Population growth can be defined as an increase or decrease in the population size of living species including human beings. Human populations are also subject to natural process of birth and death. There has been a rapid increase in the worlds human population over the last few decades (UNFPA, 2011). Unless urgent steps are taken to control population, serious problems can arise like environment damage and limited availability of food resources. Continuous population growth can be problem and therefore it is important to understand how we can manage population growth for the benefit of all.
Human beings have tried to make food resources available for all the population in many ways. Starting from the industrial revolution, advances in modern medicine, and green agriculture revolution have all made us self sufficient so far. However such technology development cannot go forever and therefore unless we manage population a day may come when all resources will be finished.
At present there are two school of thought for the theories on population growth.
The first is the pessimistic view developed by Reverend Robert Malthus, a British scholar who believed that the resources available will not be sufficient for human beings if human population is not controlled. The other theory is the optimistic view developed by Julian Simon who believed that humans can manage the issue of population because of their knowledge and skills. Therefore this paper will discuss these two theories for population growth and their effect on the resources and environment of the earth.
II. Factors affecting population growth
The population growth is determined mainly by birth rate, death rate, and migration patterns (immigration and emigration). For instance the population in the developed countries like Europe and America is growing at rate of only 0.1% per year while in developing countries the growth rate is over 1.5% per year. (Wright and Boorse,2011) (UNDP).
In developing countries where manual labour is still considered main source of labour, children form part of the labour force and therefore families tend to have more children. Similarly when the pension system is not good, people tend to raise more children to look after during old age. Wherever women are more educated and take lead role in household income activities, there tend to be less number of children raised. In areas where traditions, culture and customs are respected population tend to be higher due to less use of contraceptives.
III. Impacts of population growth
Although it may be difficult to measure the carrying capacity for humans on earth (Cohen, 1995) scientists have estimated the carrying capacity at around 7.7 billion people (Van Den Bergh and Rietveld, 2004). It is now estimated that the world population will be around 9.1 billion by the year 2050. The very high population growth has raised concerns that the planet may not be able to sustain such population in the long run. Increasing population will mean increased demand for food, water, and other resources such as fossil fuel. The impact of population growth can be seen by everyone who care for the world that we live in. Over the last few decades there has been large scale destruction of the tropical forests mainly to make land available for agriculture and for urbanization. In order to produce enough food to meet the demand of growing population, forests have been cleared to undertake farming. Due to increased industrialization and urbanization, there has been great increase in the pollution of air, water and the environment of the planet. Growing population will result in the depletion of natural resources such as water, fossil fuels (Hubert, 1982); deforestation and loss of ecosystems; and emergence of new diseases. It will also lead to more starvation, hunger and unhygienic living conditions in poor countries.
IV. Factors affecting environment
Environment means our surroundings in which all the things, living or non living, which includes atmosphere (air), hydrosphere (water), lithosphere (solid earth), biosphere (all living organisms), and geosphere (rocks and regoliths). Numerous factors affect our environment which includes anthropogenic activities such as urbanization, industrialization, deforestation, overpopulation, and use of fossil fuels. Natural disasters such as earthquakes, volcanoes, cyclones, landslide and floods can also negatively affect the environment.
V. Relationship between environment and population growth
Humans are an integral part of the eco-system of nature and there is close interconnection between human beings and environment. Ever since life existed humans have been depending on their environment for food, shelter, and other necessities. There is an inverse relationship existing between population growth and environment as overpopulation will lead to adverse effect on the environment. As human population increase, there is also increase in the demand for food and other energy sources. It is essential that the population is maintained at a level so that the natural resources are sufficient to meet the requirement for survival of all living beings.
VI. Neo-Malthusian or pessimistic views on population growth
Malthusian theories or pessimistic theories on population growth was derived from the ideas of Reverend Thomas Robert Malthus, a British scholar who wrote series of essays on the principles of population. There were six editions of his An Essay on the Principle of Population (published from 1798 to 1826) in which he said that if the human population growth is left unchecked the food supply will not be sufficient to meet the needs of humans. He proposed the idea that while human population grew exponentially, the food resources grew only arithmetically. He also believed that population will be controlled naturally by disease, famine and mortality. This was called as the pessimistic model of population growth. Malthus believed in using preventive checks such as abstinence, delayed marriage and restricting marriages in order to control population growth. Some people criticized Malthuss theory based on the fact that there has been an enhanced agricultural production and reduced human fertility over the past few decades since the publication of his theories. However, many still believe in his theory that if left unchecked, population growth can pose serious problems for resource availability (Cristina, 2010).
These are groups who also believe in the theories of Malthus and encourage population control programs for the present and future benefit of human beings. The Neo-Malthusians view however differ from Malthus in their belief on the use of contraceptive techniques for the birth control measures. The neo-Malthusians or the pessimistic view had more concerns about the effect that population growth would have on environmental degradation. While they supported the theories put forward by Malthus, this group of people strongly supported the idea of actively controlling population growth in order to prevent adverse impact on the environment. This pessimistic group are concerned about the effect overpopulation may have on resource depletion and environmental degradation. There has been a general revival in neo-Malthusian ideologies from the 1950s onwards especially after the publication of series of books by some Malthusian supporters such as Fairfield Osborn (Our Plundered Planet), William Vogt (Road to Survival) and Paul Ehrlich (The Population Bomb). Although many critics of neo-Malthusianism criticize the revival of this theory based on fact that the green revolution has led to sufficient food production, Pessimists such as Paul Ehrlich believe that unchecked population will ultimately lead to serious problems in the future (Ehrlich, 2009). Neo-Malthusian or the pessimistic view is more about the positive checks but Malthusian said that there is balance between both positive and negative checks.
Technological or Optimistic views on population growth.
The optimistic model of population growth was proposed by Julian Simon who in his book The Ultimate Resource (1981) argued that as resources become scarce the price goes up which in turn creates incentives for people to discover new source or find alternatives for the resource. Simon also claims in his book that the natural resources are infinite based on the justification that innovative methods can be used to make natural resources available. Increasing population growth and reduced resources make people to create innovations and inventions to produce more food and all basic needs. The optimistic view said that science and technology can overcome scarcity problems. Esther Boserup (1910-1999)-Danish economist said necessity is the mother of invention. So, humanity will always find a way to overcome their problems. The optimistic view also said that more people means more alternatives to find new materials and discover ways to do things.
It can be seen from the above paragraphs that population growth can impact on the state of environment of our planet. Of the two theories on population growth, I support the neo-malthusian theory of pessimistic views based on the following justifications.
Deforestation for agriculture
If the human population growth is left unchecked, a day might come when the earths resources will not be able to sustain the requirements of human beings. As overpopulation will demand increasing food, energy, and other resources, humans will engage in activities that will directly affect our environment and ecosystem. For instance, about 160,000 square kilometers per of tropical rainforests are cleared for agricultural use thus resulting in loss of habitat for the biodiversity (Laurance, 1999). Such loss of forests will contribute to global warming and other negative effects on environment.
In order to meet the growing demand of increasing population, humans have been using technologies such as industrialization for enhanced production of food and other needs. Increased industrialization and urbanization results in air pollution, noise pollution, and water pollution which are all detrimental to our environment.
Increased urbanization will also mean clearance of forests for construction of roads, buildings etc. which further adds to pollution.
Depletion of non-renewable natural resources and emission of green house gases
Uncontrolled growth of population will lead to rapid depletion of non-renewable natural resources such as fossil fuels which are used as source of energy. The burning of fossil fuel i.e. carbon based fuels, mainly wood, coal, oil and natural gas produces significant amount of CO2 which is one of the main green house gases that contributes to global warming (International Energy Outlook, 2000). The green house effect maintains the earth at comfortable temperature range but if there is excessive release of CO2 and other harmful gases from the industries and factories, the green house gases gets easily out of control and will lead to so many problems like continental drift, climate change, natural disasters and variations of suns out put.
Loss of biodiversity and habitat
Due to growing population, especially in the rural areas of developing countries, people practising shifting cultivation undertake slash-and-burn techniques which results in the extinction of native flora and fauna. It has been reported that nearly 140,000 species are lost every year due to deforestation activities (Pimm, Russell, Gittleman and Brooks, 1995). Therefore, if population growth is not controlled, increasing human activities will further result in destruction of the habitat and loss of biodiversity. In Bhutan, human-wildlife especially human-elephant conflict is increasing and this is mainly due to the loss of habitat for the elephants due to increasing human population and activities (Kuensel, 19 May 2012).
There is a need to find solutions to decrease the problems associated with overpopulation and environmental degradation. The governments around the world should have policies to decrease the population growth rate by increasing use of birth control measures. The governments should also frame good policies to protect forests and environment and prevent loss of natural habitat. Innovative ideas and research should be done to increase food production without disturbing the environment. The governments should increase funding for education and awareness of especially the poor people for them to protect and take care of their environment.
In conclusion overpopulation can lead to problems in the form of depleting natural resources, environmental pollution and degradation, and loss of habitat. Therefore, urgent steps need to be taken to manage human population growth to a level that can be managed well. The theories founded by Reverend Malthus can be still followed because the natural resources available now may not be sufficient in the future if we do not control human population growth.
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