The World Court Clarifies Countries’ Climate Change Obligations and Their Legal Consequences under International Law

Following the July 23rd unanimous advisory opinion rendered by the International Court of Justice (ICJ), or World Court, in Obligations of States in respect of Climate Change as requested by the United Nations General Assembly, the Member States of the United Nations, including the United States, have authoritative guidance available regarding their international law obligations to ensure the protection of the climate system and other parts of the environment from anthropogenic greenhouse-gas (GHG) emissions for countries and for present and future generations. The UN’s top court also clarified the legal consequences under these obligations for countries where they, by their acts and omissions, have caused significant harm to the climate system and other parts of the environment, including a duty to pay compensation as a form of reparation in the case of proven damage.

Noting “the urgent and existential threat posed by climate change” as “scientifically established” and relying on the Intergovernmental Panel on Climate Change’s reports as “the best available science on the causes, nature and consequences of climate change,” the advisory opinion identifies the existing international law obligations of countries to ensure the protection of the climate system (i.e., the global system consisting of five major components: the atmosphere, the cryosphere, the lithosphere, and the biosphere and the interactions between them) and other parts of the environment from anthropogenic GHG emissions. The ruling also elucidates the content of these obligations, and it clarifies the relationship between obligations arising from various sources of international law, especially treaties and customary international law.

The advisory opinion identifies as the most directly relevant applicable law governing anthropogenic GHG emissions the UN Charter, climate change treaties (particularly the 1992 UN Framework Convention on Climate Change, the 1997 Kyoto Protocol, and the 2015 Paris Climate Agreement), the 1982 UN Convention on the Law of the Sea, and ozone layer and other environmental treaties. It analyzes relevant provisions included in these treaties. The ruling stresses the importance of countries’ obligations to mitigate, to adapt, and to cooperate under relevant treaties.

The relevant corpus of international law governing climate change also includes customary international law—particularly the duty to prevent significant harm to the environment by acting with due diligence and the duty to cooperate in good faith to prevent significant harm to the climate system and other parts of the environment—as well as international human rights law and principles such as sustainable development.

The advisory opinion emphasizes that all countries have a legal duty to cooperate to achieve concrete emission reduction targets. While this duty leaves countries some discretion in determining the means for regulating their GHG emissions, no country may use this discretion as an excuse to refrain from cooperating with the required level of due diligence. According to the UN court, the standard of due diligence required of countries in implementing all measures necessary to address activities producing GHG emissions is stringent.  While a country’s capabilities and available resources remain relevant factors, failure to meet this standard can trigger a country’s responsibility under international law.

As regards the legal consequences arising from countries’ acts and omissions causing significant harm to the climate system, the advisory opinion observes in relation to private actors that all countries have a legal obligation to regulate the activities of private actors under their jurisdiction as a matter of due diligence. A country’s failure to take the necessary regulatory and legislative measures to protect the climate system from GHG emissions—including through fossil fuel production/consumption, the provision of fossil fuel subsidies, and the granting of fossil fuel exploration licenses—may constitute an internationally wrongful act attributable to that country, triggering responsibility under international law.  

In summary, while the ICJ advisory opinion is directed at sovereign states and not private actors, the international law pronouncements in this ruling will have significant implications for ongoing and future climate change litigation and the regulation of GHG emissions by individual countries.

While ICJ advisory opinions formally are non-binding under the Court’s Statute, an advisory opinion derives its authority from the fact that it is the official pronouncement of the principal judicial organ of the United Nations. The legal reasoning underlying an advisory opinion reflects the Court’s authoritative views on important issues of international law.

Dentons continues to be a leader in the international law space and is here to assist with any international law litigation or compliance needs.