POPULATION GROWTH: WORLD PATTERNS AND THEIR DETERMINANTS M.A. SEMESTER ...

[Pages:21]POPULATION GROWTH: WORLD PATTERNS AND THEIR DETERMINANTS M.A. SEMESTER-II, PAPER-VII

RAKESH KUMAR ASSISTANT PROFESSOR PG DEPT OF GEOGRAPHY MAGADH UNIVERSITY, BODHGAYA

DISCLAIMER

The study material for this presentation has been collected from various books, articles, online sources and it is for general information and educational purpose only. While the author makes every reasonable effort to make the information updated and correct, he claims no guarantee of any kind about the completeness and accuracy of the material. The information shared through this should be used for educational purpose only.

THIS STUDY MATERIAL IS ABOUT

How does a population grow? How quickly has the world's population grown? Where is it growing the fastest or the slowest and

why? What is the pattern of population growth across

space and time? What are the implications of population growth? What is the future scenario of population growth?

POPULATION GROWTH

Population growth refers to the change (increase or decrease) in the total population of an area in a specific period of time. It is also known as population change. It depends on its historical and cultural background and social and economic changes taking place in that area. For example: Population of India as per the 1991 Census -102.7 crore Population of India as per the 2011 Census-121.01 crore Population growth= 121.01-102.7=18.31 crore (in terms of actual numbers)

Population growth rate: The change in population expressed in terms of percentage. Natural growth of population: The change in population due to the difference in births and

deaths in an area between two given points of time. Natural growth= Births- Deaths Actual growth of population= Births- Deaths + In-migration- Out migration Positive growth of population: When the birth rate is greater than the death rate between two points of time or people from other countries migrate permanently to an area. Negative growth of population: When the population of an area decreases between two points of time, it is called negative growth of population. It takes place when death rate is higher than the birth rate or out migration to other countries is more.

WORLD POPULATION FROM 10,000 BC TO TODAY

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CONTINUED.....

The chart above shows that entire human population 12000 years from now was about 4 million. Historical demographers estimate that around the year 1800 the world population was only around 1 billion people which implies that on average the population grew very slowly over this long time from 10,000 BCE to 1700 AD(by 0.04% annually). The world population was around 1 billion in the year 1800 and increased 7-fold since then. The Industrial Revolution was the watershed in the world population growth. A huge change occurred with the Industrial Revolution: it had taken all of human history until around 1800 for the world population to reach one billion mark, the second billion had come in only 130 years (1930), the third billion in 30 years (1960), the fourth billion in 15 years (1974), the fifth billion in only 13 years (1987), the sixth billion in 12 years(1999) and the seventh billion in 12 years (2011). (Pls see the chart on the next page) The period of fastest growth occurred through 1975 to 2011, taking only 12 years to increase by one billion for the 5th, 6th and 7th. During the 20th century alone, the population in the world has grown from 1.65 billion to 6 billion. In 1970, there were roughly half as many people in the world as there are now. At the present rate of declining growth rates, it will now take over 200 years to double again.

TIME TAKEN FOR EVERY ONE BILLION INCREASE IN THE WORLD POPULATION

SOURCE:

POPULATION DOUBLING TIME

One way to easily grasp the growth rate in world population is to compare a population's rate of growth to its doubling time. It means the time taken by a country to double its population. Doubling time of any population can be calculated by using the Rule of 72. To do this, 72 is divided by the annual population growth rate.

For example, suppose the annual population growth of a country is 1.6 % at a particular point of time, time taken by its population to double itself will be 72/1.6 i.e, it has doubling period of 45 years.

The world population reached 1 billion mark in 1803 and barely more than a century after this, in 1930, it reached 2 billion. After that, the doubling time was down to less than 100 years and dropping fast; the population explosion was in full gear. It took only 45 years for the next doubling to take place, to 4 billion (1975). During the mid-1980s, when the rate declined to 1.8 percent, the doubling time was 39 years. Today, world population is doubling in 54 years, and the continuing slowdown in the estimated doubling rate is one of the bright spots in the problematic demographic picture.

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