How large are the impacts of carbon motivated border tax adjustments

"This paper discusses the size of impact of carbon motivated border tax adjustments on world trade. We report numerical simulation results which suggest that impacts on welfare, trade, and emissions will likely be small. This is because proposed measures use carbon emissions in the importing country in producing goods similar to imports rather than carbon content in calculating the size of barriers. Moreover, because border adjustments involve both tariffs and export rebates, it is the differences in emissions intensity across sector rather than emissions level which matters. Where there is no difference in emissions intensities across sectors, Lerner symmetry holds for the border adjustment and no relative effects occur. In our numerical simulation analyses border tax adjustments accompany carbon emission reduction commitments made either unilaterally , or as part of a global treaty and to be applied against non signatories. We use a four-region (US, EU, China, ROW) general equilibrium structure which captures energy trade and has endogenously determined energy supply so that global emissions can change with policy changes. We calibrate our model to 2006 data and analyze the poten