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Tuesday, 28 March 2023

Jorge E. Viñuales is Harold Samuel Professor of Law and Environmental Policy and Fellow of the Lauterpacht Centre, University of Cambridge; Legal Counsel to the Republic of Vanuatu in the referenced matters. The opinions expressed in this piece are strictly in my academic capacity.


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Seeking climate justice at the 'world court' (

Jorge Viñuales advises Vanuatu in bid to request an advisory opinion on climate change from the 'World Court'


One recent development that has attracted much attention from academics, civil society groups and international law practitioners is the resort to the advisory function of international courts and tribunals to strengthen climate action.

Drone in Vanuatu - Seiji Seiji/UnsplashThe impulsion was given by the Republic of Vanuatu, which in September 2021 formalised its initiative to have the UN General Assembly request an advisory opinion of the International Court of Justice (ICJ) on climate change. A draft resolution, carefully negotiated within a Core Support Group including 18 States from different continents was published on 30 November 2022 and, then, in revised form on 20 February 2023. A vote on this text is expected soon. Two more focused initiatives have also sprung within this broader context. One has taken the form of a request submitted on 12 December 2022 by the Commission of Small Island States on Climate Change and International Law (COSIS) to the International Tribunal for the Law of the Sea (ITLOS) on matters related to climate change under the UN Convention on the Law of the Sea (UNCLOS). The other is the joint request by Chile and Colombia for an advisory opinion of the Inter-American Court of Human Rights (ICtHR) the implications of the climate emergency for human rights, announced on 9 January 2023.

From a substantive and geographical standpoint, these initiatives differ significantly. The COSIS request stems from a specific group of States (Small Island States) and focuses only on obligations of State parties to the UNCLOS. The Chile-Colombia initiative focuses on human rights and concerns the Latin-American regional context, specifically that of parties to the American Convention on Human Rights. By contrast, the ICJ initiative has a general scope, both substantively and geographically, which makes it politically very sensitive, as the process in the UN General Assembly so far shows. Despite these differences, what is noteworthy is the recourse to a similar instrument – the advisory jurisdiction of international courts and tribunals – in relation to climate action. I would like to offer six brief observations on such recourse in the hope that they may help clarify some of the factors underpinning this choice and dispel some misconceptions.

The first observation concerns the instrument itself. Of all the judicial routes available on the international plane, advisory opinions are the most unconfrontational and constructive route. This could be seen from a glass half-full or half-empty perspective. Sceptical observers will no doubt note that advisory opinions are not binding as such, that the powers of the ITLOS to render such opinions have raised significant controversy and those of the ICtHR, which can be triggered by States, are subject to caution. However, there are clear and specific answers to each of these common objections. While an advisory opinion is, as such, not binding, the law which is examined and clarified in it is binding, and when it comes to general international law or to widely ratified treaties, the normative impact depends less on the nature of the opinion than on its specificity. As for the debates relating to the advisory jurisdiction of ITLOS and the potentially self-serving use of the ICtHR’s advisory jurisdiction, the first has been addressed in detail by the ITLOS in its 2015 advisory opinion on the Sub-Regional Fisheries Commission request, whereas the ICtHR’s opinions have greatly contributed, particularly in the last decade, to a range of general issues. In all events, the ICJ route could hardly be questioned from this perspective given the substantial number of UN parties (a simple majority of members present and voting) that must support the adoption of a request and the clear mandate of the ICJ including in the UN Charter and the Court’s Statute.

Secondly, in the past, advisory opinions have been influential instruments to address matters such as apartheid, occupation, decolonisation or the environmental dimensions of human rights, where the sole use of political processes had proven insufficient to make concrete progress. Irrespective of where one stands on the politics of some of these matters, it is the effect of the instrument that must be emphasised. A set of advisory opinions on climate change would likely be influential as a catalyst of political action and as a common base for climate-related litigation.

Thirdly, negotiations under the aegis of the UN Framework Convention on Climate Change (UNFCCC) and the Paris Agreement are in dire need of a catalyst. At the 26th UNFCCC Conference of the Parties (COP), in Glasgow, there was general agreement that the level of ambition expressed in nationally-determined contributions (NDC) had to be raised faster. Yet, at COP 27 in Sharm El-Sheikh, the momentum for increasing the ambition and the pace of NDC was largely overshadowed by the energy security concerns resulting from the fallout of Russia’s invasion of Ukraine. In such a context, a judicial statement could perform, at the international level, a catalyst – ‘word-to-deed’ – function analogous to the one climate litigation performs at the domestic level.

Fourthly, there is a strong and by now unassailable scientific consensus on the causes of climate change, expressed mainly in the reports of the Intergovernmental Panel on Climate Change (IPCC). The two latest assessment reports (2013/14 and 2021/22, and also earlier ones) leave no doubt as to the anthropogenic causes of climate change, and their summary for policy-makers are approved through a process that involves State assent, including that of major fossil-fuel producers and major emitters. This scientific consensus is compounded by increasing “everyday evidence” tangibly affecting people around the globe. Climate change is driving sea level rise, floods, desertification, food and water insecurity, conflict, disease redistribution, floods, unprecedented heat waves and “heat domes”, cyclones/hurricanes and other extreme weather events. Stories of devastation are rapidly becoming the new normal, in particularly vulnerable States but also in other countries – including developed countries – which have been tragically caught off guard by weather events of unprecedented severity.

Photo by Tobias Rademacher/UnsplashFifthly, younger people and civil society at large are justifiably concerned by the daunting prospects of a world scarred by climate change. The grass-roots support for the initiatives is extremely important, particularly for the one to request an ICJ advisory opinion, which requires navigating a challenging process at the UN General Assembly. The confluence of the scientific consensus, the increasingly tangible impacts and the wide grass-roots support go a long way in explaining the success of Vanuatu’s initiative so far, as compared to previous attempts.

Last but not least, a phenomenon as vast as climate change has implications for the entirety of international law, and such implications must be fleshed out to be actionable. At present, only a handful treaties (most notably the UNFCCC, the Kyoto Protocol and the Paris Agreement) expressly address climate change, whereas numerous others, whether environmental or not, are directly relevant to it. The requests from COSIS and Chile/Colombia, which concern two instruments that do not expressly address climate change, are good illustrations of this point. It is obvious that a range of rules of both treaty and customary international law are relevant and applicable to the conduct of States – and other duty-bearers – underpinning anthropogenic emissions of greenhouse gases. Advisory opinions offer a suitable tool to frame the issue from the perspective of existing law and clarifying in an actionable manner (unlike codification and progressive development bodies) the requirements of applicable rules. This may appear unambitious but, in fact, major legal breakthroughs often require the simple – but this time non-obvious – step of moving from what is implicit to what is explicit.

The three initiatives overlap to some extent, but this brief article is not the place to unpack their interactions. All in all, they may be seen as pieces of a puzzle, some smaller, some larger, which when put together will hopefully provide an incomplete but much clearer picture of the actionable obligations of States in relation to the conduct that is driving climate change.