世界银行-撒哈拉以南非洲干旱的福利成本（英）-2024.1-49页_2mb

Drought Impact Summary in Sub-Saharan Africa

1. Research Focus

   • Quantifies the welfare cost of drought on household consumption in five agroecological zones across nine Sub-Saharan African (SSA) countries.
   • Uses standardized drought hazard measures (e.g., soil moisture, NDVI, SPEI) and matches them with household survey data from ~100,000 households.

2. Key Findings

   • Consumption drops by 10–20% in severe drought events (≈1-in-10-year occurrences).
   • Poverty rates can be 1–12% higher under worst weather conditions compared to best conditions, increasing the national poverty gap by US$4M to US$2.4B (2011 PPP).
   • Soil moisture and vegetation indices (NDVI) provide more reliable estimates than rainfall or evapotranspiration metrics.

3. Methodology

   • Vulnerability Functions: Estimates the relationship between rainfall deficits and welfare losses using fixed-effect regressions.
   • Stochastic Modeling: Uses synthetic weather data (10,000-year simulations) to project tail risks and exceedance probability curves.
   • Spatial Aggregation: Tested radii (20 km to 50 km) for matching hazard and household data; a 20 km radius effectively captures local impacts.

4. Implications

   • Climate change exacerbates drought risk, potentially increasing welfare costs.
   • Investments in adaptive policies (e.g., soil conservation, diversification) could mitigate impacts.
   • Limited data and methodological biases (e.g., survivor bias) suggest caution in extrapolating results to extreme events.

5. Policy Relevance

   • Provides a basis for targeting social protection and financial services to address drought-induced poverty.
   • Highlights the need for standardized approaches to integrate catastrophe modeling with microeconomic analysis for better risk management.