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Tuesday, March 30, 2010

Growth of human population and its impact on natural environment

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The human population refers to the total human inhabitants of a specified area, such as a city, a country, a continent or the world, at a given time. The study of human population as a discipline is known as Demography and one who studies population at the advanced stage is known as a Demographer.The demography, as a subject of study is an interdisciplinary field which involves mathematics and statistics, biology, medicine, sociology, economics, history, geography and anthropology. It is concerned with the size, composition and distribution of populations along with patterns of changes of populations overtime through births, deaths and migration; and the determinants and consequences of such changes. Studies of population are important particularly for governments for planning in the field of health education, housing, social security, employment and preservation of environment. Demographic studies provide information which is needed to formulate population policies of governments as governments are concerned to modify demographic trends so as to achieve the objectives of economic and social developments.
The population of the world grew at an alarming rate since 1650 to 1950 and onwards. The unprecedented surge in population has caused and is still causing rise in individual consumption of food, water, and exploitation of natural resources like land, water, fossil fuels, minerals, vegetation etc. The combined effects of population growth, consumption, overuse, wastage and misuse of resources has strained the capacity of the earth to sustain life. That’s why the study and control of human population is very important today. In this lesson we are going to study the impact of growth of human population on environment in particular.
 Social Impacts of Population Growth
Explosive growth in human population causes a number of serious problems like food-scarcity, over crowding, poverty, increasing consumption, encroachment on monuments, stress on common social facilities, stress on civic services etc.
A. Food Scarcity: The population growth leading to population explosion causes severe economic disparities and gives birth to - competition for resources, price rise, hunger, malnutrition, and mass starvation.
The gap between the rich and the poor has increased due to population growth. The rich people are exploiting more resources than poor people. Malnutrition is one of the most common effects of these problems. The poorest people in developing countries do not get adequate calories to develop their health properly. In Ethiopia, almost half of all children under age of 5 suffer from malnutrition. Most poor children and adults suffer from severe vitamin and mineral deficiencies. These deficiencies cause failure of senses, mental disorders and damage to vital organs. There are millions of starving people through out the world. As per estimates, from 5 to 20 million people die of starvation across the world, every year.
B. Overcrowding: There is limited habitable place on the earth. The overpopulation has caused severe stress on land which has further stressed forests and agricultural areas.
People are migrating towards cities in search of jobs and cities are becoming overcrowded. Semi-urban lands and cultivable lands near cities have already gone under construction of houses. Even government lands like railway platforms, areas around monuments, and parks etc. are being seriously encroached. Increasing crowd in cities is aggravating the problem of pollution and insanitation leading to the spread of epidemics. Green lands in urban areas and even sea beeches have been reclaimed for housing and industrial purposes.
C. Poverty: Conditions of having insufficient resources or income are called as poverty. In its extreme form, poverty is the lack of the basic human needs like food, clothing, housing, drinking water, and health services. The world’s poorest people are found in Africa, Asia, Latin America, and Eastern Europe. They always struggle for shelter and clothing. They often suffer from malnutrition, famine, disease outbreaks, epidemics and war.
In developed countries, poverty has caused drug dependence, crime, and mental illness. Overpopulation, unequal distribution of resources, inability to meet the cost of living, inadequate education and employment, degradation of environment, demographic trends and welfare incentives are primary causes of poverty. Lives in developing countries represent a picture of misery, hunger and poverty. Many of these countries have entered the second stage of Demographic Transition in which a high birth and reduced death rates along with a rising life expectancy accelerates the population growth.
D. Increasing Consumption: It is a simple truth that more people consume more food, wear more clothes, drink more water, need more houses to live, need more medicines for cure, make more noise, create more pollution, generate more waste etc.
Some countries of the world have nearly stabilized their population but their life style has become consumption based. We may take the example of United States of America. Though, it is not overpopulated, it consumes about 40% of resources of the world alone and produces not less than 21 % of the world’s carbon dioxide which is a green-house gas.
It has been observed by ecologists the world over that powerful people and developed nations consume more resources than weak and poor people and developing or under developing countries. Thus, increase in the rate of consumption at one end is causing an increase in hunger and crime at the other end. Merely, 20% of the world’s population lives in developed and richest countries. According to United Nations the world’s richest 20% of population consumes about 86% of resources of the world. Thus, the population growth and the changing pattern of consumption are responsible for the severe stress on environment.
 E. Encroachment on Monuments   : A monument is a building, column or statue of historical importance built-in the past to remind future generations about a famous person or event. People who migrate from rural areas and work in cities often face difficulties and most of them spend their nights as homeless. They take shelter on pavements, abandoned railway buildings and on spaces left around historical monuments. Gradually, they build temporary houses on those places and start keeping their families there. Some of them start business works on those places and gradually a colony of such persons is established. So is happening with most of our uncared monuments today.
Most of our monuments and old government buildings are being badly encroached by people who after sometime try to become owners of those areas. This is illegal and criminal attitude. However, this condition is the by-product of the explosion of population.
F. Stress on Common Social Facilities: We need facilities and facilities both on home front and on social front. More people require more use of available facilities. But facilities may be limited. So, there may be a great rush and competition for availing facilities causing severe stresses on those facilities. Community Halls, Bus Stops, Railway Junctions, Parks, Play Grounds, Hospitals and even roads are some common social facilities that are facing heavy stresses due to population explosion. One can see long lines of people standing for hours for their works. There is heavy traffic on roads round the clock. All these social facilities are often heavily polluted due to careless practices of human beings.
G. Stress on Common Civic Services: Services provided by municipalities or municipal corporations to civilians are called as civic services. Those services include cleanliness, water supply, waste disposal, maintenance of drainage systems, community health care, care of animals (dogs and cattle) on roads, basic education etc.
Over population has caused severe stress on civic services. It has excessive load of work on bodies providing civic services. As a result, those services have become unable to perform properly. On the other hand, many people in our societies have lost civic sense. Some of them drop their domestic wastes (including plastics) into drains or throw away garbage on roads. Some persons draw most of the supply water through electric pumps and all the other inhabitants of the area go without water.
Ecological Impacts of Population Growth
The scientific study of inter-relationships among organisms and between organisms, and all aspects- living and non-living, of their environment is called as Ecology. Thus ecology relates to environment and ecological impacts of population means impacts of population on environment and its various components
The Ecological Impacts of population growth includes - impacts of population growth on Physical and Biological components of the natural environment.
A. Impacts of Population Growth on the Physical Environment
Physical environment means – non living environment or the land, air, water, soil and minerals. The utilization, overuse and misuse of physical resources increased manifold due to the growth of human population. As it has been told earlier, more population means more mouths to eat food which requires more agricultural production. More agricultural production demands two things – (i) more cultivable land, and (ii) advanced agriculture. More cultivable land has been made available by clearing forests and by reclaiming wet lands, ponds and green belts. Advanced agriculture requires utilization of more water, more fertilizers and more pesticides. Application of fertilizers and pesticides makes the soil infertile. Clearing of forests has its own serious impacts and the environment on the whole gets imbalanced.
More population means more space to construct houses and availability of more consumer goods. It also requires more means of transport, more consumption of fossil fuels and more pollution of air, land and water. Thus growth of population leads to pollution of air, land and water. Different types of pollutions are causing a number of problems in the physical environment that are further affecting the biological environment seriously.
B. Impacts of population growth on biological environment
The population explosion of earlier days and of present day also, has already caused and still it is causing serious impacts on the global environment. As for biological environment, Human Population has stressed most of the biological systems, comprising flora and fauna as well as biological diversity.
Ecosystem is the smallest unit of the biosphere. Since most of the components of the physical components are under serious threat due to population explosion, all the biological components are bound to suffer the consequences. And, hence most of the natural processes have been altered seriously that have caused serious imbalances in ecosystems. Let us have some glimpses of these imbalances-
  1. For expanding cultivable land, forests have been cleared on large scales. Illegal timber trade by timber mafias and local pressure for fire wood have further depleted our forest resources. These destructive activities of human being have driven away many species of wild animals and have caused extinction up to considerable level. Forests have also been cleared for setting up of industries and for urbanisation. Thus habitats of varieties of birds, and other animals have been destroyed through human activities. There are other reasons of forest destruction also. Some of those reasons are forest fires and Jhooming. Jhooming is the practice of growing crops after clearing forest land by burning the vegetation. It is also called as slash and burn cultivation. Intensive agriculture and mining have also caused large scale destruction of habitats.
  2. Frequent water crises in many parts of the world caused failure of agriculture leading to hunger and starvation. Vast varieties of plants and animals have been killed due to water crises. Frequent water crises often lead to migration of people and animals to other places thus causing overload on the resources of those areas.
  3. Poaching and killing of wild animals and illegal trade in their body parts have already caused extinction of several species of animals.
  4. Generation of waste due to increasing consumer culture and population explosion is causing spread of serious epidemics and deaths of people in many parts of the world.
Habitat destruction and overexploitation of resources etc. induced by population growth has caused serious depletion of biodiversity in many parts of the world. Bio- diversity is the species richness in a particular area and its depletion causes serious losses of a number of factors that are vital for running up of ecosystems.
Key Words:  human population ,Demographer,health education, housing, social security, employment,Explosive growth,hunger, malnutrition, mass starvation, increasing consumption, encroachment on monuments, stress on common social facilities, stress on civic services,Demographic Transition,pollution, Jhooming, poaching and killing, destruction of habitats,water crisis,epidemics

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