Your assumption is that if the US reduced their emissions as quickly as possible, it would likely not affect the emissions policies of other countries, but a lo

Your assumption is that if the US reduced their emissions as quickly as possible, it would likely not affect the emissions policies of other countries, but a lot of countries are refusing to cut emissions faster _because the US isn't doing so yet_. The process of a unilateral, bilateral, or trilateral dramatic reduction would likely work as such: 1. The United States, China, or Europe, or two or all three would internally implement programs to drastically reduce emissions. 2. In order to maintain economic competitiveness, border adjustments (tariffs and subsidies) would be applied to imports and exports to and from countries without similar carbon emission reduction programs. If these tariffs and subsidies are sufficiently carefully applied, they would be legal under international trade agreements.[1] 3. Countries without similar carbon emission reduction programs would suffer economically by losing access to large export markets due to the border adjustments. 4. The countries would have their economic incentives shifted so that it becomes much more economically viable for them to apply similarly dramatic reductions themselves and regain access to the large markets. 5. As more countries apply similarly dramatic reductions, the total volume of border adjustments would decrease, reducing market distortions and increasing international trade efficiency, while maintaining each country's programs for dramatically decreasing carbon emissions. Not just any country could do this, but the US could certainly start this process by itself. If the US started unilaterally, Europe would likely adopt similar measures and regain access to unadjusted imports and exports, which would create a very large bloc of high-consumption countries into which all countries (such as China and Australia) would want to regain cheap access. [1] http://www.carbontax.org/nuts-and-bolts/going-global/ http://www.carbontax.org/nuts-and-bolts/going-global/ (Would the WTO approve of carbon tax-related border adjustments? If the primary consequence was to discriminate because of carbon emissions rather than because of being a foreign country, then yes. Possibly...)