In our formal analysis we begin with the case in which pollution caused by an activity within the
country has effects only on this country. We use tools similar to those that we developed in
Chapter 10. If the country simply allows the pollution to occur, with no government policy to
limit the negative externality, we show that free trade can make the country worse off, and that
the country can export the wrong products. This occurs because of the marginal external costs, in
our example resulting from pollution that accompanies domestic production of the export good.
A government policy that taxes pollution or production that causes pollution (or that establishes
suitable property rights) can reverse these effects, assuring that the country exports and imports
the appropriate products and gains from free international trade.
Domestic producers subject to the pollution-related tax may complain that other countries,
especially the countries that become the suppliers of the country’s imports, are not imposing a
comparable pollution-related tax on their firms. They may complain that the foreign firms are
engaged in “eco-dumping.” From the perspective of the importing country, lax foreign controls
should not matter to its well-being, as long as the foreign pollution does not affect it.
The analysis of transborder pollution raises new issues. We use the example of production
activity in one country that pollutes a river flowing into a neighboring country. The best solution
would balance the gains to the polluting country from dumping waste into the river with the costs
of pollution to the receiving country. Generally, this best solution is less pollution than the
amount that occurs with no government policy, but more than zero pollution. However, the
government in the polluting country may resist imposing a pollution tax (or some other way to
limit pollution by its firms), because it bears the national costs while the other country gets the
national benefits. If international negotiations fail, what should the receiving country do? It
cannot tax the foreign pollution or even the foreign production that causes pollution. If the
receiving country imports the product from the polluting country, it could try to reduce the
foreign production and pollution by restricting its imports. The country will gain if its benefits
from lower foreign pollution exceed the usual deadweight losses of protection. (If instead the
receiving country is an exporter of this product to the polluting country, it could subsidize its
exports.) However, the WTO generally interprets its environmental exceptions narrowly, so it is
not clear that the WTO would uphold the import restriction (or export subsidy), if the polluting
country complained to the WTO.
The difficulty of addressing transborder pollution is also shown through a discussion of the slow
progress that NAFTA has made in attempting to ameliorate environmental problems along the
Mexico-U.S. border.
Some environmental problems are global—the whole world’s economic activity imposes an
external cost on the whole world. Each country might be willing to make some effort to reduce
its own pollution, because it recognizes that its own activities have some adverse effect on itself.
But each country on its own would not decrease enough, because it would not recognize the
costs that its pollution imposes on other countries. Yet the world, and most countries, would be
better off if the countries cooperated to reduce the pollution more. Such global agreements are
difficult to achieve, because of disagreements about the how serious the problem is, the incentive
to free-ride, and the difficulty of enforcement.