The question was the one policy that I would use, and it's such a hard one because there are specific tools that do things really well. We have to push all levers. Although, I'm inclined to say getting off coal is paramount. If you do it successfully, it's hugely influential in the rest of the world. The bulk of emissions are happening in developing countries that need to stop using coal to meet their energy needs.
On October 23rd, 2018. See this statement in context.