CNN – The world’s highest court said polluting countries may be in breach of international law if they do not protect the planet from the “existential threat” posed by climate change, in a landmark advisory opinion issued Wednesday.
It also said countries feeling the sharp end of climate change may be entitled to reparations for the harm caused by rising temperatures.
The advisory opinion marks the first time the International Court of Justice, the UN’s top court based in the Hague, has formally addressed the climate crisis.
The court was asked to consider two fundamental questions: what legal obligations nations have under international law to address climate change, and what the consequences should be for countries that harm the climate.
Its opinion, which runs to more than 500 pages, said climate change was an “urgent and existential” threat and was unequivocally caused by human activities.
“The human right to a clean, healthy and sustainable environment is essential for the enjoyment of other human rights,” said Yuji Iwasawa, president of the ICJ, as he read out the opinion.
“Failure of a state to take appropriate action to protect the climate system … may constitute an internationally wrongful act,” he added.
The court said states must cooperate to reduce planet-heating pollution and that countries harmed by the climate crisis may be entitled to reparations on a case-by-case basis.
The ruling is not legally binding, but the status of the court gives it significant weight. Experts say it could bolster climate negotiations and provide a huge boost to climate lawsuits around the world.
“This ruling is a powerful tool we can use to demand that those most responsible for this climate crisis be held accountable,” said Flora Vano, Vanuatu country manager for the non-profit ActionAid. “As the planet’s weather becomes more chaotic, this ruling paves the way for the protections and reparations we desperately need to rebuild our lives and secure a just future.”
The opinion comes in the middle of a summer punctuated by extreme weather events, made more intense, more frequent and more deadly by climate change. Vast swaths of the Northern Hemisphere have baked under searing heat waves and more than 1,000 lives have been lost to devastating flooding from the US to Pakistan.
The idea for the case originated with a group of law students in Fiji in 2019, who were trying to find a way to hold the rich world accountable for climate change, for which they are disproportionately responsible.
Their plan was endorsed by the government of Vanuatu, a Pacific island nation facing an existential threat from fast-rising seas. In 2021, it called on the ICJ to issue an advisory opinion on countries’ legal responsibility to fight the climate crisis.
More than 100 states and international organizations took part in two weeks of hearings before the court in December. Many wealthier counties argued that climate responsibilities were already set out in existing treaties including the Paris climate agreement.
Developing nations, which are paying a steep and deadly price for a climate crisis they did little to cause, argued these treaties are failing and called for stronger measures to ensure a livable planet.
Under the Paris Agreement, countries pledged to limit global warming to 1.5 degrees Celsius above levels before humans began burning large amounts of fossil fuels.
The world is currently heading towards 3 degrees Celsius of warming by the end of the century, which would bring catastrophic impacts and the risk of triggering climate tipping points, including ice sheet melting, which may be irreversible on human timescales.
The ICJ case is one of several climate-related cases launched in international courts in recent years.
In May 2024, the International Tribunal for the Law of the Sea found that carbon dioxide produced by burning fossil fuels counts as marine pollution. The court, which is based in Germany, ruled countries had legal obligations to mitigate the impacts.
Earlier this month, the Inter-American Court of Human Rights issued an advisory opinion which stated countries have a duty under international law to address the threat posed by climate change.
