Joint Statement by CGC & MEGA on the ICJ Advisory Opinion
Joint Statement by the Climate Governance Commission and Mobilizing an Earth Governance Alliance on the ICJ Advisory Opinion on Climate Change
The Climate Governance Commission (CGC) and Mobilizing an Earth Governance Alliance (MEGA) warmly welcome the recent advisory opinion issued by the International Court of Justice (ICJ) on climate change. This landmark Opinion reinforces the urgency of the climate and broader Earth system crisis and underscores the responsibility of States and other powerful actors to act decisively in the face of the most pressing global challenge of our time. We commend in particular the leadership of young climate advocates from around the world, in particular from the Global South—represented by organizations like Pacific Island Students Fighting Climate Change and World’s Youth for Climate Justice and who, in partnership with Small-Island-Developing-States and their allies, played a pivotal role in bringing about this transformative moment in climate governance. Their vision and commitment are an inspiration and will continue to inform and strengthen our own efforts to advance more effective global climate and Earth system governance.
MEGA was established on the understanding that advocacy at national levels (on national policies) is insufficient on its own to adequately address environmental issues like climate change that are global in nature, and that global governance mechanisms are required in order to build global cooperative action that is effective, fit-for purpose, equitable and accountable.
The ICJ’s Advisory Opinion provides a clarion call for enhanced climate governance. By affirming that States have clear obligations under international law to prevent transboundary harm and protect the climate system, the Court highlights both the legal and moral imperatives for action. It underscores that climate change is not a distant threat; it is an immediate and existential challenge that requires cooperation, foresight, and accountability at every level of governance. Global governance reform and innovation, building on the key proposals of the CGC and MEGA will be critical to effective implementation of the Opinion.
Key findings of the ICJ that affirm the importance of enhanced global governance:
1. Duty to cooperate
“The Court considers that the duty of States to co-operate for the protection of the environment is a rule whose customary character has been established. This duty to co-operate is intrinsically linked to the duty to prevent significant harm to the environment, because uncoordinated individual efforts by States may not lead to a meaningful result.” (ICJ AO Summary page 6)
This Opinion demonstrates that the international legal community recognizes the insufficiency of fragmented or unilateral approaches to climate action. The climate and Earth system crisis, by its nature, transcends borders, affecting the rights and livelihoods of people across the globe—today and for generations to come. In acknowledging this, the ICJ emphasizes that States must work collaboratively, aligning their national policies with the broader international cooperation framework to mitigate climate risks and accelerate the global green transition. States must now rise to the challenge by translating the Advisory Opinion into tangible normative, legal, and political measures. This includes a need to consider practical yet ambitious global governance innovations which ensure that States cooperate together to comply with international law and commit to ambitious and equitable climate action measures which are equitable, fair, and scientifically informed. States should therefore heed the calls of the CGC and MEGA to work with civil society to advance key governance innovations. These include: establishing a Planetary Emergency Platform to better coordinate efforts to address Earth system risks, linked to enhanced, foresight-oriented international scientific monitoring to ensure policy is guided by the best available Earth system science and responds and prevents catastrophic Earth system tipping points; unlocking new sources of climate finance at the requisite levels; reinforcing the UNFCCC COP process so that States align their nationally determined contributions (NDCs) with their highest possible ambition; and, in the medium term, establishing and International Environment Court.
2. Requirement for equity
“The Court is of the view that the principle of common but differentiated responsibilities and respective capabilities, which reflects the need to distribute equitably the burdens of the obligations in respect of climate change, taking into account, inter alia, States’ historical and current contributions to cumulative GHG emissions, and their different current capabilities and national circumstances, is a manifestation of the principle of equity and guides the interpretation of obligations under international environmental law beyond its express articulation in different treaties.” (ICJ AO Summary page 7)
The principle of equity, which was affirmed by the Court as a key guide to the interpretation of obligations relating to climate change, requires global governance in order to establish the differentiated responsibilities of States and ensure their implementation. These responsibilities cannot be done individually by States, as they require evaluation with respect to the differentiated responsibilities of others. The Court refers more directly to this in its discussion of Nationally Determined Contributions (NDCs) – see section 3.
3. Requirement to ensure Nationally Determined Contributions collectively meet the goals of the Paris Agreement
“The Court concludes that, rather than being entirely discretionary, NDCs must satisfy certain standards under the Paris Agreement. All NDCs prepared, communicated and maintained by parties under the Paris Agreement must, when taken together, be capable of realizing the objectives of the Agreement ….States parties listed in Annex I to the United Nations Framework Convention on Climate Change have additional obligations to take the lead in combating climate change by limiting their greenhouse gas emissions and enhancing their greenhouse gas sinks and reservoirs.”(ICJ AO Summary page 13)
The requirements on Nationally Determined Contributions (NDCs) affirmed by the ICJ point again to the need for cooperation and governance. They must “when taken together, be capable of realizing the objectives of the Agreement”. Effective governance mechanisms are required to ensure the collective implementation of the appropriate NDCs for each country.
4. Legal consequences arising from wrongful acts
“The Court cannot, in the context of these advisory proceedings, specify precisely what consequences are entailed by the commission of an internationally wrongful act of breaching obligations to protect the climate system from the anthropogenic GHG emissions, since such consequences depend on the specific breach in question and on the nature of the particular harm. As a general observation, the Court notes that breaches of States’ obligations under question (a) may give rise to the entire panoply of legal consequences provided for under the law of State responsibility.” (ICJ AO Summary page 23)
The recognition by the Court that breaches of State’s obligations with respect to climate change may give rise to an ‘entire panoply of legal consequences’ affirms further the need for global governance to ensure accountability under the law. This could involve follow-up contentious cases in the ICJ relating to breaches by certain states or groups of states, establishment of an International Environment Court with special expertise and procedures for dealing with climate cases, and enhancing judicial governance regarding individual responsibility for serious climate crimes, such as adding the crime of ecocide to the jurisdiction of the International Criminal Court.
5. Future generations and intergenerational equity
“In the Court’s view, intergenerational equity, as an expression of the idea that present generations are trustees of humanity tasked with preserving dignified living conditions and transmitting them to future generations, is a manifestation of equity in the general sense and thus shares its legal significance as a guide for the interpretation of applicable rules.” (ICJ AO Summary page 7)
The Court affirmed the rights of future generations in terms of intergenerational equity, finding that present generations have a responsibility to preserve dignified living conditions for future generations. One of the most effective governance mechanisms for ensuring implementation and accountability of this obligation is the establishment of Institutional Representatives of Future Generations at all levels of society – local, national, regional and global.
Next Steps - Implementing the ICJ Advisory Opinion
We recognize that the ICJ’s opinion is not only a legal instrument but also a moral and political compass. It calls on governments, civil society, and international institutions to reaffirm the principles of international solidarity and shared responsibility. Climate action cannot be the preserve of individual States or regions; it requires a collective commitment to the protection of the planet and the rights of present and future generations. The Court’s message is clear: inaction is not an option, and half-measures are insufficient. As organizations dedicated to promoting global climate and Earth system governance in a fair, equitable, and inclusive manner, we urge States to take immediate and coordinated steps to implement the ICJ’s guidance. This includes strengthening multilateral institutions, fostering international cooperation that goes beyond rhetoric to deliver tangible outcomes, and taking concrete steps to establish “next-generation” global governance institutions fit-for-purpose to manage the Earth system. Equally, it requires embedding human rights considerations at the heart of climate policies, recognizing that the right to a healthy environment is fundamental to the dignity and well-being of all present and future generations.
The Climate Governance Commission and Mobilizing an Earth Governance Alliance reaffirm our commitment to advancing these objectives. We stand ready to support States, intergovernmental bodies, and civil society in translating the ICJ’s advisory opinion into meaningful action. By working together, we can transform the legal imperative of the Opinion into a shared opportunity for leadership, innovation, and justice in global climate and Earth system governance.
The ICJ’s Advisory Opinion is a historic milestone, signaling a turning point in the international community’s approach to climate action. It demonstrates that a decisive, coordinated, and a youth and Global South-centered response is both necessary and achievable when pursuing transformative change. We call upon all States and powerful actors to heed this call, strengthen collective action, and commit to a future in which the global community acts decisively to safeguard the planet, protect human rights, and ensure the well-being of generations to come.
