Countries vary because their contributions to greenhouse gas emissions differ, while exposure to climate hazards and capacity to respond also differ. The most responsible countries are therefore not necessarily the most vulnerable.
Level: HL only: Subtopic 6.2 Climate change: causes and impacts.
Responsibility concerns a country's contribution to the enhanced greenhouse effect. It can be assessed through historical cumulative emissions, current total emissions, per-capita emissions, consumption patterns, and land-use change.
Vulnerability is the degree to which a society is likely to experience harm. It depends on exposure to hazards, sensitivity to their effects, and adaptive capacity to prepare, respond and recover.
| Factor | Why countries vary |
|---|---|
| Historical emissions | Early-industrializing, high-income countries have emitted for longer. |
| Current emissions | Populous industrial economies may have high totals; wealthy societies often have high emissions per person. |
| Exposure | Low-lying islands, deltas and drought-prone regions face greater physical risks. |
| Sensitivity | Dependence on rain-fed agriculture, fisheries or climate-sensitive ecosystems increases harm. |
| Adaptive capacity | Wealth, infrastructure, technology, healthcare and effective governance can reduce vulnerability. |
The United States has high historical and per-capita emissions but substantial financial and technological capacity for adaptation. Bangladesh has contributed much less historically but is highly exposed to flooding, cyclones and sea-level rise, with fewer adaptation resources.
This imbalance creates an environmental justice issue: countries least responsible may experience the greatest losses. Perspectives therefore differ over climate finance, compensation, mitigation obligations and adaptation support.