Introduction
We, humans, are the most intelligent creatures on Earth. We have developed a lot from the time of our origin. This development is definitely very good but it also brings few curses with it. One such curse is the natural increase and population growth. The population increase has many adverse effects on our nature and natural resources. And not only nature, but there are also other problems too, such as food shortage, increase in pollution, global warming, deforestation etc. Let us first understand what is population growth, natural increase and population growth.
What is Population Growth?
Population Growth is the number of increased persons in a population. Our population has grown rapidly in the past few years. It has increased from 1 billion in 1800 to 7.7 billion today. The population growth rate is the change in population over a certain period of time and mostly expressed as a percentage of the number of individuals calculated at the beginning of the time period. Population growth rate can be expressed mathematically as,
Population growth rate = P(t2) - P(t1) / P(t1)(t2 - t1)
If the population growth rate is positive, then the population is increasing and if the rate is negative, then the population is decreasing. If the population growth rate is zero, then there is no change in population over a particular period of time.
Population growth differs from population change. The main difference between population growth and population change are:
What is the Difference Between Population Growth and Population Change?
Define Natural Growth Rate
Definition of Natural Increase Rate or the Natural Growth Rate is the difference between the number of deaths and births of a population. The rate of Natural Increase is given by the formula -
Rate of Natural Increase (RNI) = [(Births in a year - Deaths in a year) ÷ Total Population at the start of the year for which the rate is being calculated.]
One drawback of RNI is that it excludes in-migration and out-migration and gives results based only on births and deaths.
Natural Population Growth
Natural Population Growth depends on the number of births and deaths. Natural Population increases with birth and decreases with death. Also, there is a natural increase when there are more births than deaths in the population. Similarly, there is a natural decrease when there are more deaths than births in the population.
Population Momentum
Population momentum is something that explains why the population continues to grow even though the fertility rate of the population declines. It is a result of the demographic transitions. When the population is calculated, the children and youth are also included in the population. These children and youth eventually grow up and start reproducing which increases the population. These changes happen over decades and are difficult to control. Eventually, there comes an equilibrium position where the fertility rate reaches the replacement rate and the population size in the reproductive age stabilizes. Population momentum is the ratio between the size of the population at the equilibrium level and the size of the initial population. Population momentum impacts the natural growth rate. To have the population zero growth rate, three conditions must occur:
The fertility rate should be at an equal level to that of the replacement rate. If the fertility rate becomes higher, the population continues to increase.
The mortality rate should remain constant.
The age structure must be in equilibrium, with the new fertility and mortality rate.
Population Composition
The most important characteristics of the population are its size, rate of growth, and the way its members are distributed according to their age, sex, ethnicity, and their residential status.
Age Distribution: Demographers generally use population pyramids to depict the age distribution. Population pyramids are the bar graphs in which the horizontal bar is for the number of persons in an age group.
Sex Ratio: It is the second structural aspect of the population. The population is structured by the relative numbers of males and females who compose it. Sex ratio is the number of females per 1000 males.
Ethnicity: The population of all nations are diverse with respect to national, cultural, religious or linguistic diversity.
Geographical Distribution: The population is very widespread. They are scattered in rural areas and urban areas. There is a flow of population mostly from rural areas to urban areas and this is one of the characteristics of population composition.
FAQs on Natural Increase and Population Growth
1. Which Factors Influence Population Fluctuation?
Ans - Factors that influence population fluctuation are:
Natality or Birth Rate - Number of births in the population in a particular time period.
Mortality or Death Rate - Number of deaths in the population in a particular time period.
Immigration - Number of people coming from other populations and adding up in a particular population in a particular time period.
Emigration - Number of people going away from the population in a particular time period.
2. What are the Adverse Effects of Population Growth?
Ans - The adverse effects of population growth are:
Scarcity of resources to meet the needs of a growing population.
Rise of unemployment and underemployment.
Eradication of poverty and hunger becomes difficult.
Providing health care facilities and education to all becomes difficult.
Deforestation to meet the needs of the growing population by building homes and factories as per the need.
Deforestation causes soil erosion and other changes which eventually disbalances our ecosystem and causes global warming.
Overexploitation of natural resources.
A rapid increase in pollution - be it air, water or soil.
Global warming and decay of the Ozone layer.
