The International Court of Justice (ICJ) has issued a historic advisory opinion recognising a clean and sustainable environment as a human right, declaring that states which fail to curb greenhouse gas emissions may be in violation of international law, DW reported on JUly 23. 

The non-binding ruling by what is in effect the world court, could, in theory, clear the way for the world’s biggest corporations to be held liable for the climate damage they do. As bne IntelliNews reported, just 111 of the world's largest fossil fuel companies are collectively responsible for an estimated $28 trillion in climate-related economic damage and the ten biggest of those are responsible for half of that damage.

In a ruling delivered on July 23, ICJ President Yuji Iwasawa stated that “greenhouse gas emissions are unequivocally caused by human activities and have cross-border effects,” warning of the “urgent and existential threat posed by climate change.”

He said governments now have a legal duty to cooperate in preventing environmental harm and must set national climate targets representing “the highest possible ambition.”

The decision follows a request by the Pacific Island nation of Vanuatu, which, backed by widespread support from developing countries, has been fighting for years for legal clarity on states' obligations to address climate change. It marks the largest case ever heard by the UN’s top court.

“This is a gift from the Pacific and the world’s youth to the global community,” said Mary Robinson, former UN high commissioner for human rights and a member of The Elders, calling the ruling “a powerful new tool to protect people from the devastating impacts of climate change.”

Speaking outside the court, Vanuatu’s Climate Change Minister Ralph Regenvanu hailed the decision as “a landmark milestone for climate action,” adding: “For the first time in history, the ICJ has spoken directly about the biggest threat facing humanity.” Although the advisory opinion is not legally binding, it carries considerable moral and legal influence. Joana Setzer of the Grantham Research Institute at the London School of Economics described it as a “turning point” for global climate litigation.

“Its authoritative interpretation of countries’ legal obligations will serve as a crucial tool for domestic courts, litigants and advocates,” she said.

The opinion is expected to influence ongoing climate negotiations, including the COP30 summit in Brazil this November. Joie Chowdhury, senior attorney at the Center for International Environmental Law, said the ruling could define “a clear legal blueprint” for holding high-emitting countries accountable. “At its heart, this case is about accountability,” she added. “It’s a signal to end the era of empty pledges.”