PORTLAND, Ore. — A court case brought by 21 children and young adults asserting a constitutional right to safe climate may turn on the judiciary’s view of its own power to create climate policy.

Much of a hearing before the 9th U.S. Circuit Court of Appeals here Tuesday afternoon centered on the judicial role in establishing a response to climate change and what rights a group of young activists have to challenge the government’s role in creating a climate crisis. If successful, the suit could require federal agencies to create a comprehensive climate action plan. The shape of such a plan is still unclear. 

The government argued that the suit violated the Constriction’s separation of powers by asking the judicial branch, rather than Congress or the president, to create climate policies.

The climate activists have argued throughout the case that the federal government’s policies supporting fossil fuel use directly contributed to global climate change, which in turn threatens their lives and security.

Circuit Judge Andrew D. Hurwitz told the activists’ lead attorney, Julia Olson, he was sympathetic to the problem, but he said the request for the court to step in was asking the court “to break new ground.”

“You present compelling evidence that we have a real problem,” he said. “It may even rise to the level of criminal neglect. The tough question for me and, I suspect, for my colleagues is do we get to act because of that.”

“We’re asking the court to apply bedrock constitutional law and principles to a wholly new set of facts,” Olson said.

She referenced anti-discrimination cases, including the Brown v. Board of Education ruling that outlawed school segregation, to argue that courts had made sweeping rulings in the past to right constitutional violations.

Jeff Clark, who argued for the Justice Department, framed the case as an end-run around regular administrative law. The activists could have brought the same claims to any of the eight departments or agencies named in the suit, or even petition for a multi-agency rule-making, he said. That process would allow for public input and build a public record that could later be reviewed.

“This case seeks to skirt all that,” he said.

Using Olson’s civil rights framing, Clark added that Thurgood Marshall didn’t bring one massive civil rights case, but rather chipped away at individual policies.  

Authorities moved Tuesday’s hearing from the 9th Circuit’s Portland courtroom to a larger one at the federal district court several blocks away to accommodate the members of the public interested in the case. Even so, security officers began directing spectators to overflow rooms minutes after the courtroom doors opened Tuesday afternoon. 

The case, Juliana v. United States, began in 2015, when the plaintiffs — the oldest of whom was then 19-year-old Kelsey Juliana — sued the Obama administration, arguing that the government has for decades violated their inherent and constitutionally protected rights to live in an ecosystem with a safe climate. 

“It’s a unique legal challenge, never been tried before,” said David Bookbinder, an environmental lawyer and chief counsel at the Niskanen Center, a centrist policy think tank in Washington. “Its success will depend on … the 9th Circuit and then the Supreme Court to declare there’s a right to a particular kind of climate”

The activists demand the federal government draft a national plan, based on the latest climate science, to ramp down heat-trapping greenhouse gas emissions. The Justice Department has said the plaintiffs don’t have legal standing.

Also watch: A GOP sea change on climate? Not quite

Question of authority

There’s also a question of whether the executive branch agencies have the existing authority from Congress to act on such a plan.

“When I read what the plaintiffs wanted as a remedy, I just didn’t see how that was possible,” said Adele Morris, policy director of the Brookings Institute’s Climate and Energy Economics Project.

Olson said in court Tuesday that the agencies could act without any new authority from Congress.

At its core, the case is built on a legal concept called the “public trust doctrine,” a centuries-old idea that natural resources are to benefit the public and that the government is responsible to protect those resources in perpetuity.

Juliana is likely bound for the Supreme Court, which lifted its stay on the case in November. 

In 2016, Ann Aiken, a federal judge in Eugene, Oregon, surprised many legal experts when she allowed the case to proceed. 

“I have no doubt that the right to a climate system capable of sustaining human life is fundamental to a free and ordered society,” Aiken wrote. “This is no ordinary lawsuit.”

At trial, the plaintiffs also seek to show how long the government has known of climate change and its dangers. For years, Our Children’s Trust, the Oregon nonprofit representing the plaintiffs, has been compiling a trove of government, corporate, military and scientific records, including many to and from the White House.

Some of these files show that every president since John F. Kennedy has been briefed about climate science, often with grim details.

White House aide Daniel Moynihan wrote to his colleague John Ehrlichman in the fall of 1969 to explain climate change. “This in turn could raise the level of the sea by 10 feet,” he said. “Goodbye New York. Goodbye Washington, for that matter.”

EPA Administrator Andrew Wheeler weighed in on Monday, telling reporters in Washington the case would not go much further. He said the children didn’t have standing because the EPA is already acting to cut earth-warming carbon emissions.

Elvina Nawaguna contributed to this report.