UN’s International Court of Justice rules that nations have a legal obligation to combat climate change
- Emily Ray
- Aug 18
- 3 min read
In a judgment poised to reverberate through international diplomacy and environmental law, the UN’s International Court of Justice (ICJ) issued its long-awaited advisory opinion on climate change in a case brought by Pacific law students, declaring that nations have legal obligations under international law to combat greenhouse gas emissions.
For the first time, the ICJ labelled climate inaction as an “internationally wrongful act,” opening the theoretical possibility of reparations—financial, restorative, or otherwise—to communities harmed by climate-related damage.
In a record-setting hearing convened in December 2024, the Court heard from 96 States, 11 international organizations, and countless civil society groups. This case, the largest the ICJ has ever undertaken, addressed two critical legal questions: the scope of states’ obligations to protect the climate, and the consequences when they fail to do so.
The Court’s 133-page opinion was unanimous - a rare outcome in the ICJ’s history - and underscored that a “clean, healthy and sustainable environment” is a human right and that failure to uphold this right constitutes a breach of international law.
“For frontline communities, this is nothing short of a legal breakthrough,” said advocates from the Pacific Islands, especially those from Vanuatu, who spearheaded the case. The campaign originated with 27 Pacific Island law students and gained diplomatic support, ultimately reaching the world’s highest court.
Watch the impressive presentation of one of the Pacific law students who brought the case, Cynthia Houniuhi from a tiny Solomon Island, give her testimony to the IJC.
The ruling emphasizes several core tenets:
Legal obligations transcend the Paris Agreement, drawing upon human rights law, environmental treaties, and customary international.
Wealthy and high-emitting nations must take affirmative action, not token gestures—a neutral position is no longer sufficient.
States failing to meet these obligations may face demands for compensation, ecosystem repair, or assurances of non-repetition.
The opinion strengthens legal frameworks for climate litigation, particularly for vulnerable nations and indigenous communities.
While the ruling is not legally binding, it does carry significant moral and normative force. Legal scholars anticipate that it will serve as a cornerstone for future lawsuits and shift the climate narrative ahead of global gatherings like COP30.
Internationally, governments will now have to grapple with what “legal responsibility” demands in an era of escalating threats to life, culture and dignity as a result of this landmark case. Australia, one of the world's biggest fossil fuel exporters, is likely to face new legal scrutiny.
"The court has really met the moment in bringing all of the legal obligations and interpreting them in the climate reality, and the urgency of this kind of existential crisis for the entire world," Retta Berryman, climate lead and lawyer for Environmental Justice Australia (EJA), said of the ICJ decision.
References & further reading:
Lauder, J. (2025, July 25). World Court climate decision lights match under Australia’s fossil fuel industry. ABC News. https://www.abc.net.au/news/2025-07-26/un-climate-case-puts-australian-fossil-fuel-industry-on-notice/105558100
Kaminski, I. (2025, July 23). Nations who fail to curb fossil fuels could be ordered to pay reparations, top UN court rules. The Guardian. https://www.theguardian.com/environment/2025/jul/23/healthy-environment-is-a-human-right-top-un-court-rules
Borkotoky, M. (2024, December 17). ICJ concludes landmark climate change hearing - climate fact checks. Climate Fact Checks. https://climatefactchecks.org/icj-concludes-landmark-climate-change-hearing/
Shrivastava, R. (2025, March 5). Explained: The climate change case in the International Court of Justice - The Analysis (TA). The Analysis (TA). https://theanalysis.org.in/explained-the-climate-change-case-in-the-international-court-of-justice/
Home | INTERNATIONAL COURT OF JUSTICE. (2025, July 23). https://www.icj-cij.org/home
The takeaways from the top UN court’s landmark opinion on climate change | AP News. (2025, July 24). AP News. https://apnews.com/article/world-court-climate-change-opinion-a9e44b1b03346d91cc91794ee00cfb49
Harlan, C. (2025, July). U.N. court rules countries have duty to limit greenhouse emissions. The Washington Post. https://www.washingtonpost.com/climate-environment/2025/07/23/world-court-climate-ruling/
González, F. (2025, July 24). The ICJ rules that failing to combat climate change could violate international law. WIRED. https://www.wired.com/story/the-icj-rules-failing-to-combat-climate-could-be-a-violation-of-international-law/
Environmental Justice Australia. (2025, June 15). Environmental Justice Australia. https://envirojustice.org.au/
