In light of the ongoing debate on Common But Differentiated Responsibilities (CBDR), we wonder whether it is worthwile for industrialized countries to take the lead in reducing emissions, rather than acting simultaneously with less advanced countries. To do this, we compare national payoffs and global emissions in each situation. We also examine whether industrial leakage is an inevitable outcome of asymmetric policies with differentiated abatement responsibilities and, if so, whether unambigously hurts the more industrialized countries. We show that leadership can improve payoffs while reducing global emissions, even though these goals appear to be at odds.