The 21 youths suing the federal government over climate change have gained a new round of supporters, including 30,000 youths who signed onto a legal brief asking an appeals court to allow the long-delayed case to go to trial.

The “Young People’s Brief” was among 15 new amicus briefs filed Friday by environmentalists, religious and women’s groups, business leaders and eight members of Congress– all in support of the case being tried in court.

The youth filing is noteworthy, as a growing youth movement calling for political leaders to act more urgently on climate change is rapidly spreading around the world. Young people in 50 nations have organized a strike from school on March 15 as part of a global protest.

“I’m part of an amazing group of plaintiffs who won’t put up with adults jeopardizing our futures any longer,” Miko Vergun, 17, of Beaverton, Oregon, one of the plaintiffs in the lawsuit, said in a statement. “…The amount of young people, in the United States and around the world, who added their names to support this brief is a representation of all the youth who know that their futures and their planet are at stake.”

The trial, originally scheduled to begin last October, has been delayed while government lawyers have sought to have the case dismissed before trial.

In court papers, the government said the “assertion of sweeping new fundamental rights” the youths claim “has no basis in the nation’s history and tradition”—and no place in a federal court. The government lawyers twice appealed to the Supreme Court, which returned the case to the Ninth Circuit Court of Appeals in San Francisco. Arguments in that appeal are scheduled to be heard the first week of June.

Four years so far

The lawsuit, Juliana v. United States,was originally filed against the government in 2015 during the Obama administration. The suit contends that the federal government pursued energy policies that caused climate change even though it knew for more than a half-century that carbon emissions would destabilize the climate. The government’s failure to forestall the effects of climate change, the suit alleges, violated future generations’ constitutional right to live in a “climate system capable of sustaining human life.”

The case hinges on the question of whether the Constitution guarantees such a right.

Both the Obama administration and now the Trump administration have argued repeatedly that the issues of climate change are more properly addressed by Congress and not by the courts.

In another amicus brief filed last week, eight Democrats in Congress disagreed and urged the court to hear the case. “[T]he intractability of the debates before Congress and state legislatures and the alleged valuing of short-term economic interest despite the cost to human life, necessitates a need for the Courts to evaluate the constitutional parameters of the action or inaction taken by the government,” the lawmakers wrote.

The Sunrise Movement Education Fund attached more than 20 testimonials to its brief, from youths in an assortment of states already suffering the effects of climate change.

“Until we force our government and our business owners to recognize that change needs to happen, it will not happen, and we will be unable to deal with the threats that await us…,” wrote Max Stefanescu, 15, of Alabama.