A U.S. federal appeals court on Friday threw out a lawsuit by children and young adults who claimed they had a constitutional right to be protected from climate change, in a major setback to efforts to spur the U.S. government to address the issue.

In a 2-1 decision, the 9th U.S. Circuit Court of Appeals said the plaintiffs, who were between the ages of 8 and 19 when the lawsuit began in 2015, lacked legal standing to sue the United States.

Circuit Judge Andrew Hurwitz said the majority reached its conclusion "reluctantly," given "compelling" evidence the government had long promoted fossil fuels despite knowing they could cause catastrophic climate change, and that failing to change policies could hasten an "environmental apocalypse."