Directly regulating the amount of pollution emitted is effective too, look at how California's auto emissions laws have become a de-facto standard. The US is th

Directly regulating the amount of pollution emitted is effective too, look at how California's auto emissions laws have become a de-facto standard. The US is the #1 source of demand in the world, entire economies (e.g China's) have been built around suppressing domestic demand in favor of making more money exporting to the US. If we change our regulations, the rest of the world will follow.