A Defining Moment for Climate Justice: What to Watch For in the ICJ Climate Ruling

1. What are States legally required to do under international law — across human rights law, the UN Charter, the Law of the Sea, international environmental law including as defined by the climate treaties, and beyond — to address climate change for both current and future generations?
2. What legal consequences do States face if they fail to meet these obligations, causing serious climate harm?

These questions strike at the heart of climate justice. Who bears responsibility for the climate crisis, and for what conduct? What is owed to those who have contributed the least to planet-warming emissions but are suffering the gravest impacts from climate harm – harm that can be traced to the policies and actions of specific states and corporations? 

This case is about more than just the level of ambition required from individual States in their future climate action. It is about reckoning with historical responsibility. It is impossible to effectively and equitably address the climate crisis without looking at its origins and drivers. Legal arguments presented by a majority of countries in the proceedings affirm a critical truth: Past emissions matter, and loss and damage already endured must be recognized and repaired — not as charity, but as legal obligation.  This means not only halting harmful practices, but also delivering climate reparations. 

Alongside the powerful climate advisory opinions from the International Tribunal for the Law of the Sea (ITLOS) and from the Inter-American Court of Human Rights (IACtHR), the ICJ’s ruling presents an unprecedented opportunity to make clear where the legal consensus lies on States’ climate obligations under international law. International legal principles dictate that the three international rulings be read coherently so as to harmonize States’ obligations under international law. Looking ahead, the African Court on Human and Peoples’ Rights has also been asked to weigh-in on climate-related legal obligations, deepening, from a regional perspective, the critical questions relating to States’ climate duties. In concert, these rulings have the transformative potential to reshape climate governance, diplomacy, and litigation for decades to come and to usher in a new era of climate accountability. 

6 Key Issues to Watch For in the ICJ Ruling

The sheer breadth of legal issues addressed in this case is significant, many of which recur in litigation, negotiations and national level legislative debates, revealing just how far-reaching its impact may be. Key legal flashpoints that have emerged throughout the proceedings serve as important indicators of what to watch for in the forthcoming ruling.

1. Beyond the Paris Agreement: The Scope and Source of States’ Legal Obligations on Climate Change

 Major polluters often try to avoid accountability by claiming that their duties on climate are limited to what is laid out in the UN climate agreements, and that those texts require very little. But climate treaties, like the UN Framework Convention on Climate Change, the Kyoto Protocol and the Paris Agreement, are not the only sources of States’ legal obligations to address the causes and consequences of the climate crisis. These agreements should help guide States’ actions, but they do not exhaustively — or exclusively — define State duties of care or what responsibilities they bear for preventing and remedying climate harm.  Recent climate advisory opinions by ITLOS and the IACtHR, as well as other landmark climate cases, make it clear: State’s climate obligations are not embedded just in climate-specific treaties, but also under broader norms of international law, including human rights law, the law of the sea, and general principles of international law.

Climate change is not just an environmental problem — it is  a global phenomenon of transversal nature affecting nearly every dimension of human existence, and ecological well-being. How the ICJ defines the full scope of States climate obligations will have far-reaching legal and practical significance.

2.  The Right to Remedy and Reparations

A key issue in the proceedings is the legal consequences for conduct that causes climate harm. The world’s biggest cumulative polluters attempted to limit their accountability before the Court. But an overwhelming majority of States urged the Court not to sweep history under the rug. They demanded that those whose actions and inaction over decades have brought the world to the brink be held to account, emphasizing the right to remedy and reparation — including measures that go beyond monetary compensation.

The Court’s conclusions  on the question of legal consequences will carry great weight, particularly because the issue has not been thoroughly addressed, let alone resolved, in law and policy to date. In this era of devastating and escalating climate harm, a clear ruling from the ICJ could establish a much stronger legal foundation for climate reparation — offering a crucial lifeline for nations and communities most affected by climate impacts.

3. Human Rights of Present and Future Generations

The climate crisis is widely recognized as the greatest threat to human rights in the 21st century. Both the European Court of Human Rights and the Inter-American Court of Human Rights have been clear and affirmative: the climate crisis is a human rights crisis. Under existing human rights obligations, States are required to act urgently and effectively —guided by the best available science — to prevent harm to people and the environment and to protect them from it.

A central debate in the ICJ proceedings was how strongly these human rights obligations should shape climate policy-making. Arguments delved deeply into the right to self-determination, the right to a healthy environment, and the rights of future generations. The Court’s analysis could strengthen the legal arguments and tools available to communities seeking to promote and defend their rights — and would help advance rights-based climate litigation around the world.

4. Preventive and Precautionary Principles

Under international law, States have longstanding duties not to cause or allow conduct within their territories that would foreseeably cause significant environmental harm to other States. States are also required to take concrete action to prevent such harm from occurring in the first place — by regulating and controlling activities that risk causing it.

These preventive and precautionary principles are central to substantive climate mitigation obligations. They are especially important for ensuring that new policies and technologies introduced as climate solutions do not themselves create risks to human rights or the environment. Recent climate advisory opinions from ITLOS and the IACtHR have strongly affirmed the importance of these principles in all climate responses. How the ICJ interprets and applies them will shape the legal framework for effective and meaningful climate action— and could strengthen the implementation of the climate agreements.

5. Equity and a Just Transition

In the climate context, the principles of equity and “common but differentiated responsibilities” mean that all countries share responsibility for addressing climate change, but their obligations vary based on their capacity and how much they have contributed to the crisis. While the principle of equity is a fundamental tenet of international law, the largest cumulative polluters have often challenged its relevance when defining individual States’ responsibility for both tackling the root causes of the climate emergency and responding to already occurring harms.

An adequate and meaningful interpretation of equity is a key to unlocking decisive progress. It paves the way for a just and rapid transition away from fossil fuels— without placing an unfair burden on countries that contributed the least to climate change. The Court now has an opportunity to break this longstanding impasse by making it clear, as a matter of law, that equity must guide global climate action.

6. Corporate Accountability and  Fossil Fuel Phaseout

Several States highlighted the duty to regulate corporations whose conduct harms the climate-destructive corporate conduct. Their legal arguments were grounded in established norms such as due diligence, the duty to prevent harm, human rights, and intergenerational equity.

Because fossil fuels are the overwhelming source of the greenhouse gas (GHG) emissions causing climate change and its devastating consequences, fossil fuel phase-out was a focal point—along with calls to end subsidies, enforce strict corporate regulation, and ensure accountability for emissions. Given the fossil fuel industry’s outsized role in driving climate change, the Court’s treatment of these issues could reinforce the  authority and duty of States to  confront corporate impunity.

There will be a reckoning in the ruling whether international law can confront its colonial roots, and the deeply entrenched inequalities that shape how climate devastation is experienced as human rights harm. 

The ICJ AO is not a theoretical legal exercise. The issues central to the case involve real and ongoing legal violations with profound consequences for Peoples and nations across all regions. The stakes could not be higher.

Why This Ruling Matters

Much like the IPCC defines the state-of-the-art science on climate change, the ICJ’s ruling could come to define the state of the law on climate change, creating a clear baseline against which to assess States’ actions (or inaction). The opinion will clarify what binding international law requires countries to do about climate change, providing a guidepost to measure whether States are meeting their obligations— or falling short.

ICJ opinions have shaped governmental policies and legal strategies in the past, contributing to the essential work of normative development and enforcement. Courts worldwide will look to this ICJ’s climate ruling as persuasive authority, shaping future judgments. The Court’s legal blueprint can also help break through political inertia at the national level, guiding the development of domestic laws and policies. 

Crucially, a strong and clear ruling from the ICJ could establish a new legal baseline for climate action in multilateral fora, playing a pivotal role in shaping outcomes at COP30 in Belém and beyond, with the potential to unlock stalled negotiations, strengthen demands for climate finance — including for loss and damage — and reinforce the need for action rooted in science. It is also expected to bolster climate-justice aligned positions relating to the plastics treaty negotiations, and developments relating to a fossil fuel non-proliferation treaty. By making clear that climate ambition must be grounded in legal obligation, the Court could signal the end of voluntary pledges across fora. 

The significance of this moment goes beyond legal doctrine. This case is not only about black letter law, emissions, and technical targets; it is about accountability and intergenerational justice. 

No matter what the final outcome is, these proceedings already represent a historic turning point. They are the result of deep collaboration, within and across regions, led by Vanuatu and many Global South countries, and a powerful campaign led by Pacific activists and youth campaigners worldwide. The unprecedented participation of States, and broad consensus on climate justice has reshaped what is possible in the realm of international law and how it works in practice. At the heart of this movement are Pacific youth and young leaders, forging a path toward a more inclusive, decolonial, and just multilateral order.

The legal clarity that the ICJ ruling provides must become a catalyst for real, tangible change: holding major polluters accountable, securing reparations for those harmed, and ensuring the law protects all of humanity and the earth we share, for present and future generations. 

The ICJ’s climate opinion could define a new era—where climate justice is not a distant aspiration, but a global mandate for the here and now. The world cannot afford more broken promises. This is the moment to make justice the law of the land. The path to a livable, just future runs through The Hague.