WASHINGTON – As the Earth grows hotter, young people facing decades of environmental disruption have turned to the courts for relief.

A group of teenagers has sued the US government because it hasn’t done enough to protect future generations from climate change. The landmark youth climate lawsuit, Juliana v United States, brought by a group of 21 young people is finally going to trial after a federal judge in Oregon on Dec 29 denied the government’s latest attempt to dismiss the case.

“Exercising reasoned judgment, the court finds that the right to a climate system that can sustain human life is fundamental to a free and ordered society,” Judge Ann L. Aiken of the US District Court for the District of Oregon said in her Dec 29 opinion.

The case claims that the government’s reliance on fossil fuels violates their constitutional rights to a stable climate. The case has been up to a federal appeals court several times – and the US Supreme Court – on procedural grounds.

Judge Aiken rejected the government’s claim that because tackling the climate crisis is complex, and no single remedy can entirely redress the young people’s harms, the judiciary is constrained by the Constitution from offering any redress at all.

The novel case has made it further than many legal observers thought possible and is getting close to trial. If the teens prevail, the government could be forced to create a plan to cut greenhouse gases more extensively than anything it’s done before.

1. What grounds are there for a lawsuit?

The group says the US government has violated their constitutional right to a liveable climate by not keeping greenhouse gas emissions at a level needed to contain global warming. They also argue that the atmosphere is part of the public trust that the government must maintain for its citizens.

2. What makes it novel?

If the court rules in favour of the group’s constitutional claims, it would acknowledge a new climate-based fundamental right. Supporters of the lawsuit sometimes compare those claims to Obergefell v Hodges, the landmark 2015 case in which the Supreme Court recognised the fundamental right to marry extended to same-sex couples.

Climate lawsuits using the public trust doctrine have become more common, although they have not had much success to date in the US.

3. What is ‘public trust’?

Under the public trust doctrine, the government holds essential natural resources, such as land, water, and wildlife, in trust for its citizens. Climate litigators, including the young people in this case, argue that should include the atmosphere.

4. Who are these young people?

A group of 21 plaintiffs, now ranging in age from 11 to 22, brought the lawsuit in 2015 against the administration of President Barack Obama. Many of the kids were involved in state-level climate cases and activism before bringing the federal suit. One plaintiff is the granddaughter of well-known climate scientist James Hansen.

The group has the backing of Our Children’s Trust, which has brought a number of similar US climate lawsuits at the state level and supported litigation in Asia, Africa and Europe.

5. How has the US government responded?

The Obama administration tried to get the case dismissed, but it had climate policies to stand behind as a defence. Before Mr Obama left office, the administration submitted a response to the court agreeing with much of the climate science information put forth by the children.

President Donald Trump’s administration, which inherited the suit, had also tried to keep it from heading to trial. The administration argued that the case would violate separation of powers by allowing the courts to dictate climate policy, which it said is squarely in the purview of the executive branch.

6. How have judges ruled so far?

Oregon district judge Aiken repeatedly has denied the government’s request to dismiss the case, ruling the question of a constitutional right to a healthy environment deserves an answer.

Both the US Court of Appeals for the Ninth Circuit in San Francisco and the US Supreme Court have rejected attempts to kill the case before trial. When the Supreme Court deferred to the Ninth Circuit in November, it ruled that the courts must consider the merits of the claims to determine if a trial is warranted.

An opinion from the Ninth Circuit is forthcoming. Judge Aiken said she is prepared to promptly schedule a trial date once the Ninth Circuit lifts its hold on the suit.

7. What might happen at a trial?

The government could find itself on the spot to counter the scientific consensus about climate change. In May, Dr Ken Caldeira, an atmospheric scientist at the Carnegie Institution for Science, turned down an opportunity to lead a team of researchers to testify on behalf of the government. And the government’s own scientists may not get on board. Thirteen federal agencies released a report in November showing that climate change could cost the US billions and threaten Americans’ health.

8. What happens if the government loses?

The government may have to develop a comprehensive policy to address greenhouse gas emissions across the economy. The court could set a specific emissions’ goal in line with the climate science presented by the young people.

The plaintiffs also want a dramatic shift away from fossil fuels that could include ceasing federal leasing and support for fossil energy projects. Critics worry that court-ordered climate policy could severely limit energy decisions a president might make based on economic conditions or security threats, which might test even a future administration that wants to act on climate. BLOOMBERG