A group of 15 young people will try again to have the courts force Ottawa to develop a climate recovery plan after it was denied by Federal Court.
The youths have filed an appeal of the court's October decision that the claims don't have a reasonable cause of action or prospect of success so the case cannot proceed to trial.
They had argued the federal government's inadequate action on climate change is violating their charter rights to life, liberty and security of the person.
They said their right to equality is also damaged because the young are disproportionately affected by climate change.
They pointed to specific policies such as the federal government's support of fossil fuel through subsidies and the purchase of the Trans Mountain Pipeline.
Justice Michael Manson said the courts should not be involved in what is a complex political matter.
Their lawyer, Joe Arvay, disagreed.
Documents filed with the Federal Court of Appeal say Manson was wrong to rule the issue wasn't appropriate for the courts.
The appeal goes on to say the judge erred in finding no reasonable cause of action and dismissing the claim without giving the plaintiffs a chance to amend it.
The youths are being supported by the David Suzuki Foundation, U.S.-based non-profit group Our Children's Trust and the Pacific Centre for Environmental Law and Litigation in British Columbia.