Urban Growth Patterns

The year the world moved indoors

Around 2007, humanity crossed a line it will not cross back over: for the first time, more people lived in towns and cities than in the countryside. In 1950 roughly 30 per cent of the world was urban. Today it is more than half, and the United Nations projects something like 68 per cent by 2050. That is urbanisation, and the word means the rising share of the population living in urban areas, not simply cities getting bigger. The other headline number is the megacity, defined as a city of more than ten million people. In 1950 there were exactly two, New York and Tokyo. By 2020 there were around 33, and most of them are in Asia. Tokyo remains the largest urban agglomeration on Earth at roughly 37 million people, more than half the population of the United Kingdom living in one metropolitan area. But the global figure hides the thing the exam actually asks about, which is the difference in rate. The UK is already about 84 per cent urban and its cities grow slowly, because there is hardly any rural population left to move. Africa is only around 44 per cent urban and is urbanising faster than anywhere on the planet, because there is a great deal of rural population still to move and its cities are young. Rich countries have mostly finished urbanising; poorer ones are in the middle of it. This module is about that pattern and about the two engines driving it.

Five urban terms

The first is the process, the second is the headline, and the third and fourth are the two engines you are asked to distinguish. The fifth is where a great many of the new arrivals actually end up.

Order the growth of a city

These six stages describe how a city in a lower-income country grows over several decades. Put them in order.

• Rural incomes fall as land is divided between more children and farm work is mechanised
• Young adults leave for the city, drawn by the prospect of paid work and services
• They arrive faster than housing is built, so settlements go up on land nobody has given them
• The city now holds an unusually young population, concentrated in the childbearing years
• Births greatly outnumber deaths, so the city keeps growing even without new arrivals
• The built-up area spreads outwards and the city joins the ranks of the very largest

Why do poorer countries urbanise fastest?

The UK urbanises slowly and much of Africa urbanises very fast. Which answer explains that difference?

• Urbanisation measures the share of people in towns, so a country that is already around 84 per cent urban, as the UK is, has almost no rural population left to move and can only grow slowly. A country around 44 per cent urban has a large rural population still available, and it also has the conditions that move them: mechanising agriculture, subdivided land and limited rural services pushing people out, and concentrated jobs and services pulling them in. On top of that its cities hold young populations, so births far exceed deaths and growth continues without any further arrivals.
• Poorer countries simply have higher birth rates everywhere.
• Richer countries have run out of space to build new cities.
• People in richer countries prefer to live in the countryside.

Two engines, and how they connect

The specification note asks you to distinguish these explicitly, so keep them in separate paragraphs when you write. What lifts an answer above that is seeing that they are not independent: the arrow at the foot of the columns runs from left to right.

Plot the megacity count

The axis across counts decades from 1950, so 0 is 1950, 4 is 1990 and 7 is 2020. The axis up counts how many cities in the world had populations above ten million. The points for 1950, when there were 2, and 1990, when there were 10, are already marked. By 2020 the count had reached 33. Plot that point.

Match each person to what moved them

Both halves, both engines, and mind the word

Three habits decide the grade on this element, and the specification note names the first two. Give both halves of migration. A question about rural-urban migration wants push and pull. An answer with four vivid reasons why the countryside is hard and nothing about what the city offers has answered half the question, and the same is true in reverse. Write them as pairs if it helps: what made staying impossible, and what made going worthwhile. Name both engines, and keep them apart. Migration and natural increase are different mechanisms and the mark scheme expects to see both identified as such. Then, if you want the top band, show the link between them rather than leaving them as two tidy paragraphs: the arrivals are young adults, so the city acquires a birth rate as well as a population, and the growth continues after the migration slows. Watch the word urbanisation itself. It means the rising share of people living in towns, not the expansion of a city. A city can double in size without its country urbanising at all, if the countryside grows just as fast. This matters for the pattern question, because it is why an already urban country appears to stall: the UK is not failing to grow, it has simply run out of countryside to draw from. Getting that distinction into a sentence is a reliable way to show you understand the measure rather than just the phenomenon. On command words: "describe the global pattern" wants what the map or graph shows, with regions named and no explanation. "Explain the causes" wants the mechanisms. "Suggest reasons" invites you to apply the model to an unfamiliar place.

Complete the urban change facts

Urbanisation means the rising _____ of a population living in towns and cities, which the world passed the halfway mark of around 2007. In 1950 just two cities held more than ten million people; by 2020 the count of megacities had reached about _____, and most of them are now in _____. Growth in poorer countries comes from two sources. Rural-urban migration needs both push factors and _____ factors to explain it, and it moves mainly young adults. Natural increase, where births outnumber deaths, is the cause most often forgotten, and it is large precisely because migration has already given the city a _____ population.

Spot the three accurate urban claims

Select the THREE statements that are true.

• Migration and natural increase are connected rather than independent, because arrivals are mostly young adults, so a city that has received migrants for decades develops a high birth rate of its own.
• A country can have rapidly expanding cities and still not be urbanising, if its rural population is growing at the same rate, because urbanisation measures the share of people in towns rather than the size of the towns.
• Around a billion people worldwide live in informal settlements, which exist because cities have gained residents far faster than they have gained legal, serviced housing.
• Rural-urban migration is caused by push factors alone, since people would not leave a place they liked.
• The UK is urbanising faster than most African countries because its cities are larger.
• Most of the world's megacities are in Europe and North America.

A 6-mark causes answer, marked

Explain the causes of rapid urban growth in lower-income countries and newly emerging economies. [6 marks] The first cause is rural-urban migration, which requires both push and pull factors to explain it. People are pushed from the countryside because farm work is disappearing as machinery replaces labour, because smallholdings have been divided between successive generations until a plot can no longer support a family, and because drought or crop failure can remove a household's income in a single season, while rural schools and clinics are often distant or absent altogether. They are pulled towards cities by the concentration of paid work, by higher wages than agriculture offers, by hospitals, secondary schools, electricity and piped water, and frequently by relatives already established who can provide a first place to stay. This migration is strongly selective by age, since it is young adults who have the fewest ties and the most working years to gain. The second cause is natural increase, meaning births exceeding deaths within the city itself, and it is the one most often left out. Death rates fall because even a poor city offers better medical care and sanitation than the villages people have left, while birth rates stay high, and the crucial point is that these two causes are connected rather than separate: because migration delivers people of childbearing age, a city that has received migrants for decades acquires a young population and therefore a high birth rate, so it continues to grow rapidly even once the flow of arrivals slows. In many fast-growing cities natural increase now contributes more than migration does. What earned the marks: both halves of migration given, with several developed factors on each side rather than a list; natural increase named as a separate cause and explained through the fall in death rates as well as the birth rate; and the link between the two mechanisms made explicit, which is the move that takes this from a competent answer to a complete one.

Find the two pull factors

Five reasons a family might end up in a city. Two of them are pull factors, meaning things about the city that attract people towards it rather than things about the countryside that drive them away. Tap those TWO.

• There is a hospital with a maternity unit within walking distance rather than a day of travel.
• Three successive failed harvests have left the household with no income and no seed for next season.
• Factory and construction work pays several times what farm labouring did, and it pays every week.
• The family plot has been divided among so many heirs that no share is now large enough to live on.
• The landowner has bought machinery, and the work that employed twenty people now employs two.

Build the link between the engines

Assemble the sentence that connects the two causes instead of listing them.

Four questions about four places

Each stage gives you a situation. Apply the model rather than guessing.

• A high-income country has barely changed its urban percentage in thirty years, although its cities have added millions of residents. A student concludes that urbanisation has failed there.
• A rapidly growing city in a newly emerging economy has an unusually young age structure, with a marked bulge in the twenties and thirties and relatively few elderly residents.
• Migration into a large city has slowed considerably over the past decade, yet its population is still climbing steeply.
• A city has added several hundred thousand residents in five years, and unplanned settlements without piped water or sewerage have spread across land on its edges.

Explain the global pattern

Describe the global pattern of urban change and explain why rates of urbanisation differ between richer and poorer countries. [9 marks]

• Describe the pattern first, with figures: the world share living in urban areas, when it passed half, and the growth in the number of megacities and where they are
• Name regions rather than writing generally, contrasting an already urban country with a fast-urbanising one and giving a percentage for each
• Explain the difference using the starting point: a country that is already highly urban has little rural population left to move
• Then explain the pressures in the faster group, giving both push and pull factors, and name natural increase as a separate cause
• Finish by linking the two engines, since migration delivers young adults and therefore creates the birth rate that keeps the growth going