18.10 Factors Affecting Food Security

A free GCSE Biology lesson for AQA (8461) from OBA School: what food security means and the biological and other factors that threaten it. Watch the video, read the explanation and worked examples, then try the revision questions. You can work through the full lesson, with every video, practice quizzes and printable worksheets with mark schemes, in our free online course.

What you will learn

• Define food security
• Describe the biological factors that threaten food security
• Explain how birth rate, diet, pests and pathogens, environmental change, costs and conflict affect food supply
• Use data to compare population growth with food production, including food per person

Key words

• Food security: Having enough food to feed a population, now and in the future.
• Birth rate: The number of babies born per 1000 people in a population each year.
• Pathogen: A microorganism (virus, bacterium, fungus or protist) that causes disease.
• Famine: A severe shortage of food across a large area, causing hunger and deaths.
• Agricultural inputs: Things a farmer must buy to grow food, such as seed, fertiliser, pesticides, animal feed and fuel.

What is food security?

Food security means having enough food to feed a population. The world population is still rising, so farmers must produce more food every year, using land and water that are already under pressure.

Biological and other threats

• Increasing birth rate; How it threatens food security In many countries the birth rate is high, so the population grows faster than food production.
• Changing diets; How it threatens food security People in richer countries want a wider range of foods all year. Scarce food resources (e.g. crops, fish, land and water) are transported to them, leaving less for local people.
• New pests and pathogens; How it threatens food security New strains of fungi, viruses or insects spread to new areas and destroy crops or livestock. Pests may become resistant to pesticides.
• Environmental change; How it threatens food security Droughts, floods and changes in climate reduce yields. When rains fail, widespread famine can follow.
• Cost of agricultural inputs; How it threatens food security If fertiliser, fuel, seed or feed become expensive, poorer farmers use less, so yields fall.
• Conflict; How it threatens food security War damages farms, roads, water supplies and markets, and people are forced to leave their land.

Worked example: effect of a drought

Mean yield in the five normal years = (4.2 + 4.5 + 4.4 + 4.1 + 4.6) ÷ 5 = 21.8 ÷ 5 = 4.36 t per ha
Drop in 2019 = 4.36 − 1.8 = 2.56. Percentage decrease = 2.56 ÷ 4.36 × 100 = 58.7%

Answer: about 59% less maize in the drought year

Food per person

Food production can rise and food security still get worse, if the population grows faster. Compare the food available per person.

Worked example: is there more food per person?

A country produced 8.0 million tonnes of grain for 32 million people. Ten years later it produced 9.0 million tonnes for 40 million people.
Before: 8.0 ÷ 32 = 0.25 tonnes per person. After: 9.0 ÷ 40 = 0.225 tonnes per person.
Change = (0.225 − 0.25) ÷ 0.25 × 100 = −10%

Answer: grain per person fell by 10%, even though total grain rose

Exam tip: In exam answers, say clearly how each factor reduces the amount of food available, e.g. “a fungal pathogen kills the wheat plants, so the yield falls, so there is less food.”

Common mistakes

• Defining food security as “food that is safe to eat”. It means having enough food to feed a population.
• Assuming that if total food production rises, everyone has more food. Always compare with population growth.
• Listing factors without explaining them. Link each one to less food being produced or available.
• Forgetting that changing diets in richer countries can reduce food security in the countries where the food is grown.

Revision questions

Try these, then check your answers below each one.

Question 1. What is meant by food security? (Choose from: Keeping food in locked stores, Eating only food grown locally, Having enough food to feed a population, Making sure food is free from bacteria.)

Answer: Having enough food to feed a population

Working: Food security means having enough food to feed a population.

Question 2. True or false? If total food production in a country rises, the food available per person must also rise.

Answer: False

Working: False. If the population grows faster than food production, food per person falls.

Question 3. A country grows 18 million tonnes of grain for 60 million people. How many tonnes of grain is that per person?

Answer: 0.3 tonnes

Working: 18 ÷ 60 = 0.3 tonnes per person.

Related lessons

• Previous lesson: 18.9 Biomass Transfers
• Next lesson: 18.11 Making Food Production Efficient
• In this chapter: 18.1 The Human Population Explosion
• In this chapter: 18.2 Land and Water Pollution
• In this chapter: 18.3 Air Pollution

Continue in the full course

This lesson is section 18.10 (AGCBH1810) of our free GCSE Biology course for AQA. In the full course you get every video for this section, a self-marking practice quiz, a printable worksheet with a mark scheme, chapter tests, and your progress saved. Go to the full GCSE Biology course.