'New Era of Climate Accountability': ICJ Says Nations Have Legal Duty to Combat Planetary Crisis

The world's highest court said in a landmark advisory opinion handed down Wednesday that countries have a legal obligation to take cooperative action against the climate crisis, which the United Nations body characterized as an "urgent and existential threat."

Reading the ruling aloud during a closely watched hearing, International Court of Justice (ICJ) President Yuji Iwasawa said that "climate change is a common concern" and "cooperation is not a matter of choice for states but a pressing need and a legal obligation."

"Non-compliance with emission-reduction commitments by a state may constitute an internationally wrongful act," the advisory opinion states, opening the door to reparations for countries harmed by the fossil fuel-driven crisis.

The ICJ ruling, which is expected to bolster new and existing climate lawsuits worldwide, stemmed from a 2023 U.N. General Assembly resolution introduced by the low-lying nation of Vanuatu, which—along with more than 130 other governments—demanded that the world's highest court issue an opinion on nations' legal obligations to combat the climate emergency.

"Tonight I'll sleep easier," Flora Vano, country manager of ActionAid Vanuatu, said in a statement following Wednesday's decision. "For the first time, it feels like justice is not just a dream but a direction. The ICJ has recognized what we have lived through—our suffering, our resilience, and our right to our future. This is a victory not just for us but for every frontline community fighting to be heard. Now, the world must act."

"As the Trump administration takes extreme steps to prioritize corporate polluters over public health and the environment, the legal recklessness of doing so has been laid bare."

Danilo Garrido, legal counsel at Greenpeace International, hailed the advisory opinion as "the start of a new era of climate accountability at a global level."

"The ICJ advisory opinion marks a turning point for climate justice, as it has clarified, once and for all, the international climate obligations of states, and most importantly, the consequences for breaches of these obligations," said Garrido. "This will open the door for new cases, and hopefully bring justice to those who, despite having contributed the least to climate change, are already suffering its most severe consequences."

"The message of the court is clear: The production, consumption, and granting of licenses and subsidies for fossil fuels could be breaches of international law," Garrido added. "Polluters must stop emitting and must pay for the harms they have caused."

The ICJ opinion comes as the Trump administration in the U.S.—historically the world's largest emitter of planet-warming greenhouse gases—works to expand fossil fuel drilling, withdraws from cooperative global efforts to fight the climate crisis, and rolls back green energy investments.

The U.S. faced backlash over its position on the case before the ICJ, which was argued last December—when the Biden administration was in power. The Biden administration's representative was accused of arguing that "countries do not have clear legal obligations to reduce carbon pollution."

Delta Merner, a lead scientist with the Science Hub for Climate Litigation at the Union of Concerned Scientists, said that Wednesday's opinion from the ICJ "leaves no room for ambiguity—governments cannot ignore their legal responsibilities to prevent further climate harm."

"This ruling makes clear that obligations under existing international law are not voluntary or symbolic; they are enforceable duties rooted in science, human rights, and intergenerational equity," said Merner. "The court also affirmed that countries must rein in corporate polluters, and if they fail, they’re responsible for helping to fix the damage."

"As the Trump administration takes extreme steps to prioritize corporate polluters over public health and the environment, the legal recklessness of doing so has been laid bare by the new advisory opinion," Merner continued. "This decision heralds a new frontier in the movement for climate accountability."