A lawsuit filed by 16 Alaska youths claimed long-term effects of climate change will devastate the country's northernmost state and interfere with their constitutional rights to life, liberty and public trust resources that sustain them.

The state's legislative and executive branches have not taken steps to lower greenhouse gas emissions and adopted a policy that promotes putting more in the air, said attorney Andrew Welle of the Oregon-based Our Children's Trust group.

"This is an issue that is squarely within the court's authority," Welle said.

Assistant Attorney General Anna Jay urged justices to affirm a lower court ruling rejecting the claims. Ultimately, the climate change issues raised by Alaska youth must be addressed by the political branches of government, she said.