The International Court of Justice (ICJ) affirmed Wednesday obligations of states relating to climate change under treaties and customary law. The court emphasized that the severe and far-reaching climate change consequences are an “urgent and existential threat.”
The court affirmed that environmental treaties, climate change treaties, and customary law inform one another and are the sources of state obligations at international law. In the instance of the Paris Agreement, state parties consent to limiting the global average temperature increase to well below 1.5°C above pre-industrial levels. This commitment, alongside other provisions and the principle of common but differentiated responsibilities and respective capabilities, is the basis of the states’ obligations relating to climate change. These include the obligation of result to prepare, communicate, and maintain nationally determined contributions with due diligence, and the obligation to implement adaptation actions such as financial assistance, technology development, and capacity-building. Apart from the Paris Agreement, states must also observe the UN Framework Convention on Climate Change, the Kyoto Protocol, and other environmental treaties.
Countries that are not a state party to any climate change treaties or environmental treaties also owe duties relating to climate change under customary law. The court held that these non-party states remain obligated to take appropriate measures in assessing the risk of significant harm and exercise due diligence to avoid activities that cause significant damage to the environment of another state. Non-party states must also cooperate to protect the environment. One of such duties to cooperate includes regulating their greenhouse gas emissions.
In addition, the court reaffirmed that the protection of the environment is “a precondition for the enjoyment of human rights.” In other words, the states’ failure to mitigate the adverse effects of climate change can be a violation of international human rights law if the climate change consequence hinders the enjoyment of basic human rights to life, health, privacy, family and home, and equality. The court also affirmed that the right to a clean, healthy, and sustainable environment is essential for the enjoyment of human rights and is a basic human right in itself.
Every injured state may now claim reparation for the non-fulfilment of these obligations upon proof of harm and causation. The court ruled that the aforesaid obligations to protect the climate system and to prevent significant harm are erga omnes obligations. It means that even non-injured states may also invoke responsibilities of a wrongful state because the court deems these obligations owed to the international community as a whole, considering “the common interest in the protection of global environmental commons.”
Director General of the International Union for Conservation of Nature Dr Grethel Aguilar welcomed the decision, urging all countries to strengthen their commitments in protecting nature, delivering climate justice, and safeguarding the collective future.
This ruling represents another landmark development of international environmental law. Earlier on July 5, the Inter-American Court of Human Rights issued its opinion, reaffirming the legal obligations of American states to confront the climate crisis. UN experts also urged in May the Council of Europe to recognize the human right to a healthy environment. The impact of this ruling on the upcoming UN Climate Change Conference (COP 30) remains to be observed.
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