International Court of Justice Issues Landmark Climate Ruling
In an historic moment for international climate law, the International Court of Justice (ICJ) has issued a sweeping advisory opinion confirming that states have binding legal obligations to prevent environmental harm caused by climate change, including from fossil fuel production and subsidies.
Back in March 2023, the UN General Assembly voted to ask the ICJ to clarify the obligations of States in relation to climate change, following a request for an ‘advisory opinion’ led by Vanuatu and youth advocates from the Pacific Islands. The proceedings drew an unprecedented level of global engagement, with written submissions from 96 countries and 11 international organisations, the highest participation ever seen in a case before the Court.
According to the ICJ, advisory opinions: “carry great legal weight and moral authority. They are often an instrument of preventive diplomacy and have peace-keeping virtues. Advisory opinions also, in their way, contribute to the elucidation and development of international law and thereby to the strengthening of peaceful relations between States.”
On Wednesday, the ICJ released their landmark advisory opinion, marking the first time the UN’s top court has laid out, in unequivocal terms, that failure to act on climate change may result in legal responsibility and reparations.
Judge Iwasawa Yuji, President of the ICJ, stated that climate breakdown poses an “urgent existential threat,” with wide-reaching consequences for ecosystems and human rights. The Court’s ruling affirms that states must not only curb greenhouse gas emissions but also regulate activities that drive those emissions, such as supporting fossil fuel industries through subsidies or exploration licenses. The decision confirms that governments are legally required to regulate private sector climate impacts, not just public-sector emissions.
As ClientEarth explains, countries that have burned fossil fuels the longest and in the largest quantities now face greater duties under international law, both to rapidly reduce emissions and to assist nations suffering the worst climate impacts.
Professor Jorge Viñuales of the University of Cambridge, part of the legal team supporting Vanuatu and key member of the counsel team, said the opinion “opens a new front” in climate litigation, offering states a potential legal route to seek reparations for loss and damage. This concept has long been championed by developing nations but often dismissed by wealthier ones.
Equally significant is the Court’s recognition that a clean, healthy, and sustainable environment is foundational for human life and human rights protected by international law. Professor Viñuales comments that this marks the first time international law’s highest authority has linked climate inaction so explicitly to potential violations of human rights obligations, with previous resolutions from the Human Rights Council and UN General Assembly being insufficient.
The ICJ also set a clear legal standard for national climate commitments, requiring that states must aim for the “highest possible ambition” in their emissions reductions and implement these pledges in good faith. Falling short, especially in the face of scientific consensus around the 1.5°C target, may itself be considered a violation of international law.
In short, ClientEarth highlights how this decision gives judges around the world clear guidance, “that will likely shape climate cases for decades to come”. The decision also acts as a powerful advocacy tool for citizens to hold their governments to account and vice versa, hopefully empowers governments to push forward with ambitious plans to avert climate impacts and protect our human rights.
Nikki Reisch, Director of Climate and Energy Program at the Center for International Environmental Law, said, “This momentous ruling by the world’s highest court doesn’t just mark a turning point in international law, but a point of no return on the path toward climate justice and accountability.”
She continued, “No state is immune to climate impacts, and no state is above climate obligations. The Court rejected fossil fuel producers’ attempts to sweep their historical emissions under the rug and signaled the end of the era of impunity for big polluters. The message is clear: there is no carve-out for climate destruction under international law, and there is no legal or technical bar to holding states responsible for resulting harm.”
UN Secretary-General António Guterres commented, “I welcome that the ICJ has just made it very clear: all States are obligated under international law to protect the global climate system. This is victory for planet, for climate justice, and for the power of young people leading the way.”
Read the Advisory Opinion press release here
Read the Advisory Opinion summary here
