Energy prices and the expansion of world trade

The share of merchandise output that is internationally traded has significantly increased while tariffs have fallen. However, standard trade models have surprising difficulty linking these two facts. Trade growth slowed in the 1970s as tariffs fell relatively sharply while after the late 1980s trade grew quickly as tariffs fell slowly. This pattern implies that the price-import elasticity has changed over time. Also, tariffs have not fallen enough to generate such a large increase in trade given estimates of this elasticity. Changes in transport costs can resolve both puzzles. I present a vertical specialization trade model with an energy-using transportation sector. In the simulated model, trade growth slows from 1974 to 1985. The oil shocks raised transport costs, offsetting falling tariffs, so the price-import elasticity no longer needs to change. It also generates the observed volume of trade growth since transport costs have fallen over the long run.