Biological and Environmental Threats to Food Security Revision Notes | GCSE AQA Higher Biology

1. The Growing Challenge of Food Security

Picture this: you walk into a supermarket and half the shelves are empty. No bread, no rice, no fresh vegetables. This isn't science fiction — it's the reality facing millions of people worldwide when food security breaks down.

Food security means having reliable access to enough nutritious food. But this security is under attack from multiple directions. Tiny insects can destroy entire harvests. Changing weather patterns leave crops withering in drought or drowning in floods. Wars disrupt the delicate networks that move food from farms to tables.

Trap: Many students think food security is just about growing enough food globally. Actually, it's about access and distribution — we already produce enough food for everyone, but it doesn't reach those who need it most.

2. Biological Threats - When Nature Fights Back

Farmers face an invisible army of biological enemies. These living threats multiply rapidly and can devastate crops faster than you might imagine.

New pests and pathogens emerge constantly. Climate change allows tropical pests to survive in previously temperate regions. Global trade accidentally transports invasive species to new continents where they have no natural predators.

The desert locust provides a stark example. A single swarm can contain billions of locusts and consume the same amount of food as 35,000 people in one day. In 2020, locust swarms devastated crops across East Africa, threatening food security for 25 million people.

Plant diseases spread just as rapidly. Wheat rust fungus can destroy entire wheat harvests. The Irish Potato Famine of the 1840s, caused by potato blight, killed over one million people and forced another million to emigrate.

This is where students often get confused about the scale of these threats. Let's test your understanding:

3. Environmental Threats - When Weather Becomes the Enemy

Environmental changes pose equally serious threats to food production. These non-living factors can make entire regions unsuitable for agriculture.

Drought represents the most widespread environmental threat. When rains fail, crops wither and die. The Sahel region of Africa experiences regular droughts that trigger widespread famine. In 2011-2012, drought in the Horn of Africa affected 13 million people.

But too much water causes equal devastation. Flooding destroys crops, washes away topsoil, and contaminates water supplies. Pakistan's 2010 floods submerged one-fifth of the country and destroyed crops worth billions of dollars.

Climate change intensifies these extremes. Rising temperatures shift growing seasons and make some regions too hot for traditional crops. Changing rainfall patterns create new deserts while flooding others.

Sea level rise threatens coastal agricultural areas with salt water intrusion. Rising seas push salt water into freshwater aquifers, making the water unsuitable for irrigation.

4. Conflict and Food Security - When War Starves Nations

Armed conflicts create food insecurity through multiple pathways. Wars don't just destroy crops — they shatter the entire food system.

Direct destruction occurs when fighting damages farmland, irrigation systems, and food storage facilities. Farmers abandon their fields when areas become unsafe. Seeds, fertilisers, and farming equipment become unavailable.

Conflicts disrupt water access, which is essential for both drinking and irrigation. Warring parties often target water infrastructure as a military strategy. The Syrian conflict damaged over 70% of the country's water infrastructure.

Food distribution networks collapse during conflicts. Roads become impassable, markets close, and transport systems break down. Even if food exists in some areas, it cannot reach hungry populations.

The conflict in Yemen demonstrates these interconnected effects. War has destroyed agricultural infrastructure, contaminated water supplies, and blocked food imports. By 2021, over 16 million Yemenis faced acute food insecurity.

5. The Interconnected Web of Threats

These threats rarely act alone. They combine and amplify each other's effects, creating cascading failures in food systems.

Climate change weakens crops, making them more vulnerable to pests and diseases. Drought-stressed plants cannot resist insect attacks as effectively. Flooding creates ideal breeding conditions for fungal pathogens.

Environmental stress often triggers conflicts over scarce resources. When water becomes scarce, communities fight for access. When crops fail, people migrate, creating tensions in destination areas.

The Lake Chad region exemplifies these interconnections. Climate change has shrunk the lake by 90% since 1960. This environmental change destroyed fishing and farming livelihoods, contributing to conflicts that further disrupted food production.

6. Sustainable Solutions for Global Food Security

Feeding Earth's growing population requires sustainable methods that protect both current and future food production. The challenge is enormous — we need to produce more food while using fewer resources and causing less environmental damage.

Sustainable agriculture focuses on maintaining soil health, conserving water, and reducing chemical inputs. Crop rotation prevents soil depletion and breaks pest cycles. Cover crops protect soil from erosion and add nutrients naturally.

Integrated pest management combines biological, cultural, and chemical controls to manage pests with minimal environmental impact. Instead of relying solely on pesticides, farmers use beneficial insects, resistant crop varieties, and targeted treatments.

Drought-resistant crop varieties help farmers cope with water scarcity. Scientists develop crops that need less water or can survive longer dry periods. These varieties are crucial as climate change makes droughts more frequent and severe.

Reducing food waste is equally important. Globally, one-third of food produced is wasted. Improving storage, transportation, and distribution systems could feed millions without producing more food.

7. Exam Technique - Mastering Food Security Questions

Food security questions appear frequently in GCSE Biology papers. Examiners test your understanding of threats, their impacts, and potential solutions.

Worked example: Worked Example: Applying Biological and Environmental Threats to Food Security

Use this method to answer an exam-style question about the growing challenge of food security.

1. Underline the key term in the question and write a one-line definition linked to biological and environmental threats to food security. — This prevents vague answers and anchors the response in required terminology.
2. Describe the process in logical order using scientific vocabulary and direction words (increase/decrease, faster/slower). — Examiners award marks for clear causal chains, not isolated facts.
3. If data is provided, show each step of working and include units. — Method marks depend on visible working, even if the final answer is not fully correct.
4. Finish with a sentence explaining what the result shows about biological and environmental threats to food security. — Interpretation secures higher-band marks.

Answer: A complete response links mechanism, evidence, and conclusion for biological and environmental threats to food security.

Common Exam Mistakes:

Mistake 1: Confusing pests with pathogens. Remember: pests are visible organisms like insects; pathogens are microscopic disease-causers like bacteria and fungi.

Mistake 2: Thinking food security is only about poor countries. Developed nations also face food security challenges from climate change, pests, and supply chain disruptions.

Mistake 3: Forgetting interconnections. Threats rarely act alone — drought makes crops vulnerable to pests, conflicts disrupt water supplies, climate change enables new diseases.

For 6-mark questions on food security, structure your answer around multiple threats and their interactions. Start with the most significant threat, explain its mechanism, provide an example, then show how it connects to other factors.