensive forms of agriculture.
  • The Green Revolution - thw widespread introduction of high-yeilding varities of grains, along with the use of fertilisers and pesticides, water control and mechanisation. The increased yeilds from these processes aloow more people tp be fed.

More recently, other writers notably Julian Simon and Bjorn Lomborg, have contributed to these optimistic views. They refer to a number of so-called environmetal scares of recent years. In the 1960s it was pesticides, carinogens and the population explosion. In the 1970s there was the oil crisis, the imminent failure of the worlds food supply and the fear of nuclear power. In the 1980s the deserts were advancing, acid rain was killing trees and the ozone layer was thinning and the elephant was on the point of extinction. The 1990s brought retreating rainforests, falling sperm counts, new disease such as ebola and genetically modified crops.

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Evidence to support this approach

They argue tha the alarmists were wrong. In their opinion none of these predictions has been fulfilled - there has been no rise in cancer caused by pesticides, population growth has slowed, oil reserves have increased, food production per head has increased even in poorer countries of the world, nuclear accidents have been rare, deserts have not advanced, acid rain has killed no forests, the elephant has never been in danger of extinction, sperm counts are not falling and rainforests are still 80% intact. They think people are being made to indulge in evenironmental guilt when technology should in fact be encouraged , to improve living standards throughout the world, rather than just for a rich minority.

Mor recently Lomborg has argued against the cost of combatting climate change. He argues that resources should be channeled into adjusting climate change and fighting global poverty and disease.

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A pessimistic approach to population change

In An essay on the Principle of Population as it Affects the Future Improvement of Society (1798), Thomas Malthus suggested that the environmet dominates or determines patterns of human life and behaviour. Ourl ives are constrained by physical, economic and social factors.

His argument was that population increases faster than the supporting food resources. If each generation produces more children, the population grows geometrically while food resources only develop arithmetrically and cannot keep pace. He believed that population/resource balance was maintained by various checks:

  • increased levels of misery through war, famine and disease
  • increased levels of moral restraints such as celibacy and later marriages
  • increased incidence of abortion, infanticide and sexual 'perversions'
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A pessimistic approach to population change contin

Malthus asserted that the power of a population to increase its numbers was greater than that of the Earth to sustain. This view is still held by so-called neo-malthusians. For example, in 1972 the Club of Rome predicted in a book entitled The Limits to Growth that a sudden decline in population growth could occur within 100 years if present day trends occur. They argued that environmetal degradation and resource depletion were not only related to population growth but were also a function if the technologies and consumption patterns of greater numbers of people. They suggested greater control and planning of both population and resource use to create more stability.

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Evidence to support this approach

Neo-malthusians believe that a number of recent issues support their views:

  • they beleive the wars and famines in Ethiopia, Sudan, and other countries of the Sahel region of Africa in recent decades suggest that population growth has outstripped food supplies. On a global scale, the Food and Agricultrual Organization of the UN suggests that over 800 million people are chronically malnourished, while 2 billion lack food sercurity.
  • population growth has accelerated rapidly in less developed countries after there mortalilty rates began to fall. Rapid population growth impedes development and brings about a number of social and economic problems. In rencent decades, however, population growth has slowed. In 2006, the population growth rate was 1.2% per annum comapred with 2.4% in 1960.
  • Water scaracity is predicted to be a major resource issue this century. The UN predicts that by 2050, 4.2 billion people (45% of the worlds population) will be living in areas that cannot provide the required 50 litres of water a day to meet basic needs.
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Evidence to support this approach

One of the most prominent neo-malthusians in recent years has been the American writer Paul Ehrlich. In the 1960s he suggested that India should not recieve Western emergency aid because of its environmental state. He said thaen that 'sober analysis sgiws a hopeless imbalance between good production and population'. However, optimists have since pointed out that India now more than feeds its population due to the advances of the Green Revoltion.

The most recent scare from the pressismists is global warming, which cannot be proven either right or wrong within our life time. In response to this threat, at the 1997 Kyoto conference on the environment, the industrialised countries agreed to cut thier carbon dioxide emissions by 30% by 2010. In the UK this was to be achieved by swich away from coal-fired power stations to alternative sources, increases in public transport and taxes on fuel consumption. However, the USA, under president Bush, refused to comply with the agreement at that time. The 2007 UN Climate Change Conference in Bali aimed to negociate a successor to the Kyoto Protcol. The 'bali roadmap' was adopted as a 2 year process reaching a binding agreement in 2009 in Denmark. Environmentalists were dissapointed by the lack of frims emissions-reduction targets.

In 2002, at the World Summit of Sustainable Development held in Johannesburg, key issues were sustainable management of the global resource base, proverty eradication and better healthcare. The last two were seen as ways in which population growth could be reduced. The population-resources debate continues.

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Population change and sustainable development - Su

The concept of sustainable development dates from the first Global Environmental Summit held in Stockholm in 1972. It was first expressed as a set of environmental objectives for example, to:

  • maintain ecological processes
  • preserve gentic diversity
  • ensure the sustainable utilisation of species and ecosystems

It was later defined by the 'Brundtland Report' in 1987 as 'development that meets the needs of the present without comprimising the ability of future generations to meet thier own needs'.

Economic sustainability takes this further by concidering the ability of economies to maintain themselves when resources decline or become too expensive, and when populations dependent on these resources are growing.

Various internation summits, held in Rio (1992), Kyoto (1997), and Johannesburg (2002), have endeavoured to produce international agreements on sustainable development, with varying degrees of sucess. There has been further development of the principles of sustainabilty at these summits as descibed next.

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Environmental and Economic


  • people should be at the heart of concerns regarding development.
  • states should have the right to exploit thier own environments, but they should not damage the environments for other states.
  • laws should be enacted regarding liabilty for pollution and compensation.
  • states should pass on information about natural disasters and notifiy neighbours of any forseen and accidental consquences on their own activities that might cross boundaries


  • the right to development must be fullfilled to meet equitably the needs of present and future generations.
  • all states should cooperate in eliminating poverty in order to decrease disparities in standards of living.
  • the special needs of developing countries, particularly that least developed and environmentally most vunerable, should be given priority.
  • unsustainable production and consumption patterns should be eliminated and appropriate demographic (i.e. population) policies should be promoted.
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