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. What is meant by the 'natural increase' of a population?
Natural increase is the change in a population's size based only on the number of births and deaths over a specific period. It is calculated by subtracting the crude death rate from the crude birth rate. This figure does not include the effects of migration (people moving into or out of a country).
2. What is the main difference between natural increase and actual population growth?
The main difference between the two is migration. Natural increase only considers births and deaths. In contrast, actual population growth provides a complete picture by including migration. The formula for actual growth is (Births - Deaths) + (Immigrants - Emigrants). This means a country's population can still grow through immigration, even if its natural increase is low or negative.
3. How is the Rate of Natural Increase (RNI) calculated for a country?
The Rate of Natural Increase (RNI) is calculated with a simple formula: RNI = (Crude Birth Rate – Crude Death Rate) / 10. The result is given as a percentage. For instance, if a country has a birth rate of 25 per 1,000 people and a death rate of 10 per 1,000 people, its RNI would be (25 - 10) / 10 = 1.5%.
4. Can the rate of natural increase be negative, and what does that mean for a country?
Yes, the rate of natural increase can be negative. This occurs when a country's death rate is higher than its birth rate over a year. A negative RNI means the population is shrinking due to more deaths than births, not accounting for migration. This trend is often seen in highly developed nations with ageing populations and lower fertility rates.
5. Why is very rapid population growth often considered a challenge?
Rapid population growth can be a significant challenge as it places a heavy strain on a country's resources and services. Some common issues that arise include:
- Increased demand for resources like food, water, and energy.
- Pressure on public infrastructure such as schools, hospitals, and transportation.
- Difficulty in creating enough jobs, which can lead to higher unemployment.
- Greater environmental impact, including pollution and deforestation.
6. What other factors besides births and deaths affect a country's total population change?
Besides the natural increase from births and deaths, the other key factor is net migration. Net migration is the difference between the number of people immigrating (moving into a country) and the number of people emigrating (moving out of a country). A country's total population change is therefore a combination of both its natural increase and its net migration.
7. What are the 'crude' birth and death rates in geography?
In geography and demography, these rates are defined as follows:
- The Crude Birth Rate (CBR) is the total number of live births per 1,000 people in a population within a year.
- The Crude Death Rate (CDR) is the total number of deaths per 1,000 people in a population within a year.
