INTRODUCTION:- Population geography is the sub-branch of Human geography which deals with population phenomena, their distribution, and spatial variations over the earth's surface by demonstrating how spatial variations in distribution, composition, migration, and growth are related to the spatial variations like places.
For a population geographer, however, the phenomena of population growth have special significance. He/she values it as a vital index of a region's economic development, social awaking, historical and cultural background, political ideology. Population growth is, thus pivotal to the region's demographic dynamism. Population growth is an area that holds the key to the understanding demographic structure of the area.
DEFINITION:- Population change or growth of population is used to connote the change in the number of inhabitants of territory during a specific period, irrespective of the fact whether change is positive or negative.
TYPES OF POPULATION GROWTH/MEASUREMENT OF POPULATION GROWTH
NATURAL GROWTH:- Natural growth rate of the population is obtained by dividing the difference between the birth and death of the population at the beginning of the period and multiplying with hundred.
NATURAL GROWTH = BIRTH RATE – DEATH RATE*100
ACTUAL GROWTH:- when the impact of in and out-migration is taken into account .when the difference between birth rate and death rate summed with the difference between in-migration and out-migration then multiplied by hundred, it is known as actual growth rate.
ACTUAL GROWTH= (BIRTH RATE - DEATH RATE) + (OUT MIGRATION – IN MIGRATION)*100
Any change in the population of an area over a certain period is expressed in the form of the rate of population growth per annum. Here population at the time (t+1) is considered as a function of the population at the time (t). the simplest and most commonly used measure is the Arithmetic rate of increase in population. According to this, the population at time t would equal to –
Pt = P0 (1+rt) . Here, P0 = population at the base year, r= rate of growth, t= interval between the base year and terminal year.
DECADE GROWTH RATE=(PRESENT DECADE POPULATION – PAST DECADE POPULATION)/PAST DECADE POPULATION*100
Since the population of an area actually grows geometrically, it is suggestible to apply the Annual compound growth rate, while analyzing the changes in population size. It can be expressed in the following manner – Pt=P0(1+r)t. The above equation is also known as the Geometric law of population growth. Under the assumption of geometric growth of population growth at a rate of 1% per annum will double its size in 70 years and 2% rate of growth in 35 years. The duration involved is called Doubling time. Still, another measure of the analysis of change in population size is the Exponential rate of growth. This measure is based on the assumption that population growth follows on exponential distribution, which is a generalization of the geometric function when time is considered to be a constant variable
ANNUAL GROWTH RATE = DECADAL GROWTH RATE/10
DETERMINANTS OF POPULATION GROWTH
Population geographers considered the following basic determinants of population growth:-
1. FERTILITY:- High fertility rate is responsible for positive growth if it is more than the death rate whereas a low fertility rate is responsible for negative growth if it is less than the mortality rate. There are several factors of fertility, such as –i) Biological factors. ii) Demographic factors. iii) Social determinants.
2. MORTALITY: -High death rate decreases the population if it is more than the birth rate whereas a low death rate increases the population if it is less than the birth rate. There are several factors of mortality, such as – i)Biological factors, ii) Demographic factors, iii) Accidental factors, iv) Political factors)Economic condition. 3. Migration: Migration is a strong determinant of actual population growth. Migration increase, the actual population growth while out-migration decreases the population growth. Migration is controlled by two types of factors – i) push factor, ii) pull factor.
4. LIFE EXPECTANCY:- Life expectancy is also considered a determinant of population change. High life expectancy decreases the death rate, hence population is increased and vice-versa.
5. OTHERS:-
(i) Population structure:–population growth (sex ratio, age structure) depends upon population structure. Where the number of 18 – 35 years population is more there population growth is more.
(ii) Economy:- Where the needs of laborers are more, especially in agricultural areas population growth is high, and in the areas of trade and commerce population growth is low.
(iii) Education:– It creates awareness among the people about the negative impact of population growth. Where the level of education is high, those regions show low growth and vice-versa. Social rituals, poverty, malnutrition, expectancy to get male children, etc. are also responsible for the high population growth of a region.
Trends of world population growth in different years are shown in the below table and the diagram. Three cultural factors that affect world population growth are – i) Agricultural Revolution- About 10000 years ago, it was marked by animal and plant domestication and then settled life possible providing food supply. Ii) Industrial Revolution- later half of the 18 century. iii) Medical Revolution-Came in the 20th century. This change marked a reduction in the death rate. Different continents show differences in population growth rate, which is shown in the below table.
PHASES OF INDIAN POPULATION GROWTH:-
(i) Phase I- Period of stagnant population growth(1901-1921):- In this period the growth was more or less stagnant. In fact the census year 1921 registered a negative growth rate of -0.31%, which happened only once throughout the demographic history of India, that’s why the year 1921 is called the Demographic divide. In this period high mortality was found due to abnormal deaths for epidemics of influenza, plague, smallpox, cholera, etc.
(ii) Phase II- Period of steady population growth(1921-51):- In this phase population of India was increased from 251 – 361 million. This duration of 30 years has thus registered a population growth of 47.3%, therefore this period is called the period of steady growth rate. In these decades mortality rate was started to decline controlled of drought and famine, supply of food, and control of epidemics, resulting in the growth of population.
(iii) Phase III- Period of rapid high population growth(1951-81):- After 1951 a steep fall in the mortality rate but fertility remained stubbornly high. Therefore this period experienced a very high rate of population growth and is often called a period of population explosion. Lack of family planning and birth control measures were responsible for the high growth rate.
(iv) Phase IV- Period of high growth rate with definite signs of slowing down(1981-2011):- Up to 2001 the growth rate slightly changed but from 1991 till 2011 growth rate was declined. The decline in growth rate was mostly due to controlling the birth rate up to some extent. So family planning strategies were adopted mostly by the urban educated population. Govt. has also taken initiative to popularize family planning and the use of medically sound birth control methods.
The population growth rate in India has shown In the table and the below graph.
EFFECTS OF POPULATION GROWTH
The population is a human resource of production. It has a two-sided effect on a country’s economy. When the population of a country takes part in economic development in terms of increasing investment and savings, it doesn’t suggest a population problem. Whether the population is helpful or not it is a relative concept. Effects of population growth are noted below:-
( A) POSITIVE EFFECT:-
(i) It increases the rate of the human population, lab-our supply.
(ii) It increases the volume of the working population.
(iii) It increases the volume of the working population.
(iv) Helpful for the formation of capital.
(v) Expand the market area of the country.
(vi) Increase the rate of trade and commerce.
(B) NEGATIVE EFFECT:-
(1) On Lithosphere:-
(i) It increases the rate of soil erosion by crop rotation, crop diversification, etc.
(ii) It causes soil degradation; change in soil structure, chemical composition, etc.
(iii) In mountainous area landslide is common due to overpopulation growth and with their activities.
(iv) Happening topographic change; lowland fills up.
(v) Salinization, deposition of plastic are also.
(2) On Atmosphere:-
(i) Increase the air pollution rate.
(ii) Change in global heat budget, change in rainfall pattern.
(iii) Ozone layer depletion and Acid rain.
(3) On Hydrosphere:-
(i) Steady rate of urbanization changing the hydrological character of the surface and sub-surface water in terms of both qualitative and quantitative characteristics.
(ii) Increase water pollution.
(4) On Biosphere:-
(i) Loss of bio-diversity, for the diminishing of the forest.
(ii) Create imbalance in the surrounding environment.
(5) On social& economic environment:-
(i) Creates living/settlement problem.
(ii) High rate of population growth creates an unemployment problem.
(iii) Hampers the nation's economy and decreases the rate of per capita income.
(iv) Increases corruption, crime rate, and political problem.
No other problem, concerning population, has attracted much attention from scholars on population growth. It has been mainly due to 5 factors -
(i) In the last 200-250 years have been seen unprecedented growth of the world population.
(ii) This continued population explosion has increased for foodstuffs and resources.
(iii) The gap of per capita income between developed and developing countries has been widening rapidly.
(iv) The environmental damage by demographic & non-demographic processes has been increased.
(v)The population pressure particularly in the less developed world has been increasing tremendously.
PREVENTIVE METHODS FOR CHECKING POPULATION GROWTH:-
1. Increasing mass education, Female education.
2. Increases social consciousness.
3. Proper family planning and implementation of the population policy.
4. Increase Industrialization, an extension of trade, and commerce.
Population growth in any region is the most important element of the region’s dynamism. It is a vital index of an area’s economic development, social awaking, historical and cultural background, and political ideology.
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