Judges with the U.N.’s top court say in a landmark climate decision that a “clean, healthy and sustainable environment” is a human right.

THE HAGUE, Netherlands — The United Nations’ top court has issued a landmark advisory opinion on climate change, its 15-black-robed judges weighing in for the first time on what the court’s president called “an existential problem of planetary proportions that imperils all forms of life and the very health of our planet.”