The Obama administration asserted Wednesday that a Supreme Court order delaying enforcement of its new clean-power rules will ultimately have little impact on meeting the nation's obligations under the recent Paris climate agreement.
But environmentalists and academic experts are more nervous.
They are concerned that any significant pause in implementing mandated reductions in carbon dioxide emissions from coal-fired power plants will imperil the credibility of the Unites States to lead on climate change, while increasing worries both at home and abroad that the whole international agreement might unravel if a Republican wins the White House in November.
Nearly 200 countries agreed in December to cut or limit heat-trapping greenhouse gases in the first global treaty to try to limit the worst predicted impacts of climate change. The goal is to limit warming to no more than an additional 1.8 degrees Fahrenheit. Each nation set its own goals under the treaty, and President Barack Obama committed the United States to make a 26 to 28 percent cut in U.S. emissions by 2030.
The Clean Power Plan is seen as essential to meeting that goal, requiring a one-third reduction in carbon dioxide emissions from existing power plants over the next 15 years. Even before the Environmental Protection Agency released the plan last year, a long list of mostly Republican states that are economically dependent on coal mining and oil production announced they would sue.
Though the case is still pending before an appeals court in Washington, a 5-4 majority on the Supreme Court issued a surprising order on Tuesday barring any enforcement of the plan until the legal challenge is resolved. Whichever side loses at the appeals level is almost certain to petition for review by the high court, almost certainly freezing any significant action on the plan's goals until after Obama's term expires in January 2017.
"The court's stay, although procedural, clearly signals trouble for the clean power plan," said John Sterman, an MIT professor who created an intricate computer model that simulates the effects of cuts in greenhouse gas emissions on global warming. "Without serious policies to promote efficiency, renewables, and low-carbon energy, there is little chance the U.S. will be able to meet its emissions-reduction pledge, undermining the willingness of many other nations to meet their commitments."
Obama has staked much of his second term on building a legacy on climate change surpassing that of any of his predecessors. Climate change now joins immigration atop the list of top Obama priorities delayed indefinitely by the courts.
Even if the justices ultimately uphold the Clean Power Plan, GOP leaders in Congress have vowed to wipe the rules away if a Republican wins November's presidential election. That raises the specter that the U.S., the world's second-largest emitter of greenhouse gases after China, might also withdraw from the Paris treaty.
"President Obama's credibility on the climate issue was crucial to reaching agreement at Paris," said Michael Oppenheimer, a Princeton University professor of geosciences and international affairs. "The entire edifice built at Paris could collapse, much as the Kyoto Protocol was seriously undermined by President George W. Bush's withdrawal of the U.S. from that agreement."
White House spokesman Eric Schultz said Wednesday that leaders in the countries participating in the agreement understand that the rulemaking process in the U.S. is often complicated and litigious. But, in the end, he said this week's setback from the Supreme Court is just a "temporary, procedural determination."
Schultz said the U.S. would continue to take aggressive steps to continue to reduce greenhouse gas emissions, citing other regulations it has put in place to reduce emissions from automobiles, airplanes and the oil and gas sector. He said the extensions of solar and wind tax credits in this year's budget will be critical in helping the U.S. meet its commitments.
"It is our estimation that the inclusion of those tax credits is going to have more impact over the short term than the Clean Power Plan," Schultz said aboard Air Force One on Wednesday as the president was flying to Springfield, Illinois.
White House officials said they expected the courts to move quickly on the case, which will benefit the administration's efforts.
Compliance with the new emissions rules isn't required until 2022, but states must submit their detailed plans for meeting the required reductions to the EPA by September or seek an extension.
Attorney General Patrick Morrisey of West Virginia, whose coal-dependent state is helping lead the lawsuit against Obama's plan, suggested Wednesday that taking any steps to meet the required emissions reductions before the final legal decision would be a waste of time and money.
He said for him, opposition to the emissions limits has "nothing to do with climate change." Rather, it's about protecting coal-mining jobs already endangered by competition from plentiful stores of cheap natural gas unleashed by the shale fracking boom.
"This rule represents a radical transformation of American energy policy and will have a sweeping impact on the American way of life," Morrisey said. "EPA is seeking to transform itself from being an environmental regulator into a central energy-planning authority for the states."
As the legal logjam over the plan plays out in the courts, however, some environmentalists are putting their hopes in the free market — that the rapidly falling costs of solar and wind infrastructure will boost investments in clean energy, even in an era of historically cheap fossil fuels.
"The transition to clean, renewable energy is rapidly becoming unstoppable," former vice president and climate crusader Al Gore said Wednesday.