Introduction to Symposium on ICJ’s Advisory Opinion on Climate Change – Indian Blog of International Law

Chhaya Bhardwaj

The International Court of Justice (ICJ) delivered its advisory opinion on climate change (the AO) on 23rd July 2025. The request for the AO was submitted to the ICJ through a United Nations General Assembly Resolution 77/276 adopted on 29 March 2023 on the questions concerning obligations of States to protect climate systems, and the legal consequences arising from these obligations. In December 2024 this blog had discussed the arguments of the South-Asian nations before the ICJ in the oral hearings of the case. As the largest proceedings before the ICJ or any other international adjudicatory forum, a total of 97 States and 11 international organisations participated in it. Due to the number of actors involved, the ICJ engaged in this mammoth task of clarifying and enunciating the laws under existing conventional and non-conventional sources of international law, while systemically integrating legal principles under several treaty bodies, customary international law and general principles of international law. 

With this background, the current Symposium aims to discuss the AO. Several scholars of international law and environmental law will present their analysis on the rich jurisprudence of the AO. The scholars engage with the obligations in a way that structurally revolves around treaties and legal principles elaborated in the AO. The aim of this Symposium is to present a platform to our readers to engage with any specific obligation and consequence in the context of climate change in a simple yet critical way. 

The Symposium begins with this introduction, which is followed by the first post by Suraj Pratim Saikia who analyses the obligations of States specifically under the United Nations Framework Convention on Climate Change (UNFCCC). Suraj touches upon the obligations to mitigate, adapt and cooperate, and how the ICJ understands these obligations. 

Suraj’s post is followed, chronologically as well, by Karishma Ramchiary’s piece which questions if the Kyoto Protocol and obligations of States within it are still alive and functional. The AO refers to the Kyoto Protocol, but briefly and not as much as it mentions obligations of States under the UNFCCC and the Paris Agreement. Is it because the Kyoto Protocol is widely considered a failure by the academic community? Can it be said that the Protocol is sandwiched between UNFCCC and the Paris Agreement, due to which it is invisible to the eye and hence not relevant? 

The third chronologically important climate treaty is the Paris Agreement, and its place in the AO is discussed by Rahul Mohanty. He elaborates on the duties of States under the Agreement, which should be reflected in the Nationally Determined Contributions (NDCs), highlighting a progression of commitment to reduce the GHG emissions. He also links the specificities of these obligations with customary international law. 

The fourth post, by Daniel Stein, then looks into the obligations of the State under the United Nations Convention on the Law of the Sea (UNCLOS) discussed by the AO, while reiterating the Advisory Opinion by the International Tribunal on the Law of the Sea (ITLOS). He asks if the ICJ decision is complementary to ITLOS decision and can also be used to determine how States make commitments and submissions to the International Maritime Organisation (IMO). 

In the fifth post, Tejas Rao writes about the obligations of States in the context of climate change, as also reiterated by the ICJ, arising under the Convention on Biological Diversity, 1992, and Convention on Desertification 1992. Tejas’s piece analyses how the two treaties set forth obligations concerning transboundary harm and protection and conservation of biodiversity and their habitat and its interlinkage with climate change related obligations. 

Foysal Quazi, continues the discussion in the sixth post reflecting on the Human Rights obligation of States in the wake of climate change, and what the AO could mean for such obligations. While the AO does not detail out all the human rights obligations of the States, it is enough, because some States do not support interpretation and application of human rights obligations in the context of climate change. It is important to note however, that J. Charlesworth’s separate opinion dives deeper into the human rights issues, and J. Tladi’s declaration analyzes the Court’s outlook on human rights and the right to a healthy environment, respectively. 

Meenakshi Priya, in the seventh post of this Symposium, looks at the due diligence obligations, and compares the due diligence obligations interpretations by the ICJ and the ITLOS. This piece is a comparative outlook on due diligence and its understanding in the general sense by the ICJ and in the context of UNCLOS by ITLOS. 

Following up on due diligence, Abhijeet Shrivastava writes in the eighth post about specific actions that States need to take with respect to fossil fuels to comply with their due diligence obligations, while also reflecting on what it could mean for the proposed Fossil Fuel Proliferation Treaty. The jurisprudence of certain legal principles governing fossil fuels, laid down in the  AO, can also guide the negotiations of this proposed treaty. 

In the ninth post, Abhinandita Biswas breaks down the AO’s position on the issue of lex specialis that formed the basis of arguments by several States before the ICJ, with an aim to persuade the court to not look at any other treaty apart from the core climate change treaties, when enunciating the obligations and legal consequences of States in the context of climate change. 

This is followed by the tenth post by Ojaswini Gupta, who looks at the duty to cooperate as a customary international law duty and its traces in the treaty obligations. Overall, she discusses what it means to comply with the duty to cooperate in international law, and what could be its future implications? 

In the eleventh post, Abhinandita Biswas writes about the legal consequences for States arising out of the rules concerning State responsibility, causation and attribution. She explains what these rules could imply for any future cases when the ICJ engages in concrete assessments of responsibilities of States, while establishing causation. 

Sudipta Roy Chowdhary, in the twelfth post of this Symposium, looks into the issue of duty to prevent a significant harm as a customary international law principle applicable in the context of climate change.  She analyses the significance and application of this duty, while also discussing the separate opinions and declaration of other judges. 

In the penultimate posts of this Symposium Suraj Pratim Saikia and I present a critical analysis of the overall outlook of the ICJ on the principle of common but differentiated responsibility based on respective capabilities and in the light of different national circumstances. Our post draws from the AO’s expanded interpretation of the principles, and the criticism of that interpretation in Judge Xue’s separation opinion. 

I conclude the symposium with my piece where I assert that generally the jurisprudential understanding of the ICJ is a common sense understanding, something that the global community of states had known since 1992. However, no robust actions to reduce GHG emissions have been undertaken by States. Additionally, there is another common sense understanding in the context of climate change, which is the particular vulnerability of several states like Small Island Developing States (SIDS), however, the AO does not seem to engage in any expanded interpretation of right of these specially affected States, while the ICJ quite comfortably expanded the jurisprudence concerning CBDR-RC. 

(Chhaya Bhardwaj is an Associate Professor at the O P Jindal Global University, and a PhD Candidate at Dublin City University.)