The Landmark Advisory Opinion on Climate Change by the International Court of Justice
On July 23, the International Court of Justice (ICJ) issued an advisory opinion on the obligations of states concerning climate change. This decision is seen as a significant milestone for global environmental law and human rights. The initiative was spearheaded by Vanuatu and later supported by 132 countries. Following discussions at the United Nations General Assembly, a resolution was passed to refer the matter to the ICJ.
The UN General Assembly posed two critical questions in its referral: first, what are the legal obligations of states under international law to protect the climate system and other parts of the environment from greenhouse gas emissions? Second, what are the legal consequences for states that cause significant harm to the climate system through their actions or inactions?
This advisory opinion is historic for several reasons. It marks the first time the ICJ has addressed climate change directly. The proceedings attracted widespread global attention, with even non-parties to the Paris Agreement participating. The court’s unanimous response highlighted the severity of climate change, taking a comprehensive approach that considered all aspects of international law. The court emphasized that causing significant harm to the environment would constitute a breach of international law, requiring all states—regardless of their participation in the Paris Agreement—to act accordingly.
For Nepal, this moment was particularly significant. The country's bureaucratic processes were stirred into action by young lawyers and students, leading to the submission of a statement after receiving an extension. This allowed Nepal to present its case before the ICJ for the first time.
The ICJ examined the obligations of all states under the broader framework of international law. Key principles such as sustainable development, common but differentiated responsibilities, equity, intergenerational equity, and the precautionary principle guided the interpretation. The court analyzed various human activities, including greenhouse gas emissions, which have severe and far-reaching consequences. These impacts underscore the urgent and existential threat posed by climate change.
Three principles of customary international law were central to the court’s reasoning: the duty to prevent significant environmental harm, the duty to cooperate, and due diligence. The court emphasized that these norms should be interpreted consistently to form a unified set of obligations. Preventing harm to the climate system is a paramount duty recognized by both treaties and customary law. The standard of due diligence requires states to take all necessary measures to avoid activities within their jurisdiction that could cause significant damage to another state’s environment.
Cooperation is a core obligation under the UN Charter and climate change treaties. The court noted that trust and confidence are essential in international cooperation, governed by the principle of good faith. While states have some discretion in regulating emissions, this flexibility cannot excuse them from fulfilling their duties. Cooperation involves more than just financial or technological transfers; it demands continuous development and implementation of equitable climate policies based on the CBDRRC principle.
The court also analyzed the Paris Agreement in detail, highlighting its temperature goals as a binding obligation for states. Through nationally determined contributions, mitigation efforts, adaptation, and technology transfer, states must work towards achieving these objectives. The procedural and result-oriented nature of NDCs ensures that they reflect progressive ambition, even if their content remains discretionary.
In considering human rights, the court stressed that a healthy environment is fundamental to the enjoyment of basic rights such as health, adequate living standards, food, water, housing, privacy, and the rights of women, children, and indigenous peoples. The court concluded that securing a clean and sustainable environment is essential for upholding these rights.
Regarding the consequences of failing to meet obligations, the court addressed the concept of lex specialis, attributing responsibility based on international law. It clarified that climate change treaties do not override general rules on state responsibility. State actions, including fossil fuel production and subsidies, can be attributed to the state itself, constituting an internationally wrongful act.
Causation was assessed based on scientific evidence, allowing for the determination of sufficient links between actions and environmental harm. The court stated that failure to prevent significant harm is a violation of international law, necessitating reparation, including cessation, assurance, restitution, compensation, and satisfaction.
Overall, the ICJ’s advisory opinion represents a major step forward in climate accountability. It offers moral and legal support to developing nations affected by climate change. The universal nature of the law applies to all, empowering future generations to continue the dialogue. This landmark ruling sets the stage for a new era of international law, emphasizing the importance of climate action and accountability.