International Court of Justice at the announcement of its advisory opinion on climate change. Credit: Cecilia Russell/IPS
By Cecilia Russell
THE HAGUE & JOHANNESBURG, Jul 23 2025 – The case was “unlike any that have previously come before the court,” President of the International Court of Justice Judge Yuji Iwasawa said while reading the court’s unanimous advisory opinion outlining the legal obligations of United Nations member states with regard to climate change. This case was not simply a “legal problem” but “concerned an existential problem of planetary proportions that imperils all forms of life and the very health of our planet,” Iwasawa said.
“A complete solution to this daunting and self-inflicted problem requires the contribution of all fields of human knowledge, whether law, science, economics or any other; above all, a lasting and satisfactory solution requires human will and wisdom at the individual social and political levels to change our habits, comforts, and current way of life to secure a future for ourselves and those who are yet to come,” the judgment read.
The opinion was welcomed by Ralph Regenvanu, Minister of Climate Change Adaptation, Meteorology & Geo-Hazards, Energy, Environment and Disaster Management for the Republic of Vanuatu – the country that pushed for the advisory opinion.
“Today’s ruling is a landmark opinion that confirms what we, vulnerable nations have been saying, and we’ve known for so long, that states do have legal obligations to act on climate change, and these obligations are guaranteed by international law. They’re guaranteed by human rights law, and they’re grounded in the duty to protect our environment, which we heard the court referred to so much,” Regenvanu said.
Margaretha Wewerinke-Singh, legal counsel for Vanuatu’s ICJ case and international lawyer at Blue Ocean Law, hailed the opinion, saying it even held the United States, which recently under President Donald Trump recently withdrew from the Paris Agreement, as it bound all states within the United Nations.
Wewerinke-Singh said the opinion meant that the “era where producers can freely produce and can argue that their climate policies are a matter of discretion—they’re free to decide on the climate policies—that era is really over. We have entered an era of accountability, in which states can be held to account for their current emissions if they’re excessive but also for what they have failed to do in the past.”
The detailed advisory opinion dealt with obligations of states under various climate conventions and treaties and humanitarian law.
The court concluded that in terms of the climate agreements, state parties
- To the United Nations Framework Convention on Climate Change have an obligation to adopt measures with a view to contributing to the mitigation of greenhouse gas emissions and adapting to climate change;
- Have additional obligations to take the lead in combating climate change by limiting their greenhouse gas emissions and enhancing their greenhouse gas sinks and reservoirs;
- To the United Nations Framework Convention on Climate Change, have a duty to cooperate with each other in order to achieve the underlying objective of the convention;
- To the Kyoto Protocol must comply with applicable provisions of the protocol;
- To the Paris Agreement have an obligation to act with due diligence in taking measures in accordance with their common but differentiated responsibilities and respective capabilities capable of making an adequate contribution to achieving the temperature goal set out in the agreement;
- To the Paris Agreement have an obligation to prepare, communicate and maintain successive and progressive, nationally determined contributions, which, when taken together, are capable of achieving the temperature goal of limiting global warming to 1.5 degrees Celsius above pre-industrial levels;
- State parties to the Paris agreement have an obligation to pursue measures which are capable of achieving the objectives set out in their successive nationally determined contributions; and
- State parties to the Paris agreement have obligations of adaptation and cooperation, including through technology and financial transfers, which must be performed in good faith.
In addition, the court was of the opinion that customary international law sets forth obligations for states to ensure the protection of the climate system and other parts of the environment from anthropogenic greenhouse gas emissions.
These obligations include the following:
- States have a duty to prevent significant harm to the environment by acting with due diligence and to use all means at their disposal to prevent activities carried out within their jurisdiction or control from causing significant harm to the climate system and other parts of the environment in accordance with their common but differentiated responsibilities and respective capabilities.
- States have a duty to cooperate with each other in good faith to prevent significant harm to the climate system and other parts of the environment, which requires sustained and continuous forms of cooperation by states when taking measures to prevent such harm.
- State parties to the Vienna Convention for the Protection of the ozone layer and to the protocol and to the Montreal Protocol on Substances that Deplete ozone layer and its Kigali amendment, the Convention on Biological Diversity, and the United Nations Convention to Combat Desertification in those countries experiencing serious drought and/or desertification, particularly in Africa, have obligations under these treaties to ensure the protection of the climate system and other parts of the environment from anthropogenic greenhouse gas emissions.
- State parties to the United Nations Convention on the Law of the Sea have an obligation to adopt measures to protect and preserve the marine environment, including from the adverse effects of climate change, and to cooperate in good faith.
However, the court did not end there; it was of the opinion that states have obligations under international human rights law and are required to take “measures to protect the climate system and other parts of the environment.”
IPS UN Bureau Report