In July 2025, the International Court of Justice (ICJ) issued an advisory opinion affirming that states have a legal obligation under international law to combat climate change. This opinion has been framed as a step forward for global climate action. Yet its interpretation also raises deeper questions about how international law engages with enduring inequalities forged through colonial extraction, dispossession, and racialized hierarchies and sustained through enduring global power structures.

At the heart of the advisory opinion lies the question of differentiation in climate mitigation: how responsibility for reducing greenhouse gas emissions should be distributed between countries with vastly different national circumstances. In addressing that question, the court gives greater practical weight to present-day capabilities than to historical responsibility, treating current capabilities and available resources as the main reference point for what they are expected to do.

This interpretative choice should be read in light of the way the advisory opinion request was brought before the court. The campaign for an advisory opinion was rooted in climate justice concerns, especially the vulnerability of small island and other low-emitting states. Yet the request was ultimately expressed in broad terms of obligations and legal consequences rather than as a direct invitation to apportion historical liability.

This broader framing made it possible for states with sharply different positions to support the request, but it did not prevent the court from clarifying how historical responsibility and present capabilities should interact in defining differentiated responsibilities today. The court’s decision to acknowledge historical responsibility while operationalizing differentiation mainly through present capabilities should therefore be understood as an interpretative choice and as a judicial intervention into the political compromise that made the request possible.

The court’s interpretation matters politically as much as legally. It narrows the terms on which equity can be argued and defended within the climate regime and risks hardening asymmetries that a more equitable international legal order should confront rather than endorse.

The Tension at the Heart of the Paris Agreement

The Paris Agreement reflects both approaches to differentiation. On the one hand, it requires each country’s nationally determined contribution (NDC) to represent a progression over time and to reflect its “highest possible ambition” in light of national circumstances (Article 4.2). This forward-looking logic encourages governments to strengthen climate policies as their capacities evolve.

On the other hand, the Paris Agreement is implemented in line with the principle of common but differentiated responsibilities and respective capabilities in light of different national circumstances (Article 2.2). This principle allows space to recognize that countries differ substantially in their historical contributions to climate change, economic resources, and ability to respond, even as they pursue a shared collective objective of limiting global warming.

In principle, these two ideas operate together, supporting stronger collective ambition while recognizing unequal responsibility and capacity. At the same time, they can pull in different directions as ambition pushes toward more uniform expectations while differentiation foregrounds unequal responsibility and capacity.

Bringing both approaches into the Paris Agreement was essential for its adoption. This compromise allowed parties with different priorities and circumstances to see their concerns reflected in a common framework while preserving room to interpret its provisions in ways that support their positions in ongoing negotiations over ambition, responsibility, and support.

The Court’s Reasoning

The ICJ reaffirmed the relevance of both approaches to differentiation but gives greater practical weight to present-day capabilities while leaving unclear how historical responsibility should operate in practice. It reaches this position by bringing climate change within states’ existing obligation under international law to prevent significant environmental harm (para. 279). This shifts the analysis to due diligence, asking not whether states prevented climate harm but whether they acted with sufficient care in trying to do so (para. 280).

In line with its established case law, the court treats due diligence as a flexible standard that depends on each state’s circumstances, including its capabilities and available resources (paras. 280, 290–292). The key issue remains how those circumstances are defined. The court recognizes that common but differentiated responsibilities and respective capabilities reflect both historical contributions to climate change and current capabilities (para. 148). Yet in applying that principle, it centers each state’s “specific situation” and “all the means at its disposal” while sidelining how historical factors—including historical responsibility for greenhouse gas emissions—would translate into differentiated mitigation responsibilities (para. 292).

This approach may provide a stronger legal basis for demanding higher ambition on mitigating climate change, particularly from high-emitting states with greater present-day economic and institutional capacity. But what are its implications for those least responsible for climate change?

Power Politics in Climate Negotiations

Although the ICJ’s reasoning may appear technical, it intersects with the politics of climate negotiations. Differences in cumulative emissions, economic structure, and vulnerability to climate impacts are central to how countries approach climate diplomacy. In a climate regime that depends on consensus, equity is therefore not simply a moral claim but a political condition for sustaining states’ commitment to collective climate action.

Although climate debates are often framed around the broad divide between the Global North and Global South, in practice negotiations unfold through shifting “negotiating blocs.” Blocs including Global North countries—such as the members of the European Union (EU)—generally frame stronger mitigation ambition around universality and present capabilities while arguing that responsibilities for finance, technology transfer, and capacity building should increasingly be shared with other higher-capacity countries.

In contrast, blocs representing wealthier Global South countries—particularly the Like-Minded Developing Countries—resist outcomes that prioritize prescriptive mitigation pathways such as a fossil-fuel phase-out over nationally determined approaches or that shift support obligations toward them.

Caught between these positions are countries that contribute very little to cumulative emissions but face the most immediate climate risks. Small island developing states (SIDS) and least developed countries (LDCs) urgently require rapid emissions reductions globally, alongside stronger support for adaptation and compensation for climate-related loss and damage.

How the ICJ’s Interpretation May Exacerbate Inequities

Framing differentiation primarily in terms of present capabilities may strengthen the legal language of climate ambition. But without confronting the unequal conditions in which states negotiate and implement climate commitments, there is little reason to assume this will translate into stronger action in practice; there are several reasons why it may instead deepen existing asymmetries and weaken perceptions of equity within the climate regime.

First, the court’s interpretation overlooks the considerable discretion powerful states retain in determining the ambition of their climate policies. At the 2025 UN Climate Change Conference (COP30), for example, a coalition of more than eighty countries sought to build on the advisory opinion by pushing for a roadmap to phase out fossil fuels. However, major fossil-fuel producers leveraged their economic and political influence to resist the proposal, ultimately succeeding in keeping any roadmap outside the COP30 decision text and shifting the issue into voluntary initiatives outside the formal negotiation process of the UN Framework Convention on Climate Change (UNFCCC). The First Conference on Transitioning Away from Fossil-Fuels, co-hosted by Colombia and the Netherlands and attended by over fifty countries, shows that such initiatives are gaining traction. But it also confirms that progress on a fossil-fuel phase-out is moving through parallel forums rather than the formal COP outcome.

Similarly, despite the Paris Agreement stating that “developed country parties” should “take the lead” in mitigation efforts (Article 4.4), countries like the US and the members of the EU have repeatedly exercised political discretion over their commitments, including by withdrawing from international agreements or prioritizing spending in other areas, particularly military expenditures, which reached $2.7 trillion in 2024 and are projected to rise to $4.7–$6.6 trillion by 2035 if current trends continue.

Second, and crucially, the advisory opinion risks presenting existing inequalities between states as neutral starting points, effectively shifting the baseline against which obligations are assessed under the international climate regime. By placing less emphasis on historical responsibility, the court’s reasoning disconnects climate debates from processes that shape not only responsibility for past emissions but also states’ financial, technological, and institutional capacities for responding to climate change today.

Its implications, however, extend beyond mitigation. If historical responsibility is given little practical role in differentiating states’ obligations, claims for adaptation finance, technology transfer, capacity building, redistribution, and compensation for loss and damage become harder to frame as matters of accountability rather than discretionary assistance. This helps explain why climate-vulnerable states have also pursued other, difficult avenues for securing support, including vulnerability-based finance metrics and reforms to lending terms that allow payment pauses after extreme weather events.

This sits uneasily with the institutional compromise on which the Paris Agreement rests. The agreement’s adoption depended on striking a balance between a common expectation of increasing ambition and differentiated provisions on support, finance, and means of implementation. Provisions such as Article 4(5) reflect this logic: they recognize that less-resourced states cannot be expected to pursue climate action on the same terms as wealthier states, particularly where mitigation and adaptation must be pursued alongside sustainable development, poverty eradication, and, in many contexts, the effects of conflict or instability.

In this sense, the court’s interpretation does not simply clarify legal obligations; it affects the distribution of leverage between states within the climate regime.

A Deeper Imbalance in Negotiation Dynamics

When historical responsibility plays a smaller role in differentiation, structural disparities in economic and political capacity remain firmly in place. This entrenches the dependency of negotiating blocs representing climate-vulnerable states as they are compelled to align strategically with more influential actors to secure their interests in negotiation outcomes.

On issues such as adaptation, means of implementation, and loss and damage, these blocs rely on arguments grounded in historical responsibility to press for finance and support from those most responsible for emissions. On mitigation, however, their acute climate vulnerability and limited contribution to global emissions make them dependent on securing rapid emissions reductions from major emitters, pushing them to draw on framings based on present capabilities and more universal mitigation commitments.

Meanwhile, more powerful blocs across the Global North–South divide mobilize these competing logics as part of their geopolitical competition around the low-carbon transition. Here, differentiation functions as a strategic tool to secure comparative advantage within the evolving climate regime: the Like-Minded Developing Countries invoke historical responsibility to sustain pressure on Global North countries to lead on mitigation and to provide finance and support, whereas Global North actors emphasise present capabilities to press other major emitters to increase their mitigation commitments.

In this context, the priorities of climate-vulnerable states are reduced to bargaining chips in wider disputes between more powerful actors as they seek to build the coalitions needed to secure outcomes within the UNFCCC’s consensus-based system.

Law, Power, and Climate Coloniality

The Colonial Matrix of Power
(adapted from Mignolo, 2007, 2010, 2011; Quijano, 2000).

To understand these risks more fully, it is useful to read the court’s reasoning through a political ecology lens grounded in climate coloniality. Such a reading allows us to recognize the advisory opinion not only as a legal intervention but as part of a wider struggle over power in climate governance.

Climate coloniality foregrounds how the court’s interpretation interacts with colonial histories of extraction, dispossession, and racial hierarchy that continue to structure climate politics today. It draws attention not only to unequal patterns of climate vulnerability but also to struggles over political authority: who gets to define responsibility, capacity, and legitimate climate action within the international climate regime.

The concept of the “colonial matrix of power” provides a framework for understanding how these dynamics are reproduced. It situates political authority within a wider structure of domination, showing how authority is sustained through its entanglement with economic control, knowledge production, and forms of subjectivity and social identity.

From this perspective, the ICJ’s interpretation is more than a technocratic clarification of legal obligations; it helps set the terms of political authority in climate governance: who can define responsibility, capacity, and legitimate climate action and whose account of equity gains institutional force. In this sense, it is part of the wider struggle over how power is distributed, legitimized, and reproduced within the international climate regime.

Rethinking Equity in Global Climate Governance

The ICJ’s advisory opinion strengthens international climate law by affirming that states have legal obligations to prevent climate harm and cooperate in addressing it. Yet its significance also lies in what it leaves unresolved. By acknowledging historical responsibility without explaining how it should shape differentiated obligations in practice, the court leaves one of the central equity questions in the climate regime legally underdeveloped. This gap is significant because the allocation of differentiated responsibilities is not only a legal question; it is also a site of political struggle.

The climate regime has long depended on a degree of ambiguity between historical responsibility and present capabilities, allowing states with divergent interests to remain within a shared framework. The request for the advisory opinion reflected this ambiguity: it gave the court room to clarify the role of historical responsibility but did not require it to decide how that basis should be weighed against present capabilities. Yet by giving greater practical weight to present capabilities while leaving historical responsibility without clear operative force, the advisory opinion strengthens one way of arguing about differentiation over the other.

For climate-vulnerable states, this creates a difficult tension: the opinion may strengthen demands for faster mitigation, but it does less to support the historical responsibility arguments on which claims for finance, adaptation, technology transfer, and loss and damage continue to depend.

A climate coloniality lens makes the broader stakes of this interpretative shift clearer. It shows that inequities in the international climate regime are not simply legal or technical problems; they are tied to broader structures of power that shape whose interests are prioritized, whose knowledge is treated as authoritative, and whose claims to justice become politically actionable.

From this perspective, the ICJ should not be understood as standing outside the political struggles that shape climate governance or as capable of providing purely objective legal clarification. Its interpretations are shaped by, and can help stabilize, the same asymmetries of power that structure the climate regime itself.

For scholars, advocates, states, and movements seeking climate justice, the task is therefore not simply to welcome legal clarification but to scrutinize the conditions under which it is produced and the inequalities it may leave intact. Without confronting these dynamics, international law’s promise of climate justice risks being absorbed into the very structures of climate coloniality it should help dismantle.