Reduce greenhouse gas without new US legislation?

Reduce greenhouse gases without new legislation? Yes you can. Greenhouse gas emissions can be reduced significantly in the United States through actions taken at the federal and state levels, without the need for new legislation.
From the World Resources Institute - slideshow:

Interactive graphic: The Obama Administration can pursue a suite of policies even without new legislation. If pursued with “Go-Getter” level ambition, those policies can achieve the 17 percent commitment. With this interactive graphic we look at five possible emissions scenarios, from "Business-as-Usual" to "2050". Click through each scenario to learn more. (State levels not included - opens on a new page)