By considering a model with identical firms, Paul Krugman (1980) predicts that a higher elasticity of substitution between goods magnifies the impact of trade barriers on trade flows. In this paper, I introduce firm heterogeneity in a simple model of international trade. When the distribution of...

We propose a new sufficient statistic to measure the gains from trade in models where the extensive margin trade elasticity is not necessarily constant. This statistic is a function of one data moment, the market share of continuing domestic products, and one parameter, the elasticity of...

We show that climate policy can unlock large environmental gains from trade by inducing economies to specialize according to their environmental comparative advantage. We make this point by exploring the effects of a carbon tax in a quantitative trade model. Our main result is that the...