I examine the implementation of emission policy in a union of countries. Production in any country incurs emissions that pollute all over the union, but efficiency in production can be improved by research and development (R&D). I compare four cases: laissez-faire, Pareto optimal policy, lobbying with centrally-determined emission quotas and lobbying with emission trade. The main findings are as follows. With emission quotas, the growth rate is socially optimal, but welfare sub-optimal. Emission trade speeds up growth from the initial position of laissez-faire, but slows down from the initial position of centrally-determined emission quotas.Journal of Economic Literature: 041, H23, F15