International Court Of Justice Rules Climate Change Is “Existential Threat” – CleanTechnica

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The International Court Of Justice is an instrumentality of the United Nations. According to Wikipedia, the court is one of the six principal organs of the UN and was established when the UN was founded in 1945. It settles legal disputes submitted to it by member nations and provides advisory opinions on legal questions referred to it by UN organs and agencies. It is the only international court that adjudicates general disputes between countries, with its rulings and opinions serving as primary sources of international law.

This week, the ICJ issued a momentous ruling that could have far ranging consequences for the Earth and everyone on it. In a groundbreaking advisory opinion delivered at the Peace Palace in The Hague on Wednesday, July 23, 2025, the Court said states must act urgently to address the “existential threat” of climate change by cutting emissions, following through on global climate agreements, and protecting vulnerable populations and ecosystems from harm.

The ruling has the potential to open the door for affected nations — island nations, primarily — to seek reparations in future legal cases. According to Al Jazeera, ICJ President Yuji Iwasawa said in announcing the court’s decision that greenhouse gas emissions are “unequivocally caused by human activities” and have cross-border effects.

“Failure of a state to take appropriate action to protect the climate system … may constitute an internationally wrongful act,” Iwasawa said. He called the climate crisis “an existential problem of planetary proportions that imperils all forms of life and the very health of our planet.”

Of particular interest to CleanTechnica readers, the court said in its written opinion that a “clean, healthy and sustainable environment” is a human right. Many readers will recognize the similarity between the finding of the ICJ and the ruling by the Supreme Court of Montana last year that upheld the express provision in that state’s constitution that says in Section 1, Article IX:

• The state and each person shall maintain and improve a clean and healthful environment in Montana for present and future generations.
• The legislature shall provide for the administration and enforcement of this duty.
• The legislature shall provide adequate remedies for the protection of the environmental life support system from degradation and provide adequate remedies to prevent unreasonable depletion and degradation of natural resources.

While the ICJ’s ruling is not binding, it said that countries themselves have an obligation to take binding measures to comply with climate treaties. Crucially, the Court said that industrialized nations have a legal obligation to take the lead in combating climate change due to their greater historical responsibility for emissions. The judges also affirmed that countries that signed the 2015 Paris Accords must ensure their individual national climate plans, are “progressive” and reflect the “highest possible ambition,” in line with the treaty’s aim to limit global temperature rise to 1.5º C (2.7ºF).

The opinion was immediately welcomed by environmental groups. Oxfam climate change policy lead Nafkote Dabi said, “This ruling elevates national climate commitments everywhere by confirming that countries must reduce emissions enough to protect the universal rights to life, food, health and a clean environment. All countries, particularly rich ones, now have to cut their emissions faster and phase out fossil fuels. Rich countries have to increase their financing to Global South countries to help them reduce emissions and protect their people from past and future harm. This is not a wish list — it is international law.”

Danilo Garrido, legal counsel at Greenpeace International, said the opinion marked the “start of a new era of climate accountability at a global level. The message of the court is clear: the production, consumption and granting of licences and subsidies for fossil fuels could be breaches of international law. Polluters must stop emitting and must pay for the harms they have caused.”

Years In The Making

The ruling came after years of activism by vulnerable countries, especially those island nations that are facing the immediate threat posed by rising ocean levels. The case was led by the Pacific island nation of Vanuatu and backed by more than 130 countries. That group had requested the UN General Assembly to seek an advisory opinion form the ICJ in 2023. The ruling by the court this week represented a unanimous finding of all 15 members of the court. Al Jazeera said the opinion “will carry legal and political weight and is likely to determine the course of future climate action across the world, including whether polluters should be made to pay for their actions.”

In its reporting on the ICJ opinion, The Guardian said the court’s ruling means “a nation’s failure to take appropriate action to protect the climate system from greenhouse gas emissions, including through the production and consumption of fossil fuels, the granting of fossil fuel exploration licences or the provision of fossil fuel subsidies, ‘may constitute an international wrongful act which is attributable to that state.’”

The countries that are the largest emitters of greenhouse gases denied they had any obligations beyond what they agreed to in Paris in 2015, but the court rejected those arguments. If found that a range of other treaties applied, including the UN convention on the law of the sea, the Vienna convention for the protection of the ozone layer, the Montreal protocol, the convention on biological diversity, and the UN convention to combat desertification.

It ruled that customary international law also applied, which includes principles of sustainable development, common but differentiated responsibilities, equity, inter-generational equity, and the precautionary principle. States also had a duty to work together to protect the climate, the court said, because uncoordinated action “may not lead to a meaningful result.”

The judges of the International Court of Justice reviewed tens of thousands of pages of written submissions and heard two weeks of oral arguments in their quest to pull together different strands of environmental law into a definitive international standard.

Two Questions For International Court Of Justice

The two questions the UN asked the ICJ to consider were:

• What are states obliged to do under international law to protect the environment from greenhouse gas emissions now and for future generations?
• What are the consequences for states whose emissions cause harm, particularly to vulnerable island states?

Legal experts told Al Jazeera the ruling is a victory for small island and low-lying nations. “The ICJ rejected arguments by the likes of the US and UK that governments are bound only by climate treaties such as the Paris Agreement and did not have stronger obligations under international law,” Oxfam’s Dabi said. “We now have a powerful tool for holding countries to account for their obligations, especially in protecting the world’s most marginalized people and future generations of humanity.”

Curb Your Enthusiasm

After all the jubilation and celebration over the ruling, reality will set in. It is, after all, nothing more than an opinion, one that neither the court nor the UN has the power to enforce. It counts no more than the statement by UN Secretary General Antonio Guterres this week that the world has turned the corner on fossil fuels and is now well along on the path toward emissions-free energy.

If the UN really wanted to make a statement, it would dump the UN World Headquarters in New York City into the East River and find a new home. The US pays absolutely no attention to anything the UN says or does. Rather than follow the commitments it made to the world in Paris in 2015, it has twice withdrawn from those agreements, making a mockery of the whole process. Only nations that actively support the mission of the UN should be allowed as members, which would automatically exclude the US.

The practical effect of this ruling by the ICJ will be similar to that of the decision by the Montana Supreme Court. MAGA-soaked politicians in that state are now hell-bent on repealing the offending provision of the state’s constitution rather than altering their position on protecting the environment one iota. A court’s opinion is a lot like money — it is only worth what people believe its worth to be. A dollar bill or a bitcoin has no intrinsic value until people give it one.

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