The World’s Highest Court Weighs in on Climate Responsibility

In a landmark development, the International Court of Justice (ICJ) is set to deliver an advisory opinion that could reshape global climate policy. This opinion, though not legally binding, will provide a powerful legal framework on the responsibilities of nations in the face of climate change and the consequences of failing to act.

The ICJ’s advisory opinion will address two central questions: what are the legal obligations of states under international law to prevent climate harm? and what are the legal consequences for countries that have caused significant environmental damage? These are questions that have been pressing for decades, especially for small island nations on the frontlines of climate change.

The campaign for this advisory opinion began in 2019, led by Vanuatu, one of the most vulnerable nations to climate impacts. Supported by 132 member states, including New Zealand and Australia, the request was formally made by the United Nations General Assembly in March 2023. Now, after over two years of public consultation, the world is watching closely as the ICJ prepares to deliver its findings.

The scope of this advisory opinion is broad. It will examine not only the UN’s climate change framework but also a range of international laws, including human rights, environmental, investment, and trade laws. This comprehensive approach may lead to a nuanced and integrated legal opinion on the responsibilities of states to protect both the environment and future generations.

One of the most significant aspects of this opinion will be its recognition of intergenerational responsibility. Recent climate-related court cases have highlighted the need to address not only the current climate crisis but also its long-term impacts on future generations. This is a shift that could have far-reaching implications for how nations plan and execute their climate policies.

Another key aspect is the potential for the ICJ to outline the consequences of inaction by states. This could provide a much-needed legal foundation for domestic climate litigation and policy discussions, pushing governments to take more ambitious steps toward emissions reductions.

Recent judicial developments offer a glimpse of where the ICJ might be heading. In June 2025, the Inter-American Court of Human Rights affirmed that states have a duty to prevent irreversible harm to the climate system, linking human rights directly to environmental protection. However, a contrasting ruling in Australia’s federal court dismissed a similar claim, stating that climate policy is a matter of core government responsibility and not subject to common law duties of care.

The ICJ’s opinion may bridge this divide or take a more definitive stance, offering clarity on the legal obligations of states. This is particularly timely as the next major global climate summit approaches in November, where nations will be expected to submit updated emissions reduction pledges.

For New Zealand, this moment is especially significant. The country has committed to ambitious climate targets, including net-zero emissions by 2050. However, current policies may not be sufficient to meet these goals. Transport and agricultural emissions remain major challenges, and recent decisions to lift offshore gas exploration bans have drawn criticism from environmental advocates.

If the ICJ affirms that states have binding legal obligations to prevent climate harm, New Zealand’s climate policies could face increased scrutiny. This could serve as a catalyst for more aggressive action, aligning the country’s commitments with international legal standards.

As the world waits for the ICJ’s advisory opinion, the stakes have never been higher. The outcome may not only shape the legal landscape of climate governance but also influence the trajectory of global climate action for decades to come.