Three dimensions of vulnerability
Physical (exposure), social (conditions), economic (capacity to cope). All three interact.
Pearson 4GE1 spec 3.2b names THREE dimensions of vulnerability — Physical, Social, Economic.
1) Physical vulnerability.
Based on PHYSICAL exposure that countries cannot easily change:
- Geographic location: Pacific Ring of Fire countries face tectonic risk; cyclone-basin countries face annual storms; low-lying delta + atoll countries face flooding + sea-level rise.
- Topography: steep slopes (landslide risk); low altitude (flooding); coastal exposure.
- Climate: tropical cyclone latitudes 5°-30° N/S; monsoon regions face seasonal flooding.
- Geology: soft soils (liquefaction); volcanic substrate; permeable vs impermeable rocks.
Examples:
- Bangladesh delta: ~30% at significant cyclone risk; mostly <12 m altitude.
- Japan: Pacific Ring of Fire; multiple subduction zones.
- Maldives: max altitude 2.4 m; existential sea-level rise threat.
- Pacific atoll nations: similar.
- Nepal + Pakistan + Iran: alpine seismic + landslide risk.
Physical vulnerability is the FIRST DIMENSION — it cannot easily be changed, but it determines what other vulnerabilities matter.
2) Social vulnerability.
Based on social conditions that COMMUNITIES + COUNTRIES can change:
- Building quality: earthquake-resistant codes save lives (Japan, Chile); weak construction kills (Haiti 2010 ~230k deaths in M7.0).
- Population density: crowded slums amplify casualties (Port-au-Prince, Manila, Mumbai).
- Education + drills: trained populations evacuate correctly (Japan schools; Bangladesh CPP volunteers).
- Demographic + social inequality: elderly, children, poor, women + minorities disproportionately suffer.
- Governance + community organisation: strong local governance enables response; weak governance amplifies damage.
Examples:
- Bangladesh: CPP provides community organisation despite poverty.
- Haiti: weak governance + informal settlements + minimal codes.
- Japan: post-1923 reforms led to systematic preparedness.
Social vulnerability is DYNAMIC — countries can REDUCE it through investment + education + community organisation.
3) Economic vulnerability.
Based on economic capacity to invest in protection + recover from disasters:
- Wealth / GDP: Japan ~1,300 GDP/capita cannot.
- Infrastructure investment: warning systems + building codes + emergency services are expensive.
- Insurance: US property insurance covers some losses; poor populations excluded.
- Economic structure: subsistence agriculture vulnerable to disruption; industrial economies more diversified.
- International aid: poor countries depend on humanitarian response that may be slow.
Examples:
- Japan: invested ~$14bn strengthening New Orleans-style defences after Katrina.
- Bangladesh: CPP infrastructure built over decades with international support.
- Maldives: depends on international climate finance.
Economic vulnerability is DYNAMIC — countries can BUILD economic capacity over time.
The interaction.
Vulnerability is a PRODUCT of all three dimensions:
- High physical + low social + low economic = manageable (Japan).
- High physical + high social + high economic = catastrophic (Haiti).
- High physical + variable social + high economic = improving (Bangladesh CPP success).
Magnitude vs vulnerability.
The canonical comparison: 2010 Haiti (Mw 7.0) killed ~230,000; 2011 Tōhoku (Mw 9.1) killed ~16,000.
The LARGER earthquake (~1,000× more energetic) killed 14× FEWER people because Japan's WEALTH + SOCIAL preparation + ENGINEERING dwarfed Haiti's vulnerability.
Vulnerability matters MORE than magnitude in MOST cases.
This is THE key insight of disaster geography.
- Three dimensions: physical, social, economic.
- Physical: exposure (cannot easily change).
- Social: conditions (can change through education, codes, community).
- Economic: capacity (can build over time).
- Haiti M7.0 ~230k vs Tōhoku M9.1 ~16k = vulnerability >> magnitude.
- Bangladesh CPP: poor country reduced cyclone deaths through community organisation.