(AP) — A Montana judge on Monday sided with young environmental activists who said state agencies were violating their constitutional right to a clean and healthful environment by permitting fossil fuel development without considering its effect on the climate.

The ruling in the first-of-its- kind trial in the U.S. adds to a small number of legal decisions around the world that have established a government duty to protect citizens from climate change.

Julia Olson, an attorney representing the youth and with Our Children’s Trust, an Oregon environmental group that has filed similar lawsuits in every state since 2011, celebrated the ruling.

Emily Flower, spokeswoman for Montana Attorney General Austin Knudsen, decried the ruling as “absurd,” criticized the judge and said the office planned to appeal.

“This ruling is absurd, but not surprising from a judge who let the plaintiffs’ attorneys put on a weeklong taxpayer-funded publicity stunt that was supposed to be a trial,” Flower said.

Attorneys for the 16 plaintiffs, ranging in age from 5 to 22, presented evidence during the two-week trial in June that increasing carbon dioxide emissions are driving hotter temperatures, more drought and wildfires and decreased snowpack.