The International Court of Justice will clarify states’ legal responsibility for impacts of climate change. Although non-binding, its opinion will matter for thousands of climate lawsuits.

Who is legally responsible for climate harms? The world’s top court will now decide.

This is where the entry of the world’s highest court could be a game changer. In the next few months, the International Court of Justice (ICJ), the United Nations’ principal judicial organ in The Hague, the Netherlands, will begin hearing evidence on two broad questions: first, what are countries’ obligations in international law to protect the climate system from anthropogenic greenhouse-gas emissions, and second, what should the legal consequences be for states when their actions — or failure to act — cause harm?