Demographic data help governments plan. Here we look at models, policies and the trends reshaping the world.
📉 Fertility transition
The total fertility rate (TFR) fell from about 5 children per woman in 1950 to about 2.3 today. Reasons: urbanisation, education of girls, contraception and falling child mortality. The doubling time of a growing population ≈ 70 ÷ growth rate (%). Population momentum means a young population keeps growing even after fertility falls, because many people are entering childbearing age.
TFR: 1950 about 5; today about 2.3; Niger about 6.7; South Korea about 0.7
doubling time at 2% growth = 70 / 2 = 35 years
at 1% = 70 years
🖼️ See it
The gap between births and deaths is population growth: it opens in Stage 2, narrows in Stage 3 and almost closes in Stage 4.
🏛️ Policy responses
Pro-natalist policies encourage births (France, Hungary, South Korea cash incentives). Anti-natalist policies limit births (China’s one-child policy, 1980–2015; India’s family planning). Ageing societies respond with later retirement ages, immigration, automation and encouraging women’s employment. Youthful societies invest in education to capture a demographic dividend.
demographic dividend: more workers than dependants
support ratio = working-age / dependants
60 / 40 = 1.5 workers per dependant
Policies often have unintended effects. China’s one-child policy led to an ageing society and a gender imbalance.
✏️ Quick check · 1 of 7
TFR
The total fertility rate is:
Per woman.
✏️ Quick check · 2 of 7
Momentum
Population momentum occurs because:
Many parents-to-be.
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Pro-natalist
A pro-natalist policy aims to:
For births.
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Dividend
A demographic dividend occurs when:
Workers.
✍️ Type your answer · 5 of 7
A country’s population grows at 2% a year.
Using 70 ÷ growth rate, how many years to double?
Enter an exact answer, without rounding.
years
Rule of 70.
✍️ Type your answer · 6 of 7
A country has 60 million working-age people and 40 million dependants.
How many workers per dependant?
Enter an exact answer, without rounding.
Divide.
✍️ Type your answer · 7 of 7
TFR fell from 5 to 2.3 children per woman.
By how many children did it fall?
Enter an exact answer, without rounding.
Subtract.
📝 Lesson quiz · 5 questions
0 / 5
Re-read the lesson, then give it another go.
Question 1 of 5
A TFR below 2.1 in the long term will cause:
Question 2 of 5
Which country had a one-child policy until 2015?
Question 3 of 5
Rule of 70 gives:
Question 4 of 5
One cause of falling fertility is:
Question 5 of 5
One way to cope with an ageing society is:
Lesson 2 · Global issues
🍚 Food Security
The world produces enough calories for everyone, yet hundreds of millions go hungry. Why?
🌾 Production and access
Food security has four dimensions: availability, access, utilisation (nutrition) and stability. About 9% of people (over 700 million) are undernourished, while 40% of adults are overweight. The Green Revolution (1960s) boosted yields through high-yield seeds, fertiliser and irrigation, but increased dependence on chemicals and water. Yield = output ÷ area.
yield = tonnes / hectares
600 t from 150 ha → 4 t/ha
India wheat yield: 1960 ~0.85 t/ha; now ~3.5 t/ha
🖼️ See it
Hunger can exist even where food is plentiful, if people cannot reach or afford it.
⚖️ Threats and solutions
Threats: drought and climate change, conflict, price spikes, land degradation and waste. Solutions: sustainable intensification, agroforestry, GM crops (debated), vertical farming, reducing waste and social safety nets. Food miles measure distance travelled, but transport is often a small share of a food’s emissions.
waste: ~1/3 of food produced
reducing waste by half could feed hundreds of millions
Niger: ~45% of children stunted (chronic malnutrition)
Hunger is often about poverty and access, not total supply. Famines have often occurred even when food was available nearby.
✏️ Quick check · 1 of 7
Dimensions
Which is NOT a dimension of food security?
Not about clothes.
✏️ Quick check · 2 of 7
Green Revolution
The Green Revolution raised yields through:
Inputs.
✏️ Quick check · 3 of 7
GM crops
GM crops are:
Gene changes.
✏️ Quick check · 4 of 7
Safety net
A social safety net such as school meals:
Support.
✍️ Type your answer · 5 of 7
A farm produces 600 tonnes of grain from 150 hectares.
What is the yield, in t/ha?
Enter an exact answer, without rounding.
t/ha
Divide.
✍️ Type your answer · 6 of 7
A country has 80 million tonnes of food and wastes one third.
How many million tonnes are wasted? (round)
Round your answer as the question asks.
million t
One third of 80.
✍️ Type your answer · 7 of 7
About 9% of 8 billion people are undernourished.
How many million people is that?
Enter an exact answer, without rounding.
million
9% of 8000 million.
📝 Lesson quiz · 5 questions
0 / 5
Re-read the lesson, then give it another go.
Question 1 of 5
Agroforestry combines:
Question 2 of 5
Land degradation reduces:
Question 3 of 5
Vertical farming grows crops:
Question 4 of 5
Stunting in children results from:
Question 5 of 5
Which action most reduces pressure on the food system?
Lesson 3 · Global issues
🚰 Water Security
Fresh water is unevenly spread and increasingly stressed by demand and climate change.
💧 Supply and demand
Water stress occurs when supply falls below about 1700 m³ per person per year; scarcity below 1000 m³. Agriculture uses about 70% of freshwater withdrawals, industry 20% and households 10%. About 2 billion people lack safe drinking water. Physical scarcity (not enough water, such as the Middle East) differs from economic scarcity (water exists but there is no infrastructure, as in parts of Africa).
water per person = supply / population
20 000 million m³ / 10 million = 2000 m³ per person → no stress
8000 million m³ / 10 million = 800 m³ → scarcity
virtual water: 1 kg of beef ≈ 15 000 litres
🖼️ See it
Only about 3% of the world’s water is fresh, and almost all of that is frozen or underground. Rivers and lakes hold about 1% of it.
🛠️ Management strategies
Hard engineering includes dams, reservoirs and inter-basin transfers (China’s South–North project). Desalination turns seawater into fresh water but is energy-hungry. Soft strategies include rainwater harvesting, drip irrigation, water pricing and fixing leaks. Rivers crossing borders (the Nile, Mekong, Indus) can cause conflict, though cooperation treaties are common.
Nile: 11 countries share it
GERD dam (Ethiopia) → tensions with Egypt
leaks in some cities lose up to 40% of supplied water
Efficiency is often cheaper than new supply. Fixing leaks can be more cost-effective than building a dam.
✏️ Quick check · 1 of 7
Water stress
Water stress occurs when supply is below about:
A set threshold.
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Economic scarcity
Economic water scarcity means:
Cost and access.
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Desalination
Desalination:
Make seawater drinkable.
✏️ Quick check · 4 of 7
Transboundary
Why can shared rivers cause conflict?
Sharing a resource.
✍️ Type your answer · 5 of 7
A country has 8000 million m³ of water and 10 million people.
How many m³ per person per year?
Enter an exact answer, without rounding.
m³
Divide.
✍️ Type your answer · 6 of 7
Agriculture uses 70% of 4000 km³ of withdrawals.
How many km³ does agriculture use?
Enter an exact answer, without rounding.
km³
70% of 4000.
✍️ Type your answer · 7 of 7
A city supplies 500 000 m³ per day and loses 20% in leaks.
How many m³ per day are lost?
Enter an exact answer, without rounding.
m³
20% of 500 000.
📝 Lesson quiz · 5 questions
0 / 5
Re-read the lesson, then give it another go.
Question 1 of 5
Which sector uses most freshwater globally?
Question 2 of 5
Rainwater harvesting is:
Question 3 of 5
Virtual water refers to:
Question 4 of 5
An inter-basin transfer:
Question 5 of 5
Which is a soft management strategy?
Lesson 4 · Physical geography
🌪️ Hazard Risk & Resilience
A hazard becomes a disaster when it meets a vulnerable population. Resilience reduces the damage.
🧮 Risk and management
Risk depends on the hazard, the exposure and vulnerability of people, and their capacity to cope. The Park model shows how a community recovers from a disaster. The hazard management cycle: mitigation (reduce impacts, e.g. building codes), preparedness (drills, early warning), response (rescue, relief) and recovery (rebuild, resilience).
risk ≈ hazard × vulnerability / capacity to cope
Japan 2011 M9.0: ~18 000 deaths, advanced warning and codes
Haiti 2010 M7.0: ~200 000+ deaths, poor buildings
🖼️ See it
Communities become more resilient when each stage feeds the next: lessons from recovery improve mitigation before the next hazard.
🌋 Case thinking
A magnitude 7.0 earthquake can be catastrophic in Haiti but moderate in Japan: the difference is building quality, preparation and governance. Climate change raises the frequency of intense storms and floods. Early warning for tsunamis (the Indian Ocean system after 2004) and cyclones (Bangladesh shelters) has cut deaths dramatically: cyclone deaths in Bangladesh fell from about 300 000 (1970) to a few thousand today.
A 7.0 earthquake releases how many times the energy of a 6.0? (Each step is about 32 times.)
How many times more energy?
Enter an exact answer, without rounding.
×
One magnitude unit.
✍️ Type your answer · 7 of 7
Haiti’s 2010 quake killed about 200 000 and Japan’s 2011 quake about 18 000.
About how many times more died in Haiti? (round)
Round your answer as the question asks.
×
Divide.
📝 Lesson quiz · 5 questions
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Re-read the lesson, then give it another go.
Question 1 of 5
Which is a recovery action?
Question 2 of 5
Hazard maps help by:
Question 3 of 5
Which strategy reduces flood risk?
Question 4 of 5
Disaster risk is higher when:
Question 5 of 5
Early warning systems save lives mainly by:
Lesson 5 · Global issues
🧭 Geopolitics & Sustainable Development
Power, borders and resources shape international relations; sustainable development tries to align growth with a livable planet.
🗺️ Geopolitics
Geopolitics studies how geography affects power and politics. Factors: location, resources, chokepoints (the Strait of Hormuz carries about 20% of the world’s oil; Suez about 12% of trade), borders and alliances. Contested areas include the South China Sea and the Arctic, where melting ice opens routes and resources. Soft power (culture, aid) complements hard power (military, sanctions). International organisations (UN, WTO, NATO, AU) manage cooperation.
Strait of Hormuz: ~20% of world oil
Suez: ~12% of world trade
Arctic route cuts Asia–Europe shipping by about 40%
🖼️ See it
Development is sustainable only when all three pillars are met together, which is the idea behind the UN Sustainable Development Goals.
🌱 Sustainable development
The Sustainable Development Goals (2015–2030) cover 17 goals, including no poverty, zero hunger, clean energy and climate action. Tools: circular economy (reuse and recycle), green finance, carbon pricing, fair trade and ecotourism. Challenges: balancing growth with emissions, financing the poorest countries and accountability. Measures such as the ecological footprint and Gini coefficient track sustainability and inequality.
SDG deadline 2030; started 2015 → 15 years
circular: make → use → reuse → recycle (not take → make → waste)
Sustainability needs three pillars in balance: economic, social and environmental.
✏️ Quick check · 1 of 7
Chokepoint
A chokepoint is:
Narrow route.
✏️ Quick check · 2 of 7
Soft power
Soft power is the ability to influence others through:
Not hard.
✏️ Quick check · 3 of 7
Circular economy
A circular economy aims to:
Loop.
✏️ Quick check · 4 of 7
SDGs
How many Sustainable Development Goals are there?
Seventeen.
✍️ Type your answer · 5 of 7
The SDGs were agreed in 2015 for delivery by 2030.
How many years are allowed?
Enter an exact answer, without rounding.
years
Subtract.
✍️ Type your answer · 6 of 7
About 20% of world oil passes through Hormuz. World oil trade is 100 million barrels a day.
How many million barrels pass through?
Enter an exact answer, without rounding.
million
20% of 100.
✍️ Type your answer · 7 of 7
An Arctic route cuts a 20 000 km voyage by 40%.
How many km are saved?
Enter an exact answer, without rounding.
km
40% of 20 000.
📝 Lesson quiz · 5 questions
0 / 5
Re-read the lesson, then give it another go.
Question 1 of 5
Which is a disputed area because of resources and shipping routes?
Question 2 of 5
Sanctions are:
Question 3 of 5
A Gini coefficient measures:
Question 4 of 5
Carbon pricing:
Question 5 of 5
A feature of ecotourism is:
Final Challenge
🏆 10-Question Challenge Quiz
Questions from every topic in this course. Pick an answer for each one, then hit Check My Answers.
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💪 Keep practicing — go back through the lessons and retake the quiz!
Q1 · Population Dynamics & Policy
Which pair of countries are facing population ageing?
Q2 · Population Dynamics & Policy
One way to cope with an ageing society is:
Q3 · Food Security
The main cause of hunger today is:
Q4 · Food Security
Which action most reduces pressure on the food system?
Q5 · Water Security
Which approach tackles both supply and demand?
Q6 · Water Security
Which is a soft management strategy?
Q7 · Hazard Risk & Resilience
Why did the 2010 Haiti earthquake cause so many more deaths than Japan’s similar-sized events?
Q8 · Hazard Risk & Resilience
Early warning systems save lives mainly by:
Q9 · Geopolitics & Sustainable Development
Why is the Arctic increasingly important in geopolitics?