The Hague (AFP) – The top United Nations court will on Wednesday hand down a landmark global legal blueprint for tackling climate change that also sets out top polluters’ responsibilities towards the countries suffering most.

The International Court of Justice (ICJ) has been tasked with crafting a so-called advisory opinion on countries’ obligations to prevent climate change and the consequences for polluters whose emissions have harmed the planet.

Experts say this is the most significant in a string of recent rulings on climate change in international law, with major potential repercussions for states and firms around the world.

Climate-vulnerable countries and campaign groups hope it will have far-reaching legal consequences in the fight against climate change, unifying existing law, shaping national and international legislation, and impacting current court cases.

“It will be the compass the world needs to course correct,” said Vishal Prasad, director of the Pacific Islands Students Fighting Climate Change.

“It will give new strength to climate litigation, inspire more ambitious national policies and guide states toward decisions that uphold their legal duties to protect both people and planet,” said Prasad.

But some critics argue the ruling will be toothless, as ICJ advisory opinions are not binding and major polluters can choose simply to ignore it.