The Supreme Court on Monday declined to hear an appeal in a landmark climate case brought by 21 young people against the federal government, ending its 10-year journey through the courts.

But the case provided a blueprint for numerous other climate-related lawsuits that have had greater success.

Juliana v. United States argued that the government had violated the constitutional rights of the plaintiffs with policies that encouraged the use of fossil fuels. But it was dismissed by the United States Court of Appeals for the Ninth Circuit, where the judges ruled that courts were not the right venue to address climate change.

“Rather, the plaintiffs’ impressive case for redress must be presented to the political branches of government,” Judge Andrew D. Hurwitz wrote in the 2020 opinion.

Our Children’s Trust, the Eugene, Ore., nonprofit law firm that represents the plaintiffs, made its final legal gambit in the case last year, when it asked the Supreme Court to vacate the appeals-court ruling and allow Juliana to proceed to trial in a lower court. That petition was denied on Monday.

Some observers had also considered it risky to ask the Supreme Court to consider the appeal, out of concern that a conservative court might use the case to jettison longstanding environmental protections.

The plaintiff the case is named for, Kelsey Cascadia Rose Juliana, now 29 and a teacher in Oregon, is the daughter of environmentalists and a longtime climate activist herself. The story of how she came to participate in the lawsuit was chronicled in the documentary “Youth v. Gov.”

The legal framework of Juliana has since been replicated in numerous lawsuits and legal actions across the country. And last year, Our Children’s Trust, which has filed many of the cases, scored two notable wins.

The group reached a settlement in Navahine v. Hawaii Department of Transportation in which the state agreed to cut emissions of carbon dioxide, the main greenhouse gas warming the planet, from its transportation system within 20 years. And it won Held v. Montana, in which a judge ruled that the state must consider climate change when approving fossil fuel projects. An appeals court upheld that decision in December.

The plaintiff that case is named for, Rikki Held, 23, grew up on a cattle ranch in Montana where she saw the effects of climate change firsthand, which led to her decision to participate in the lawsuit. She is now a science educator in Kenya through the Peace Corps.

On Monday, she said that the Juliana case had paved the way for her. “Juliana, through the unwavering dedication of its plaintiffs and legal team, has left an indelible mark on the landscape of climate litigation,” she said.

Julia Olson, the founder of Our Children’s Trust, had called on the Biden administration to discuss a settlement in the Juliana case, pointing to expressions of support from lawmakers and academics. She said on Monday that Juliana had “ignited a legal movement.”

But lawyers for the Justice Department had maintained that the court was not the right setting to address climate change, because a judge could not order or enforce any “workable remedy” to the problem.

And some experts had raised concerns about the organization’s strategy at the Supreme Court, noting the risk that the court’s conservative supermajority might take the Juliana case as a way to reconsider legal precedents that undergird environmental protections.

“Be careful what you ask for from this court,” said Patrick Parenteau, an expert on environmental law at Vermont Law and Graduate School, in an interview last year. “If you want an answer to this question, you probably will not like the answer you’re going to get.”

But he added that he still applauded the efforts of the young people and their lawyers.

Ms. Olson said environmentalists should not shy away from the courts. “If we don’t show up and we don’t bring claims forward, and we don’t shine light on injustice, then other forces will always prevail,” she said.