The Biden administration isn’t awaiting a final price tag on a final greenhouse gas assessment metric before it starts working on new regulations — even though the final number could support even tougher regulation. … Lengthy legal challenges that have plagued the EPA across administrations put “real pressure” on the agency to move fast, said Hana Vizcarra, a staff attorney with the Harvard Law School’s Environmental & Energy Law Program. That’s especially true, she said, when another four years in office isn’t guaranteed. “They want to see these things reach conclusion, they want to see courts actually consider the issues and make decisions, because that’s the only way anything will be lasting,” Vizcarra said.