2016年-世界发展银行全球_Does_the_Global_Trade_Slowdown_Matter__26页_860kb

Does the Global Trade Slowdown Matter?

Core Content

This working paper investigates the implications of the global trade slowdown since the Global Financial Crisis (GFC) on economic growth. It analyzes the changing trade-income relationship and its effects on both demand and supply sides of the economy.

Main Viewpoints

• Global trade growth has slowed significantly since the GFC, growing at 3% or less compared to a pre-crisis average of 7%.
• The trade-income relationship has weakened, with the long-run elasticity of trade to GDP declining from over 2 in the 1990s to 1.3 in the 2000s.
• The trade slowdown is not only cyclical but also reflects structural changes, particularly a shift in vertical specialization and reduced trade liberalization.
• There are two main channels through which the trade slowdown may affect economic growth:
  • Demand-side: Sluggish global import growth limits export opportunities, potentially reducing economic growth.
  • Supply-side: Slower trade may hinder productivity growth by reducing specialization and technology diffusion.

Key Information

1. Global Trade Growth Trends

• World trade (total trade volumes) grew at 2.8% in 2012 and 3.4% in 2013 and 2014.
• This is well below the pre-crisis average of 7% for 1987–2007.
• Trade growth has lagged behind GDP growth, which has hovered around 3% in recent years.

2. Structural Change in Trade-Income Relationship

• The long-run trade elasticity decreased from 2.2 in the 1990s to 1.3 in the 2000s.
• This suggests that trade is less responsive to GDP growth in recent years.
• The slowdown is attributed to:
  • Slower trade liberalization in the 2000s.
  • Reduced vertical specialization, as global value chains (GVCs) expansion slowed.

3. Demand-Side Effects (Keynesian Concern)

• Export growth is less responsive to global GDP growth in the 2000s than in the 1990s.
  • For high-income economies, the elasticity of gross exports to world GDP decreased from 2.5 to 1.9.
  • For developing economies, it decreased from 2.7 to 1.9.
• However, when using value-added exports, the elasticity remained relatively stable.
• The sensitivity of domestic GDP to export growth increased for developing economies (from 0.7 to 1.0 in gross terms and 0.5 to 0.7 in value-added terms).
• The impact of the trade slowdown on demand is not conclusive, as the effects are not statistically significant when using value-added data.

4. Supply-Side Effects (Smithian Concern)

• Productivity growth in vertically specialized sectors declined in the 2000s compared to the 1990s.
• Vertical specialization was associated with higher productivity growth in the 1990s, but this relationship weakened in the 2000s.
• This implies that the slowdown in GVC expansion may be a contributing factor to the decline in productivity growth.
• The contribution of vertical specialization to productivity growth has decreased by half in recent years.

5. Empirical Evidence and Methodology

• The paper uses an Error Correction Model (ECM) to estimate trade and GDP elasticities.
• Gross exports data spans 1986–2014, while value-added exports data is limited to 1995–2011.
• The sample includes 29 high-income and 11 emerging economies.
• The elasticity of exports to GDP is estimated using:
  $$
  \Delta \ln x_{it} = \alpha_i^x + \beta_i^x \Delta \ln y_{it} + \gamma_i^x \ln x_{it - 1} + \delta_i^x \ln y_{it - 1} + \eta_i \Delta \ln \text{reer}{it} + \theta_i \ln \text{reer}{it - 1} + \varepsilon_i
  $$
• The elasticity of GDP to exports is estimated using:
  $$
  \Delta \ln y_{it} = \alpha_i^g + \beta_i^g \Delta \ln x_{it} + \gamma_i^g \ln y_{it - 1} + \delta_i^g \ln x_{it - 1} + \varepsilon_{it}
  $$

6. Conclusion

• The trade slowdown matters, but the quantifiable effects are not large.
• The demand-side effects are not clearly significant when using value-added data.
• The supply-side effects suggest a diminished contribution of trade to productivity growth.
• Further research and data are needed to fully assess the Keynesian concern.

Summary of Findings

• Global trade growth has slowed significantly post-GFC.
• The trade-income relationship has become less responsive, indicating structural change.
• Vertical specialization and trade liberalization are key drivers of the trade slowdown.
• The demand-side impact is mixed, with some evidence of reduced responsiveness.
• The supply-side impact suggests a decline in productivity growth due to slower GVC expansion.
• Value-added exports show less change in elasticity, indicating they are a better measure of trade's role in growth.
• The paper concludes that the trade slowdown has implications for growth, but not necessarily large.