“While the ruling did not technically require the EPA to regulate such emissions, the Court did say that the agency would have to make a determination of ‘whether greenhouse gas emissions contribute to climate change,’ and, if so, proceed with appropriate regulations,” explains Josiah Neeley, an energy scholar at the R Street Institute. “While not regulating anything itself, the endangerment finding thus became the necessary prerequisite for all subsequent regulations on GHGs issued by the EPA.”