Unbundling the Pollution Haven Hypothesis

The "Pollution Haven Hypothesis" (PHH) is one of the most hotly debated predictions in all of international economics. This paper explains the theory behind the PHH by dividing the hypothesis into a series of logical steps linking assumptions on exogenous country characteristics to predictions on trade flows and pollution levels. I then discuss recent theoretical and empirical contributions investigating the PHH to show how each contribution either questions the logical inevitability, or the empirical significance of one or more steps in the pollution haven chain of logic. Suggestions for future research are also provided.