The ICJ’s Climate Advisory Opinion: The World Court Speaks, and Bangladesh Should Listen

How the case reached The Hague

It began, fittingly, with students. A campaign that started among Pacific islander law students grew into a diplomatic initiative led by Vanuatu, and in March 2023 the United Nations General Assembly — by consensus — asked the International Court of Justice two questions: what obligations do States have under international law to protect the climate system from greenhouse gas emissions, and what are the legal consequences for States which, by their acts or omissions, have caused significant harm to the climate system, particularly for small island developing States and for peoples and individuals affected?

The proceedings became the largest in the Court’s history, drawing written and oral participation from an unprecedented number of States and organisations. In July 2025, the Court delivered its opinion.

What the Court said

The opinion’s central message is that climate obligations are not confined to the climate treaties. States’ duties arise from the UN climate regime — the Framework Convention, the Kyoto Protocol and the Paris Agreement — but also from customary international law, including the long-established duty to prevent significant harm to the environment of other States, and from human rights law, since a clean, healthy and sustainable environment underpins the enjoyment of human rights. Obligations of conduct must be discharged with due diligence, and a State’s discretion over its national contributions is not unlimited.

On consequences, the Court confirmed that the ordinary law of State responsibility applies: a State whose wrongful acts or omissions cause significant climate harm may be required to cease the conduct, offer guarantees of non-repetition, and make reparation — including, where appropriate, compensation. The familiar objection that climate change has too many authors for causation ever to be established was addressed rather than avoided: multiple contributing States do not dissolve responsibility.

Facade of the United States Supreme Court building original

Why it matters here

Advisory opinions do not bind States as judgments do. But they carry great authority: they state what the law is, and courts — international and domestic — cite them accordingly. For Bangladesh, among the most climate-vulnerable nations on Earth, the opinion strengthens every negotiating position on loss and damage, supplies authoritative material for climate litigation at home and abroad, and reframes climate harm as a question of legal obligation rather than charity. Expect it to be quoted for a generation. A full-length analysis of the opinion’s implications for Bangladeshi law and policy will follow in our Legal Writing section.