The Challenge of Natural Hazards — AQA GCSE Geography
A natural hazard is a natural event (such as an earthquake or tropical storm) that threatens people or property. A natural disaster occurs when a hazard actually affects people. Hazard risk is the probability of being affected, increased by factors such as population density, poverty, urbanisation and a lack of preparation.
Tectonic hazards
The Earth's crust is split into tectonic plates that move because of convection currents in the mantle. Hazards occur at plate margins:
- Destructive margins — plates move together; one is subducted, causing earthquakes and explosive volcanoes.
- Constructive margins — plates move apart; magma rises, causing gentler volcanoes.
- Conservative margins — plates slide past each other, causing earthquakes (no volcanoes).
The effects (primary and secondary) and responses (immediate and long-term) of earthquakes often differ between a high-income country (HIC) and a low-income country (LIC) because of differences in wealth, building quality and preparation. People continue to live in hazardous areas for reasons such as fertile soil, geothermal energy, mining and tourism. Risks are reduced by monitoring, prediction, protection (e.g. earthquake-proof buildings) and planning.
Weather hazards
Tropical storms (hurricanes/cyclones/typhoons) form over warm oceans (above 27 °C) near the Equator. They are linked to global atmospheric circulation (the movement of air in cells such as the Hadley cell). Climate change may make storms more intense and change their distribution. Effects can be reduced by monitoring and prediction, planning, defences and education.
The UK experiences its own weather hazards (storms, flooding, drought, heavy snow). An example of recent extreme weather in the UK can be used to show causes, effects and management. Evidence suggests UK weather is becoming more extreme.
Climate change
Climate change has natural causes (orbital changes — Milankovitch cycles, volcanic activity, solar output) and human causes (burning fossil fuels, agriculture, deforestation increasing greenhouse gases). Effects include rising sea levels, ice melt and changing weather patterns. Management uses mitigation (reducing causes, e.g. renewable energy, carbon capture, planting trees, international agreements) and adaptation (responding to effects, e.g. flood defences, drought-resistant crops, managing water supply).
Exam tips
- Define hazard, disaster and risk precisely.
- Learn the three plate margins and link them to earthquakes/volcanoes.
- Use a named case study to compare effects and responses in an HIC vs LIC.
- Distinguish mitigation (reducing causes) from adaptation (responding to effects).