Population projections and policy for QCE Geography Unit 4
“Explain projected 21st century population change and the policies governments use to manage growth, decline and ageing”
Population projections estimate future population using current age structure, fertility, mortality and migration, usually as a range of scenarios rather than a single forecast. Global population is projected to grow through the century then level off and possibly decline, with growth concentrated in Africa and decline and ageing in Europe and East Asia. Governments respond with population policies: pronatalist policies to raise birth rates, antinatalist policies to lower them, and migration policies to manage numbers and skills. Their effectiveness varies, and ageing is the dominant twenty-first century challenge for developed countries including Australia.
What this dot point is asking
QCAA wants you to explain how population change is projected into the twenty-first century and how governments respond with policy. This builds on the demographic transition: now you look forward and at intervention. The command word "explain" means you set out how projections are made and why populations are heading toward growth, decline or ageing, then explain how policies aim to change that trajectory and with what effect. Strong answers distinguish a projection from a prediction, name real policies, and judge their effectiveness with evidence rather than assuming policy simply works.
The answer
How projections are made
A population projection estimates a future population by taking the current age and sex structure and applying assumptions about fertility, mortality and migration. Because those assumptions are uncertain, projections are usually given as a range: a high, medium and low scenario. A projection is not a prediction of what will happen but a calculation of what would happen if the assumptions hold. The current age structure carries enormous weight: a youthful population has built-in growth (demographic momentum) even if fertility falls, while an old population has built-in decline.
The twenty-first century outlook
Global population, around eight billion, is projected to keep growing for several decades before levelling off and possibly declining late in the century. The pattern is highly uneven. Almost all future growth is projected for sub-Saharan Africa and parts of South Asia, where populations remain youthful and fertility is still relatively high. In contrast, much of Europe and East Asia faces population decline and rapid ageing as fertility sits well below replacement level. The replacement level is about 2.1 children per woman; below it a population eventually shrinks without migration.
Ageing as the dominant challenge
For developed countries the defining twenty-first century issue is ageing: a rising share of older people and a shrinking working-age population. This raises the aged dependency ratio, pressures pensions and health systems, and can slow economic growth as the workforce contracts. Japan is the clearest case, with a shrinking, rapidly ageing population. Australia is ageing more slowly, cushioned by migration.
Population policies
Governments use policy to influence population trajectories:
- Antinatalist policies aim to lower birth rates. China's former one-child policy is the best-known example; it slowed growth but contributed to a skewed sex ratio and now a rapidly ageing, shrinking population, which is why it was abandoned.
- Pronatalist policies aim to raise birth rates through baby bonuses, parental leave, subsidised childcare and family payments. France and parts of Scandinavia use generous family support; Australia has used measures such as the former baby bonus and paid parental leave.
- Migration policies manage numbers, skills and ageing. Countries with low fertility, including Australia, use immigration to sustain the workforce, fill skill shortages and slow ageing.
Judging effectiveness
Policy effects are often weaker and slower than intended. Pronatalist incentives rarely lift fertility far, because the cost and lifestyle factors behind low fertility are large. Antinatalist policies can overshoot and create long-term ageing problems. Migration can offset ageing quickly but raises housing, infrastructure and social questions. Strong answers weigh a policy against its actual outcomes and side effects rather than assuming it achieves its aim.
The replacement fertility level is about 2.1 children per woman. Below this, a population will eventually shrink unless sustained by net migration. Most developed countries, including Australia at well under 2.0, are already below replacement, which is why migration rather than births is the main driver of population growth in these countries.
- Calling a projection a prediction
- A projection is conditional on assumptions and usually given as a range. Treat it as a scenario, not a certain forecast.
- Assuming policy works as intended
- Pronatalist incentives often barely move fertility, and the one-child policy created long-term ageing. Judge policies by outcomes.
- Ignoring the uneven global pattern
- Growth is concentrated in Africa and South Asia while Europe and East Asia decline. A single global figure hides this.
- Forgetting migration in the Australian case
- Australia's growth and slower ageing are driven largely by migration, not births. Include it.
Examples in context
Example 1. China. The one-child policy slowed growth but produced a rapidly ageing, now shrinking population and a skewed sex ratio, leading to its reversal and new pronatalist measures with limited effect so far.
Example 2. Japan. Sustained below-replacement fertility and limited migration produce projected long-term population decline and severe ageing, pressuring its pension and health systems.
Example 3. Australia. Below-replacement fertility offset by high net migration keeps the population growing and ageing slowly, while raising housing and infrastructure pressure in growth regions.
Exam-style questions
Questions in the style of QCAA exam questions on this dot point, each with a worked answer. They are written by ExamExplained unless tagged "Past paper"; the year shows the paper a question is modelled on.
Practice4 marksExplain the population trends shown in the graph. [The graph in the exam showed world population from 1700 to a projection for 2100: about 600 million in 1700, 1 billion around 1803, 2 billion in 1928, 5 billion in 1987 and 7.7 billion in 2019, with the annual growth rate peaking at about 2.1 per cent in 1968 and falling since.] Provide one reason to explain the projected trend beyond 2019.Show worked answer →
A 4-mark answer reads the world population growth graph (1700 to 2100) and then explains the projected slowdown.
Describe the trend with data. World population rose slowly from about 600 million in 1700 to 1 billion in 1803, then accelerated sharply through the twentieth century (2 billion in 1928, 5 billion in 1987, 7.7 billion in 2019). The annual growth rate peaked at about 2.1 per cent in 1968 and has since fallen to about 1.08 per cent in 2019.
State the projection. The UN medium-fertility variant projects continued but slowing growth to about 9.7 billion in 2050 and 10.9 billion in 2100, with the curve flattening.
Give one reason for the projected trend. The slowdown reflects falling global fertility as countries pass through the demographic transition: rising education and status of women, greater contraceptive access and urbanisation reduce family size, so growth decelerates even as total numbers rise.
Markers reward an accurate described trend with figures and a valid reason for the post-2019 projection.
Practice5 marksAnalyse the graph you constructed in Question 4a) to describe the trends evident. Provide a reason to explain the projected trend for Italy.Show worked answer →
This 5-mark part rewards describing the old-age dependency trends from the constructed graph (2020 to 2075) and explaining Italy's trajectory.
Describe the overall trend. Old-age dependency is projected to rise for every country, but at different rates. Japan and Italy start highest and stay high (Italy about 40 in 2020 rising to about 74 in 2050 before easing to about 67 by 2075), while India stays lowest (about 11 rising to 32). China shows the steepest climb (about 18 to 59).
Compare with evidence. Developed, already-aged countries cluster high; less developed and younger countries remain lower throughout.
Explain Italy's projected trend. Italy's persistently high old-age dependency reflects sustained below-replacement fertility combined with rising life expectancy, so large older cohorts survive while small younger cohorts enter the workforce, pushing the ratio up.
The top band needs accurate trends with figures plus a sound demographic reason for Italy.
Practice5 marksUse evidence from the population pyramid to explain population momentum and the impacts on China's population structure.Show worked answer →
A 5-mark answer defines population momentum and applies it to China's 2015 and 2040 pyramid.
Define population momentum. Population momentum is the tendency of a population to keep growing (or shrinking) for decades after fertility changes, because the existing age structure carries the change forward. A large cohort of young adults keeps birth numbers high even after fertility per woman falls.
Use pyramid evidence. China's 2015 pyramid shows a large working-age bulge moving upward by 2040, while the base narrows as fewer children are born, the legacy of past fertility decline.
Explain the impacts on structure. As the bulge ages into the upper bars by 2040, the pyramid becomes top-heavy: the median age rises, the old-age dependency ratio increases, and the working-age share falls, so momentum here drives ageing and eventual decline rather than growth.
Markers reward a correct definition, pyramid evidence for both years, and the structural impacts of ageing.