11 September 2025
International Law’s Administrative Law Turn and the Paris Agreement
In the recent Advisory Opinion on States’ Obligations in respect of Climate Change, various remarks by the International Court of Justice (ICJ) lean into an increasingly “administrative” law turn in international law. In this blog post, we investigate this phenomenon by looking at the ways in which States’ preparation, communication, and maintenance of their Nationally Determined Contributions (NDCs) under the Paris Agreement are coming to be characterised by requirements or standards with a domestic administrative law tone. Continue reading >>
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09 September 2025
A Step Forward in Italian Climate Litigation
Climate litigation achieved an important milestone in Italy. In a landmark order on 18 July 2025, the Supreme Court of Cassation confirmed that Italian courts may assert jurisdiction over climate-related damages for the first time. The ruling opens the door to holding both public and private actors liable for climate inaction. Continue reading >>
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28 August 2025
Can Africa Still Drill?
While the ICJ found that any State suffering from climate change can bring charges against others for their contribution to climate change, the opinion does not distinguish between the obligations of developed and developing States (except where treaty law already imposes different obligations). African States and the African Union have continued to support fossil fuel development on the continent. In light of this advisory opinion, what obligations are imposed on developing States, like African States, to protect the climate, particularly regarding the further development of fossil fuel industries? Continue reading >>26 August 2025
Closing the Silences
At COP 30 in Belém, ministers will wrangle over how “sufficient” the new climate-finance goal must be, and whether “phase-down” of coal is a slogan or a legal trigger. In Brussels, the 2040 climate target faces the same test, while in Geneva, the WTO’s fossil-subsidy reform stalls over which tax breaks to cut. Read through a strict consent-only lens, and these are political choices. Read through the ICJ’s frame – science, equity, no-harm, precaution – they become legal ones: finance must be capable of delivering 1.5°C and repairing loss and damage, coal and subsidy policies must be plausibly 1.5°C-compatible, and the burden falls on governments to prove it. Continue reading >>
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26 August 2025
Klimaschutz in Karlsruhe 5.0
Vor kurzem ließen mehrere Pressemitteilungen deutscher Umweltverbände Verfassungsrechtler:innen aufhorchen. Die vom Bund für Umwelt und Naturschutz Deutschland (BUND), Greenpeace, Germanwatch, dem Solarenergie-Förderverein Deutschland und der Deutschen Umwelthilfe (DUH) im Sommer/Herbst 2023 eingereichten „Zukunftsklagen“ werden in Karlsruhe offenbar ernst genommen. Im weiteren Verfahren könnte auch das kürzlich ergangene Gutachten des Internationalen Gerichtshofs (IGH) zu völkerrechtlichen Verpflichtungen der Staaten mit Bezug zum Klimawandel eine wichtige Rolle spielen. Continue reading >>
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19 August 2025
Is Montevideo Sinking?
Following the ICJ’s opinion, only time will tell whether the Montevideo criteria are themselves “sinking,” and what might replace them. It remains doubtful whether sunken States could be sovereign equals to States with territory, as they would necessarily rely on the goodwill of their host State to cede jurisdiction to some degree. Even though the ICJ’s opinion is a big step forward (especially) for small island States, it cannot, by itself, preserve a State’s full sovereignty once its territory is submerged. Small island States have contributed the least to climate change, yet now face an existential threat. This unfair fate must be prevented. I Continue reading >>
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19 August 2025
Statehood in the Climate Crisis
In this blog post, we zero in on the part of the ICJ's climate advisory opinion that concerns statehood. Specifically, we analyze the ICJ’s restatement of the presumption of state continuity, examining both what the Court says and doesn’t say, and what the implications could be. We also consider the individual opinions that discuss statehood and add some brief reflections on the applicability of Article 1 of the Montevideo Convention on the Rights and Duties of States (Montevideo Convention) and on State extinction. Our analysis is preliminary, and certainly much ink will be spilled on the ICJ’s remarks going forward. Continue reading >>
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15 August 2025
When Custom Binds All States
The ICJ affirmed that States have binding customary obligations to prevent significant harm to the climate system and to cooperate in addressing the crisis. Rejecting arguments that climate treaties override these duties, the Court clarified that non-parties remain bound. While acknowledging law’s limits, the ICJ’s opinion provides a powerful legal foundation to guide climate negotiations, litigation, and collective action worldwide. Continue reading >>
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12 August 2025
A Panoply of Consequences?
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? Continue reading >>
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11 August 2025
Harmonizing Sources, Hardening Duties
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. Continue reading >>
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