Trade Gains, Paretian Transfer and the Tragedy of the Commons

Consider trade liberalization between two countries, each of which produces two private goods and provides on a voluntary basis one public good (the common). In these circumstances, what are the consequences of trade liberalization on the production of the public good and on welfare in both countries? Using a Ricardian framework, we first show that the opening of trade increases the opportunity cost of producing the public good in both countries and will therefore reduce the aggregate supply of the public good. On the other hand, at the autarky equilibrium, only one country supplies the public good, the other “free rides”. The analysis of the welfare incidence of the opening of trade then reveals that the country which provides the public good under autarky always enjoys a welfare gain from trade while the free rider under autarky does not unless the terms of trade are sufficiently in its favour to compensate for the reduction in the supply of the common. Finally, if all countries involved in trade liberalization can without cost coordinate their supplies of the common, then the implementation of the first-best outcome is shown to be possible with a conditional Paretian transfer scheme.