Maria Antonia Tigre, Camille Martini, Miriam Cohen, Armando Rocha
Among the most significant – but underexplored – aspects of the ICJ’s climate advisory opinion is its treatment of reparations and remedies. This blog post unpacks the legal consequences outlined by the ICJ, examining what the opinion says – and does not say – about how climate-related harm should be remedied. At the heart of this analysis lies a central question: can the affirmation of legal responsibility, without clear guidance on the design of reparations, meaningfully advance climate justice?
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Margaretha Wewerinke-Singh
The ICJ’s advisory opinion on climate change may come to be remembered as the moment international law explicitly rose to the climate challenge. Yet, what the opinion offers is not a new edifice but a sturdier legal architecture. By advancing an “all of the above” approach to international law’s sources; by treating these sources as interlocking parts of a living legal system; and by recognizing erga omnes and erga omnes partes duties with concrete consequences for responsibility, the Court has given States, courts and litigants a legally rigorous, source‑sensitive map.
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Eva Baudichau
Despite mounting attention to the impacts of military activities and conflicts on climate mitigation and adaptation in recent years, the issue remains largely absent from international legal scrutiny. Therefore, the very fact that several States and organizations raised it during the advisory proceedings held last December left the few scholars and practitioners working on this issue hopeful. This post reviews how the issue of armed conflicts and military emissions was addressed during the ICJ advisory proceedings. Despite the ICJ’s silence, the post highlights a few interpretative openings that may have legal implications for the regulation of wartime climate harms and explores what the ICJ’s ruling means for the legal visibility and accountability of military emissions.
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Niklas S. Reetz
After the International Court of Justice (ICJ) issued its advisory opinion on Obligations of States in Respect of Climate Change, many observers were quick to conclude that it “[opens] the door to a cascade of lawsuits” (Politico). The opinion is indeed an important confirmation that the rules of State responsibility apply in the climate change context. In this post, I assess the ICJ’s treatment of State responsibility in light of the particularities of climate change, especially the plurality of States that contribute to, and suffer from, climate harm. The advisory opinion places trust in the capabilities and flexibility of the applicable rules, yet defers complex decisions on questions like causation to a case-by-case assessment.
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Jochen von Bernstorff, Ingo Venzke
Over the course of decades, law has primarily functioned to enable and support the extraction, production, and consumption of fossil energy. As a result, planetary destruction remains not only awfully lucrative but also, in many cases, legally protected. The substantive impact of the ICJ’s advisory opinion on climate change will depend largely on how effectively it contributes to dismantling the stronghold of fossil sovereignty. That tangled web of fossil-friendly laws has often obstructed or blunted progressive climate politics or any other interference with unsustainable, fossil-driven profit-making.
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Joe Udell, Floris Tan
The ICJ advisory opinion articulates very clearly States’ international obligations with respect to climate change. Its findings that States’ mitigation efforts must reflect their highest possible ambition, be capable of achieving the 1.5oC goal, and be fair and ambitious, determined through the application of CBDR-RC are momentous, as are its conclusions on remedies. Government framework litigation can serve to hold States to these obligations – just as plaintiffs have done for the past 10 years. Given the multitude of lawsuits pending against governments around the world.
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Antoine De Spiegeleir, Armando Rocha
The advisory opinion rendered by the International Court of Justice (ICJ) on 23 July 2025 marks a pivotal moment in the articulation of States’ obligations concerning climate change. While based on broader rules and principles of international law, the opinion foregrounded the United Nations Convention on the Law of the Sea (UNCLOS) as a key legal framework relevant to defining States’ climate obligations. As the ICJ itself stated, UNCLOS ‘forms part of the most directly relevant applicable law’ (para. 124). Thus, far from peripheral, the law of the sea emerged as a primary site for interpreting and enforcing States’ climate obligations under international law.
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Corina Heri
This summer has seen two major climate advisory opinions published – first from the Inter-American Court of Human Rights, and then from the International Court of Justice (ICJ). Both opinions address human rights law, embedding human rights in a broader overarching framework of international law that also includes international climate treaties and customary international law. But how do these opinions compare, and what room does the ICJ leave for continuing development of human rights standards by other relevant courts and treaty bodies?
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Antoine De Spiegeleir
Much of the commentary that has emerged so far, in this symposium and in seemingly every other corner of the internet, focuses on the legal content of the opinion: the articulation of States’ obligations under international law, the rejection of the lex specialis argument, and the recognition of the right to a healthy environment, inter many alia. Yet beyond the legal reasoning and doctrinal outcomes lies something else. The opinion is also an act of identity performance: a way for the ICJ to speak about itself.
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Jed Odermatt
The aim of this blog post is not to summarise the ICJ’s opinion or assess its overall relevance for international law. Instead, it draws attention to some of the issues that the ICJ did not address, or where it might have gone further, by providing more depth, precision, and guidance. By focusing on what the ICJ did not say, we can gain a better understanding of how it navigates its institutional constraints, political sensitivities, and the evolving terrain of international climate litigation.
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David R. Boyd
For the second time in a month, one of the world’s highest judicial authorities has issued an advisory opinion on the climate crisis that highlights the importance of the human right to a clean, healthy and sustainable environment. Echoing the Inter-American Court of Human Rights in its Advisory Opinion 32/25, on July 23, the International Court of Justice (ICJ) unanimously held that this right constitutes a binding norm of international law.
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Lena Riemer
One topic in the ICJ's advisory opinion on climate change has unfortunately garnered little attention: climate-induced displacement. The ICJ dedicates just one single, 105-word paragraph to this pressing issue. Still, this one seemingly modest paragraph may have profound implications for millions of people fleeing across borders due to climate change, potentially reshaping the legal landscape for those seeking protection and at least offering minimum guarantees against their removal to a place where they would be at risk.
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Maria Antonia Tigre, Maxim Bönnemann, Antoine De Spiegeleir
“An existential threat” – this is how the International Court of Justice (ICJ) characterized climate change in its long-awaited advisory opinion on the obligations of States with respect to climate change. In the most significant development in international climate law since the adoption of the Paris Agreement, the ICJ outlined numerous obligations that could significantly shape the contours of international environmental law and global climate governance.
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