What is food security?
Food security exists when all people, at all times, can get enough safe, nutritious food to meet their needs for an active, healthy life. Food insecurity is when they cannot. An adult usually needs about 2,000–2,500 kcal a day.
The four pillars:
- Availability: enough food is grown, stored or imported.
- Access: people have the money, land or transport to obtain it.
- Utilisation (use): the body can use the food: balanced diet, clean water, sanitation, safe cooking.
- Stability: the other three stay steady through droughts, price shocks and wars.
Global patterns of food supply and consumption
Daily food supply per person is highest in North America, Europe and Australia (often over 3,300 kcal) and lowest in parts of sub-Saharan Africa and South Asia (some places under 2,300 kcal). Big food exporters include the USA, Brazil, Argentina, Canada, Australia, India (rice) and Thailand.
Patterns are shaped by physical factors (climate, soil, water, relief) and human factors (wealth, technology, trade, government policy, conflict). Rich countries also have the opposite problem: over-eating and obesity, and large amounts of waste. Roughly one-third of the food produced in the world is lost or wasted.
Why is demand rising, and what limits supply?
Demand rises because of:
- Population growth: about 8 billion today, near 10 billion by 2050.
- Higher incomes: people eat more meat, dairy and processed food. Meat needs several kilograms of grain per kilogram.
- Urbanisation: city dwellers buy food rather than grow it.
- Biofuels: some crops are grown for fuel, not food.
Supply is limited by climate change (heatwaves, floods, droughts), water shortage, soil erosion and salinity, pests and disease, poor storage and roads, high fuel and fertiliser prices, and conflict.
Impacts of food insecurity
- Health: hunger, undernutrition, stunting in children, weak immunity, anaemia; hidden hunger from missing vitamins and minerals.
- Economic: high food prices, lower worker productivity, children missing school.
- Social and political: food riots, unrest, conflict over land and water.
- Migration: families move to cities or abroad in search of food and work.
- Environment: pressure to clear forests or overgraze fragile land, causing soil erosion.
A famine is the extreme case: widespread lack of food causing many deaths.
Increasing food supply
- Irrigation: canals, wells, drip and sprinklers bring water to dry land.
- The Green Revolution: high-yield seeds, fertiliser and irrigation raised wheat and rice output in India and Mexico from the 1960s. It also caused problems: falling water tables, soil damage and costs for small farmers.
- Biotechnology: genetically modified or gene-edited crops that resist pests or drought (debated for safety and cost).
- New technology: hydroponics, vertical farms, precision farming with sensors and drones.
- Aquaculture: fish farming.
- Better storage and roads: less food is lost after harvest.
- Large dam and land schemes: can raise output but may displace people and harm rivers.
Sustainable food: feeding people without harming the planet
A sustainable food system meets today's needs without damaging the land, water and climate that future people need.
- Cut waste on farms, in shops and at home.
- Eat more local, seasonal and plant-based food; millets need less water than rice.
- Organic and agroforestry methods, crop rotation, mixed cropping.
- Permaculture and urban farming: community gardens, rooftop farms.
- Fair trade and support for small farmers, who grow much of the world's food.
- Safety nets: ration shops, school meals and food banks protect access.
Exam tips
Learn the definition and four pillars word-perfect. Use case studies: a large-scale scheme (for example, a big irrigation project) and a local sustainable scheme (for example, a community garden or millet programme). For “to what extent” questions, give benefits and problems, then a judgement.
Try it at home
For one week, weigh or count the food your family throws away. Multiply by 52 to estimate a year. Then use the waste slider in step 6 of the 3D and see how much extra food the world would have if waste fell from 30% to 10%.
Key formulas and definitions
- Food security = availability + access + utilisation + stability
- Daily need ≈ 2,000–2,500 kcal per adult
- Food per person = total food supply ÷ population
- Demand ↑: population, income, diet change, urbanisation, biofuels
- Supply ↓: climate change, water shortage, soil erosion, pests, conflict, waste
- Sustainable = enough for now + safe for the future
Worked examples
1. A country has 120 million people and 300 trillion (3 × 10¹⁴) kcal of food a year. Is there enough on average?
Per person per day = 3 × 10¹⁴ ÷ 1.2 × 10⁸ ÷ 365 ≈ 6,850 kcal. Yes, on average there is plenty. But hunger is still possible if poor people lack access, so check the other pillars.
2. Which pillar fails: shops are full of rice, but daily-wage workers lose jobs during a lockdown.
Access. Food is available, but people cannot afford it. Solutions: free rations, cash transfers, community kitchens.
3. Waste falls from 30% to 20% of a 10,000 t harvest. How much more food reaches people?
Before: 70% of 10,000 = 7,000 t. After: 80% = 8,000 t. Extra = 1,000 t, about 14% more food, without planting one extra field.
4. Evaluate the Green Revolution in India.
Benefits: wheat and rice output rose many times, famines ended and India became self-sufficient. Problems: over-use of groundwater in Punjab and Haryana, soil damage from chemicals, loss of crop variety, and richer farmers gained more. Judgement: it solved the urgent problem of availability but created sustainability problems that need new methods.
Common mistakes
- Thinking food security only means producing enough food. Access, use and stability matter too.
- Saying hunger exists only because the world grows too little. The world grows enough calories; distribution, poverty and waste are major causes.
- Listing solutions with no downside. Every large scheme has costs; evaluate them.
- Mixing up undernutrition (too little food) and malnutrition (wrong balance, which includes obesity).