International Court of Justice, ICJ, climate change, treaty law, customary international law, United Nations General Assembly, Advisory Opinion, climate obligations, universal responsibility
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Abstract
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Abstract
The International Court of Justice clarifies the relationship between treaty and customary international law in addressing climate change, emphasizing their complementarity and universal applicability.
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[...] It thus establishes a universal level of responsibility in the field of climate. A universal and evolving scope of customary obligations - According to the ICJ, 'customary obligations are the same for all States whether a State is or is not a party to the treaties related to climate change'. - From then on, even a non-signatory State to a treaty must respect its customary obligations from the moment its practice conforms to it. - This affirmation consecrates the truly universal scope of custom, which goes beyond the conventional framework. [...]
[...] International Court of Justice July 2025, United Nations General Assembly, Advisory Opinion - How does the International Court of Justice articulate the obligations arising from treaties and those of customary international law in the matter of climate? - Detailed Plan Treaties and customs: a complementarity asserted Two distinct sources meant to be reconciled - The ICJ recalls that the rules coming from treaties and customary international law 'retain a distinct existence', but also emphasizes that they are both sources of international law. [...]
[...] - Multilateral agreements therefore participate in the consolidation and evolution of customary principles. Some of them 'develop under the influence of a treaty' conventional law is susceptible of enriching/specifying custom. - Customary rules, on the other hand, offer a general framework for interpretation that sheds light on the scope of conventional provisions. II) The autonomy and universal scope of customary obligations Of independent customary obligations from conventional engagements - The Court affirms the complementarity between the two sources but also recalls their autonomy. [...]
