The hearings, taking place at The Hague from December 2 to 13, will lead to an advisory opinion expected in 2025. The proceedings are especially significant for small island states, which have long pushed for this opinion, coming just a week after developing countries criticized a COP29 deal that promised $300 billion annually in climate finance by 2035 as grossly insufficient.
Why the ICJ Is Being Asked for an Opinion
The call for an advisory opinion stems from an effort to create a stronger legal framework for accountability in climate action. Small Island Developing States (SIDS) have spearheaded the push, with the idea first proposed by law students in Fiji five years ago. Vanuatu took the lead in rallying support, successfully pressuring the UN General Assembly to seek an opinion from the ICJ on states' obligations in relation to climate change.
The court will address two key questions: What are states' legal duties to protect the climate, and what are the legal consequences if they fail in this duty, causing significant harm?
Before the hearings began, the UN's Intergovernmental Panel on Climate Change briefed the judges on the science behind climate change.
Although the ICJ's advisory opinion won't be legally binding, its political and legal significance will be immense. It could ground climate action in the rule of law, holding countries accountable for failing to meet their climate commitments. This opinion may also influence climate litigation globally, including lawsuits where small island states seek compensation from developed nations for historical climate damage.
The Need for an Advisory Opinion
Vanuatu, one of the nations most affected by climate change, emphasized that the outcome of the ICJ proceedings will have long-lasting effects on the survival of nations. Vanuatu's Special Envoy for Climate Change, Ralph Regenvanu, noted that despite the Paris Agreement's adoption seven years ago, small island states like Vanuatu continue to face climate-induced losses and damages with insufficient action from major emitters.
Regenvanu stressed that SIDS contribute only a small fraction of global emissions but are disproportionately impacted by climate change. He argued that the lack of progress in lowering emissions calls for urgent legal action to enforce accountability.
Could This Be the Biggest Legal Case in Human History?
The ICJ hearing has seen unprecedented participation, with 98 states and 12 international organizations involved—many of them first-time participants in such proceedings. A total of 91 written statements and 62 additional comments have been submitted, marking the most extensive participation in ICJ hearings to date. According to Margaretha Wewerinke-Singh, legal counsel for Vanuatu, this case could be the largest legal case in human history, not just in terms of participation, but also in terms of its substance.
What makes these hearings historic is that they deal with real, current impacts of climate change—disappearing territories, destroyed livelihoods, and human rights violations. The actions causing these violations have often been falsely regarded as lawful.
A Trio of Historic Legal Opinions
The ICJ case is part of a broader series of legal actions addressing climate change. Earlier this year, the International Tribunal for the Law of the Sea confirmed that countries must take action to combat marine pollution caused by climate change. In 2025, the Inter-American Court of Human Rights is expected to release its advisory opinion on climate-related human rights issues.