“Will The Law Rise to Meet Its Highest Calling?” The Historic ICJ Climate Hearings on Climate Justice

In December 2024, the world’s highest court became the stage for what may be the “biggest case in human history.”   Over two weeks,  96 States from every region of the world as well as 11 International Organizations gathered at the International Court of Justice (ICJ) in The Hague to present arguments in its climate advisory opinion (AO) proceedings, on two defining questions,: What are States’ legal obligations to address climate change, and what are the legal consequences for failing to meet them? Parallel to the hearings youth campaigners from the Pacific and across the world led powerful mobilizations, creating space for frontline voices to directly demand justice for climate harm.  

At its core, this case is about accountability.  For too long, States most responsible for the climate crisis and its devastating impacts have evaded legal responsibility. But climate-vulnerable nations and their legal experts made their voices heard at the ICJ, urging the Court to affirm clear legal consequences for climate destruction. These legal proceedings could become a turning point for climate justice, and counter decades of political inertia. An ambitious advisory opinion could reshape global climate policy, reinforce human rights protections, and pave the way for major polluters to remedy and repair the damage they have caused. 

A Crossroad For Climate Justice 

To zoom in on the hearings: Tuvalu’s oral submission, emblematic of many climate-vulnerable States, was a sobering one. Despite producing less than 0.01% of GHG emissions, Tuvalu is expected to be the first country to be completely lost to climate-related sea level rise. In a struggle against erasure, Tuvaluans are even exploring a digital Nation initiative to recreate Tuvalu’s land, culture, and government in digital form. Highlighting the near-certain risk of existential harm to Tuvalu, their counsel forcefully argued for States’ right to survival, and people’s rights to self-determination, namely the right of peoples to determine their own fate.

During the hearings and in the face of existential stakes, a clear divide emerged: a few major contributors to the climate crisis, including the United States, the United Kingdom, Kuwait, Germany, and Russia, sought to evade their legal responsibility by downplaying obligations, overstating complexities, and ignoring historical emissions. Meanwhile, most nations and international organizations, led by climate-vulnerable Global South countries, pushed for a broader framework incorporating equity, historical responsibility, self-determination, and the human rights of present and future generations. 

Key Highlights From The Hearings: Inside And Outside The Courtroom

The Legal Issue at the Heart of the Proceedings

On the very first day, counsel for Vanuatu and the Melanesian Spearhead Group compellingly argued in their joint intervention that the conduct responsible for climate change, and its catastrophic consequences, is unlawful under multiple sources of customary and conventional international law, including, human rights law, law of the sea, as well as climate and environmental law. States engaging in such unlawful conduct, must then cease such conduct, guarantee non-repetition, and provide full reparation. A majority of interventions coalesced around this position, united in clarity and rigor.

Applicable Law

Central to oral arguments was the question: What law governs State duties in relation to climate change? 

The United States along with other big polluters argued that climate obligations were limited to legal duties under the climate treaties, in particular, the Paris Agreement, while a majority of States and international organizations, including Vanuatu, the Philippines, and the African Union, rightly advocated for drawing on the entire spectrum of relevant international law. The climate regime should inform State obligations, but it neither exhaustively nor exclusively defines States’ legal obligations to tackle the climate crisis.

Human Rights

Several nations, such as Spain, Samoa, the Philippines, Cameroon, Colombia, Albania, and Saint Vincent and the Grenadines ⎯ just to name a few ⎯ mounted a strong defense of human rights obligations. Notably, the right to self-determination, the right to a clean, healthy, and sustainable environment, as well as the rights of future generations, among other rights, were powerfully argued before the Court. Meanwhile, big polluters sought to deny or weaken their legal duties by rejecting or restricting the application of human rights treaty obligations to climate change. 

Preventive Obligations

The US and Australia, among other big polluters, argued that the duty to prevent transboundary harm does not apply to global greenhouse gas emissions or climate change, but rather is limited to narrow situations of transboundary pollution. But, as also interpreted by the ICJ itself, States have longstanding duties under international law, not to cause or allow conduct in their territories that would cause significant environmental harm to other States. Counsel for Vanuatu argued: 

“..if an isolated incident of transboundary pollution is unlawful, it is unthinkable that the ultimate form of pollution is not. It would be like accepting the tragic irony, famously noted by Raphael Lemkin, that murder is unlawful, but genocide is not.”

Legal Consequences for Climate Destructive Conduct

A flashpoint in the proceedings concerned the legal consequences of climate-destructive actions. Such consequences encompass cessation of harmful conduct, and provision of full reparations – restitution, compensation, and satisfaction. The world’s major polluters, such as the United States and Russia, attempted to erect legal barriers to establishing the basis for triggering legal consequences and were forcefully countered by many of the world’s most climate-vulnerable nations, including Fiji and Costa Rica. Calls for remedy and reparation went far beyond monetary compensation, including structural measures such as equitable fossil fuel phase-out; avoiding reliance on measures that may exacerbate harm, such as geoengineering;  eco-restoration; and debt cancellation. 

Confronting Structural Injustice

This “wicked” problem of climate change, as we deem it in the environmental world, is colonization on repeat. Shernell Hadaway, Counsel, Saint Vincent and Grenadines

The structural links between climate harm and systemic injustice made unequivocally clear in the oral proceedings were a reminder that the fight for climate justice is also a fight for equity and dignity. Multiple delegations, including the Cook Islands,  Marshall Islands, and Kenya, argued the importance of addressing structural drivers of the climate crisis, such as colonial pasts, as well as racial and gender injustice, while Palestine highlighted the critical issue of State responsibility for the impacts on climate caused by armed conflict and other military activities, including in situations of occupation. 

Inside the Courtroom and Beyond: A Clarion Call for Climate Justice

The unique elements of these proceedings lie both in unprecedented engagement of States and international organizations, a result of the substantive collaboration, within and across regions, led by Vanuatu and many Global South countries, as well as the accompanying campaign led by Pacific activists and youth campaigners worldwide. Many delegations appeared before the Court for the first time, with countries represented in many cases, not by well-known law firms or academics, as is often the norm, but by diverse national delegations composed of diplomats, national lawyers, youth campaigners as well as community and Indigenous leaders.

Small Island nations and other climate-vulnerable countries presented technically rigorous arguments, while also painting a vivid picture of their climate realities through videos, witness statements and resonant storytelling. Some delegations ceded time to youth leaders from the Pacific Island Students Fighting for Climate Change (PISFCC) and World’s Youth for Climate Justice (WYCJ) to speak directly to the Court, and they each issued powerful calls for climate justice.

Undoubtedly the ICJ proceedings were among the most inclusive in the history of the Court, creating a unique space for the infusion of alternative perspectives rooted in Indigenous and cultural practices, place-based knowledge, and lived experiences of people in Global South countries to inform international law —perspectives that are often overlooked by the Western-centric dominant forces behind international law. This ‘opening up’ of international law marks a shift where Global South countries, that have not historically been part of such processes, make up the majority, in what could prove to be transformative not just for the court’s final AO  but for the practice and development of international law for generations to come.

Meanwhile, outside the Courtroom, campaigners organized dynamic mobilizations, including a Peoples’ Assembly, an extraordinary testament to collective lived experiences, the outcome document of which was submitted to the Court ensuring peoples’ demands for climate justice were formally on the record. The youth-led civil society campaign also organized a series of other events — demonstrations, art exhibitions, museums, and cultural events — to support and complement the formal proceedings in an attempt to maximize inclusivity and participation. The use of technology via the Witness Stand campaign, online petitions, coupled with comprehensive social media and news coverage of the hearings, all creatively rendered legally-heavy proceedings relevant and accessible to a whole new audience. Perhaps the biggest reflection from these mobilizations is the fact that law and activism need not be separate silos. In the ICJ AO proceedings, meaningful activism effectively dismantled the traditional exclusivity and mystery surrounding legal processes. The journey of democratizing international law has now begun. 

By appearing before the ICJ, more than 90 States made clear their belief in the rule of law and the legitimacy of the ICJ.  The ICJ, emerging post World War II, on the heels of utter devastation, represents “the culmination of a long process of developing methods for the pacific settlement of international disputes…” In terms of institutional legitimacy, the Court has long occupied a preeminent position. 

At a time when international law and its institutions are deliberately being weakened, the forthcoming AO and its proceedings provide the world an opportunity to counter the growing trends of isolationism and rejection of multilateral cooperation, demonstrating how existing mechanisms and processes can be reimagined to address some of the biggest global challenges of our time. While geopolitics may currently be in flux, “[u]bridled hegemonic power” cannot be the way: the response must be to strengthen the rule of law and internationalism.

Looking Ahead: A Defining Moment for International Law

The ICJ’s advisory opinion is expected in 2025 and could provide a legal blueprint for holding major polluters accountable and affirming the right to remedy and reparations. 

Alongside the advisory opinion from the International Tribunal for the Law of the Sea and the forthcoming one from the Inter-American Court of Human Rights, the ICJ’s opinion presents an unprecedented opportunity to clarify States’ climate obligations under international law. The three opinions will need to be read together in alignment with the legal mandate to harmonize States’ duties under international law. Together, these opinions could reinforce the legal duty of States to rapidly phase out fossil fuels, protect human rights, and ensure reparations for communities already suffering from climate disasters. 

An ICJ advisory opinion ⎯ that can draw on all relevant sources of international law, and, in this instance, has such deep engagement from a multitude of States facing severe climate impacts⎯ provides an unmatched avenue to address the breadth and depth of issues at stake. As an authoritative interpretation of binding law,  the ICJ AO could provide critical guidance to States and courts, shaping future litigation,informing regional or cross-regional initiatives — for example, on sovereignty and sea level rise, or debt cancellation —  and national level policies. The AO is also expected to critically contribute to climate negotiations, as well as to developments in relation to the global plastics treaty and the fossil fuel non-proliferation treaty. 

The Broader Impact

Regardless of the final outcome, these hearings have already changed the landscape of climate law and justice. The overwhelming participation and the very alignment of Global South nations in the course of the ICJ climate advisory proceedings, as well as  the tremendous leadership of those most affected by the climate crisis, could be transformative, driving future negotiations, cases, and policy initiatives. The powerful solidarity on display holds the potential to challenge existing power dynamics and may contribute to ushering in a new era of multilateralism, one rooted in a decolonial vision of the rule of law, as well as public and planetary well-being.

The fight for climate justice is not just happening in courtrooms but in legislatures, negotiations, and our streets, led by movements demanding action. The ICJ hearings have ignited momentum, but the real work lies ahead: translating legal discourse into real-world action – and ensuring major polluters are held accountable. 

By Joie Chowdhury, Senior Attorney at the Center for International Environmental Law, and Vishal Prasad, Director of Pacific Islands Students Fighting Climate Change

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Read more : 

• Arguments to Watch For in the  Written Submissions 

• Oral Hearings During Climate Justice Proceedings at the ICJ

• Questions posed by the Judges to all delegations