Global environmental problems are often assumed to imply extensive inefficiencies since there is no global authority corresponding to the government at a national level.

This paper shows, on the contrary, that rich countries in a free unregulated market may still undertake globally efficient abatement investments, given the existence of limited non-paternalistic altruism.

Food with inputs from genetically modified organisms (GMOs) has met considerable skepticism among European Union (EU) consumers. The EU import ban on GM food has triggered a great deal of controversy and has been partly replaced by a mandatory labeling scheme. Although there is no measure in the General Agreement on Tariffs and Trade that directly addresses the use of product labeling, WTO and others have been skeptical to mandatory product labeling on the grounds that they may be used as hidden protectionism hampering global welfare. This study has two foci.

In this paper, we address the issue of optimal environmental taxation under imperfect competition. The problem is analysed for three different types of duopoly models, the Cournot open and closed loop models, and the Stackelberg model.