The Current Column

A tool for turbulent times?

What the ICJ's climate ruling means in a fracturing global order

Bauer, Steffen / Reuben Makomere / Kennedy Mbeva
The Current Column (2026)

Bonn: German Institute of Development and Sustainability (IDOS), The Current Column of 20 July 2026

Bonn, 20 July 2026.One year after the ICJ's climate ruling – legally clear, yet politically contested – the Advisory Opinion should serve as a tool for international climate diplomacy, not a substitute.

This week marks the first anniversary of a remarkable ruling: on 23 July 2025, the International Court of Justice (ICJ) issued an Advisory Opinion (AO) on „Obligations of States in respect of Climate Change“. Strikingly, it coincided with the ten-year anniversary of the Paris Agreement, two milestones bookending a decade in which climate ambition has lagged even as the legal case for climate action has hardened. The apex court found that states must do their utmost to protect the climate system, including through international cooperation and by regulating private actors whose activities drive emissions, and regardless of whether they are party to the UNFCCC and its Paris Agreement. Underscoring its authority, the AO was endorsed on 20 May 2026 by a UN General Assembly (UNGA) resolution initiated by Vanuatu and hailed by Secretary-General Guterres as „a victory for our planet“.

Yet the AO struggles to gain traction beyond legal and climate-justice circles, as climate policy faces mounting pushback. That is short-sighted. Multilateral institutions are needed more than ever when geopolitics is increasingly shaping global cooperation. As international cooperation remains essential to deal with global challenges, an authoritative, unanimous opinion from the world's highest court should generate leverage for global climate action, even though it is non-binding and allows states to shape their own responses.

This is where a nuanced, rather than selective, reading matters. Reception of the Advisory Opinion differs sharply, not least across the North-South fault line that is still prevalent in international climate politics. Many developed countries welcomed it chiefly for reinforcing mitigation ambition and due diligence. Many developing countries, African states not least, read it through a wider lens of development, justice and historical responsibility. For them the question was never whether climate action is necessary, but how obligations reconcile with industrialisation, energy access and poverty reduction. This reflects a legitimate concern rather than a binary of climate laggards versus leaders.

The ICJ's own separate opinions mirror this tension. Some judges argued the Court missed a historic opportunity by favouring an abstract exposition of legal principles over the central question: what legal consequences follow for states whose acts have contributed disproportionately to climate change, and for small island and least developed states that have suffered the gravest harm? Others felt the Court engaged insufficiently with the principle of common but differentiated responsibilities and respective capabilities (CBDR-RC), treating it largely as an issue of equity rather than exploring remedies such as debt relief, technology transfer or climate reparations. This matters as climate governance intersects with trade and finance, including through carbon border adjustment mechanisms, conditional finance and mounting litigation risk narrowing developing countries' policy space even as they pursue just energy transitions. Some warn of a drift from CBDR-RC towards a de facto „common but shifted responsibility“, its burden falling hardest on those least responsible.

Still, the Court demonstrates a remarkable consensus: climate obligations exist. The differences rather reflect how contested the politics of implementation remain. Moreover, it signals that the so-called Global South is no longer merely a subject of international climate law but increasingly shaping it. A Pacific youth campaign and Vanuatu's diplomacy set the AO in motion; African, Pacific and Latin American states shaped its proceedings as well as the emerging landscape of climate litigation. As the global order rapidly evolves, this agency in shaping legal and diplomatic agendas will likely grow, not recede.

For international climate cooperation, the practical implication is that the Advisory Opinion should be best understood not as a substitute for diplomacy but as a welcome addition to its toolbox. States carry both legal and political obligations, and judicial and diplomatic tracks work better as complements than alternatives. As the law becomes clearer, the more challenging task – catching up politically – now falls to states themselves.

Three things could help. First, developed countries should read the separate opinions of the justices as seriously as the headline ruling, treating genuine Southern concerns over sovereignty as legitimate, not obstructive. Second, governments should use the AO to reinvigorate, not bypass, multilateral climate diplomacy, thus driving climate action while also advancing equity and justice. Third, the newly launched South-North Commission, co-chaired by former German Chancellor Olaf Scholz and former Costa Rican President Laura Chinchilla, should prioritise the AO on its emergent agenda. Indeed, it could emerge as a high-level champion that helps to translate the AO’s authority into equitable cooperation across geopolitical divides, thereby creating a visible counterweight to unwarranted climate policy pushback. Understood holistically and taken seriously, the AO could become a catalyst for equitable international climate cooperation and as such a rare point of convergence in a fracturing world order – but only if states, not only judges, decide to make it so in spite of geopolitical power politics.

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Steffen Bauer is a senior researcher in the research department “Environmental Governance” at the German Institute of Development and Sustainability (IDOS). 

Kennedy Mbeva is a research associate at the Centre for the Study of Existential Risk (CSER) at the University of Cambridge and co-convenor of the Taskforce on Climate Governance of the international Earth System Governance (ESG) Project. He is the lead author of “Africa’s Right to Development in a Climate-Constrained World”.

Reuben Makomere is a research associate at the University of Tasmania (UTAS) School of Law in Hobart, Australia and a research affiliate at the Centre for the Study of Existential Risk (CSER) at the University of Cambridge. He is a co-author of “Africa’s Right to Development in a Climate-Constrained World”.