B44: Food Security
Food security and sustainable food production
Key Definitions
Food security: Having enough food at all times for all people to lead an active, healthy life. This means food must be available, affordable and nutritionally adequate.
Sustainable food production: Producing food in ways that can be continued long-term without depleting natural resources, damaging the environment or compromising the ability of future generations to produce food.
Factory farming: Intensive livestock farming where animals are kept indoors at high densities, with controlled temperature, feeding and lighting to maximise growth rate and food production efficiency.
Mycoprotein: A protein-rich food produced from the fungus Fusarium, grown in fermenters on glucose syrup as a food source. Sold commercially as Quorn.
Factors Affecting Food Security
Food security is threatened by several global challenges:
| Factor | How It Threatens Food Security |
|---|---|
| Population growth | The global population is increasing (over 8 billion and rising). More people means greater demand for food, putting pressure on agricultural systems and resources |
| Changing diets | As countries become wealthier, people eat more meat and dairy. Producing meat requires far more land and energy than producing plants (due to energy losses at each trophic level), so this shift increases pressure on food supplies |
| Environmental changes | Climate change causes droughts, floods and changing temperatures that reduce crop yields in affected regions. Soil erosion and desertification reduce the area of productive farmland |
| Pests and diseases | Insect pests, fungal diseases and viruses destroy crops and livestock. New pests and diseases are emerging due to climate change and global trade, threatening food production |
| Cost | Rising costs of fertilisers, fuel, seeds and transport make food production more expensive. Poor people and countries cannot afford sufficient food or the technology to produce it efficiently |
| Conflict | Wars and political instability disrupt farming, transport and food distribution, causing famine in affected regions |
Example 1: Population Growth and Changing Diets in China
As China's economy has grown, meat consumption per person has increased dramatically (from around 14 kg per person per year in 1980 to over 60 kg today). Producing this meat requires vast amounts of grain to feed livestock – it takes approximately 7 kg of grain to produce 1 kg of beef. This means more land is needed to grow feed crops, and less grain is available for direct human consumption. This shift from plant-based to meat-based diets in large populations significantly threatens global food security.
Reducing Energy Waste in Food Chains
Key principle: Energy is lost at each trophic level (approximately 90%). This means eating plants directly is far more energy-efficient than eating animals that ate plants. Only about 10% of the energy in plant food is transferred to the animal that eats it.
Example 2: Why Eating Plants Is More Efficient Than Eating Meat
Consider 100,000 kJ of energy in wheat:
- If humans eat the wheat directly, they receive approximately 10,000 kJ (10% efficiency – some lost in digestion and not all parts eaten)
- If wheat is fed to cattle and humans eat the beef, they receive only approximately 1,000 kJ (10% of 10%)
This means the same area of farmland can feed roughly 10 times more people if they eat the crops directly rather than feeding them to livestock first. This is a key argument for plant-based diets in the context of food security.
Sustainable Food Production Methods
1. Factory Farming
Factory (intensive) farming keeps livestock such as chickens and cattle indoors in controlled conditions:
| Advantages | Disadvantages |
|---|---|
| Animals grow faster – reach slaughter weight sooner | Ethical concerns – cramped conditions, no natural behaviour, stress and suffering |
| More food produced per unit area of land | Risk of disease spreading rapidly in dense populations (e.g. avian flu, swine flu) |
| Temperature controlled – less energy wasted on keeping warm | Antibiotics overused to prevent disease – contributes to antibiotic resistance in bacteria |
| Feed is carefully controlled – less waste | Poor animal welfare – restricted movement, inability to express natural behaviours |
| Lower cost per unit of food produced | Large quantities of waste (manure, slurry) can pollute local waterways |
2. Fishing Quotas and Sustainable Fisheries
Overfishing has severely depleted fish stocks. To make fishing sustainable:
- Fishing quotas limit the amount of each fish species that can be caught in a given area per year
- Mesh sizes on nets are regulated so young fish can escape and grow to breeding age
- Marine protected areas are zones where fishing is banned, allowing fish populations to recover
- Seasonal restrictions prevent fishing during breeding seasons
These measures ensure fish populations can reproduce fast enough to replace the fish that are caught, maintaining stocks for the future.
3. Organic Farming
Organic farming avoids artificial fertilisers and pesticides:
- Uses natural fertilisers (manure, compost) instead of chemical fertilisers
- Uses crop rotation and biological pest control instead of pesticides
- Maintains soil fertility and biodiversity
- However, yields are typically 20–40% lower than conventional farming, so more land is needed
4. Hydroponics
Hydroponics grows plants in nutrient solutions without soil:
- Plants are grown in water containing dissolved minerals, often in greenhouses
- Conditions (temperature, light, mineral supply, CO₂) can be controlled for optimal growth
- Uses less water than soil-based farming (water is recycled)
- No soil-borne pests or diseases
- Can be used in areas with poor soil (deserts, cities, space stations)
- Disadvantages: expensive to set up, requires constant energy for pumps and lighting
Example 3: Hydroponic Tomato Farming in Greenhouses
In the Netherlands, tomatoes are grown hydroponically in vast greenhouses. The plants grow in rockwool (an inert growing medium) and receive precise amounts of water and minerals through drip irrigation. CO₂ from nearby power stations is pumped into the greenhouses to boost photosynthesis. Yields are up to 70 kg/m²/year – many times higher than outdoor soil-grown tomatoes. The closed system recirculates water and nutrients, making it highly efficient and reducing pollution from fertiliser runoff.
5. Mycoprotein (Quorn)
Mycoprotein is a meat substitute produced using the fungus Fusarium:
- The fungus is grown in large fermenters on glucose syrup (from starch) as a food source
- Conditions in the fermenter are controlled: warm temperature, adequate oxygen and a slightly acidic pH
- The fungus grows rapidly, producing protein-rich biomass (mycoprotein)
- The mycoprotein is harvested, processed and shaped into products that mimic the texture of meat
Advantages of mycoprotein over meat: It is produced much more efficiently because the fungus is at the same trophic level as the animal that would eat the crop – there is one fewer trophic level, so less energy is lost. It also uses less land, produces less greenhouse gas, and contains no cholesterol. It is suitable for vegetarians and is a more sustainable source of protein.
Example 4: Quorn Production
Quorn is the commercial name for mycoprotein. The Fusarium fungus doubles its mass every 3–4 hours under optimal conditions, making it incredibly productive. A fermenter can produce several tonnes of mycoprotein per day from a relatively small area, compared to the vast land area needed to raise cattle for an equivalent amount of beef protein. The glucose syrup used as food for the fungus comes from crops like maize, so the process still relies on photosynthesis – but it avoids the 90% energy loss that occurs when feeding crops to livestock.
Comparison: Sustainable Food Production Methods
| Method | How It Works | Advantages | Disadvantages |
|---|---|---|---|
| Factory farming | Intensive indoor rearing of livestock | High yield, low cost, efficient land use | Welfare concerns, disease risk, antibiotic resistance |
| Fishing quotas | Limits on catch size and methods | Maintains fish stocks, protects marine ecosystems | Reduces short-term income for fishers, hard to enforce |
| Organic farming | No artificial chemicals, natural methods | Better for environment, soil health and biodiversity | Lower yields, more land needed, higher costs |
| Hydroponics | Plants grown in nutrient solution, no soil | High yields, efficient water use, works in any location | Expensive setup, needs energy for pumps and lights |
| Mycoprotein | Fungus grown in fermenters on glucose | Very efficient, low land use, no cholesterol | Some people prefer real meat, limited product range |
Practice Questions
Q1: Foundation Define food security and state three factors that threaten it.
Q2: Foundation Explain why eating plants directly is more energy-efficient than eating meat from animals that were fed plants. Refer to energy transfer between trophic levels.
Q3: Higher Discuss the advantages and disadvantages of factory farming. Include both efficiency and ethical considerations.
Q4: Higher Explain how mycoprotein is produced and why it is a more sustainable source of protein than beef. Refer to trophic levels in your answer.
Q5: Foundation Describe how fishing quotas help maintain sustainable fish stocks. Give two other measures that help prevent overfishing.
Answers
- Food security means having enough food at all times for all people to lead an active, healthy life. Food must be available, affordable and nutritionally adequate. Three factors that threaten it: (1) Population growth – increasing numbers of people require more food; (2) Environmental changes – climate change causes droughts, floods and changing temperatures that reduce crop yields; (3) Pests and diseases – insects, fungi and viruses destroy crops and livestock, reducing food production.
- Energy is lost at each trophic level (approximately 90%). When humans eat plants (producers) directly, they are at trophic level 2 (primary consumers) and receive about 10% of the original energy in the plants. When humans eat meat from animals that ate plants, they are at trophic level 3 (secondary consumers). The animals have already lost 90% of the plant energy through respiration, excretion and movement, so humans receive only about 1% of the original plant energy (10% of 10%). This means the same area of farmland can feed roughly 10 times more people on a plant-based diet than on a meat-based diet, making plant-based eating far more energy-efficient and better for food security.
- Advantages of factory farming: (1) Animals grow faster because movement is restricted and temperature is controlled, so less energy is wasted on heat loss and exercise – more biomass is produced per animal. (2) More food is produced per unit area of land, making efficient use of limited space. (3) Food is cheaper for consumers due to economies of scale. Disadvantages: (1) Ethical concerns – animals are kept in cramped, unnatural conditions and cannot express natural behaviours (e.g. chickens cannot peck, scratch or spread their wings), causing stress and suffering. (2) Disease spreads rapidly in dense populations, requiring routine antibiotic use which contributes to antibiotic resistance in bacteria. (3) Large volumes of waste (manure, slurry) can pollute local waterways. (4) Some consumers consider the taste and nutritional quality of factory-farmed products inferior to free-range alternatives. The efficiency gains must be weighed against the ethical and environmental costs.
- Mycoprotein is produced by growing the fungus Fusarium in large fermenters. The fungus is supplied with glucose syrup (obtained from starch crops like maize) as its food source, along with oxygen and a controlled environment (warm, slightly acidic). The fungus grows rapidly, doubling its mass every 3–4 hours, and is harvested as protein-rich biomass called mycoprotein. It is more sustainable than beef because: (1) The fungus is at the same trophic level as livestock – both eat crops (glucose from maize). But by eating the fungus directly, humans avoid an entire trophic level of energy loss. Instead of: maize → cow → human (two 90% losses), the chain is: maize → fungus → human, and the fungus converts the glucose to protein very efficiently. (2) It requires far less land than cattle farming. (3) It produces far fewer greenhouse gas emissions than livestock (cows produce large amounts of methane). (4) It uses less water and produces no cholesterol.
- Fishing quotas set a limit on the amount of each fish species that can be caught in a given area per year. This prevents more fish being caught than can be replaced by natural reproduction, allowing fish populations to remain stable and avoiding stock collapse. Two other measures: (1) Regulating mesh sizes on fishing nets so that young, immature fish can escape and grow to breeding age before they can be caught. (2) Establishing marine protected areas where fishing is banned entirely, creating safe zones where fish populations can recover and from which fish can migrate to repopulate surrounding areas.
Exam Tips
- When discussing food security, always make the link to trophic levels and energy loss – this is the biological principle behind why eating plants is more efficient
- For factory farming questions, present a balanced argument – examiners reward answers that consider both efficiency and ethics
- When explaining mycoprotein, always name the fungus (Fusarium), state it is grown in a fermenter on glucose syrup, and link it to the trophic level advantage
- Don't just say "eating plants is better" – explain why using the 10% efficiency rule and energy losses at each trophic level
- For fishing questions, explain how quotas maintain the balance between catching and reproduction
- Remember that sustainable food production means producing food without depleting resources for future generations – always link back to this definition
🔢 Maths Skills
Mathematical Skills
Interpreting food yield data: compare crop yields from different farming methods. For example, if conventional farming produces 8 tonnes/ha and organic farming produces 5.5 tonnes/ha, the percentage difference = (8 − 5.5) / 8 × 100 = 31.25% lower yield for organic.
Energy efficiency comparison: if eating plants directly gives humans 10% of the original energy, but eating meat from animals fed on plants gives only 1% (10% of 10%), the same land can feed 10 times more people on a plant-based diet.
⚠️ Common Misconceptions
Watch Out!
Students often think organic farming always produces enough food. Wrong: Organic farming produces enough food for everyone Correct: Organic yields are typically 20–40% lower than conventional farming, so more land would be needed to feed the same number of people
Students often think GM crops are the only solution to food security. Wrong: GM is the only way to solve food insecurity Correct: GM is one approach among many — reducing food waste, improving distribution, sustainable fishing, mycoprotein and hydroponics are also important
✍️ 6-Mark Question
Extended Answer
6 marks: Evaluate methods to improve food security.
Several methods can improve food security. Factory farming produces high yields at low cost by keeping animals indoors with controlled conditions, but raises ethical concerns about animal welfare and risks of disease and antibiotic resistance. GM crops can increase yields and improve nutrition (e.g. golden rice), but some people have concerns about long-term environmental effects and corporate control of seeds. Sustainable fishing with quotas prevents overfishing and maintains fish stocks, but is hard to enforce internationally. Mycoprotein (Quorn) is produced efficiently in fermenters, avoiding the energy loss of an extra trophic level, but consumer acceptance varies. Hydroponics allows food production in any location with high yields, but is expensive to set up. Organic farming benefits the environment but has lower yields. The best approach combines multiple methods depending on local conditions.
Mark scheme: 1 mark per method evaluated with both advantage and disadvantage (up to 3 methods = 6 marks)
📊 AO3: Analyse & Evaluate
Analysis and Evaluation
Compare the following yield data (tonnes/ha/year): conventional wheat = 8.0, organic wheat = 5.5, hydroponic tomatoes = 70, soil-grown tomatoes = 25. Calculate the percentage yield increase for each comparison. A country currently uses conventional farming for all crops. Evaluate whether switching entirely to organic farming would be advisable, considering both food security and environmental impact.
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