After twenty years of global negotiations, the world is still far from a comprehensive climate agreement. The "top … potentially reduce overall costs of tackling climate change by leveraging the differences in the marginal costs of emissions …

the world imposes a climate policy and the rest of the world does not. A climate policy in one region shifts activities … emissions, (ii) a tax on imports of energy and goods, and a rebate of taxes on exports of energy but not goods, both at a lower …