HL only; Subtopic 8.1 Human populations. Climate change and land degradation drive migration by damaging homes, reducing access to essential resources, and undermining livelihoods. These pressures can cause temporary or permanent movement.
The Mechanism
Environmental migration is the movement of people partly or mainly because environmental change threatens safety or well-being. Migration is an output from one population and an input to another, so it can be analysed through the ESS systems approach.
Climate change produces rapid-onset hazards, including floods and tropical cyclones, and slow-onset changes, including drought, sea-level rise, and changing rainfall. These may destroy settlements or reduce water and food security.
Land degradation is a decline in land's productive capacity. Soil erosion, salinization, desertification, and nutrient depletion reduce crop yields and ecosystem services. Farmers and pastoralists may lose income, livestock, or productive land, making migration an adaptation strategy.
| Environmental pressure | Migration pathway | Example |
|---|---|---|
| Sea-level rise and storm surges | Flooding, erosion, and salinization make coastal settlements less habitable | Coastal Bangladesh: displacement toward Dhaka |
| Drought and unreliable rainfall | Crop failure and livestock losses reduce food security and rural income | Seasonal and urban migration in the Sahel |
| Desertification | Lower productivity increases poverty and competition | Rural out-migration from degraded drylands |
A common misconception is that climate change alone causes migration. Migration is usually multicausal: environmental pressures interact with poverty, conflict, employment, governance, and social networks. Vulnerability is unequal, creating an environmental justice issue because low-income groups may be highly exposed but lack the money to relocate safely.
Exam Technique
For an ESS explain question, show a complete causal chain: environmental change leads to resource or livelihood loss, which increases migration. For discuss or evaluate, address multiple causes, unequal vulnerability, and at least one named example before reaching a supported conclusion.
