Essay by Eric Worrall

“States … have additional obligations to take the lead in combating climate change by limiting their greenhouse gas emissions …”

The press release;

If anyone has the patience, the full 133 page judgement (mostly in English) is available here (backup copy here).

From the advisory opinion press release + judgement;

…

The climate change treaties set forth binding obligations for States parties to ensure the protection of the climate system and other parts of the environment from anthropogenic greenhouse gas emissions. These obligations include the following:

(a) States parties to the United Nations Framework Convention on Climate Change have an obligation to adopt measures with a view to contributing to the mitigation of greenhouse gas emissions and adapting to climate change;

(b) States parties listed in Annex I to the United Nations Framework Convention on Climate Change have additional obligations to take the lead in combating climate change by limiting their greenhouse gas emissions and enhancing their greenhouse gas sinks and reservoirs;

(c) States parties to the United Nations Framework Convention on Climate Change have a duty to co-operate with each other in order to achieve the underlying objective of the Convention; (d) States parties to the Kyoto Protocol must comply with applicable provisions of the Protocol;

(e) States parties to the Paris Agreement have an obligation to act with due diligence in taking measures in accordance with their common but differentiated responsibilities and respective capabilities capable of making an adequate contribution to achieving the temperature goal set out in the Agreement;

(f) States parties to the Paris Agreement have an obligation to prepare, communicate and maintain successive and progressive nationally determined contributions which, inter alia, when taken together, are capable of achieving the temperature goal of limiting global warming to 1.5∞C above pre-industrial levels;

(g) States parties to the Paris Agreement have an obligation to pursue measures which are capable of achieving the objectives set out in their successive nationally determined contributions; and

(h) States parties to the Paris Agreement have obligations of adaptation and co-operation, including through technology and financial transfers, which must be performed in good faith.

– Customary international law sets forth obligations for States to ensure the protection of the climate system and other parts of the environment from anthropogenic greenhouse gas emissions. These obligations include the following:

(a) States have a duty to prevent significant harm to the environment by acting with due diligence and to use all means at their disposal to prevent activities carried out within their jurisdiction or control from causing significant harm to the climate system and other parts of the environment, in accordance with their common but differentiated responsibilities and respective capabilities;

(b) States have a duty to co-operate with each other in good faith to prevent significant harm to the climate system and other parts of the environment, which requires sustained and continuous forms of co-operation by States when taking measures to prevent such harm.

…

Read more: Same link as above

Despite the court claiming the judgement is advisory, the body of the judgement appears to claim that under the UN charter all members of the UN including the USA have an obligation to respect this ICJ judgement, due to customary respect for a rules the USA has not necessarily explicitly embraced.

b) Duty to co-operate for the protection of the environment 140. The duty to co-operate lies at the core of the Charter of the United Nations. Article 1 of the Charter commits States “[t]o achieve international co-operation in solving international problems of an economic, social, cultural, or humanitarian characterø. This obligation has been spelled out in the foundational “Declaration on Principles of International Law concerning Friendly Relations and Co-operation among States in accordance with the Charter of the United Nations (General Assembly resolution 2625 (XXV) of 24 October 1970) (hereinafter the “Declaration on Friendly Relations). The Court has held that “the adoption by States of this text affords an indication of their opinio juris as to customary international law (Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States of America), Merits, Judgment, I.C.J. Reports 1986, p. 101, para. 191). That observation also applies to the duty to co-operate in so far as it finds expression in many binding and non-binding instruments relating specifically to the environment. The duty to co-operate is a central obligation under the climate change treaties and other environmental treaties, as discussed below (see paragraphs 214-218 and 260-267). Other examples include Principle 24 of the Stockholm Declaration and Principle 7 of the Rio Declaration on Environment and Development (hereinafter the “Rio Declaration”), which both recognize co-operation as an essential element in the protection of the environment. In view of the related practice of States, the Court considers that the duty of States to co-operate for the protection of the environment is a rule whose customary character has been established (see Climate Change, Advisory Opinion, ITLOS Reports 2024, p. 110, para. 296; MOX Plant (Ireland v. United Kingdom), Provisional Measures, Order of 3 December 2001, ITLOS Reports 2001, p. 110, para. 82).

Read more: https://www.icj-cij.org/sites/default/files/case-related/187/187-20250723-adv-01-00-en.pdf

I’m not a legal expert, but the argument that customary law with respect to international relations carries weight appears to be weak, though not necessarily weak enough to have it immediately dismissed without lots of time and money.

The US Senate did ratify the UN Charter in 1945, though arguably the UN has since granted itself powers which were not part of the original charter. I don’t recall the senate ever ratifying the USA’s alleged climate obligations under that 1945 charter. The claim the USA has a climate obligation under a charter ratified by the US Senate long before the UN got involved in the climate game seems a stretch.

Perhaps the “customary character” argument that states have a duty of compliance is a reference to the acquiescence of previous US administrations to unratified UN extensions of authority. If this is correct, that would make the ICJ advisory an assertion that the USA should shut up and do what they are told.

Obviously this ICJ ruling provides a lot of scope for mischief by NGOs and state governors who disagree with President Trump’s climate policies. I can see this ICJ ruling making a lot of lawyers rich.

Interestingly there has been a recent bump in Lithium prices, from around $8.50 / lb in late June to around $10 / lb today, though the explanations I’ve read claim this is due to a global cleardown of excess inventory rather than speculation the ICJ ruling might boost demand for EVs.