Relying on a North-South model of economic geography, our paper attempts to discuss the management of global pollution issues such as greenhouse gas emissions. As firms are increasingly mobile, they become sensitive to differences in environmental standards across countries and subject the regulatory power of a country to the rule of competition. In this context, we first consider a unilateral environmental policy implemented by the North. Besides considering its costs for the Northern country, we show that efficiency of unilateralism in terms of global pollution abatement appears ambiguous. Globalization of the world economy, by affecting the interaction between the forces at work, can make global pollution even worse. We then turn to investigate the outcomes of a harmonization of environmental policy between the North and the South. Although better from an ecological point of view, this second scenario harms the South both in terms of industrial relocation and real income.