Published On: December 12th 2025
Authored By: Abhiraj Verma
Dr. B.R. Ambedkar National Law University, Sonepat
Introduction
Climate change represents one of the most pressing challenges of our time, demanding urgent legal responses that adequately address both mitigation and adaptation while ensuring environmental justice. The International Court of Justice (ICJ) advisory opinion of July 23, 2025, on the Obligations of States in Respect of Climate Change, marks a watershed moment in international environmental law, definitively establishing that states have legally binding obligations under international law to address climate change. This landmark ruling, coupled with evolving domestic jurisprudence worldwide, has fundamentally transformed the legal landscape surrounding climate action and environmental justice.
Environmental justice, at its core, seeks to ensure the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to environmental laws, regulations, and policies. In the climate context, this principle becomes particularly salient as the impacts of climate change disproportionately affect vulnerable populations, developing countries, and future generations who bear the least responsibility for historical greenhouse gas emissions. The convergence of climate science, international law, and human rights frameworks has created new pathways for holding states accountable for their climate obligations while promoting equitable solutions.
Legal Foundations of State Obligations in Climate Change
- International Treaty Framework
The legal architecture governing state obligations in climate change is built upon a complex web of international treaties, with the United Nations Framework Convention on Climate Change (UNFCCC)[1], the Kyoto Protocol[2], and the Paris Agreement[3] forming the cornerstone of the global climate regime. The ICJ’s 2025 advisory opinion has clarified that these treaties create binding legal obligations for states, rejecting arguments by some high-emitting countries that climate treaties are merely aspirational or that broader international law does not apply to climate issues.
Under the Paris Agreement, states have binding obligations to prepare, communicate, and maintain successive Nationally Determined Contributions (NDCs) that represent a progression beyond the previous one and reflect the highest possible ambition. The ICJ emphasized that the implementation of NDCs through mitigation measures constitutes an international obligation of conduct, subject to a “stringent” due diligence standard that limits states’ discretion in preparing their NDCs. This interpretation transforms what were previously considered discretionary national commitments into legally enforceable international obligations.
The Court further established that the Paris Agreement’s temperature goal of limiting warming to 1.5°C above pre-industrial levels is legally binding, not merely aspirational. This determination carries profound implications for state accountability, as it provides a clear benchmark against which to assess compliance with international climate obligations.
- Customary International Law Obligations
Beyond treaty law, the ICJ confirmed that customary international law imposes binding obligations on states to address climate change, even for non-parties to climate treaties. The Court identified several key customary obligations:
The no-harm principle requires states to prevent significant transboundary environmental harm, including climate damage caused by greenhouse gas emissions. This principle, rooted in the 1972 Stockholm Declaration[4] and confirmed in numerous international cases, establishes that states must exercise due diligence to prevent activities within their jurisdiction from causing significant harm to the climate system.
The duty of cooperation mandates that states work together in good faith to prevent significant harm to the climate system, requiring “sustained and continuous forms of cooperation” in taking preventive measures. This obligation reflects the global nature of climate change and the need for coordinated international action.
The precautionary principle requires states to take preventive measures even in the face of scientific uncertainty, provided there are threats of serious or irreversible damage. The UNFCCC explicitly incorporates this principle, stating that “lack of full scientific certainty should not be used as a reason for postponing such measures.
- Human Rights Obligations
The ICJ advisory opinion also recognized that human rights law applies in the climate context, affirming that states must take human rights into account when implementing their climate obligations. The Court acknowledged that climate change can significantly impair the enjoyment of numerous human rights, including:
- The right to life
- The right to a clean, healthy, and sustainable environment
- The right to health
- The right to an adequate standard of living
- The rights of women, children, and indigenous peoples
This human rights dimension adds another layer of legal obligation, as states must ensure that their climate policies protect and promote human rights, particularly for vulnerable populations most affected by climate impacts.
Due Diligence and Standards of Conduct
- The Stringent Standard
The ICJ established that climate change obligations are subject to a stringent due diligence standard, significantly more demanding than ordinary due diligence requirements. This heightened standard reflects the extreme gravity and urgency of the climate crisis, with the Court noting that climate change poses an existential problem of planetary proportions.
Due diligence in the climate context requires states to use all means at their disposal to prevent activities within their jurisdiction from causing significant harm to the climate system. This includes the obligation to regulate private actors’ emissions, establish appropriate regulatory frameworks, and implement effective enforcement mechanisms.
The stringent standard means that states must demonstrate they are doing their utmost in addressing climate change. This objective standard leaves little room for states to claim discretionary policy space in meeting their climate obligations, particularly regarding emission reduction targets and regulatory measures.
- Regulatory Obligations
States have a clear duty to regulate private sector activities that contribute to greenhouse gas emissions. The ICJ emphasized that failure to regulate emissions-intensive activities, including fossil fuel production, subsidization, and licensing, could constitute an internationally wrongful act. This regulatory due diligence extends to:
- Establishing and enforcing emission reduction targets
- Implementing comprehensive regulatory frameworks for high-emitting sectors
- Phasing out fossil fuel subsidies and exploration licenses
- Ensuring corporate accountability for climate impacts
- Monitoring and reporting on emission reductions
Erga Omnes Obligations and Universal Standing
- Nature of Erga Omnes Obligations
A groundbreaking aspect of the ICJ advisory opinion was its determination that states’ climate obligations under both customary international law and climate treaties have the character of erga omnes obligations owed to the international community as a whole. This characterization fundamentally changes the enforcement landscape for climate law. The Court found that climate change[5] is a common concern of humankind, and therefore all states have a legal interest in ensuring compliance with climate obligations. This means that any state, not just those directly injured by climate harm, can invoke the responsibility of other states for failing to meet their climate commitments.
- Implications for Climate Litigation
The erga omnes characterization opens new avenues for climate litigation and state-to-state disputes. States can now bring cases against high-emitting countries based on their failure to meet climate obligations, even without demonstrating direct injury. This development could lead to a cascade of lawsuits as predicted by various observers.
The universal standing granted by erga omnes obligations also strengthens the position of particularly vulnerable states, including small island developing states, in holding major emitters accountable for inadequate climate action.
Environmental Justice Principles in Climate Law
- Distributive Justice and Common but Differentiated Responsibilities
The principle of Common but Differentiated Responsibilities and Respective Capabilities (CBDR-RC) remains fundamental to climate justice. This principle recognizes that while all states have obligations to address climate change, developed countries bear greater responsibility due to their historical contributions to greenhouse gas emissions and superior economic and technological capabilities.
- The CBDR-RC principle operates across multiple dimensions of climate action:
Mitigation responsibilities: Developed countries must take the lead in reducing emissions and provide support to developing countries for their mitigation efforts.
Financial obligations: Developed countries have commitments to provide climate finance for mitigation and adaptation in developing countries.
Technology transfer: Advanced economies must facilitate access to clean technologies for developing nations.
Capacity building: Support for institutional and technical capacity development in developing countries.
- Procedural Justice and Participation Rights
Environmental justice requires meaningful participation of all affected communities in climate decision-making processes. The principles of environmental justice emphasize:
Fair treatment: No group should bear a disproportionate share of environmental burdens or climate impacts.
Meaningful involvement: All people have the right to participate as equal partners in decisions affecting their environmental health.
Access to information: Communities must have access to information about climate risks and policies affecting them.
Access to justice: Effective remedies must be available for climate-related harms.
- Intergenerational Equity
Climate justice encompasses obligations to future generations, reflected in the concept of sustainable development and intergenerational equity. The Stockholm Declaration’s Principle 1[6] establishes that humans bear a solemn responsibility to protect and improve the environment for present and future generations.
This intergenerational dimension is particularly relevant to climate change given the long-term nature of both greenhouse gas emissions and climate impacts. States must consider the rights and interests of future generations in their climate policies, ensuring that present actions do not compromise the ability of future generations to meet their own needs.
Adaptation as Legal Obligation
- Binding Adaptation Duties
The ICJ advisory opinion represents a major shift in how adaptation is perceived under international law, establishing that states have binding legal obligations to implement adaptation measures. Previously often treated as optional or secondary to mitigation, adaptation is now on equal legal footing with emission reduction requirements.
States’ adaptation obligations include:
- Conducting climate risk assessments and vulnerability analyses
- Developing and implementing national adaptation plans
- Integrating climate considerations into all relevant policies and sectors
- Protecting vulnerable populations and ecosystems
- Providing adaptation finance and support to developing countries
- Human Rights Dimensions of Adaptation
The Court emphasized that inadequate adaptation measures can constitute violations of human rights obligations. States must ensure that adaptation efforts protect the rights of all people, with particular attention to vulnerable groups including women, children, indigenous peoples, and the poor.
This human rights framing of adaptation obligations provides additional legal grounds for holding states accountable for failing to protect their populations from foreseeable climate impacts.
Loss and Damage and Reparative Justice
- Legal Framework for Loss and Damage
The emergence of loss and damage as a distinct pillar of climate action addresses unavoidable climate impacts that cannot be prevented through mitigation or managed through adaptation. While the Paris Agreement explicitly states that loss and damage provisions “do not involve liability or compensation,” the broader international law framework may provide alternative pathways for reparative justice. The Warsaw International Mechanism for Loss and Damage[7], established under the UNFCCC, provides a framework for addressing loss and damage through:
- Risk assessment and management approaches
- Comprehensive risk management strategies
- Facilitating the mobilization of support
- Enhancing action and coordination among relevant stakeholders
- Climate Finance and Justice
The establishment of the Loss and Damage Fund at COP27[8] represents a significant step toward climate justice, although its voluntary contribution basis falls short of the binding compensation mechanisms advocated by vulnerable countries. Climate justice advocates argue for mandatory, adequate, and additional public funding based on principles of equity and common but differentiated responsibilities.
Key principles for just climate finance include:
Adequacy: Finance must be sufficient to meet the scale of climate impacts and needs.
Accessibility: Funding mechanisms must be accessible to those most in need, including local communities.
Additionality: Climate finance should be additional to existing development aid commitments.
Accountability: Clear mechanisms for monitoring and ensuring effective use of climate finance.
State Responsibility and Legal Consequences
- Attribution and Causation
The ICJ provided detailed guidance on how state responsibility applies in the climate context, addressing complex questions of attribution and causation. The Court distinguished between scientific attribution (assessing causal contributions to climate change) and legal attribution (imputing conduct to states).
States can be held responsible for climate harm through:
- Direct state actions: Government policies and decisions that increase emissions
- Regulatory failures: Inadequate regulation of private sector emissions
- Omissions: Failure to take required preventive measures
- Remedial Obligations
When states breach their climate obligations, they incur international responsibility and must provide full reparation for injury caused. Available remedies include:
Cessation: States must stop wrongful conduct that breaches climate obligations.
Non-repetition: Guarantees that similar breaches will not recur, including through legal and institutional reforms.
Restitution: Restoring the situation that would have existed but for the wrongful act.
Compensation: Financial compensation for damage that cannot be repaired through restitution.
Satisfaction: Acknowledgment of the breach, expressions of regret, or other forms of satisfaction.
Domestic Implementation and Constitutional Rights
- Constitutional Environmental Rights
Many national constitutions now recognize the right to a clean and healthy environment as a fundamental right. In India, for example, the Supreme Court has interpreted Article 21[9] (right to life) to include the right to a pollution-free environment.
Key constitutional developments include:
- Recognition of environmental rights as fundamental rights
- State duties to protect and improve the environment
- Citizens’ fundamental duties regarding environmental protection
- Procedural rights including access to information and participation
- Judicial Activism and Environmental Protection
Courts worldwide have played crucial roles in expanding environmental rights and holding governments accountable for climate inaction. Notable developments include:
Rights of nature: Recognition of legal rights for natural entities like rivers, forests, and ecosystems.
Future generations standing: Courts allowing representation of future generations’ interests in climate cases.
Urgency of climate action: Judicial recognition of the urgent nature of climate threats requiring immediate action.
Government framework litigation: Cases challenging the adequacy of national climate frameworks and policies.
Sectoral Applications and REDD+
- Forest-Based Climate Solutions
The Reducing Emissions from Deforestation and Forest Degradation (REDD+)[10] mechanism exemplifies the integration of climate mitigation with environmental justice concerns. REDD+ legal frameworks must address multiple cross-cutting issues:
Indigenous and community rights: Recognition of traditional land tenure and forest management systems.
Benefit-sharing mechanisms: Equitable distribution of REDD+ benefits to forest-dependent communities.
Safeguards implementation: Ensuring REDD+ activities do not harm biodiversity or community rights.
Governance requirements: Transparent and accountable institutions for REDD+ implementation.
- Integration with Sustainable Development
Effective REDD+ implementation requires integration with broader sustainable development strategies, addressing economic, environmental, and social dimensions. Legal frameworks must ensure coherence between forest, agricultural, and land-use policies while promoting participatory processes at the national level.
Future Challenges and Opportunities
- Strengthening International Cooperation
The ICJ advisory opinion provides a strong foundation for enhanced international cooperation on climate action. Key areas for future development include:
- Strengthening compliance mechanisms for climate treaties
- Developing more robust international institutions for climate governance
- Enhancing technology transfer and capacity building mechanisms
- Expanding climate finance commitments and delivery
- Emerging Legal Doctrines
Several legal doctrines are evolving to address climate challenges:
Planetary boundaries framework: Legal recognition of Earth system limits and safe operating spaces.
Rights of future generations: Enhanced legal standing and representation for intergenerational interests.
Corporate climate accountability: Expanding legal obligations for private sector actors.
Climate migration and displacement: Legal frameworks for climate-induced mobility.
Conclusion
The International Court of Justice’s advisory opinion on climate change obligations represents a transformative moment in international environmental law, establishing clear legal duties for states while opening new avenues for climate litigation and accountability. The convergence of treaty law, customary international law, and human rights frameworks creates a robust legal architecture for addressing climate change through the lens of environmental justice.
The recognition that climate obligations have erga omnes character fundamentally changes enforcement possibilities, empowering all states to hold others accountable for inadequate climate action. The stringent due diligence standard leaves little room for discretionary inaction, requiring states to use all available means to address the climate crisis.
Moving forward, the legal framework for climate action must continue evolving to address emerging challenges while ensuring that solutions are grounded in principles of justice, equity, and fairness. The most vulnerable populations and countries, who bear the least responsibility for climate change but suffer its greatest impacts, must remain at the center of legal and policy responses.
The path ahead requires strengthening international cooperation, enhancing domestic implementation of climate obligations, and developing innovative legal mechanisms to address the unprecedented challenges of the climate crisis. Only through such comprehensive legal transformation can we hope to achieve the ambitious goals of limiting warming to 1.5°C while ensuring a just transition to a sustainable future for all.
As the international community prepares for COP30 and beyond, the legal foundations established by the ICJ advisory opinion provide both the framework and the imperative for transformative climate action grounded in environmental justice. The time for action is now, and the law provides both the mandate and the means to secure a livable planet for present and future generations.
References
[1] United Nations Framework Convention on Climate Change, May 9, 1992, S. Treaty Doc. No. 102-38, 1771 U.N.T.S. 107.
[2] Kyoto Protocol to the United Nations Framework Convention on Climate Change, Dec. 11, 1997, 2303 U.N.T.S. 162.
[3] Paris Agreement to the United Nations Framework Convention on Climate Change, Dec. 12, 2015, T.I.A.S. No. 16-1104; 3156 U.N.T.S. 79.
[4] Declaration of the United Nations Conference on the Human Environment, June 16, 1972, U.N. Doc. A/CONF.48/14/Rev.1; 11 I.L.M. 1416 (1972)
[5] Maxine Burkett, Climate Reparations, 10 Melb. J. Int’l L. 509 (2009)
[6] Declaration of the United Nations Conference on the Human Environment, principle. 1, June 16, 1972, U.N. Doc. A/CONF.48/14/Rev.1; 11 I.L.M. 1416 (1972).
[7] Decision 2/CP.19, Warsaw International Mechanism for Loss and Damage Associated with Climate Change Impacts, U.N. Doc. FCCC/CP/2013/10/Add.1 (Jan. 31, 2014)
[8] Decision 2/CMA.4, Funding arrangements for responding to loss and damage associated with the adverse effects of climate change, including a focus on addressing loss and damage, U.N. Doc. FCCC/PA/CMA/2022/10/Add.1 (Mar. 23, 2023)
[9] India Const. art. 21 (“No person shall be deprived of his life or personal liberty except according to procedure established by law.”).
[10] Decision 12/CP.17, Guidance on systems for providing information on how safeguards are addressed and respected and modalities relating to forest reference emission levels and forest reference levels, U.N. Doc. FCCC/CP/2011/9/Add.2 (Mar. 15, 2012)
