A few weeks ago, a federal judge in Oregon made headlines when she ruled that a groundbreaking climate lawsuit will proceed to trial. And some experts say its outcome could rewrite the future of climate policy in the United States.
The case, brought by 21 youths aged 9 to 20, claims that the federal Government isn't doing enough to address the problem of climate change to protect their planet's future - and that, they charge, is a violation of their constitutional rights on the most basic level.
The case has already received widespread attention, even garnering the support of well-known climate scientist James Hansen , who has also joined as a plaintiff on behalf of his granddaughter and as a guardian for "future generations".
The US Government under President Barack Obama, with several others representing members of the fossil fuel industry, filed to have the lawsuit dismissed. But on November 10, federal judge Ann Aiken denied the motion, clearing the case to proceed to trial.
According to Our Children's Trust, the nonprofit representing the youth plaintiffs, a recent case management conference indicated that the case would likely go to trial by the the middle of next year.
"It's been called the biggest trial of the century, and it is," said Mary Wood, a law professor at the University of Oregon and expert in natural resources and public trust law.
"Literally, when I say the planet is on the docket, it would be hard to imagine a more consequential trial, because the fossil fuel policies of the entire United States of America are going to confront the climate science put forth by the world's best scientists. And never before has that happened."
Theoretically, the trial's outcome could have major implications for the incoming Trump Administration, which aims to dismantle many of the climate and energy priorities established under Obama.
Should the plaintiffs prevail, the federal Government could be forced to develop and adhere to stringent carbon-cutting measures aimed at preserving the planet's climate future for generations to come. The only other place such action has ever been ordered by a court is in the Netherlands, where a similar case resulted in a landmark ruling last year requiring the Dutch Government to slash its emissions by a quarter within five years.
Julia Olson, chief legal counsel for the plaintiffs and executive director of Our Children's Trust, said she's optimistic that the youths will prevail in court. But while other experts agree on the case's historical importance, they're less sure about its outcome.
"It's a terrific case," said James May, a distinguished professor of law and chief sustainability officer at Widener University. "It finally constitutionalises climate change."
But he added that he thinks the plaintiffs' odds of success are unlikely.
The case relies on several specific claims. One of these references something called the "public trust doctrine", which holds that the Government is responsible for preserving certain resources, such as lakes and rivers, for public use. The plaintiffs assert that "the overarching public trust resource is our country's life-sustaining climate system, which encompasses our atmosphere, waters, oceans, and biosphere".
The suit also addresses a principle known as substantive due process, which prohibits the Government from depriving any person of life, liberty or property without due process of law.
The plaintiffs argue that "our nation's climate system ... is critical to plaintiffs' rights to life, liberty, and property", and that these rights are threatened by federal action, such as the continued development of fossil fuels.
But while May notes that "strictly speaking, legally, the [plaintiffs'] causes of action have legs", the case's pioneering nature may make it difficult to argue in court.
"The federal judiciary of the United States is not yet ready, by and large, to apply federal common law public trust doctrine and substantive due process to climate change," he said. "I think it's likely that the cases will be struck."
But some experts are more optimistic. Wood, the University of Oregon law professor, feels that the case overcame its biggest challenge already when the motion to dismiss was denied. By declining to dismiss the lawsuit, the court was indicating that the plaintiffs do indeed have a right to sue the Government over their constitutional right to a healthy environment in the context of the climate change threat - something that has never been done before.
And even experts who are sceptical about the lawsuit's eventual outcome agree this was an important milestone.
"I think the fact that the plaintiffs have survived a motion to dismiss means that it's got to be taken somewhat seriously," said Daniel Esty , an expert in environmental law and policy at Yale University.
Esty, like May, nevertheless suspects that the suit will not proceed much further.
However, in Wood's opinion, the plaintiffs should have plenty of support to win the case.
"If the children can show that the federal Government is neglecting its fiduciary duty of trustee ... then they can force a remedy," she said. "And it seems fairly straightforward based on existing climate science that the federal Government is not fulfilling its just duties to protect these potential resources." While the lawsuit is currently aimed at the Obama Administration, it will target the Trump Administration by default after January. This means that if the plaintiffs prevail, a court order could require climate action from the new administration, such as halting new permits for oil drilling or reducing greenhouse gas emissions by a certain amount over a given period of time, according to Wood.
However, such an outcome would almost certainly be appealed.
According to Wood, the case could also end with a consent decree - a kind of settlement in which the federal Government agrees to take action rather than go through with a trial.
"If [President Obama] really wants to secure the climate legacy, he could come forward and put measures on the table as a down payment for the climate recovery owed to these plaintiffs," Wood said.
"He could make the first down payment on this huge climate debt. And if he did that, that would signal to everybody that he was serious about this climate crisis."
Still, this outcome could also be appealed by the new Administration - and in any event that the case made it all the way to the Supreme Court, May said, it would likely be "dead on arrival".
It may turn out that the greatest action on climate change in the coming years will take place at the state and local level instead, experts say.
In addition to the federal case, Our Children's Trust has also filed similar climate lawsuits at the state level throughout the nation - and they've enjoyed some success in Washington state, securing court orders requiring the state Department of Ecology to develop a plan to regulate carbon dioxide emissions. (Although the agency did develop a plan in response, the petitioners have recently deemed it inadequate and have taken the issue back to court.)
Because state constitutions differ across the nation, it's difficult to predict exactly how these cases might play out in other places, May noted. But some states may go on to develop or continue strengthening their own climate plans regardless.
"I see across the US the number of governors and the number of mayors who are pursuing climate change agendas in their own places with great vigour," Esty said.
"I expect that that will continue to be an important element of why the United States moves forward on its climate change agenda, even if there's some resistance from a Trump Administration."
And even if the federal lawsuit fails, its effects could still reverberate in other ways.
It's opened up a new legal avenue for fighting climate change that may become more common in the future, May said.
And according to Esty, the case may end up serving "as a source of inspiration to young people across the world who might, in their own countries and in their own legal context, decide that they should pursue court cases or other legal action against those who appear to be foot-dragging on the issue of climate change".
In fact, according to Olson, Our Children's Trust is already supporting similar cases in several other countries, including Pakistan and Uganda.
"I think we will win this case, and it will transform our federal climate policy so that it's focused on protecting the constitutional rights of young people," Olson said.
"But I agree that whichever way the case goes, it is serving a very important purpose in reframing the climate crisis as one which affects human rights, and fundamental rights that citizens of the United States hold, and also citizens of other nations across the world."