Introduction
Soil degradation is one of the most important environmental challenges explored in IB Environmental Systems and Societies (ESS). For the 2026 first assessment, students must understand not only what soil degradation is, but also its causes, consequences, and management strategies.
Soil degradation is defined as the decline in soil’s ability to support life, whether for agriculture, ecosystems, or human needs. This makes it a key exam topic, especially since it links directly to food production systems, land use, and sustainability. By mastering the causes of soil degradation, you’ll be ready to explain, evaluate, and apply case studies in both Paper 1 and Paper 2.
Quick Start Checklist for ESS Students
When studying soil degradation, make sure you can:
- Define soil degradation clearly.
- Identify the main causes (natural and human).
- Explain the impacts on ecosystems, food security, and sustainability.
- Link soil degradation to case studies.
- Evaluate management strategies to prevent further loss.
Main Causes of Soil Degradation
1. Erosion
- Cause: removal of topsoil by wind or water. Often accelerated by deforestation, overgrazing, or poor farming practices.
- Impact: loss of fertile soil, reduced agricultural productivity, desertification.
- Case study: Dust Bowl (USA, 1930s) — unsustainable plowing practices combined with drought.
2. Salinization
- Cause: over-irrigation in arid areas leads to accumulation of salts in the soil.
- Impact: crops fail due to toxic salt levels; long-term soil infertility.
- Case study: Irrigation in the Indus Valley (Pakistan) has led to widespread salinity problems.
3. Nutrient Depletion
- Cause: continuous cropping without replenishing soil nutrients.
- Impact: reduced yields, dependency on fertilizers, food insecurity.
- Case study: Sub-Saharan Africa — poor soils combined with overuse lead to nutrient exhaustion.
4. Desertification
- Cause: overgrazing, climate variability, and unsustainable land use.
- Impact: expansion of deserts, displacement of communities.
- Case study: The Sahel region (Africa) — overuse of fragile soils combined with climate pressures.
5. Pollution
- Cause: industrial chemicals, heavy metals, pesticides, and waste.
- Impact: soil toxicity, groundwater contamination, reduced biodiversity.
- Case study: Minamata Bay (Japan) — while known for water pollution, heavy metals also contaminated surrounding soils.
6. Compaction
- Cause: overuse of heavy machinery in industrial farming.
- Impact: reduced soil porosity, poor water infiltration, erosion risk.
- Example: commercial farming in North America.
Human vs. Natural Causes
ESS exams often expect you to distinguish between human-induced degradation (e.g., over-irrigation, deforestation, overgrazing) and natural processes (e.g., drought, floods). Most degradation is accelerated by human activities, making it both an ecological and social issue.
Consequences of Soil Degradation
- Environmental: biodiversity loss, erosion of ecosystems, altered nutrient cycles.
- Economic: declining agricultural productivity, higher costs of fertilizers and irrigation.
- Social: food insecurity, migration, conflict over scarce fertile land.
Case Studies for ESS Exams
- Dust Bowl (USA, 1930s): human mismanagement combined with drought.
- Sahel (Africa): desertification driven by overuse and climate change.
- Loess Plateau (China): severe erosion reversed through large-scale soil conservation programs.
Soil Degradation in ESS Exams
Paper 1
Expect maps, graphs, or soil quality data in the case study booklet. You may need to interpret erosion rates, salinity levels, or land productivity.
Paper 2
Essay questions could include:
- “Discuss the main causes of soil degradation.”
- “Evaluate the role of human activity in soil degradation.”
Exam Tips
- Always connect cause → consequence → case study.
- Use systems thinking: soil degradation affects water, food, and biodiversity.
- Balance natural and human causes—exams often ask you to distinguish them.
FAQs
1. Do I need to memorize soil degradation statistics?
No, but knowing general figures (like desertification affecting one-third of global land) can make your answers stronger.
2. Should I focus more on human or natural causes?
Emphasize human causes—they accelerate natural processes and are the focus of sustainability discussions in ESS.
3. Could soil degradation link to other topics?
Yes. It’s directly linked to food production, water management, climate change, and sustainability. Use these connections in essay answers.
Conclusion
Soil degradation is a key ESS topic because it demonstrates how human activity and natural processes combine to threaten ecosystems and food production. By mastering erosion, salinization, nutrient depletion, desertification, pollution, and compaction—and supporting your answers with case studies—you’ll be ready for any exam question on this topic in the 2026 first assessment.
RevisionDojo Call to Action:
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