State Inaction May Lead to Legal Liability
On 23 July 2025, the International Court of Justice (ICJ), the principal judicial organ of the United Nations, issued an advisory opinion confirming that states are not only politically but also legally accountable under international law for their actions — or inaction — in addressing climate change.
The opinion was issued in response to two questions submitted by the UN General Assembly in March 2023, following an initiative led by Vanuatu. The questions concerned the legal obligations of states to protect the climate system for present and future generations, and the legal consequences for states that fail to meet these obligations.
In its opinion, the ICJ emphasized that states have a duty to prevent significant environmental harm, and that this duty arises not only from multilateral treaties but also from customary international law.
Although the advisory opinion is not legally binding, it marks a pivotal reference point in international environmental law and adds a new dimension to the legal interpretation of state responsibility in the context of climate change.
Background and Development of the Advisory Opinion
The International Court of Justice’s advisory opinion dated 23 July 2025 stems from United Nations General Assembly Resolution 77/276, adopted on 29 March 2023. The resolution was initiated by Vanuatu—a Pacific Island nation facing existential threats due to rising sea levels—and supported by over 130 countries.
The General Assembly submitted two core legal questions to the Court:
- What are the obligations of states under international law to protect the climate system and other components of the environment from anthropogenic greenhouse gas emissions, for both present and future generations?
- What are the legal consequences for states that fail to meet these obligations, particularly for those countries most affected by the climate crisis?
The Court examined these questions through 12 days of public hearings, informed by written and oral submissions from 91 states, as well as several regional and international organizations. In its deliberations, the Court considered numerous key international instruments, including the UN Framework Convention on Climate Change (UNFCCC), the Kyoto Protocol, and the Paris Agreement.
The advisory opinion was delivered at the Peace Palace in The Hague, where ICJ President Judge Iwasawa Yuji read the decision in a public session. President Iwasawa described climate change as “an urgent and existential threat,” emphasizing that environmental harm affects not only natural ecosystems but also directly threatens human rights.
The Content of the Decision: Legal Basis and Consequences
In its advisory opinion, the International Court of Justice (ICJ) systematically evaluated the obligations of states in addressing climate change under international law. The Court grounded its opinion on three key legal sources: multilateral environmental agreements, customary international law, and human rights law.
a) Obligations Arising from Multilateral Agreements
Referring primarily to the United Nations Framework Convention on Climate Change (1992), the Kyoto Protocol (1997), and the Paris Agreement (2015), the Court identified the following state obligations:
- States are required to take appropriate measures to reduce greenhouse gas emissions and to adapt to climate change.
- Under the Paris Agreement, they must formulate, update, and implement Nationally Determined Contributions (NDCs) aimed at limiting the global temperature rise to 1.5°C.
- States also have a duty to cooperate, particularly in areas such as technology transfer, financial support, and capacity-building.
b) Obligations Under Customary International Law
The ICJ emphasized that the duty to prevent significant environmental harm does not rely solely on treaty law, but also forms part of customary international law. Key principles outlined include:
- States must exercise “due diligence” to prevent activities within their jurisdiction or control from causing serious environmental damage.
- The precautionary principle applies: the lack of absolute scientific certainty is not a valid excuse for failing to take preventive action.
- States are expected to engage in continuous and good faith cooperation to avoid environmental harm.
c) The Human Rights Dimension
Acknowledging the direct and indirect impact of the climate crisis on fundamental human rights, the Court held that:
- States must take necessary measures to protect the climate system as part of their positive obligations to uphold human rights.
- This obligation is particularly critical for vulnerable groups and for safeguarding the rights of future generations.
d) Legal Consequences
The ICJ clearly stated that non-compliance with these obligations may constitute an internationally wrongful act by a state. In such cases, the following legal consequences may apply:
- The responsible state must cease the wrongful act.
- It must provide assurances and guarantees of non-repetition.
- It may be required to offer full reparation to injured states, which could take the form of restitution, compensation, or satisfaction.
The Court explicitly declared:
“A state’s failure to comply with the obligations defined above constitutes an internationally wrongful act and entails legal responsibility for any resulting harm.”
Symbolic and Political Significance of the Decision
Although the advisory opinion issued by the International Court of Justice is not legally binding, it carries significant normative weight. In accordance with Article 96 of the UN Charter and Article 65 of the ICJ Statute, advisory opinions do not impose direct obligations on states. However, such opinions often play a critical role in shaping and interpreting international law.
The ICJ’s opinion of 23 July 2025 has the potential to become a landmark reference in the fields of environmental law and state responsibility. It is expected to be cited by a wide range of judicial bodies, from national high courts to regional human rights tribunals, including the European Court of Human Rights, the Inter-American Court of Human Rights, and the African Court on Human and Peoples’ Rights.
Furthermore, the opinion may influence the nearly 3,000 ongoing climate-related legal cases around the world. Its implications could be particularly relevant in areas such as the scope of legal responsibility, environmental harm reparations, and the review of national energy and environmental policies.
UN Secretary-General António Guterres reacted to the decision in a video message, describing it as:
“A landmark moment for climate justice. The Court has made it clear that all states have a duty to protect the climate system.”
Similarly, Ralph Regenvanu, Vanuatu’s Minister of Climate Change and one of the key figures behind the initiative, emphasized:
“This is not just our fight — it is the voice of future generations. This opinion will reshape the narrative on climate justice.”
Implications for Turkey
As of 2021, Turkey is a party to the Paris Agreement. It has announced a target of net-zero emissions by 2053 and submitted an updated Nationally Determined Contribution (NDC) in 2023 under the UN Framework Convention on Climate Change. In this submission, Turkey committed to reducing its greenhouse gas emissions by 41% by 2030, relative to a business-as-usual scenario. Accordingly, Turkey is already subject to many of the obligations outlined in the ICJ’s advisory opinion.
Although the ICJ opinion is not legally binding, it may influence how Turkey interprets and implements its climate-related obligations in both foreign and domestic legal frameworks. Key principles emphasized in the opinion — such as the duty to prevent environmental harm, due diligence, acting despite scientific uncertainty, and good-faith cooperation — may offer new interpretative avenues under both Turkish constitutional and administrative law.
Considering the recent rise in environmental lawsuits and civil society’s increasing legal activism in Turkey, it is likely that Turkish courts — particularly in the context of Article 56 of the Constitution (the right to live in a healthy and balanced environment) — may consider referencing the ICJ opinion as an element of international jurisprudence.
Moreover, the opinion could have indirect impacts on environmental impact assessment (EIA) procedures for Turkey’s energy, transport, and industrial investment projects. Evaluating, minimizing, and offsetting the climate impacts of such investments could increasingly be viewed not just as matters of environmental policy, but as components of compliance with international legal standards.
From Turkey’s perspective, the ICJ opinion underscores the importance of not only advancing climate diplomacy but also developing broad-based projects and expert advisory mechanisms that are grounded in the principle of sustainable development.
A Historic Wake-Up Call on Climate: States May Now Be Held Legally Accountable
The advisory opinion delivered by the International Court of Justice on 23 July 2025 sends a clear message: the climate crisis is no longer just a political debate — it is a legal responsibility under international law. The Court evaluated states’ duties to prevent environmental harm and to cooperate in good faith, based on both treaty law and customary international law.
While the opinion is not binding, its normative influence is likely to shape national and international legal systems for years to come. It is expected to have a direct impact on a growing number of climate lawsuits, as well as on the formulation of new energy policies and environmental regulations.
Above all, the ICJ’s opinion reminds the international community that in the face of escalating environmental destruction, states are accountable not only morally, but also legally.
