Are All International Climate Obligations Erga Omnes?

Executive Summary

On 5 August 2026, the Centre for International Law (CIL), National University of Singapore convened a webinar on “Are All International Climate Obligations Erga Omnes?”

Moderated by Conrado M. Cornelius (Research Associate, Climate Law and Policy at CIL), the webinar featured Dr Priya Urs, Junior Research Fellow in Law at St John’s College, University of Oxford and Dr Craig Eggett, Associate Professor of International Law at Maastricht University.

The webinar examined whether, and to what extent, international climate obligations may be characterised as obligations erga omnes, meaning obligations owed to the international community as a whole, or as obligations erga omnes partes, meaning obligations owed to all parties to a particular multilateral treaty.

Key themes included:

• the uncertainty surrounding the legal test for identifying erga omnes obligations;
• the relevance of the no-harm rule and due diligence;
• the role of non-injured states in invoking responsibility; and
• the difficulty of applying traditional remedies to cumulative and irreversible climate harm.

Thank you to the distinguished speakers for such a thoughtful and timely discussion.