The World Population

Written and reviewed by Subhra Gupta, Humanities faculty at UniDrill (M.A. Sociology, University of Delhi · 7 years teaching Humanities). Based on NCERT Geography Class XII (Fundamentals of Human Geography), Chapter 2.

Why does almost everyone live on a tenth of the land?

Look at the earth from space at night and you will see lights bunched in clusters, with huge dark patches between them. That is not an accident. Broadly, 90 per cent of the world's population lives in about 10 per cent of its land area. A geographer's first job is to ask why people choose some places and avoid others. The geographer George B. Cressey said it neatly about Asia: it has many places where people are few and few places where people are very many. The same is true of the whole world.

Distribution and density: two different questions

Population distribution is the way people are spaced over the earth's surface: where they live. Density is how crowded a place is: the number of people compared with the size of the land. Each unit of land can support only a limited number of people, which is why the ratio matters.

$$\text{Density of population} = \dfrac{\text{Population}}{\text{Area}} \quad (\text{persons per sq km})$$

Worked example: a region's density. Region X has 1,50,000 people living in 100 sq km. What does its density tell you?

The common wrong step is to divide area by population, which gives sq km per person. Density always has people on top.

The 10 most populous countries together hold about 60 per cent of the world's people, and 6 of these 10 are in Asia. Distribution is therefore very uneven: a handful of countries and a small slice of land carry most of humanity.

Why people live where they do

The factors fall into three groups. Learn them as a set, because CUET often gives a place and asks which factor explains it.

Why the geographical factors come first. Water, flat land, a gentle climate and good soil together make farming easy, and farming feeds large numbers. Economic factors then pile more people onto the same places: a factory belt or a city grows fastest where roads, water and food are already available. That is why the densest regions are usually both well watered and well connected.

Pause and predict: a mineral rich desert region has almost no rainfall but a large copper mine. Will it be sparsely or densely populated?

Check your answer: it can still be locally dense. Minerals are an economic factor that attracts workers, as the Katanga Zambia copper belt shows. Harsh climate holds numbers down overall, but the mining area can become a crowded pocket.

Population growth and its vocabulary

Population growth or change is the change in the number of inhabitants of a territory over a given period. It can be positive or negative and can be given in absolute numbers or in percentage. It is an important indicator of economic development, social upliftment and the historical and cultural background of a region.

Three components of population change

Population changes through births, deaths and migration, nothing else. The first two are measured as rates per thousand of the mid year population.

$$\text{CBR} = \dfrac{B}{P} \times 1000 \qquad \text{CDR} = \dfrac{D}{P} \times 1000$$

Here $B$ is live births in the year, $D$ is deaths in the year, and $P$ is the estimated mid year population. Mortality is shaped by the region's demographic structure, its social advancement and its level of economic development. A population can also grow because the death rate falls, not only because the birth rate rises.

Worked example: from rates to actual growth. In a year a region has a mid year population of 24,00,000, with 36,000 live births, 18,000 deaths, 5,000 people moving in and 8,000 moving out. Find CBR, CDR, natural growth and actual growth.

The common wrong step is to forget that the region loses people to out migration, or to count only the births. Natural growth ignores migration. Actual growth never does.

Migration: the third component

When people move, the place they leave is the place of origin and the place they reach is the place of destination. Origin loses population and destination gains it. Migration may be permanent, temporary or seasonal, and may run rural to rural, rural to urban, urban to urban or urban to rural. It can be seen as a spontaneous effort to restore a better balance between population and resources.

The same person is both an emigrant (from the place they leave) and an immigrant (into the place they reach). Whether you say emigrant or immigrant depends on which end of the journey you are describing.

Two views. For the exam: migration is a spontaneous effort to balance population and resources, driven by push and pull factors. Another reading: some scholars say the push and pull picture makes migration look like a free personal choice, when in many cases families are pushed out by conflict or disaster and have few real options. They suggest looking at who gets to move, and where they can afford to go, alongside the two lists.

Demographic transition: how societies change

The demographic transition theory describes how a region's population changes from high births and high deaths to low births and low deaths as society moves from a rural, agrarian and illiterate state to an urban, industrial and literate one. The stages together are called the demographic cycle. The theory can describe and predict the future population of any area.

Reading the graph in words. The graph plots birth rate and death rate against time, with both on a scale from about 15 to 35 per thousand. In Stage I the two lines run high and wiggle together. In Stage II the death rate falls steeply while the birth rate stays high at first and then slowly declines, leaving a wide wedge between the two lines that represents natural increase. In Stage III both lines run low and wiggle close together.

Two hundred years ago, all countries of the world were in Stage I. Different countries today are at different stages. The lesson of the theory is that human beings are extremely flexible and able to adjust their fertility.

Why Stage II has the fastest growth. Think of a bathtub. Medicine and sanitation close the drain (deaths fall), but the tap (births) is still fully open. Only when families gradually decide to have fewer children does the tap close too. The gap between the two is the surge of population in Stage II.

Beyond the textbook. For the exam: three stages, with the examples in the table above. In reality: the model was built from the experience of early industrialising countries, and many countries have not followed its path exactly. Some have moved from Stage II to low birth rates much faster than the early industrialisers did, and the idea of a settled "low fluctuating" end point has been questioned because some populations have begun to shrink. Why it matters: in an answer, describe the stages as a general pattern, and do not say that every country must pass through them on the same timetable.

Pause and predict: a country improves vaccination and clean water programmes but family sizes stay large for another generation. Which stage's feature does this produce?

Check your answer: Stage II, expanding. Death rates fall quickly while the birth rate stays high, so the net addition to the population is large.

Population growth in perspective

Human population increased more than ten times in the past five hundred years, and in the twentieth century alone it increased four times. The world at the beginning of the 21st century held over 6 billion people.

Population control and Malthus

Family planning means spacing or preventing the birth of children. Access to family planning services is a significant factor in limiting population growth and improving women's health. Propaganda, free availability of contraceptives and tax disincentives for large families are among the measures that can help.

Thomas Malthus (1798) argued that population would increase faster than food supply. Further increase would then cause a population crash through famine, disease and war. He believed preventive checks (people choosing to limit births) are better than the physical checks (famine, disease and war). For the sake of sustainable resources, the world will have to control rapid population growth.

Two views. For the exam: Malthus warned that population outruns food and that preventive checks are better than physical ones. Another reading: the economist Ester Boserup argued the opposite emphasis: when population presses on land, farmers adopt new methods and technology, so food output can rise with population. Many scholars take a middle position that both pressures can operate, depending on technology, institutions and how food is shared. The exam answer is still the Malthusian one.

Exam traps

60-second revision

Where this chapter connects

• Previous: Human Geography gave the idea that human phenomena such as population vary over space, which is the starting point here.
• Next: Human Development moves from counting people to asking how well they live, using the same ideas of resources and well-being.
• Applied to India: Population: Distribution, Density, Growth and Composition uses these same concepts and formulas to study India's population.