Pollution Regulation of Competitive Markets

We develop a model of oligopolistic firms that produce partially differentiated products and generate pollution as a byproduct. We analyze and compare two types of pollution regulation: Cap-and-Trade and Taxes. Firms can respond to regulation by any combination of pollution abatement, output reduction, emissions trading (under Cap-and-Trade), or payment of pollution taxes (under Taxes). We prove that well-chosen regulation can, besides reducing pollution, actually improve firms’ profits relative to laissez-faire (unregulated markets), and simultaneously improve consumer surplus and welfare. Thus, regulation Pareto-dominates laissez-faire under a wide range of plausible conditions. These results are driven by an unintended consequence of pollution regulation: Competing firms can use the regulation to tacitly (and credibly) collude to reduce production and improve their profits. We show that the degree of competition plays a critical role in determining the economic consequences of pollution regulation. Our results suggest that the regulator’s primary consideration should be the impact of regulation on consumers rather than producers.