Due Diligence, Obligations to Cooperate and to Regulate Private Actors: Insights from Three Climate Change Advisory Opinions

Climate change is the justice challenge of our century, and the increasingly serious impacts of climate change on human societies and ecosystems are raising important international legal challenges. States and stakeholders are appealing to international courts for clarity concerning their responsibilities in the global response to climate change, as well as their accountability for climaterelated loss and damage. Through advisory proceedings, these institutions are being asked to clarify the legal obligations of States in addressing climate change, including the prevention of ocean impacts, the protection of human rights, and in international law more broadly. The International Tribunal for the Law of the Sea (ITLOS), the Inter-American Court of Human Rights (IACtHR) and the International Court of Justice (ICJ) are at the forefront of such proceedings with the potential to reshape international climate law and governance. In this article, expert legal scholars highlight the significance of climate advisory proceedings in these tribunals, briefly underlining the legal reasoning of the ITLOS advisory opinion, its implications for international climate governance, and the questions and arguments before the IACtHR and the ICJ. The article explores, in the context of global efforts to implement the Paris Agreement under the United Nations Framework Convention on Climate Change (UNFCCC) and other climate litigation including in international courts and tribunals, the transformative potential of recent advisory opinions sought from the ITLOS, the IACtHR and the ICJ. In their responses to the pressing need for legal clarity in a world grappling with unprecedented climate challenges, the article suggests, courts are offered an historic opportunity to shape the contributions of international law to global sustainability, justice and the survival of life on Earth.

The ICTs as the Climate Change Sentinels: Three Advisory Opinions & Beyond

Climate change increasingly affects various aspects of human activity each year, resulting in growing transboundary damage. Consequently, the author aims to analyze the obligations of states to prevent transboundary damage, drawing on the 1982 UN Convention on the Law of the Sea and the principles of customary international law. The article examines the obligations of states under the 1982 UN Convention on the Law of the Sea, with a particular focus on the principles of prevention of transboundary damage and due diligence, as well as their interrelationship. To deepen the understanding of due diligence within the context of international environmental law and climate change, the author analyses both the position of the Commission of Small Island States on Climate Change and International Law on due diligence, as well as the Advisory Opinion of the International Tribunal for the Law of the Sea on the request of the Commission of Small Island States. In examining the ITLOS Advisory Opinion, the positions of States on climate change and its impact on public order and life are also explored. Currently, there is a discernible trend towards increased climate litigation and the development of international environmental law, as evidenced not only in the multitude of disputes before national and international courts but also in the pending Advisory Opinions before the International Court of Justice and the Inter-American Court of Human Rights. The article also discusses the problem of determining the existence of international legal liability for transboundary damage and explores the ways and forms of redress. In situations involving transboundary damage, the affected state, as the victim, must prove a wrongful act, namely a breach of an international obligation, attributable to the other state. Thus, the paper analyzes the obligations of states to prevent transboundary damage, using the law of the sea as an illustrative example, and also raises the issue of state liability.

Currently, there are pending requests for advisory opinions regarding State obligations on climate change before both the International Court of Justice (ICJ) and the Inter-American Court of Human Rights (IACtHR). Additionally, the International Tribunal for the Law of the Sea (ITLOS) recently issued its advisory opinion on Climate Change and International Law on 21 May 2024. This article aims to compare these requests, analysing their contextual backgrounds and the extent of States’ involvement in the advisory proceedings. The aim is to examine the jurisdictional scope and future prospects of the proceedings before the two courts and the tribunal by exploring the distinct normative, practical and political strategies shaping each request. Furthermore, the article assesses how these factors influence the framing of the requests for advisory opinions and shape the contributions received by interested States. By providing a holistic analysis of these legal interpretations, the author evaluates the potential impact of the aforementioned opinions on the future behaviour of States and the development of international law. Ultimately, this analysis aims to inspire the progress of strategic climate change litigation and inform about potential enhancements in the interpretation and development of future international agreements.

Resumen: Este artículo examina cómo los procesos consultivos se han convertido en un mecanismo de participación y acceso a la justicia climática para los defensores de intereses de las generaciones futuras. En la primera parte, se analizan los fundamentos normativos de la protección intergeneracional desde el marco de la sostenibilidad y los derechos humanos. En la segunda parte, se estudia la cuestión desde la perspectiva práctica, el rol de los actores no estatales en los procesos consultivos sobre cambio climático ante la Corte Internacional de Justicia (CIJ) y la Corte Interamericana de Derechos Humanos (CtIDH). Esta sección analiza el caso del movimiento World Youth for Climate en el marco de la CIJ y el uso del mecanismo de Amicus Curiae ante la CtIDH. Finalmente, se plantean reflexiones sobre el grado de participación y el impacto potencial de estas iniciativas para ampliar el espectro de protección de intereses de las generaciones futuras desde los derechos humanos frente a la crisis del cambio climático. Abstract: This article examines how advisory proceedings have become a mechanism for participation and access to climate justice for advocates of the interests of future generations. The first part analyzes the foundations of intergenerational protection in response to the human rights crisis caused by climate change. In the second part, the issue is studied from a practical perspective: the role of non-state actors in advisory proceedings on climate change before the International Court of Justice (ICJ) and the Inter-American Court of Human Rights (IACtHR). This section examines the case of the World Youth for Climate movement within the ICJ framework and the use of the Amicus Curiae mechanism before the IACtHR. Finally, reflections are offered on the degree of participation and the potential impact of these initiatives to broaden the spectrum of human rights protection of future generations in the face of the climate change crisis. Palabras clave: Derechos Humanos. Cambio Climático. Futuras Generaciones. Actores no Estatales. Keywords: Human Rights. Climate Change. Future Generations. Non-State Actors. Índice: 1. Introducción 2. Fundamentos de la protección intergeneracional ante la crisis climática 2.1. El cambio climático: una crisis de derechos humanos 2.2. El desarrollo sostenible y su conexión con los derechos humanos desde una perspectiva intergeneracional 3. Oportunidades de acceso a la justicia climática de las futuras generaciones en procesos consultivos sobre derechos humanos: una mirada hacia el movimiento climático juvenil y los amicus curiae 3.1. World Youth for Climate Justice: el movimiento transnacional que intenta redefinir el acceso de actores no estatales ante la Corte Internacional de Justicia 3.2. El amicus curiae ante la Corte Interamericana de Derechos Humanos: su contribución a la transformación del acceso a la justicia para las futuras generaciones 4. Conclusiones 5. Bibliografía Index: 1. Introduction 2. Foundations of intergenerational protection in the face of the climate crisis 2.1. Climate change: a human rights crisis 2.2. Sustainable development and its connection to human rights from an intergenerational perspective 3. Opportunities for access to climate justice for future generations in advisory proceedings on human rights: an approach to the youth climate movement and amicus curiae 3.1. World Youth for Climate Justice: the transnational movement that seeks to redefine the access of non-state actors before the International Court of Justice 3.2. The amicus curiae before the Inter-American Court of Human Rights: its contribution to transforming access to justice for future generations 4. Conclusions 5. Bibliography

This contribution describes and critiques the Advisory Opinion of the International Tribunal for the Law of the Sea (‘ITLOS’ or ‘Tribunal’) on the obligations of States in relation to the sea and its marine environment that was delivered on 21 May 2024. Although the Advisory Opinion is not explicitly about sea level rise, it considers the relationship between climate change, the marine environment, and the consequence of sea level rise. The Opinion clarifies the legal obligations of States for preserving the marine environment and thereby makes a significant contribution to addressing the consequences of sea rise caused by climate change. The ITLOS Advisory Opinion was a precursor for the Advisory Opinions on climate change given by the Inter-American Court of Human Rights and the International Court of Justice in 2025. Much of this contribution relies on the ITLOS Advisory Opinion itself as well as the submissions by United Nations Member States and non-States actors. The background to the Request for an Advisory Opinion is discussed together with the questions that were submitted to the Tribunal. The submissions of States and non-State actors are described. And the unanimous Advisory Opinion of the Tribunal is described and evaluated together with the separate opinions of individual judges that accompanied it. Finally, some conclusions are drawn about the future impact of the Advisory Opinion.

Esmé Shirlow presented the findings of a policy paper developed in collaboration with the International Institute for Sustainable Development (IISD), titled Approaches of International Courts and Tribunals to the Award of Compensation in International Private Property Cases and Implications for the Reform of Investor-State Arbitration. The policy paper follows previous IISD work on compensation in investor-state arbitration, which left open the question of whether approaches to issues of compensation in investor-state arbitration differ from the approaches of other international courts and tribunals (hereinafter, courts), and the extent to which this comparative practice might offer inspiration or ideas for ongoing investor-state dispute settlement reform. The research presented by Dr. Shirlow seeks to answer this question by analyzing how issues of compensation have been analyzed in cases concerning alleged state interferences with private property filed before the Permanent Court of International Justice (PCIJ), International Court of Justice (ICJ), International Tribunal for the Law of the Sea (ITLOS), United Nations Convention of the Law of the Sea Annex VII Tribunals, European Court of Human Rights (ECtHR), African Court on Human and Peoples’ Rights (ACtHPR), and the Inter-American Court of Human Rights (IACtHR).

This article examines the advisory proceedings in relation to climate change before the International Court of Justice, the International Tribunal for the Law of the Sea, and the Inter-American Court of Human Rights through the lens of the broader phenomenon of public interest litigation. It focuses on certain substantive, institutional, and procedural dimensions of the advisory proceedings, construed as a form of public interest litigation. First, it argues that international courts and tribunals should innovate by allowing broader participation while considering the constraints of their statutes and rules of procedure. Second, this article examines how prior advisory opinions, even though non-binding, may shape the subsequent practice of States, and considers the impact that the advisory opinions on climate change may have. Ultimately, this article questions whether these advisory opinions may have a catalytic effect on ensuring the protection of other global commons in the future.

Activists in international courts: Backlash, funding, and strategy in international legal mobilization

for Scopus Indexing: In May 2024, the International Tribunal on the Law of the Seas (ITLOS) issued a historic advisory opinion on the obligations of States regarding climate change under the United Nations Convention on the Law of the Seas. This advisory opinion was issued in response to a request submitted by the Commission on Small Island States on Climate Change and International Law. Significantly, the Tribunal stated that: a) States must interpret their obligations under the Convention in light of the best available science; b) greenhouse gas (GHG) emissions constitute pollution of the marine environment; and c) they must take all necessary measures to reduce, prevent and control GHG emissions. ITLOS also noted that developed States have an obligation under the Convention to assist developing States in mitigating the effects of climate change. This advisory opinion marks an important first step in the fight for climate justice for small island States. Forthcoming are advisory opinions concerning climate change from the International Court of Justice (ICJ) and the Inter-American Court of Human Rights (IACHR). In this article, we explore the jurisdictional arguments some participants raised, the significance of the Tribunal’s opinion, and we contextualize the opinion in light of broader efforts towards climate justice.

In a situation where international climate treaties do not establish firm commitments in the area of reducing green-house gas emissions, leaving significant room for state discretion in its actions, there is a growing need to fill the gaps in the regulation of measures to combat climate change, and international courts are now called upon to play an im-portant role in this process. In 2023, the International Court of Justice and the Inter-American Court of Human Rights received requests for advisory opinions on climate change issues (from the UN General Assembly and from Chile and Colombia, respectively). The International Tribunal for the Law of the Sea received a request on 12 December 2022 and on 21 May 2024 issued an advisory opinion on the obligations of states parties to the 1982 UN Convention on the Law of the Sea in the field of protecting the marine environment from anthropogenic greenhouse gas emissions. The request for an advisory opinion was filed by the Commission of Small Island States on Climate Change and International Law, established by two island states (Antigua and Barbuda and Tuvalu). The case took one and a half years to consider, and the text of the advisory opinion was approved unanimously by the judges. The tribunal noted that anthropogenic emissions of greenhouse gases are a pollutant within the meaning of the 1982 UN Convention on the Law of the Sea (Article 1, paragraph 4) and, accordingly, states have specific obligations to prevent, reduce and control pollution of the marine environment resulting from anthropogenic emissions of greenhouse gases. This article examines this advisory opinion in detail, noting its potential impact on the formation of legal positions of the International Court of Justice and the Inter-American Court of Human Rights, which will also issue advisory opinions on climate change in the near future.

The limited use of dispute settlement mechanisms under the UN Framework Convention on Climate Change and the Paris Agreement explains the recent upsurge in requests for advisory opinions on issues specific to climate change to international courts, namely the International Court of Justice (ICJ), the International Tribunal of the Law of the Sea (ITLOS), and the Inter-American Court of Human Rights. However, it is still unclear how these courts will answer the questions posed, and in particular whether they will coordinate or compete with each other. As the requesting states and bodies are well aware of this uncertainty, requesting an advisory opinion from three courts simultaneously was an ingenious (not ingenuous) strategy to clarify states’ obligations to mitigate or adapt to climate change through the international judiciary. This essay assesses how the parallel jurisdiction of courts in these cases presents an opportunity to enhance states’ obligations concerning climate change through requesting concurrent views on the same rules and obligations. It considers the potential for contradictory views between courts on the same obligations. Finally, the essay analyzes the extent to which these courts may compete or cooperate in their approach to the resolution of these issues.

International law generally applies to legal relations and disputes among states. This chapter addresses the issue concerning disputes arising out of domestic civil actions with regard to three international bodies: the International Court of Justice (ICJ), the International Tribunal for the Law of the Sea (ITLOS) and the European Court of Human Rights (ECHR). It discusses recent cases and explores procedural mechanisms and the courts' investigative powers which may be used to permit the affected individual to present his/her own views on the case to the tribunal. The chapter presents two of the cases currently pending before the International Court of Justice concern the constellation presented: Jurisdictional Immunities of the State and Jurisdiction and Enforcement of Judgments in Civil and Commercial Matters . The developments in the practice of the ECHR demonstrate a possible way forward for other international tribunals like the ICJ and the ITLOS. Keywords:European Court of Human Rights (ECHR); International Court of Justice (ICJ); International law; ITLOS

Climate Justice through International Courts and Tribunals: Advisory Opinions in the International Tribunal on the Law of the Sea (ITLOS), the Inter-American Court of Human Rights (IACtHR) and the International Court of Justice (ICJ)

The International Courts Project, M.W. Janis. Part 1 The classical universal institutions: peaceful settlements of disputes, L.B. Sohn the Hague peace conferences of 1899 and 1907, D.J. Bederman the international court, M.W. Janis the Hague Permanent Court of Arbitration, W.E. Butler inter-state arbitration since 1945 - overview and evaluation, C. Gray and B. Kingsbury. Part 3 The regional international courts: the Court of Justice of the European Communities and the prospects for international adjudication, J.W. Bridge the European Court of Human Rights, M.W. Janis the Inter-American Court of Human Rights, C.M. Cerna. Part 3 Specialized international tribunals and procedures: the glorious past and uncertain future of international claims tribunals, D.J. Bederman the mandatory component in the CSCE dispute settlement system, K. Oellers-Frahm the case for an international court of criminal justice and the formulation of international criminal law, J.W. Bridge international legal aid - the Secretary General's trust fund to assist states in the settlement of disputes through the International Court of Justice, M.E. O'Connell the Law of the Sea Tribunal, M.W. Janis.