World’s top court to weigh in for the first time on countries’ legal obligations to combat climate change.

The International Court of Justice (ICJ), the world’s top court, is set to issue its first-ever legal guidance on countries’ obligations to combat climate change, according to a resolution adopted by the United Nations on Wednesday.

The advisory opinion, which could be invoked in climate court cases, was proposed by Vanuatu, an island nation in the Pacific Ocean that is vulnerable to the impact of rising sea levels.

The motion was supported by over 130 countries and was greeted with cheers as it was passed.

Vanuatu’s Prime Minister, Ishmael Kalsakau, hailed the resolution as “a win for climate justice of epic proportions.” The idea for the legal opinion was first proposed by law students in Fiji four years ago and later taken up by Vanuatu, a country that has experienced the severe effects of global warming.

Earlier this year, Vanuatu was hit by devastating twin cyclones that left thousands homeless and caused damages with an estimated cost of roughly half of the country’s annual GDP. These experiences gave added weight to Vanuatu’s UN resolution, which seeks legal clarity on responsibilities for climate change.

The resolution managed to gain broad support from many countries because it was carefully crafted to avoid blaming countries such as China and the US, who have historically emitted the most greenhouse gases.

While the ICJ’s opinion will not be legally binding, the hope is that it can be cited in legal cases brought against governments and businesses across the globe. The ICJ, which is based in the Netherlands, will now have two years to consider its opinion.

“Vanuatu sees today’s historic resolution as the beginning of a new era in multilateral climate co-operation, one that is more fully focused on upholding the rule of international law and an era that places human rights and intergenerational equity at the forefront of climate decision-making,” said Ishmael Kalsakau, Prime Minister of Vanuatu, in a video statement to the UN.

“A win for climate justice of epic proportions.”

Supporters of the case believe that an ICJ decision will likely have a galvanising effect worldwide on climate action. It will be used in future UN negotiations on climate change, as a basis for court cases, as well as in decisions made by private companies about their long-term investments. Meanwhile, it will be more clear to governments that not taking action to curb carbon emissions is in breach of international law.

“If you ask, in good faith, 10 international environmental lawyers whether what’s happening with emissions in many states is unlawful under the Paris agreement, you will have an honest divide,” said Jorge Viñuales, professor of law and environmental policy at Cambridge University, who’s drafted the legal question to go in front of the court.

“Under international law, that can’t make sense. So instead of looking at the Paris Agreement, you zoom out, and you look at the entirety of international law. It cannot be possible that destroying the planet is legal.”

“I think it’s going to shape the discourse; it could be a game changer for new policies and for tightening existing policies,” continued Prof Viñuales.

“It may empower and embolden civil society to do more, and it may create a new political narrative that can be used in elections, for example.”