Comparative Advantage - Effect of Trade Costs

Effect of Trade Costs

Trade costs, particularly transportation, reduce and may eliminate the benefits from trade, including comparative advantage. Paul Krugman gives the following example.

Using Ricardo's classic example:

In the absence of transportation costs, it is efficient for Britain to produce cloth, and Portugal to produce wine, as, assuming that these trade at equal price (1 unit of cloth for 1 unit of wine) Britain can then obtain wine at a cost of 100 labor units by producing cloth and trading, rather than 110 units by producing the wine itself, and Portugal can obtain cloth at a cost of 80 units by trade rather than 90 by production.

However, in the presence of trade costs of 15 units of labor to import a good (alternatively a mix of export labor costs and import labor costs, such as 5 units to export and 10 units to import), it then costs Britain 115 units of labor to obtain wine by trade – 100 units for producing the cloth, 15 units for importing the wine, which is more expensive than producing the wine locally, and likewise for Portugal. Thus, if trade costs exceed the production advantage, it is not advantageous to trade.

Krugman proceeds to argue more speculatively that changes in the cost of trade (particularly transportation) relative to the cost of production may be a factor in changes in global patterns of trade: if trade costs decrease, such as with the advent of steam-powered shipping, trade should be expected to increase, as more comparative advantages in production can be realized. Conversely, if trade costs increase, or if production costs decrease faster than trade costs (such as via electrification of factories), then trade should be expected to decrease, as trade costs become a more significant barrier.