What is food security and what threatens it?
Food security means every person, at all times, can get enough safe and healthy food. Food insecurity means some people cannot.
Things that make food security harder
- More people: the world population passed 8 billion and still grows.
- Changing diets: as countries get richer, people eat more meat. Meat needs much more land and feed than plants.
- New pests and diseases: they can destroy a whole crop.
- Climate change: droughts, floods and heat waves cut harvests.
- Cost of farming: seeds, fuel and fertiliser cost money.
- War and conflict: farms and transport stop working.
How food production began and spread
For most of human history people hunted animals and gathered wild plants. About 10,000–12,000 years ago people in several regions began to farm: they planted seeds and kept animals. Wheat and barley were tamed in West Asia, rice in East Asia, maize in the Americas. Farming gave a steady food supply, so villages and towns grew.
After 1492 ships carried crops and animals between the Americas and the rest of the world (the Columbian exchange). Maize, potato, tomato and chilli spread to Asia, Africa and Europe; wheat, cattle and horses went to the Americas. Diseases also travelled, with terrible results for many native peoples. This mixing still shapes what the whole world eats.
Farming techniques that raise output
Crops: fertilisers give plants the minerals they need (like nitrate); pesticides and herbicides stop pests and weeds; irrigation gives water; greenhouses keep plants warm.
Animals: energy is lost at every step of a food chain. An animal uses most of the energy in its food for moving and keeping warm. In intensive farming, animals are kept in small, warm pens and given high-protein food. They move less and lose less heat, so more of the food energy becomes meat.
The other side
- Many people think it is cruel to keep animals in small spaces.
- Diseases spread fast in crowded pens, so antibiotics are often used, which can help resistant bacteria grow.
- Heating uses fuel; waste can pollute rivers.
Efficiency of food production = energy in the useful product ÷ energy in the food eaten × 100%. Eating plants directly (lower in the food chain) feeds more people from the same land.
Sustainable fisheries
Fish stocks in the oceans are falling because too many fish are caught (overfishing). If stocks fall too low, some species may die out. To keep fish for the future:
- Net mesh size: bigger holes let young fish escape so they can grow and breed.
- Fishing quotas: a limit on how many fish of each kind can be caught each year.
- Closed seasons (no fishing at breeding time) and protected sea areas also help.
Fish farming (aquaculture) is another way to produce fish without emptying the sea, but it needs clean water and feed.
The role of biotechnology
Biotechnology uses living things, such as microbes, to make useful products.
Mycoprotein
The fungus Fusarium is grown in big tanks (fermenters) on glucose syrup, with oxygen, at a controlled temperature and pH. The fungus mass is harvested and cleaned to make mycoprotein, a protein-rich food for vegetarians.
GM crops
Genetic modification puts a useful gene into a crop. Examples: crops that resist insects, crops that resist a weedkiller, and Golden Rice that makes beta-carotene (used by the body to make vitamin A). GM crops can give bigger, more nutritious harvests. Some people worry about effects on wild plants, insects and human health, so GM foods are tested and labelled in many countries.
Key formulas and definitions
- Food security: Available + Accessible + Adequate + Always
- Efficiency of food production = (energy in product ÷ energy in food eaten) × 100%
- Overfishing: catch faster than fish can breed → stock falls
- Mycoprotein: Fusarium fungus + glucose + oxygen in a fermenter
- GM crop: a crop with a useful gene added from another organism
Worked examples
1. A cow eats feed containing 50,000 kJ. Its body gains 2,000 kJ of energy as meat. What is the efficiency?
Efficiency = 2,000 ÷ 50,000 × 100% = 4%. The other 96% was used for moving, keeping warm, or lost in faeces and urine.
2. Why can 1 hectare of wheat feed more people than 1 hectare used to grow feed for cattle?
When people eat wheat, all the energy in the grain reaches humans. When cattle eat the grain, most energy is used by the cattle for movement and heat, so only a few percent reaches us as beef.
3. A fishery changes from 6 cm to 10 cm mesh nets. Explain what happens to the fish stock over 5 years.
Young, small fish pass through the bigger holes. They survive to adult size and breed. More young are born each year, so the stock rises and stays healthy, even though the catch in the first year may be a little smaller.
Common mistakes
- Thinking food security just means growing more food. People must also be able to reach and afford it, and it must be safe and healthy.
- Saying intensive farming makes animals use less food. It makes them waste less of the food's energy on movement and heat.
- Thinking quotas stop fishing. They only limit the catch so fish can breed and stocks recover.
- Calling mycoprotein a meat or a plant. It comes from a fungus grown in a fermenter.