In a landmark ruling, the International Court of Justice declared that failure to act on climate change can be an “internationally wrongful act”—meaning countries could face legal consequences for harming the planet.

The UN's top court on Wednesday ruled climate change an "existential problem of planetary proportions" and said countries had a legal duty to act or face consequences.

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.