IMF-全球贸易的碎片化：商品核算（英）-2023.3-35页_1mb

Fragmentation in Global Trade: Accounting for Commodities

Authors: Marijn A. Bolhuis, Jiaqian Chen, Benjamin Kett

This working paper analyzes the economic impacts of trade fragmentation scenarios, with a focus on the role of primary commodities. The study constructs a new multi-country, multi-sector general equilibrium model incorporating granular commodity trade and production data for 136 commodities across 145 countries.

Key Findings

• Impact of Trade Fragmentation:

  • Fragmentation-induced output losses can be substantial, particularly for Low-Income Countries (LICs).
  • In severe scenarios, LICs could experience up to 4.3% output loss in the long run.
  • Output losses increase with severity of fragmentation, with LICs being most affected due to high exposure to commodity trade.

• Role of Commodities:

  • Granular commodity data reveals that commodities are often less substitutable than in aggregated models.
  • Failing to account for commodity specifics leads to underestimating output losses compared to aggregated sector approaches.

• Scenario Analysis:

  • Mild fragmentation (Strategic Decoupling) results in minimal welfare losses for major economies.
  • Severe fragmentation (Geo-economic Fragmentation) leads to significant global GDP losses ranging from 0.3% to 7% depending on elasticities.
  • LICs are disproportionately affected, with welfare losses up to 10.8% in severe scenarios.

Methodology

• Data Development:

  • Created a comprehensive database covering 136 primary commodities and 24 manufacturing/service sectors across 145 countries.
  • Incorporated trade and production elasticities calibrated from recent literature.

• Model Framework:

  • Multi-country, multi-sector general equilibrium model accounting for input-output linkages.
  • Mode adapted to distinguish between commodity and non-commodity sectors, with specific demand elasticities for commodities.

Robustness Checks

• Trade Elasticities:

  • Results sensitive to elasticity assumptions, with losses ranging from 1.9% to 7.0% for severe fragmentation scenarios.
  • Baseline estimates are conservative, reflecting more gradual trade adjustments.

• Country Groupings:

  • Using geopolitical rather than economic-based blocs increases losses due to less trade-efficient fragmentation.
  • Closing inter-bloc imbalances does not significantly alter overall outcomes.

Conclusion

• Trade fragmentation imposes significant economic costs, with LICs bearing the brunt due to reliance on commodity trade.
• Granular commodity data and detailed modeling are essential for accurate impact assessment.
• Policy implications highlight risks of fragmentation to global welfare and the need for resilient trade systems.