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Quiz yourself on Natural Hazards OverviewGet your flashcardsBuild my revision planTrack my progress⛓️ Why Is Hazard Risk Increasing? The Five-Step Cause Chain
The number of people exposed to natural hazard risk is rising. Here is the causal chain that explains why:
1. Population growth → more people in all environments
Global population has grown from 3 billion in 1960 to over 8 billion today. More people means more settlements in marginal, hazardous environments — river floodplains, steep hillsides, coastal zones, the flanks of volcanoes — simply because all the "safe" land is already occupied or too expensive.
Global population has grown from 3 billion in 1960 to over 8 billion today. More people means more settlements in marginal, hazardous environments — river floodplains, steep hillsides, coastal zones, the flanks of volcanoes — simply because all the "safe" land is already occupied or too expensive.
2. Urbanisation → megacities in hazard zones
Over 55% of the world's population now lives in cities, rising to 68% projected by 2050. Many of the world's fastest-growing megacities sit directly in major hazard zones: Manila (typhoons + earthquakes), Jakarta (flooding + earthquakes + volcanic ash), Istanbul (overdue major earthquake on the North Anatolian Fault), Tehran (earthquakes), and Tokyo (one of the most seismically active cities on Earth). As these cities grow, the number of people exposed to hazards grows with them.
Over 55% of the world's population now lives in cities, rising to 68% projected by 2050. Many of the world's fastest-growing megacities sit directly in major hazard zones: Manila (typhoons + earthquakes), Jakarta (flooding + earthquakes + volcanic ash), Istanbul (overdue major earthquake on the North Anatolian Fault), Tehran (earthquakes), and Tokyo (one of the most seismically active cities on Earth). As these cities grow, the number of people exposed to hazards grows with them.
3. Poverty → unable to relocate from hazardous areas
Poor communities often cannot afford to move away from flood plains, unstable hillsides, or volcanic zones. In many LICs, land in hazardous areas is cheaper — attracting the urban poor. After a disaster, the same communities often rebuild in the same locations because they have no financial alternative. This creates a cycle of poverty and vulnerability that is extremely difficult to break.
Poor communities often cannot afford to move away from flood plains, unstable hillsides, or volcanic zones. In many LICs, land in hazardous areas is cheaper — attracting the urban poor. After a disaster, the same communities often rebuild in the same locations because they have no financial alternative. This creates a cycle of poverty and vulnerability that is extremely difficult to break.
4. Climate change → more intense and frequent weather hazards
Global average temperatures have risen by approximately 1.1°C since pre-industrial times. This additional energy in the atmosphere is intensifying the hydrological cycle — producing heavier rainfall events, more intense tropical storms, longer droughts, and rising sea levels that increase coastal flood risk. The IPCC (Intergovernmental Panel on Climate Change) projects that extreme weather events will become more frequent and more severe throughout the 21st century.
Global average temperatures have risen by approximately 1.1°C since pre-industrial times. This additional energy in the atmosphere is intensifying the hydrological cycle — producing heavier rainfall events, more intense tropical storms, longer droughts, and rising sea levels that increase coastal flood risk. The IPCC (Intergovernmental Panel on Climate Change) projects that extreme weather events will become more frequent and more severe throughout the 21st century.
5. Environmental degradation → destroying natural protection
Deforestation removes tree root systems that bind hillside soil, dramatically increasing landslide risk. Draining wetlands removes natural flood buffers that absorb excess water. Destruction of coastal mangrove forests removes a natural barrier against storm surge and tsunami. Human modification of environments removes the natural defences that once reduced hazard impact.
Deforestation removes tree root systems that bind hillside soil, dramatically increasing landslide risk. Draining wetlands removes natural flood buffers that absorb excess water. Destruction of coastal mangrove forests removes a natural barrier against storm surge and tsunami. Human modification of environments removes the natural defences that once reduced hazard impact.
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