The U.S. Supreme Court on Friday added climate change to an already consequential docket by agreeing to decide the scope of the Environmental Protection Agency's authority to restrict emissions from the power sector.

"This is the equivalent of an earthquake around the country for those who care deeply about the climate issue," environmental law scholar Richard Lazarus of Harvard said.

The justices consolidated four cases led by West Virginia v. Environmental Protection Agency in which a group of states, and coal and mining companies challenge a decision by the U.S. Court of Appeals for the D.C. Circuit rejecting an industry-friendly, Trump administration rule for regulating carbon dioxide emissions.

The appellate court said the rule's goal was "to slow the process for reduction of emissions," and "hinged on a fundamental misconstruction" of the Clean Air Act.

In urging the justices to review the D.C. Circuit decision, West Virginia Solicitor General Lindsay See wrote the EPA "now has a judicial edict not to limit itself to measures that can be successfully implemented at and for individual facilities. It can set standards on a regional or even national level, forcing dramatic changes in how and where electricity is produced, as well as transforming any other sector of the economy where stationary sources emit greenhouse gases."

The Biden administration is reportedly working on proposing a new rule to limit greenhouse gas pollution from the nation's power plants. In opposing the petition, then-acting Solicitor General Elizabeth Prelogar said any court reviews should await the new rulemaking "when the courts can review a concrete and considered EPA rule, rather than speculate as to the regulatory approaches the agency might take."

"There is consequently no sound reason for this court to grant review now to resolve the legality of a prior agency regulation that has no present operative effect and that EPA does not intend to revive," she argued.

The justices added another potentially controversial case to this term's argument docket: Arizona v. City of San Francisco. Republican-led state attorneys general have asked the court to decide whether states with an interest in the Trump administration's public charge rule should be permitted to intervene to defend the rule when the United States ceases to defend it.

The rule made an alien inadmissible "if at the time of application for admission or adjustment of status, [the alien] is likely at any time to become a public charge." A number of lawsuits challenging the rule were filed and resulted in preliminary injunctions blocking it.

The Trump administration appealed to the U.S. Supreme Court and the justices granted review in Dept. of Homeland Security v. New York, from the Second Circuit. But with the change in administrations, the United States announced in March that it would no longer pursue its appeals.

Arizona and a coalition of states moved to intervene to defend the rule in the Ninth Circuit, but a circuit panel denied their motion by a 2-1 vote.

"By stipulating to dismiss pending appeals challenging the Rule, the Administration managed to circumvent the APA rulemaking processes entirely, depriving the States of the input they would normally have," Arizona solicitor general Brunn Roysden III wrote in Arizona v. San Francisco. "This procedural gamesmanship has harmed and will continue to harm the Petitioning States for years to come."

The United States, opposing review, told the court, "Even if this litigation had not already become moot, moreover, intervention would have been improper because petitioners' alleged economic interests in the Rule are insufficient to support intervention, and equitable considerations weigh strongly against granting their belated request to intervene in an appeal challenging preliminary injunctions that do not apply in their jurisdictions."