世界银行-作物_冲突和气候变化（英）-2025.1_71页_1mb

Crops, Conflict and Climate Change
Erhan Artuc, Guido Porto, Bob Rijkers

Abstract

This paper studies the welfare impacts of agricultural shocks caused by the Russian Federation’s invasion of Ukraine and climate change across 51 developing countries, using a discrete-choice general-equilibrium trade model that incorporates household heterogeneity. The results show that both shocks reduce real incomes and exacerbate inequality, with varying effects across countries and income groups. Climate change has more severe and heterogeneous impacts, while war-induced price hikes primarily affect the cost of living. Adjustment mechanisms provide some relief but do not fully offset losses, particularly for poorer households.

Key Findings

War Shock (Ukraine Invasion)

• Income Losses: 99.6% of households in the sample experience income losses, averaging -2.90% across countries.
  • The poorest households (bottom 25%) face average losses of -3.11%, while the richest (top 25%) see losses of -2.78%.
• Trade Exposure: Countries heavily reliant on imports from Ukraine and Russia (e.g., Azerbaijan, Mongolia) suffer larger losses due to price hikes.
• Mechanism: The cost of living effect dominates, with non-homothetic preferences worsening the impact for poorer households.

Climate Change Shock

• Income Impact: Averages 11.99% income decline, but impacts are highly heterogeneous.
  • 37% of countries experience losses, while 14% see gains.
  • Poor households (bottom 25%) lose -14.63% on average, while the richest (top 25%) lose -9.93%.
• Mechanism: Land and labor income effects drive losses, with poorer households affected more due to specialization in climate-sensitive crops and lower land/labor elasticities.

Key Mechanisms

1. Household Heterogeneity:

   • Poorer households spend a larger share of income on food, making them more vulnerable to price increases.
   • Land and labor allocations vary across income groups, affecting exposure to shocks.

2. War vs. Climate Change:

   • War primarily impacts consumption prices, while climate change directly reduces agricultural productivity.
   • Both shocks are amplified by non-homothetic preferences, but climate change has a stronger land-income effect.

3. Adjustment and Adaptation:

   • Trade and input adjustments mitigate losses but do not fully offset impacts.
   • Factor reallocations (e.g., labor to less productive crops) are limited, particularly for land.

Conclusion

• Distributional Inequality: Both shocks disproportionately harm poorer households, widening inequality.
• Policy Implications: Models leveraging household heterogeneity are essential for accurate impact assessment. Policies must address trade barriers, adaptation to climate change, and social protection for vulnerable groups.