Countries have a legal obligation to tackle climate change, International Court of Justice rules
Photo by Sang Hyun Cho via Pixabay
Wealthy nations must comply with international commitments to limit pollution or risk having to pay compensation to countries hardest hit by climate change, the International Court of Justice (ICJ) has ruled.
The court said a violation of states’ climate obligations may justify “the award of full reparation to the injured states”, provided that “a sufficiently direct and certain causal link can be established between the wrongful act and the damage suffered”.
The court president judge Yuji Iwasawa said during last week’s ruling that countries’ failure to take appropriate action to protect the climate, and meet the “stringent obligations” placed on them by climate treaties such as the Paris Agreement, was a breach of international law.
The court also emphasised that countries have a duty of cooperation, particularly in terms of financing, technology transfer, and support for the most vulnerable countries.
Though not legally binding, the unanimous decision by the ICJ – the UN’s highest court, based in The Hague – is being hailed as a ‘landmark’ by civil society groups and climate experts, who say it puts pressure on the most polluting countries to act more robustly to tackle climate change.
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Biggest climate case in history
The case is the biggest climate court case in history. The UN General Assembly formally requested the ICJ to hear the case in 2023, following years of campaigning by youth groups and the government of Vanuatu, an island nation of the South Pacific.
The court was tasked with considering the legal obligations of states to protect the climate, and the consequences if they fail to do so, particularly with regard to the most vulnerable countries.
The case involved 96 countries, 11 international organisations, 10,000 pages of documents, 15 judges and two weeks of hearings in December 2024.
The resulting Advisory Opinion on the Obligations of States in respect of Climate Change clarifies existing principles of international law with regard to addressing climate change.
It affirmed that states have an “obligation to prevent significant damage to the environment” and must “cooperate in good faith” to curb climate change.
Judge Iwasawa added that a “clean, healthy and sustainable environment” is a human right, and warned that climate change continues to be an “urgent and existential threat,” whose “serious and far-reaching effects […] affect both natural ecosystems and human populations”.
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Ruling rejects most polluting countries’ position
The world’s most polluting countries – China, the United States, and the European Union – argued that obligations to address climate change were derived solely from climate-specific treaties like the Paris Agreement, and, as such, there could be no legal consequences for climate harm arising from other sources of international law, such as those related to human rights.
Developing nations and small island states at greatest risk from rising sea levels had sought clarification from the court after the failure so far of the 2015 Paris Agreement to limit global warming to 1.5 degrees Celsius above pre-industrial levels.
According to the UN, current climate policies will result in global warming of more than 3 degrees Celsius above pre-industrial levels by 2100.
The court’s advisory opinion rejects the wealthy nations’ position.
Iwasawa stressed that national climate plans must be of the highest ambition and collectively maintain standards to meet the aims of the Paris Agreement.
UN secretary-general Antonio Guterres said the court’s opinion “has made clear that all states have an obligation under international law to protect the global climate system” and that it affirmed that Paris Agreement goals should be the basis of all climate policies.
“This is a victory for our planet, for climate justice, and for the power of young people to make a difference,” he added. “The world must respond.”
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Setting a precedent
Experts say the ruling carries legal and political weight and that it sets a precedent for future climate cases, which would be unable to ignore it.
According to the UN there are nearly 3,000 climate-related lawsuits already underway in some 60 countries around the world.
It is also likely to lead to greater calls for loss-and-damage funding at COP30, taking place in Brazil in November.
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