Chapter 15: Population — The Increasing Numbers and Rising Problems
In 1798 an English clergyman and scholar named Thomas Robert Malthus published a small book without putting his name on it. Its title was plain: ‘An Essay on the Principle of Population’.
Malthus was not guessing. He had been reading the registers in which English parishes entered every birth and every death, and reports from the United States, where the number of people seemed to double in about twenty-five years. Two patterns struck him. People multiply. Two parents may leave four children, those four may leave eight, and those eight sixteen. Farmland does not multiply. A farmer can drain a marsh, clear a wood or manure a field and add a little to the harvest each year — but only add.
From this he drew a conclusion that disturbed his readers. Numbers that double must sooner or later overtake numbers that merely add, and when they do, food runs short. The world he was writing about held fewer than one billion (1,000 million) people.
Malthus was wrong about the timing. He could not foresee steel ploughs, chemical fertilisers or crop varieties bred for heavier yield, and food production climbed faster than he thought possible. But the question he asked has never gone away, and you live inside the answer to it.
Diagram
Fig. 15.0-1 — Two Ways Of Growing Two-panel line drawing. Left panel: an open eighteenth-century parish register on a writing desk with a quill, its two columns headed ‘Births’ and ‘Deaths’. Right panel: a single graph with time on the horizontal axis and quantity on the vertical axis, carrying two curves — a steeply bending curve labelled ‘numbers that double: 2, 4, 8, 16’ and a straight sloping line labelled ‘numbers that add: 1, 2, 3, 4, 5’; mark the point where the two lines cross.
15.1 Rising Population — A Global Threat
Stand at a bus stop in any Indian city in the morning and you will see the same thing: more people than seats. Your grandparents’ school probably had fewer classrooms than yours does. Something has changed, and it has changed quickly.
In biology, a population means all the individuals of one species living in a particular area at a particular time — the tigers of a reserve, the mosquitoes of a pond, the people of a country. The human population is one such population, and it is the one this chapter follows. What makes it worth a chapter of its own is the speed at which it has grown.
Human numbers have risen sharply across the world, and in India in particular, over the last two hundred years or so. Every one of those people needs food, clean water, fuel, land to live on and space to work in. The numbers rise faster than the supply of any of these.
Why It Is A World Problem
It would be comfortable to treat this as one country’s difficulty. It is not. The air and the oceans are shared, fuel and food are traded across borders, and forests cut down in one place change rainfall and climate far beyond it. A shortage or a pollutant does not stop at a boundary line, so a rise in numbers anywhere is felt everywhere.
This is why newspapers, radio, television and public campaigns keep returning to the subject. Their aim is not to alarm people but to inform them, because a problem of this kind is solved by ordinary decisions taken by very large numbers of families.
The rest of the chapter takes the question in three steps: how human numbers grew to their present size, what pressures that size puts on the earth’s resources, and what can be done to slow the rise.
15.2 World Population Through The Ages
Human beings are not a new species on this planet, but large human numbers are very new indeed. For almost the whole of our history there were remarkably few of us, and the total rose so slowly that no one alive would have noticed it changing.
About fifty thousand years ago, the best estimates put the entire world population at around one million people — fewer than live in a single large city today. Spread over every continent then occupied, that is a very thin scattering of human beings.
The reason is not hard to see once you look for it. Food was found, not grown. A band of people could only take what the land happened to offer that season, and cold, injury, hunger and disease removed many of them early. Like any other population, ours could grow only as fast as its food supply and its safety allowed.
15.2.1 Life Before Farming — The Tool-Making Revolution
Early humans knew nothing about farming. They wandered in search of food and took shelter in caves. They killed animals and ate the meat raw or roasted it on a fire, caught fish from rivers, collected eggs from birds’ nests, and gathered fruits, roots and leaves from wild plants.
Living alone was dangerous, so people lived in groups. A group could drive away a predator, share a large kill and look after children while others searched for food. In groups they also learned to hunt animals far larger than themselves, such as the mammoths.
Their great advantage was not strength but making things. From stones, sticks and bones they shaped tools, and over thousands of years those tools grew sharper, lighter and better suited to particular jobs. Because the tools were still mainly of stone, this long period is called the stone age, and the steady improvement in them is called the tool-making revolution — the first great change in the human way of life.
Think about what a sharpened stone edge actually does. A human being has no claws and no cutting teeth, so without a tool a carcass is almost impossible to open. A stone flake does the work of a carnivore’s teeth: it cuts hide, separates meat from bone and scrapes the bone clean. More of every animal killed became food, and less was wasted. Some of the earliest such tools are shown in Fig. 15.2-1.
Diagram
Fig. 15.2-1 — Early Stone Tools Line drawing of four stone-age tools in a row, drawn to a common scale bar: a hand axe, a side scraper, a pointed flake and a stone point bound with sinew to a wooden shaft. Label each tool, and label the worked cutting edge on the hand axe and the scraper.
Tool-making did not begin with our own species. Earlier members of the human line, such as Homo erectus, were already shaping stone tools and sheltering in caves long before, and our species, Homo sapiens, inherited the craft and carried it much further.
15.2.2 Settled Life — The Agricultural Revolution And The Metal Age
About ten thousand years ago the world population had reached roughly five million, and the human way of life began to change in a way it never had before. Four changes came together, and each one fed the others.
People stopped wandering and began to live in settled communities of simple huts. They began domestication — keeping and breeding useful animals in place of hunting them, choosing the tamer and more useful ones in each generation. The dog was the first animal to be domesticated, from wolves that stayed near human camps.
They also learned to sow seed, wait for it to ripen, harvest it and store the grain. This was the beginning of agriculture — growing food deliberately instead of gathering whatever grew wild. Later their stone tools and weapons were gradually replaced by tools of bronze and iron, and the metal age began, with ploughs and sickles that cut deeper and lasted longer.
Now follow what these changes did to human numbers, which is the point of the whole story. Grown food yields far more on one patch of land than gathered food does. Stored grain carries a family through a bad season instead of letting hunger thin it out. A settled family does not have to carry its infants from camp to camp, so children can be born closer together. Each of these makes survival more likely, and together they turned a nearly flat population line upward. The chain is set out in FC 15.1.
Flowchart
FC 15.1 — How The Early Revolutions Raised Human Numbers Better stone tools → more food from each animal killed → settled life in huts → domestication of animals and sowing of crops → surplus food stored for lean seasons → metal ploughs and sickles raise the harvest further → more children survive to become parents → population begins to grow faster
Diagram
Fig. 15.2-2 — An Early Farming Settlement Line drawing of a small settlement: a cluster of thatched huts, a fenced enclosure holding goats and cattle, a standing crop of cereal with a person cutting it using a sickle, a large storage jar of grain, a grinding stone, and a dog beside the huts. Label huts, penned animals, cereal crop, sickle, grain store, grinding stone and dog.
From Millions To Billions
Once the line turned upward it never turned back. It took the whole of human history to reach the first thousand million people, and then a shrinking number of years to add each thousand million after that. Table 15.1 sets out the milestones.
Read down the last column rather than the first. The world took 123 years to go from one billion to two, and 11 years to go from seven billion to eight. The same amount of people is being added in less than a tenth of the time. Why that happened is the subject of the next section.
15.3 Rapid Rise In Population
Farming had lifted human numbers, but it had not made life safe. For thousands of years after it, a poor harvest still meant hunger and an epidemic still emptied villages. The line rose, then flattened, then rose again.
The third great change was different, and it is the one that produced the world you live in.
15.3.1 The Scientific And Industrial Revolution
From the sixteenth and seventeenth centuries onwards, people began to study nature by careful measurement and experiment rather than by argument alone. Out of that scientific work came machinery, and from about the middle of the eighteenth century, factories, steam engines and railways spread outward from Britain across the world.
Industry changed daily life quickly. There were more jobs, more goods, and more comfort in the home. Just as importantly, more food was produced and, once railways existed, grain could be carried from where it grew to where it was needed instead of rotting in a good district while a bad one starved.
All of this favoured a rise in population, because more people could be fed and employed than before. But industry brought one serious drawback with it.
Factory towns packed people together far more closely than villages ever had. Close contact is exactly what an infectious disease needs — a disease caused by a micro-organism that passes from one person to another. Crowded housing, shared water and poor drainage gave such diseases the conditions they were waiting for, and outbreaks became widespread.
At the same time nutritional diseases appeared — illnesses caused not by any germ but by a diet that lacks something the body needs. A worker’s family living on a cheap, monotonous diet might eat enough to feel full and still fall ill for want of a particular nutrient.
So the picture at the end of the nineteenth century is a mixed one. More people were being born and fed than ever before, but a great many of them were still dying young.
15.3.2 New Discoveries In Medical Science
The twentieth century (1901–2000) is when the second half of that picture changed. Two kinds of discovery did most of the work.
The first were antibiotics — medicines that kill bacteria or stop them multiplying inside the body. Penicillin, the first of them to be widely used, turned infections that had regularly killed people into illnesses that could be treated in a few days.
The second were prophylactic vaccinations — preparations given to a healthy person so that the body is ready to fight a particular disease before it ever meets it. The word ‘prophylactic’ means guarding beforehand, and that is the whole idea: the protection is arranged in advance, not after the person falls ill.
Together these brought a sharp fall in the number of deaths in every age group, and the fall was steepest among the two groups that had always died most easily — infants and the elderly.
Now comes the step that is easy to miss. Medicines add no babies to a family. What they do is let babies who would have died grow up. More children per family began to reach the reproductive age, and every one of them who became a parent added children of their own. A single generation of saved lives therefore goes on multiplying long after the medicine has done its work, and the rate of growth of the population began to rise very rapidly.
15.3.3 Three Cultural Revolutions And The Two Question Marks
Put the whole story on one pair of axes, as in Fig. 15.3-1, and its shape becomes clear. Three great cultural revolutions stand out: the tool-making revolution, the agricultural revolution, and the scientific and industrial revolution.
Diagram
Fig. 15.3-1 — Three Great Cultural Revolutions Line graph, population on the vertical axis and time on the horizontal axis, marked ‘not to scale’. A single curve rises steeply three times, each rise followed by a long flattened stretch; break each flattened stretch with a wavy gap to show that a great deal of time has been left out. Label the three rises ‘(1) tool-making revolution’, ‘(2) agricultural revolution’ and ‘(3) scientific and industrial revolution’. End the solid curve at the present day and continue it as two broken branches, one climbing steeply and one levelling off, with a question mark against each.
The pattern repeats itself each time. A revolution gives people a better means of livelihood, the population climbs steeply, and then it settles at a new level and stays there — the flattened stretches, shown with wavy gaps because they lasted a very long time. Then the next revolution arrives and lifts it again, from a higher starting point and more steeply than before.
Notice where the solid curve stops. We are living in the third rise, and nobody knows what the next part of the line looks like. That is why the figure ends in two question marks.
The two possibilities have shapes of their own. A curve that keeps climbing ever more steeply is described as J-shaped. A curve that climbs and then levels off, because the surroundings cannot support any more individuals, is described as S-shaped. Which of the two the human population is drawing, and how soon, is the question the rest of this chapter is really about.
15.4 Population Explosion — A Serious Global Concern
When a population that has crept along for centuries suddenly multiplies several times over in a few generations, the change deserves a name of its own. The name in use is population explosion.
The explosion began about the middle of the nineteenth century. It is not spread evenly across the world: roughly two-thirds of all people alive today live in the developing countries, where average incomes are lower and industry is still growing. India and China alone account for about one-third of the world’s people.
That is why this is treated as a global concern rather than a local one. The countries adding the most people are, in general, the countries with the least to spare.
15.4.1 How The Growth Rate Has Changed Since 1750
To follow what has happened you have to watch two things at once: how many people there are, and how fast that number is increasing each year. Fig. 15.4-1 shows both on the same time axis, from 1750 to the projections for 2100.
Diagram
Fig. 15.4-1 — World Population And Annual Rate Of Increase, 1750–2100 Combined graph. Horizontal axis: years from 1750 to 2100, marked every 50 years, with a vertical dashed line at 2024 labelled ‘projection beyond this line’. Left vertical axis: world population in billions, drawn as a shaded area rising from about 0.8 billion in 1750, through about 1.65 billion in 1900 and about 2.5 billion in 1950, to 8 billion in 2022, then flattening near a projected peak of about 10.3 billion in the mid-2080s. Right vertical axis: annual rate of increase as a percentage, drawn as a single line staying below 0.5 per cent before 1800, climbing through the first half of the twentieth century to a peak of about 2.1 per cent in the early 1960s, falling to about 0.9 per cent in 2024, and continuing as a broken line towards about 0.1 per cent in 2100. Label the peak of the rate line ‘2.1% — highest ever recorded’ and the population curve at 2022 ‘8 billion, 15 November 2022’.
Before 1800 the human population increased by well under one per cent a year, which is slow enough that a person could live a whole lifetime without seeing much change. The scientific and industrial age then gave it fresh momentum.
Through the first half of the twentieth century the annual rate of increase climbed, and it reached its peak of about 2.1 per cent in the early 1960s — the highest annual rate ever recorded for our species. The world population crossed the 8 billion mark on 15 November 2022.
Since that peak the rate has come down steadily, and current projections put it near 0.1 per cent by the year 2100.
15.4.2 Six Main Reasons For The Sharp Rise
Six causes are usually picked out for the sharp rise in world population in the recent past. Notice as you read them that every one saves lives rather than adding births.
Better health care for all age groups. There are far more health centres, hospitals and trained doctors within reach of an ordinary family than there were a century ago.
Fewer deaths from disease. Regular vaccination programmes have brought many diseases under control or removed them altogether, and of the patients who do fall ill, far more are cured and go on to live long lives.
Food shortages minimised. More food is produced and, just as importantly, stored, so that starvation deaths have become rare where once they followed every failed harvest.
Improved nutrition. Families understand far better what a growing child needs to eat, and well-fed children resist disease better and live longer.
Large-scale immunisation against fatal diseases. Immunisation means giving protection against a disease before a person ever meets it, carried out for whole populations at a time rather than one patient at a time.
Fewer infant deaths. In earlier times a family might have four to six children and expect to lose one or more of them to disease. Today most newborn babies survive, and care during childbirth protects the mother as well as the child.
Put the six together and one conclusion follows. Even a couple who have only two or three children now add more to the next generation than a couple with six children once did, because almost all of those two or three survive. More and more children are reaching the reproductive age, and it is they who carry the growth forward.
15.5 A Highly Simplified Model Of Population Growth
Percentages and billions are hard to feel. A small imaginary example does the job better, because you can count every person in it.
Imagine a starting group of 20 people — 10 couples — who are between 20 and 30 years old. Give each couple an average of four children. Assume the children grow up, and that each of them in turn pairs off and has four children on reaching the same age of 20 to 30. Then simply count heads every twenty years.
A generation here means all the individuals standing at the same step in the line of descent: the parents are one generation, their children the next, their grandchildren the next. Table 15.2 follows four generations over sixty years.
Sixty at the start, six hundred at the end. In about sixty years — a single long lifetime — the population has multiplied ten times.
Why The Numbers Double
Look at the second row of the table rather than the totals. Ten couples produce 40 children; those 40 children make 20 couples; those 20 couples produce 80. The number of couples doubles at every step, and it doubles because four children make two new couples where there was one.
That single sentence contains the whole engine of the model. The size of each generation is not added to, it is multiplied — and multiplying a number that is already large has an effect that adding never has.
Why The Total Is Larger Still
There is a second reason the total climbs so steeply, and it is easy to miss. At year 40 the great-grandchildren have arrived, but the grandparents and great-grandparents are still alive. Four generations are on the earth together.
In earlier centuries that rarely happened, because people did not live long enough. The medical advances of the last hundred years did not only save infants; they kept older generations alive alongside the new ones. A population grows both by adding at the bottom and by holding on at the top.
Fig. 15.5-1 shows the same doubling as a branching diagram, which makes the shape of the growth easier to see than a column of figures.
Diagram
Fig. 15.5-1 — Doubling Across Four Generations Branching tree diagram drawn left to right. Start with a single pair of figures labelled ‘1 couple’. Branch to four figures labelled ‘4 children = 2 couples’, then to eight labelled ‘8 grandchildren = 4 couples’, then to sixteen labelled ‘16 great-grandchildren = 8 couples’. Below each stage write the running total of descendants alive: 4, 12, 28. Add a time scale beneath the diagram marked Year 1, Year 20, Year 40, Year 60.
What The Model Leaves Out, And What It Shows
No real population behaves this neatly. Not everyone marries, families differ in size, some people die young, and people move from one place to another. The model is deliberately stripped down so that one effect can be seen on its own.
That effect is enough to be going on with. If a doubling of this kind is not checked at some point, the arithmetic becomes absurd rather quickly. It has been calculated that, with no checks at all, human numbers in about seven hundred years would leave roughly one square foot of the earth’s surface per person. Nobody expects that to happen — but the reason it will not happen is either that families will grow smaller by choice, or that food, water and disease will do the checking instead.
15.6 Population In India
India’s population has followed the world’s pattern closely, and in places more sharply. To see how sharply, you need figures that were actually counted rather than estimated, and India has them.
A census is a count of every person in a country, taken on a fixed date. India has held one about every ten years since 1881, which gives an unbroken record of the country’s numbers stretching back well over a century.
15.6.1 A Century Of Indian Population Figures
Table 15.3 gives the census figure for each decade from 1901 to 2011, and beside it the number of people added since the previous census. The second column is the one that tells the story.
Run your eye down the third column. Every entry is positive except one, and the entries grow steadily larger: 14 million added in one decade at the start of the century, and about 182 million added in the last decade of the table. India added more people between 2001 and 2011 than it contained in the whole of 1901 — nearly the same number again.
The single negative entry is worth stopping at. Between 1911 and 1921 India’s population actually fell, by about a million. The influenza pandemic of 1918–19 swept through the country and killed many millions of people, and famine and other epidemics of those years added to the toll. It is the only decade in the whole record when deaths outran births.
Since 1951 the additions have been very large in every decade. Notice, though, what happens at the bottom of the column: the figure for 2001–2011 is slightly smaller than the one before it. The pace of addition has finally begun to ease, which is the same turn you saw in the world growth-rate curve, arriving here rather later.
Diagram
Fig. 15.6-1 — India’s Population, 1901 To 2011 Line graph. Horizontal axis: census years from 1901 to 2011 at ten-year intervals. Vertical axis: population in millions, 0 to 1300. Plot the twelve census figures as points joined by a smooth line, and mark each point with its value. Mark the small dip between 1911 and 1921 with an arrow labelled ‘influenza pandemic, 1918–19’.
Projections made in earlier decades have repeatedly been overtaken by the actual count. India crossed the one billion mark around the year 2000, sooner than many of those projections had expected.
15.6.2 India’s Population Today
India’s population is now a little more than 1.45 billion, which is about 145 crore. In 2023, by United Nations estimates, India passed China to become the most populous country in the world.
Set that against the country’s size. India is the seventh largest country in the world by area, so it holds the largest number of people on rather less than the seventh largest share of land. At the 2011 Census, about 382 people shared every square kilometre of the country — a figure well above the world average.
The 2011 Census also recorded that India had grown by 17.7% since 2001, adding 181.5 million people in ten years. The yearly rate of growth has since come down to about 1%, and it continues to fall slowly.
Growth is not spread evenly across the country. It is heaviest where people are moving to, and the large urban agglomerations of Delhi and Mumbai are now among the biggest in the world. What that concentration does to land, water and services is the subject of the sections that follow.
15.7 Factors Responsible For Population Explosion In India
The world’s population rose because deaths fell. In India the same thing happened, but the number of births stayed high for much longer afterwards, and the gap between the two is what produced the country’s explosion.
Why did births stay high? Not because of anything unusual about the people, but because of the conditions they were living in. A family’s decision about how many children to have is a reasonable decision taken inside a particular set of circumstances, and when those circumstances change the decision changes with them. Seven such circumstances have mattered most in India.
Limited education, particularly of girls. Where schooling ends early, a young woman usually marries earlier and begins having children earlier, and both she and her husband are less likely to have been taught how reproduction works or what methods exist for spacing births. Of all the factors on this list, this one shows the strongest and most consistent link to family size.
Traditional beliefs about children. In many societies, India among them, children have long been regarded as a blessing and a large family as a sign of prosperity. Where that view is strongly held, a couple may make no attempt to limit the number of children they have.
High infant mortality rate — the number of babies who die before their first birthday, for every 1000 born alive. Where many babies died, parents had more children so that some would survive to adulthood. This is a rational response to a real risk, and it is one that outlives the risk itself, as FC 15.2 shows.
Economic reasons. In a household that farms its own land or runs a small trade, children are working hands from an early age, and where there is no pension they are also the only support their parents will have in old age. Under those conditions more children means more security, not less.
Social customs, especially around the age of marriage. The earlier a couple marries, the longer the span of years over which they may have children, so early marriage by itself raises the number of births in a lifetime. Acceptance of family planning also varies a great deal from place to place, and where it is low the birth rate stays high.
Preference for a son. Many families have continued having children until a boy was born, in the belief that a son will carry on the family name and look after his parents in their old age. A couple following this practice may end up with several children, and sometimes still without the son they were hoping for.
Limited access to recreation and to information. Households with little access to entertainment, to media or to health services are also the households that reliable information about family planning reaches last.
Flowchart
FC 15.2 — Why Infant Deaths Keep Families Large Many babies die in infancy → parents have extra children so that some survive → health care improves and infant deaths fall → but families continue with the old expectation for a generation → many children now survive → family size falls only after parents come to trust that their children will live
What The Evidence Points To
Look at the seven factors together and a pattern appears. Not one of them is a belief that has to be argued away. Each of them is a response to a condition — poor schooling, insecure old age, babies who might not live — and each of them weakens when that condition is removed.
This is why work on population in India has concentrated on schooling, on child health and on making family planning services available, rather than on persuasion alone. Where those three have gone furthest, family sizes have fallen furthest, and they have fallen without anybody being compelled.
15.8 Rising Population — Pressure On Natural Resources
So far this chapter has counted people. Now it turns to what those people need, because a population does not exist by itself — it lives on the supply of things around it, and every extra person draws on that supply.
15.8.1 What A Resource Is
Notice how wide that definition is. Water is a resource, and so is sunlight, and so is a forest tree, and so is the iron ore under a hillside. Anything people draw on to live counts.
Six resources come under the heaviest pressure as human numbers rise: food, water, land, forests, energy and minerals. Each of the sections below takes one of them. For every one, the same difficulty appears — production rises, but not nearly as fast as the demand does.
One distinction runs through all six and is worth fixing now. A renewable resource is one that nature replaces within a human lifetime, provided it is not used up faster than it is replaced — a forest, or the water in a river. A non-renewable resource is one that took millions of years to form and is not replaced on any timescale that helps us — coal, petroleum, and every mineral ore.
15.8.2 Food
Food is the first need of humans, as it is of any living organism. People have found better and better ways of producing it, but the increase cannot match the increase in the number of mouths, and the reason lies in the shape of the two increases rather than in the effort put into either.
If unchecked, a population grows in geometrical progression — a pattern of 1, 2, 4, 8, 16, and so on, in which each step is the previous one multiplied. You saw exactly this in the model in section 15.5.
Food production grows in arithmetic progression — a pattern of 1, 2, 3, 4, 5, and so on, in which each step is the previous one with a fixed amount added. Bringing new land under cultivation adds a field; a better farming method adds a further quantity to the harvest. Each improvement adds; none of them multiplies.
Put the two side by side and the conclusion is unavoidable. A quantity that multiplies must eventually overtake a quantity that only adds, however large a head start the second one is given. Food would run short for an unchecked rising population.
Malthus, whose reasoning opened this chapter, could not foresee how much better farming would become, and food production has in fact risen far faster than he expected. But no improvement changes the shape of the two curves — it only shifts the arithmetic line upward and buys time.
15.8.3 Water
Clean, germ-free drinking water becomes scarcer as the population rises, and the reason is not only that more people drink. It is that more people also pollute.
The same rivers, ponds and lakes that supply drinking water receive sewage from growing towns and waste from growing industry. A rising population therefore attacks its own water supply from both ends at once: it draws more out and it puts more filth in.
15.8.4 Land
The amount of land on the earth is fixed. Nothing anyone does adds to it, and a rising population needs it for two purposes that compete directly with each other.
More land is brought under cultivation to feed the extra people. At the same time more land is taken for residential colonies, factories and industries to house and employ them. Every hectare used for the second purpose is a hectare unavailable for the first, and usable land becomes less and less available.
15.8.5 Forests
Forests are, in a way, the most important natural resource of all, because they supply materials and services at the same time.
They provide timber, firewood, resins, medicines and wood-pulp for paper. They are the main contributors of life-sustaining oxygen to the atmosphere, and act as natural air purifiers through photosynthesis. They help to bring rain, by adding moisture to the air through transpiration, and at the same time prevent floods, because their roots hold soil particles firmly and slow the run-off of rainwater.
They also stabilise climatic conditions, including atmospheric temperature, by absorbing carbon dioxide. And they are the natural homes of an immense variety of large and small wild animals.
Deforestation — the cutting down of forests — has been one of the most serious outcomes of rising population, carried out to obtain land for cultivation and housing and to obtain timber and wood. Its consequences follow directly from the list above.
- Droughts, because less moisture is returned to the air.
- Flash floods, because nothing now slows the rainwater.
- Soil erosion, because no roots hold the soil in place.
- Extinction of several wild animals, and a threat of extinction to hundreds of species that have lost their homes.
- Global warming, because the carbon dioxide the trees would have absorbed remains in the atmosphere.
Forests are a renewable resource, and this is the hopeful part. With careful management, and with afforestation — the planting of trees on land where forest has been lost — existing forests can be maintained and even improved. The shrinking of forest cover has to be stopped without delay if the planet is to remain habitable.
15.8.6 Energy
Energy is needed for cooking in homes, for running factories, for transport and for almost everything else that a modern population does. More people mean more of all three.
15.8.6.1 Conventional Sources Of Energy
The two major sources of energy at present are coal and petroleum. Both are fossil fuels — fuels formed from the remains of organisms buried and compressed over millions of years — and their underground reserves are depleting fast, while the rate at which we consume them is still rising.
Once these are finished they cannot be formed again within any human timescale, since the process that made them takes millions of years. Coal and petroleum are described as conventional sources of energy simply because they have been in use for a long time.
15.8.6.2 Non-Conventional Sources Of Energy
An increasing population needs more and more energy, and newer sources are being brought into use to meet it: solar energy, nuclear energy, tidal energy and wind energy.
Solar cookers and solar batteries harness the energy of sunlight directly. Biogas, produced from organic wastes such as cowdung, farm wastes and sewage, is already in use in many villages. All of these need to be popularised much further than they have been.
15.8.7 Mineral Resources
More population means more requirements — more industries, more means of transportation, more buildings and more machines. Every one of these uses minerals such as iron and copper.
Minerals are a non-renewable resource. An ore body formed over millions of years, and once it has been dug out and used it can never be replaced. Recycling can return metal that is already above ground to use again; nothing can return the ore to the rock.
15.9 Population Growth, Urbanisation And Pressure On Resources
Rising numbers put pressure on resources. But numbers are only half of the story, and in some ways the smaller half. Where people live, and how much each of them uses, matter just as much.
15.9.1 Changing Face Of The Earth
The human population is growing fast everywhere, but it is not staying where it grows. Villages are turning into towns, towns into cities, and cities into megacities or metropolises. This process is called urbanisation — the movement of people from rural areas into towns and cities, and the spreading of those towns and cities over the land around them.
Urbanisation brings a predictable set of changes with it.
- More residential buildings, and with them more markets, schools and hospitals.
- More streets and roads, more highways, railway lines and airports.
- More industrial installations, godowns and reservoirs.
Every one of these is built on something. Development of this kind encroaches on open land, on the agricultural land next to the city, and often on forest as well. The result is a steady loss of natural vegetation, which degrades the environment and, as section 15.8 explained, the local climate along with it.
Diagram
Fig. 15.9-1 — A Settlement Spreading Outward Three-panel line drawing of the same stretch of land at three stages, drawn to the same scale and from the same viewpoint. Panel 1, ‘village’: scattered houses, fields, a pond, trees along the boundary. Panel 2, ‘town’: houses multiplied into blocks, a road and a railway line crossing, fewer fields, the pond smaller. Panel 3, ‘city’: continuous built-up area, multi-storeyed buildings, highway and flyover, the pond gone, a single remaining group of trees. Label each panel and mark the position of one surviving landmark in all three.
15.9.2 Rising Living Standards Of A Growing Population
Alongside the rise in numbers, there has been a rise in what each person owns and uses. Living standards are rising very fast.
- More household equipment per household — furniture, crockery, electronic gadgets, decorative articles.
- More clothing and accessories per individual — more shirts, suits or sarees, skirts, belts, bags and shoes than any earlier generation owned.
- More personal transport — a cycle, a motorcycle, a car, sometimes several of each in one family, besides taxis and other means of transport.
Every item on that list is made of materials taken from the earth and made with energy that came from somewhere. So the demand on resources is not simply the number of people. It is the number of people multiplied by the amount each person uses — and both of those numbers are climbing at the same time.
That is why a country with a smaller population can place a larger demand on the world’s resources than a country with a bigger one. Numbers alone do not settle the question.
15.9.3 Need To Check Exploitative Use Of Resources
Put the two halves of this section together. The increasing numbers in the population, and even more than that the increasing standards of modern living, are causing very rapid depletion of natural resources.
Among those resources, some are non-renewable — once lost they are lost for ever and are never regained. Others are renewable but take a very long time to be renewed, and are being used far faster than that. It is therefore necessary that every citizen becomes conscious of the problem and contributes to the sustainable use of natural resources.
The word ‘sustainable’ means simply that something can be continued without ill effect on the availability of the items required. A rate of use that empties the store is not sustainable, however convenient it may be today.
Sustainable development is achieved mainly in three ways, often remembered as the three Rs.
- Reduce — cut down the excessive use of natural resources, so that less is demanded in the first place.
- Reuse — use an article again, in the same form or another, instead of discarding it after one use.
- Recycle — process used material back into raw material, so that fresh material need not be extracted.
To these is added a fourth measure: greater use of renewable resources such as solar energy and wind power, in place of the fossil fuels that cannot be replaced at all.
15.10 Rate Of Population Growth Must Be Reduced
Everything the last three sections described points the same way. For a better future, the rate at which the human population grows has to come down.
The gains from a slower rise are direct ones: less burden on depleting resources, better health care because the same doctors and hospitals serve fewer people, and better education because the same schools and teachers serve fewer children. How to bring the rate down is a question engaging governments and social organisations across the world.
But before any measure can be judged, the thing being measured has to be defined precisely. You cannot tell whether a rate is falling unless you know exactly what is being counted, and against what. So this section begins with the terms.
15.10.1 A Few Statistical Terms
Demography is the statistical study of human population — its size, its density, its distribution and its other vital statistics. The word comes from the Greek demos, meaning people, and graphos, meaning measurement.
Population density is the number of individuals per square kilometre (km²) at any given time. It answers a different question from population size: not how many people there are, but how closely they are packed.
Towns and larger cities always have a much greater population density than rural areas, because the same land holds far more people. Densities also differ enormously between countries, as Table 15.4 shows.
Compare the last row with the others. The United States has a large population, but spread over a very large area, so its density is about a twelfth of India’s. Density and size are not the same thing, and it is density that decides how much land, water and open space each person actually has.
Birth rate, also called natality, is the number of live births per 1000 people of the population per year. For example, if a population of 20,000 recorded 440 live births in a year, the birth rate would be:
\[\text{birth rate} = \frac{440}{20{,}000} \times 1000 = 22\]
Death rate, also called mortality, is the number of deaths per 1000 people of the population per year. In India the registration of every birth and every death is compulsory by law, which is what makes these figures possible to collect at all.
Notice why both rates are expressed per 1000 rather than as plain totals. A large country will always record more births than a small one, so raw totals cannot be compared. Dividing by the size of the population removes that difference and lets any two populations be set side by side.
Everything follows from that subtraction. As long as the birth rate exceeds the death rate, the population grows. If the birth rate falls below the death rate, the population declines. And if the two are equal, the population neither grows nor shrinks — this is zero population growth.
15.10.2 Birth Rate And Death Rate In India
Now apply those terms to India, and the whole explosion can be read off two numbers.
In 1901 India’s birth rate and death rate stood at about 46 and 44 per 1000 respectively. Births barely exceeded deaths, and the population hardly moved. By 1973 the figures were roughly 37 and 14.
Look at what each number did. The birth rate fell — from 46 to 37. But the death rate collapsed, from 44 to 14, because of better medical care for infants and for the old alike. Both rates fell, yet the gap between them widened from 2 to 23, and it is the gap that is the growth rate.
This is the whole mechanism of India’s population explosion in one comparison: not a rise in births, but a fall in deaths that births did not keep pace with.
Since 1973 the birth rate has continued to fall, and the gap has begun to close again. India’s annual growth rate is now about 1%, roughly comparable with the world figure, and it is still declining slowly.
A closely related measure shows the same trend from another angle. The total fertility rate is the average number of children a woman would have in her lifetime at current birth rates, and Table 15.5 tracks it for three countries over about thirty-five years.
Every figure in the second row is lower than the one above it. India’s fell from 5.4 to 2.8 — roughly half — and it has since fallen further, to about 2.0. A population stops growing, after a delay of some decades, once this figure settles at about 2.1, the level at which each couple is simply replaced.
People are also living longer, for the same two reasons that cut the death rate: better nutrition and better health care. An adult who reaches the age of 60 today can expect a good many more years of healthy life, and this too adds to the total population at any moment, since fewer people are leaving it each year.
15.11 Need For Adopting Control Measures
A country can support a certain number of people comfortably. Once the population density rises beyond what its land, water, industry and services can carry, the effects show up in ordinary life rather than in statistics.
Three of them are worth setting out plainly.
- Per capita income comes down. Per capita means per person: the country’s total income divided by the number of people in it. Even if the total income of a country rises, the share of each person falls if the number of people rises faster.
- Natural resources decrease. Land, minerals, wood and fuel are drawn on faster than they are replaced, exactly as section 15.8 described.
- General health goes down. More people share the same hospitals, the same doctors and the same water supply, so each receives less.
There is a further difficulty that follows from the last two. Crowded housing spreads infectious disease more easily, and a shortage of clean water makes it easier still, so the health of a dense population is under pressure from several directions at once.
Where The Chain Begins And Ends
Notice how these effects link back to one another. A large population is, in the end, the result of many families being large. Where families are large, the same household income supports more people, so less is available for each of them — for food, for medical care, for school fees.
That in turn is one of the conditions listed in section 15.7 that keeps family size high in the first place. The chain closes on itself, which is why the problem does not solve itself and why deliberate measures are needed to break it.
Flowchart
FC 15.3 — The Cycle Of Large Families And Low Quality Of Life Large families → household income shared among more people → less spent per child on food, health and schooling → children leave school early and marry earlier → large families again in the next generation
The point at which this cycle is most easily broken is the one marked in the third and fourth steps. Keeping children — especially girls — in school longer delays marriage, and delaying marriage shortens the span of years over which children are born. That single change interrupts the loop without anyone being compelled to do anything.
The other point of intervention is the size of the family itself, and here the necessary measures are medical. Population growth is reduced mainly by contraception — the deliberate prevention of pregnancy — and the methods available are the subject of section 15.13.
Before those, though, comes something that no clinic can supply: knowing that the methods exist, understanding what each of them does, and being free to choose. That is what the next section is about.
15.12 Population Education And Population Control
No method of population control works unless people know it exists, understand what it does, and decide for themselves to use it. That is why education comes before any clinic.
Population education means informing people about the need to limit family size and about the steps that can be taken to do so. It is not persuasion by pressure; it is the supply of accurate information to people who will make their own decisions with it.
15.12.1 Educating People About Family Size
Six things are needed if that information is to reach and convince people.
The message about the population problem should reach as many people as possible, including those living in very remote areas. Information that stops at the edge of a town leaves out the households where family sizes are largest.
People should be made aware of the advantages of having a small family, and equally of the disadvantages of having many children — for the children’s health and schooling, and for the mother’s health.
The view that a family must have at least one son should be addressed through education, since it is one of the commonest reasons why couples continue to have children they had not otherwise planned for.
The age at marriage should be higher. Under Indian law the minimum age of marriage is 18 years for women and 21 years for men, and the law must be followed strictly. Every year that marriage is delayed shortens the span over which children can be born, and a mother older than 18 also faces far fewer risks in childbirth.
Married couples should be helped to delay the birth of their first child, to space the second with a sufficient interval so that each child can be brought up properly, and to stop at two.
People should be advised about family planning — deciding how many children to have and when to have them — and about the contraceptive methods that make such a decision possible.
The methods themselves fall into a few groups: devices and preparations for both men and women, including condoms, intrauterine devices such as the Copper-T, and oral contraceptive pills. Section 15.13 describes each of them in detail.
Countries have approached the same problem very differently, and the results are worth comparing. China enforced a strict one-child policy for decades; India has relied on education and voluntary family planning to move towards a two-child norm. India’s slower route has taken longer, but a policy that people accept is a policy that lasts, and China has since had to abandon its own.
15.12.2 Family Welfare
Family planning is one part of a wider idea. Family welfare covers the whole health and wellbeing of a small family, and has three aspects.
- Family planning, in the sense of having a small family.
- Total welfare of that small family, including the diet and nutrition of the child and of the pregnant mother.
- Subsequent care of the children — immunisation, oral rehydration therapy for diarrhoea, and other measures that ensure the young ones survive.
The third aspect matters more than it looks. Section 15.7 showed that parents have extra children when they fear losing some, so keeping children alive is itself a way of reducing the number born. Health care and population control are not two separate programmes; each supports the other.
In India, the inverted red triangle is the sign for family welfare. It is displayed prominently at offices, health centres and hospitals where help or advice about family planning is available free of cost, and such places are known as family welfare centres.
Diagram
Fig. 15.12-1 — The Family Welfare Symbol Line drawing of the family welfare sign as displayed in India: a triangle pointing downwards, shaded solid, mounted on a signboard outside a health centre. Label the triangle ‘inverted red triangle’ and the building ‘family welfare centre’.
15.13 Methods Of Contraception
Contraception is the deliberate prevention of pregnancy. Every method works by interrupting the sequence that leads to it, and that sequence has three separable steps: an egg must be released, sperms must reach it, and the fertilised egg must become implanted in the wall of the uterus.
Block any one of those three and pregnancy does not occur. That is the whole logic of the methods below, and it is worth carrying with you as you read them, because it explains why there are several kinds rather than one.
Flowchart
FC 15.4 — Where Each Group Of Methods Acts Ovary releases an egg → [hormonal methods act here] → sperms deposited and travel towards the egg → [barrier methods and surgical methods act here] → fertilisation → embryo travels to the uterus → [intra-uterine devices act here] → implantation in the uterine wall → pregnancy
15.13.1 Hormonal Methods
Hormonal preparations are taken in the form of tablets, commonly called contraceptive pills. The hormones they contain prevent the ovary from releasing an egg.
The reasoning connects to what you have already studied about the menstrual cycle. Ovulation is triggered by a rise in certain hormones, and if the level of hormones in the blood is held steady by the pill, that trigger never arrives. No egg is released, so there is nothing for a sperm to fertilise.
15.13.2 Barrier Methods
Barrier methods act on the second step. Each of them physically prevents sperms from reaching the egg, or destroys them before they can.
Condom. A thin sheath of latex worn by the man, which collects the semen and prevents sperms from being deposited in the vagina.
Diaphragm. A round latex cap with a flexible coil spring, fitted deep in the vagina over the cervix — the neck of the uterus. It covers the opening and prevents sperms from entering the uterus.
Spermicidal agents. Chemical preparations placed in the vagina near the cervix, which kill any sperms present there.
15.13.3 Intra-Uterine Devices
An intra-uterine device (IUD) is a small object fitted inside the uterus by a trained health worker, where it stays for several years. The two commonly used in India are the Copper-T and Lippe’s loop.
These devices do not stop fertilisation. They act at the third step of the sequence: they change conditions inside the uterus so that the blastocyst — the early embryo — cannot become implanted in the uterine wall. Without implantation, the embryo cannot develop and the pregnancy does not begin.
15.13.4 Surgical Methods
All the methods so far are temporary — stop using them and fertility returns. The surgical methods are different: they are intended to be permanent, and they are chosen by couples who have decided they do not want any more children.
Both work on the same principle. A tube that a gamete must travel along is cut and closed, so the egg and the sperm can never meet. One operation does this in the woman, the other in the man. Neither removes any organ, and neither stops the making of eggs or sperms.
15.13.4.1 Tubectomy
Tubectomy is the surgical method of sterilisation in the human female. The abdomen is opened, and the fallopian tubes, also called the oviducts, are cut and then ligated — tied off with nylon thread — to close the passage of the egg.
The ovary continues to release an egg as before, but it can no longer travel down the blocked oviduct, and sperms cannot travel up it. Since fertilisation normally takes place in the oviduct, it can no longer occur anywhere.
Diagram
Fig. 15.13-1 — Tubectomy Line drawing of the human female reproductive system in front view. Label uterus, cervix, vagina, ovary, oviduct (fallopian tube) and oviducal funnel. On both oviducts show the cut portion with the two ligated ends drawn tied, and label ‘cut and ligated part of oviduct’. Show one ovum emerging from the ovary, labelled, on the side nearer the ovary than the cut. All labels on straight, non-crossing lead lines.
15.13.4.2 Vasectomy
Vasectomy is the corresponding operation in the human male. The word is built from vasa, meaning vessel, and tomy, meaning cutting.
A small cut is made in the scrotum, the vas deferens or sperm duct from each testis is ligated in two places, and the short piece between the two ligatures is removed. Sperms are still produced in the testes, but they can no longer pass into the urethra, so the semen released contains none.
Diagram
Fig. 15.13-2 — Vasectomy Line drawing of the human male reproductive system in front view. Label testis, vas deferens (sperm duct), seminal vesicle, prostate gland, urinary bladder, ureter and urethra. On both sperm ducts show two ligatures with the short segment between them removed, and label ‘cut part of vas deferens’. All labels on straight, non-crossing lead lines.
Vasectomy is the simpler of the two procedures. It is performed through a small opening in the scrotum rather than by opening the abdomen, it takes less time, it needs less recovery, and it carries a lower risk of complications. For these reasons it is often recommended as the better choice where a couple has decided on a permanent method.
Two things about it are widely misunderstood, and both are worth stating plainly. The operation has no effect on a man’s masculinity, because the testis continues to make and release the male sex hormone into the blood exactly as before — only the duct is blocked, not the gland. Nor does it reduce sexual desire or pleasure in any way.
15.14 Induced Abortion Or Medical Termination Of Pregnancy
All the methods in the previous section prevent a pregnancy from beginning. This section deals with something different: the ending of a pregnancy that has already begun.
Medical termination of pregnancy (MTP), also called induced abortion, is the deliberate removal of the foetus from the uterus before it is able to survive outside. It is carried out for a small number of definite reasons.
One is where a couple does not wish to continue with a pregnancy. Another is where a special test has given definite evidence that the embryo carries a serious genetic disease. A third, and medically the most urgent, is where continuing the pregnancy would endanger the health of the pregnant woman.
Two points about MTP need to be understood clearly, and both are important.
The first is that it is not a method of contraception. Contraception prevents a pregnancy from starting; MTP ends one that has started. It is a last step to be taken when the situation calls for it, not an alternative to the methods described in section 15.13, and any of those methods is safer for the woman than a termination.
The second is that it must be carried out only by a trained doctor at a registered hospital or clinic. A termination performed outside such a place, by someone without training, is one of the leading causes of avoidable death and permanent injury among women, and this is the whole reason the law regulates it.
What The Law Provides
In India, medical termination of pregnancy is governed by the Medical Termination of Pregnancy Act, 1971, as amended in 2021. Its provisions are these.
- A pregnancy may be terminated up to 20 weeks on the opinion of one registered medical practitioner.
- Between 20 and 24 weeks it may be terminated for specified categories of women, including survivors of assault and women whose circumstances have changed, on the opinion of two registered medical practitioners.
- Beyond 24 weeks it is permitted only where a medical board has diagnosed a substantial foetal abnormality.
- Only the woman’s own consent is required. The consent of her husband is not necessary, and where she is below 18 years, the consent of a guardian is required instead.
- The identity of any woman who undergoes the procedure may not be disclosed except to a person authorised by law.
- The service is available at government hospitals at no cost.
The last two provisions exist for the same reason as the first four. A law that permitted the procedure but allowed a woman’s name to become public, or required someone else’s permission, would push women back towards the unsafe and untrained practitioners the law was written to protect them from.
15.15 Summary
A population is all the individuals of one species living in a particular area at a particular time. Human numbers have risen sharply worldwide over the last two centuries, and because air, oceans, food and fuel are shared, the rise is a concern for the whole world rather than for any one country.
About 50,000 years ago the world population was around one million. People wandered in search of food, sheltered in caves and made tools of stone, stick and bone — the tool-making revolution, the first great cultural change.
About 10,000 years ago people began to live in settled communities, domesticated animals with the dog first, learned to sow crops and store food, and later replaced stone tools with bronze and iron. This agricultural revolution, together with the metal age, made survival more likely and turned human numbers upward.
The scientific and industrial revolution brought more jobs, more comfort and more food, but crowded factory towns also brought widespread outbreaks of infectious diseases and nutritional diseases caused by unbalanced diets.
In the twentieth century, antibiotics and prophylactic vaccinations sharply reduced deaths in all age groups, especially among infants and the old. Medicines add no births; they allow more children to reach the reproductive age, and each of those children adds a family of their own.
Three cultural revolutions — tool-making, agricultural, and scientific and industrial — each raised the population steeply and were each followed by a long flattened stretch. The curve ends today in two question marks, since it is not known whether growth will continue as a J-shaped curve or level off as an S-shaped one.
Population explosion is the rapid and massive increase in the size of a population within a short period of time. The world annual growth rate stayed below 1% before 1800, peaked at 2.1% in 1962 — the highest ever recorded — and has fallen since. The world population reached 8 billion on 15 November 2022.
A falling growth rate can still add record numbers of people, because the same percentage is taken from a much larger population. Size and growth rate are different quantities.
Six reasons account for the recent sharp rise: better health care, fewer deaths through better medical aid, minimised food shortages, improved nutrition, large-scale immunisation, and fewer infant deaths.
A simplified model of 20 people, each couple having four children, multiplies ten times over in 60 years, because each generation is double the one before it.
India’s census figures rose from 238 million in 1901 to 1211 million in 2011, falling only in 1911–21 because of the influenza pandemic. India’s population is now a little more than 1.45 billion, and it became the most populous country in the world in 2023.
Family size in India has stayed high because of limited education, traditional beliefs, high infant mortality, the economic value of children, customs of early marriage, a preference for sons, and limited access to information — each of them a response to a circumstance rather than a fixed belief.
A resource is any substance, energy or organism used by humans for their welfare. Six come under heaviest pressure: food, water, land, forests, energy and minerals. Renewable resources are replaced by nature; non-renewable ones are not.
Population, if unchecked, grows in geometrical progression — 1, 2, 4, 8, 16 — while food production rises in arithmetic progression — 1, 2, 3, 4, 5. A quantity that multiplies must eventually overtake one that only adds.
Forests supply timber, firewood, resins, medicines and wood-pulp, add oxygen to the air, bring rain by transpiration, prevent floods and soil erosion by holding soil, stabilise climate by absorbing carbon dioxide, and house wild animals. Deforestation causes droughts, flash floods, soil erosion, extinction of species and global warming; afforestation can reverse it.
Coal and petroleum are conventional sources of energy and are fossil fuels whose reserves are depleting fast. Solar, nuclear, tidal, wind and biogas are non-conventional sources. Minerals are non-renewable and can never be replaced once used.
Urbanisation — villages becoming towns and towns becoming cities — encroaches on open land, agricultural land and forest. Rising living standards raise the demand per person, so total demand is the number of people multiplied by the amount each uses.
Sustainable development meets the needs of the present without compromising the ability of future generations to meet their own. It is achieved mainly by reducing, reusing and recycling, and by greater use of renewable resources.
Demography is the statistical study of human population. Population density is the number of individuals per square kilometre. Birth rate or natality is the number of live births per 1000 people per year; death rate or mortality is the number of deaths per 1000 people per year.
Growth rate of population is the difference between the birth rate and the death rate. The population grows while the birth rate exceeds the death rate, declines when it falls below, and stays steady when the two are equal.
In India the birth and death rates were about 46 and 44 per 1000 in 1901, and about 37 and 14 in 1973. Both fell, but the death rate fell far more steeply, and the widening gap is what produced the population explosion.
High population density lowers per capita income, decreases natural resources and reduces general health, and these in turn keep family size high — a cycle broken most easily by keeping children in school and delaying marriage.
Population education informs people about limiting family size: spreading the message to remote areas, explaining the advantages of a small family, addressing the preference for a son, observing the legal marriage age of 18 for women and 21 for men, delaying and spacing births, and making family planning known.
Family welfare has three aspects — family planning for a small family, the total welfare of that family including the nutrition of child and mother, and the subsequent care of children through immunisation and oral rehydration therapy. The inverted red triangle is its sign in India.
Contraception prevents pregnancy by blocking one of three steps: the release of the egg, the meeting of sperm and egg, or implantation. Hormonal pills prevent ovulation; condoms, diaphragms and spermicidal agents are barrier methods; intra-uterine devices such as the Copper-T and Lippe’s loop prevent implantation.
Tubectomy cuts and ligates the oviducts in the female; vasectomy cuts and ligates the vas deferens in the male. Both are permanent, both prevent the gametes from meeting, and vasectomy is the simpler, quicker and safer of the two.
Medical termination of pregnancy ends a pregnancy already begun and is not a method of contraception. It must be performed only by a trained doctor at a registered hospital, within the limits set by the Medical Termination of Pregnancy Act, and requires only the woman’s own consent.
Flowchart
FC 15.5 — The Chapter In One Chain Better tools, farming and finally medicine → deaths fall sharply while births stay high → birth rate exceeds death rate by a widening gap → population multiplies in geometrical progression → food, water, land, forests, energy and minerals fall short → urbanisation and rising consumption deepen the shortage → growth rate must be reduced → population education, later marriage, spaced births and contraception → birth rate falls towards the death rate → population steadies
15.16 Key Terms
Afforestation — the planting of trees on land where forest has been lost, to restore forest cover.
Agriculture — the deliberate growing of crops for food, in place of gathering whatever grows wild.
Antibiotics — medicines that kill bacteria or stop them multiplying inside the body.
Arithmetic progression — a series in which each step is the previous one with a fixed amount added, as in 1, 2, 3, 4, 5; the pattern in which food production rises.
Birth rate — the number of live births per 1000 people of a population per year; also called natality.
Census — a count of every person in a country, taken on a fixed date; held in India about every ten years.
Condom — a thin latex sheath worn by the man, which prevents sperms from being deposited in the vagina.
Contraception — the deliberate prevention of pregnancy.
Death rate — the number of deaths per 1000 people of a population per year; also called mortality.
Deforestation — the cutting down of forests.
Demography — the statistical study of human population, especially its size, density and distribution.
Diaphragm — a round latex cap fitted over the cervix, which prevents sperms from entering the uterus.
Domestication — the keeping and selective breeding of useful animals over generations, so that they come to differ from their wild ancestors.
Family planning — deciding how many children to have and when to have them.
Family welfare — the whole health and wellbeing of a small family, covering family planning, the nutrition of mother and child, and the subsequent care of the children.
Fossil fuels — fuels such as coal and petroleum, formed from the remains of organisms buried and compressed over millions of years.
Geometrical progression — a series in which each step is the previous one multiplied, as in 1, 2, 4, 8, 16; the pattern in which an unchecked population grows.
Growth rate of population — the difference between the birth rate and the death rate of a population.
Infant mortality rate — the number of babies who die before their first birthday, for every 1000 born alive.
Infectious disease — a disease caused by a micro-organism, which can pass from one person to another.
Intra-uterine device (IUD) — a small device fitted inside the uterus, which prevents the embryo from becoming implanted in the uterine wall.
Medical termination of pregnancy (MTP) — the deliberate ending of a pregnancy already begun, by removal of the foetus; also called induced abortion.
Mortality — see death rate.
Natality — see birth rate.
Non-renewable resource — a resource that took millions of years to form and cannot be replaced once used, such as coal, petroleum or a mineral ore.
Nutritional disease — an illness caused by something missing from the diet rather than by any micro-organism.
Per capita — per person; a total quantity divided by the number of people it is shared among.
Population — all the individuals of one species living in a particular area at a particular time.
Population density — the number of individuals per square kilometre at any given time.
Population education — informing people about the need to limit family size and about the steps by which it can be done.
Population explosion — the rapid and massive increase in the size of a population within a short period of time.
Recycle — to process used material back into raw material, so that fresh material need not be extracted.
Red triangle — the inverted triangular sign displayed in India at centres where family welfare advice and services are available free of cost.
Reduce — to cut down the excessive use of a resource, so that less is demanded in the first place.
Renewable resource — a resource that nature replaces within a human lifetime, provided it is not used faster than it is replaced.
Resource — any substance, energy or organism, natural or artificial, that is used by humans for their welfare.
Reuse — to use an article again instead of discarding it after one use.
Spermicidal agents — chemical preparations placed in the vagina near the cervix, which kill sperms.
Sustainable — able to be continued without ill effect on the future availability of what is being used.
Sustainable development — development that meets the needs of the present without compromising the ability of future generations to meet their own needs.
Tool-making revolution — the first great cultural change in human life, in which stone, bone and wooden tools were shaped and steadily improved.
Total fertility rate — the average number of children a woman would have in her lifetime at current birth rates.
Tubectomy — the surgical method of sterilisation in the human female, in which the oviducts are cut and ligated.
Urbanisation — the movement of people from rural areas into towns and cities, and the spreading of those towns and cities over the land around them.
Vaccination — the giving of a preparation to a healthy person so that the body is ready to fight a particular disease before it is ever met; a prophylactic measure.
Vasectomy — the surgical method of sterilisation in the human male, in which the vas deferens on each side is cut and ligated.
15.17 Points To Ponder
Every one of the six reasons for the recent rise in world population is something we would want for ourselves and our families — better hospitals, fewer deaths, more food. If the causes of the problem are all good things, what does that tell you about the kind of solution the problem can have?
The world’s annual growth rate has more than halved since 1962, yet more people are being added each year now than were added then. What does this suggest about using a single percentage figure to judge whether a situation is improving?
Section 15.7 argued that having many children was a reasonable response to the risk of losing some of them. If that is so, would a programme that improved child health achieve more than one that only urged parents to have fewer children — and how long would you expect to wait before the effect showed?
Total demand on the earth’s resources is the number of people multiplied by the amount each person uses. Which of those two numbers is easier for a country to change, and which does more damage when it rises? Are they the same number?
Forests are called a renewable resource and iron ore a non-renewable one, yet a forest cut faster than it regrows disappears just as permanently. Is ‘renewable’ a property of the resource, or of the way it is used?
Malthus concluded in 1798 that food supply must fall behind population, and he was wrong about the timing by more than two centuries. Does that make his reasoning wrong, or only his prediction — and what would it take to settle the difference?
15.18 Objective Questions
Multiple Choice
- The number of live births per 1000 people of a population per year is called: (1 mark)
- mortality
- natality
- population density
- growth rate
- The first animal to be domesticated by humans was the: (1 mark)
- cow
- goat
- dog
- horse
- The highest annual growth rate of world population ever recorded was: (1 mark)
- 1.1% in 1804
- 2.1% in 1962
- 3.1% in 1987
- 0.9% in 2024
- A contraceptive method that permits fertilisation but prevents implantation is: (1 mark)
- the contraceptive pill
- the diaphragm
- the Copper-T
- vasectomy
- In tubectomy, the structure that is cut and ligated is the: (1 mark)
- vas deferens
- oviduct
- cervix
- ureter
- Which of the following is a non-renewable resource? (1 mark)
- Wind energy
- Solar energy
- Forest timber
- Copper ore
- Food production is said to rise in: (1 mark)
- geometrical progression
- arithmetic progression
- exponential progression
- no regular pattern
- If a population has a birth rate of 24 per 1000 and a death rate of 24 per 1000, the population will: (1 mark)
- double in one generation
- decline steadily
- neither grow nor shrink
- grow by 24 per 1000 per year
- Under Indian law, the minimum age of marriage for women and men respectively is: (1 mark)
- 16 years and 18 years
- 18 years and 21 years
- 21 years and 18 years
- 18 years and 18 years
Assertion–Reason
For each of the following, choose the correct option: (1) A is true and R is false (2) A is false and R is true (3) Both A and R are true (4) Both A and R are false
Assertion (A): Vasectomy does not reduce a man’s masculinity. Reason (R): In vasectomy the sperm duct is blocked, but the testis continues to release the male sex hormone into the blood. (1 mark)
Assertion (A): The world’s annual population growth rate has fallen since 1962, so fewer people are now added each year than were added then. Reason (R): A smaller percentage taken from a much larger population can still amount to a larger number. (1 mark)
Assertion (A): Deforestation increases the risk of flash floods. Reason (R): Tree roots hold soil particles firmly and slow the run-off of rainwater. (1 mark)
Assertion (A): Medical termination of pregnancy is a reliable method of contraception. Reason (R): Contraception acts before a pregnancy is established. (1 mark)
The statistical study of human population is called ____. (1 mark)
The number of individuals per square kilometre at any given time is the ____ of a population. (1 mark)
Planting trees on land where forest has been lost is called ____. (1 mark)
Coal and petroleum are together classed as ____ fuels. (1 mark)
True Or False
- State whether each of the following is true or false. Rewrite the false statements correctly. (5 marks)
- An intra-uterine device prevents the release of the egg from the ovary.
- India’s population declined between the census years 1911 and 1921.
- Minerals are a renewable resource.
- A diaphragm is a barrier method of contraception.
- The growth rate of a population is the sum of its birth rate and death rate.
Match The Following
- Match each item in Column A with the correct item in Column B. (5 marks)
| Column A | Column B |
|---|---|
| a. Tubectomy | i. prevention of ovulation |
| b. Contraceptive pill | ii. statistical study of human population |
| c. Demography | iii. non-conventional source of energy |
| d. Biogas | iv. cutting and ligating the oviducts |
| e. Copper-T | v. prevention of implantation |
Name The Following
- Name the following. (6 marks)
- The cultural revolution that began when people started sowing crops and storing food.
- The class of medicines that kill bacteria or stop them multiplying inside the body.
- The number of babies who die before their first birthday, per 1000 live births.
- The gas that forms the major part of biogas.
- The sign displayed at family welfare centres in India.
- The pattern of growth in which each step is double the one before it.
Odd One Out
- In each set, pick the odd one out and give a reason for your choice. (4 marks)
- Condom, diaphragm, spermicidal agent, contraceptive pill
- Solar energy, wind energy, tidal energy, petroleum
- Timber, resins, wood-pulp, iron ore
- Natality, mortality, demography, population density
15.19 Check Your Concepts
Define population density and state the unit in which it is expressed. (2 marks)
Give a reason: a country’s total income may rise and yet its per capita income may fall. (2 marks)
Name two non-conventional sources of energy and state one advantage they have over coal. (2 marks)
State the three aspects covered by the term ‘family welfare’. (3 marks)
Differentiate between the following pairs, stating the basis of difference in each case. (6 marks)
- Renewable and non-renewable resources
- Natality and mortality
- Deforestation and afforestation
Give a reason for each of the following. (3 marks)
- Birth rate and death rate are expressed per 1000 people rather than as plain totals.
- Deforestation can lead to drought in a region.
- A family in which many infants died in the past tended to be a large family.
Why is medical termination of pregnancy not regarded as a method of contraception? (3 marks)
In a certain town of 25,000 people, 500 live births and 200 deaths were recorded in one year. Calculate the birth rate, the death rate and the growth rate of that population, showing your working. (3 marks)
Explain, with an example, why a fall in the death rate raises the population more steeply than a rise in the birth rate of the same size would. (4 marks)
What would happen to the population of a country in which the birth rate fell below the death rate and stayed there for several decades? State two problems such a country would face. (4 marks)
Explain how population, if unchecked, grows in geometrical progression while food production rises in arithmetic progression, and state what this means for the food available to each person. (5 marks)
Describe five reasons for the rapid rise in world population during the twentieth century, and explain why medical discoveries, which add no births, increased the rate of growth. (5 marks)
Discuss the effects of urbanisation on land, forests and natural vegetation, and state three measures by which the use of resources can be made sustainable. (5 marks)
15.20 Figure-Based Questions
- Study Fig. 15.3-1, which shows three great cultural revolutions. (4 marks)
- Name the three revolutions marked (1), (2) and (3).
- Why is the curve drawn flat for long stretches between the three rises?
- What do the two question marks at the end of the curve indicate?
- Study Fig. 15.4-1, which plots world population and annual growth rate from 1750 onwards. (4 marks)
- In which year did the annual growth rate reach its highest value, and what was that value?
- Describe what happens to the population curve after the growth-rate curve begins to fall.
- Explain how both of these can be true at the same time.
- Study Fig. 15.13-1, which shows a surgical method of contraception. (4 marks)
- Name the operation shown.
- Name the structure that has been cut and ligated, and state its normal function.
- Does the ovary continue to release eggs after this operation? Give a reason.
- Study Fig. 15.13-2. (5 marks)
- Name the operation depicted and the sex on which it is performed.
- Name the duct that has been cut, and state where it begins and where it leads.
- State one reason why this operation is often preferred over the corresponding operation in the other sex.
- Redraw the outline of the duct system and label the testis, the cut duct and the urethra.
- Study Fig. 15.6-1, which shows India’s population at each census from 1901 to 2011. (3 marks)
- Between which two census years did the population fall, and what caused the fall?
- Approximately how many people were added between 2001 and 2011?
- Comment on the shape of the curve after 1951.