A reexamination of the role of income for the trade and environment debate

Recent work on the relationship between international trade and the environment has found small but negative effects of increased openness on measures of pollution for the average country. On a panel of 128 countries it is shown that, like previous studies, the trade intensity effect is negative and significant for the average country for emissions of four localized pollutants (SO₂, NO_X, CO, and VOCs). However, trade intensity effects are not uniform across countries of different income levels. In fact, a strong non-monotonicity exists in trade intensity elasticities. It is found that countries with relative world incomes less than 0.5 or greater than 2.5 tend to have positive trade intensity elasticities, while countries with relative world incomes between 0.5 and 2.5 tend to have negative trade intensity elasticities. The results imply that both factor abundance and pollution haven effects may be at work, but that the dominance of one effect over the other depends on a country's level of development.