ITLOS Advisory Opinion on Climate Change and Oceans: Possibilities and Benefits

ITLOS Advisory Opinion on Climate Change and Oceans: Possibilities and Benefits

[Carlos A. Cruz Carrillo is a PhD Candidate at the University of Basel. Twitter: @Carcru1118.]

The rule of law for oceans faces the challenges presented by climate change. Scientific evidence shows that climate change is causing menacing issues in the oceans. For example, sea-level rise, acidification, and deoxygenation of the oceans, amongst others. (see: 2019 IPCC Special Report on the Ocean and Cryosphere in a Changing Climate). In this regard, the 1982 United Nations Convention on the Law of the Sea (UNCLOS) requires an interpretative adjustment, enabling it to provide legal guidance in tackling the consequences of climate change. 

Far from starting treaty negotiations to amend UNCLOS or starting a contentious proceeding before an international judicial body, advisory opinions may be a suitable option to clarify the scope and content of obligations in light of new global concerns such as climate change. Some countries are crafting a request for an advisory opinion from the ICJ (e.g. 50th Pacific Island Forum, para.16). Yet, it is necessary for a complex political discussion at the General Assembly or the Security Council. 

This contribution analyses the alternative of requesting an advisory opinion on oceans and climate change from the plenary of the International Tribunal for the Law of the Sea (ITLOS). Considering the peculiar configuration of the ITLOS advisory function, this post seeks to share some considerations on jurisdiction, admissibility, and utility. 


The advisory jurisdiction of the plenary of the ITLOS has been the object of debate following the 2015 ITLOS SRFC Advisory Opinion (see: Lando, 2016Ruys-Soete, 2016), where the Tribunal recognized the possibility of exercising this judicial function under particular parameters. This advisory function derives from Article 21 of the Statute, which confers jurisdiction to the ITLOS on any other matters established in an agreement. Likewise, Article 138 of its Rules; elaborates on the requirements to request an advisory opinion. In the 2015 ITLOS SRFC Advisory Opinion (para. 60), the Tribunal held that its advisory jurisdiction requires three elements for it to be triggered: 1) An international agreement related to the purposes of UNCLOS clear providing for the submission to the Tribunal of a request for an advisory opinion; 2) the request must be transmitted to the ITLOS by an authorized body by or per that agreement; 3) A legal question. The Tribunal pointed out that the basis of the advisory jurisdiction is the international agreement conferring this judicial function. Yet, the Statute and the Rules are silent on the nature of this agreement. 

The requirement of “an international agreement” is not clear on the nature of the legal instrument. Thereby, considering the characteristic of a treaty under international law (VCLT, Article 2(1)(a) and ICJ, Somalia v Kenya, para. 42), this may include foundational agreements to international or regional organizations, substantive agreements, or ad-hoc jurisdictional agreements (compromis). Arguably, the advisory jurisdiction might derive from an ad-hoc jurisdictional agreement concluded between two or more entities, with the sole purpose of requesting an advisory opinion. Thus, a group of interested entities, such as already affected States by climate change, could rely on this opportunity, negotiate the terms of the agreement and discuss the complex task of drafting the legal question.

Legal questions

A legal question should be framed in terms of law, addressing problems of international law, and is susceptible to a reply based on the law (2011, ITLOS advisory opinion on the Area, para.39). Drafting a legal question is crucial to determine the potential direction and reasoning expected from the ITLOS. In this regard, an advisory opinion from the ITLOS should comprise a legal question on the interpretation and application of UNCLOS and other international agreements, according to the jurisdiction ratione materiae. Bearing this in mind; potential topics to conform a legal question could include:

  • Sea-level rise. Regardless the topic is now part of the ILC agenda (see: ILC, First Issue Paper, 2020), legal questions could address similar subjects to those identified by the ILC. For example, a potential question could address the legal consequences of sea-level rise in the interpretation and application of Article 121 in connection with other provisions of UNCLOS. This may be relevant in the light of the exhaustive interpretation made in the South China Sea Arbitration and to understand the legal impact of the disappearance of cays, low tide elevations, and islands;
  • Ocean acidification and deoxygenation. For centuries, the ocean has functioned as a carbon sink, absorbing a considerable percentage of heat and greenhouse gas emissions. Yet, the consequences are evident through ocean acidification and deoxygenation. Both topics have been almost absent from climate forums and have only been included recently (see: UNFCCC Summary Report, 2021). In this context, another legal question could aim at clarifying the obligations of States under Part XII of UNCLOS, to prevent and mitigate the effects of ocean acidification and deoxygenation. It might be an opportunity to create a breach between the law of the sea and the UNFCCC regime. 

Discretion and potential compelling reasons

Using ad-hoc jurisdictional agreements to confer advisory jurisdiction to the ITLOS may be a two-sided blade. On the one hand, this opportunity could open the door for requesting advisory opinions on common concerns such as climate change. On the other hand, it could derive from potential abuses from States (Separate Opinion of Judge Cot, para.9). In this regard, the Tribunal should be cautious in deciding on its jurisdiction by exercising its discretionary powers and –if applicable- abstain from entertaining the request due to compelling reasons.  

In the context of an advisory opinion on climate change, potential compelling reasons may arise from the lack of factual information; the circumvention to the principle of consent to jurisdiction, or the lack of utility of an opinion for the requesting entity. Here are some considerations related to those aspects: 

  • Fact-finding and scientific evidence. The Tribunal requires sufficient information and evidence to establish the necessary factual background for rendering a legal opinion (Chagos Advisory Opinion, paras.71 and 72). In the context of climate change, the fact-finding stage comprises the analysis of scientific evidence, relevant for understanding the legal consequences (e.g. the 2019 IPCC Special Report on the Ocean and Cryosphere in a Changing Climate). As Professor Sands suggested, a finding of fact on one or more of the climate change consequences would be significant and authoritative, and could well be dispositive on the range for future actions, including negotiations.

Under Article 131 of the Rules of the Tribunal applicable to the advisory function of the plenary, a requesting entity should submit all documents likely to throw light on the question. Among these documents, the requesting parties may attach scientific reports and relevant information for the ITLOS. Similarly, the participant entities could address scientific reports in their written and oral submissions. Furthermore, the Tribunal could rely on Article 133 (2) to identify relevant intergovernmental organizations which can furnish information on the legal question. For example, this may open the participation of the UNFCCC Secretariat, the UNESCO Intergovernmental Oceanographic Commission, among others. 

  • Principle of consent to jurisdiction. The ITLOS should assess whether delivering an opinion would circumvent the principle of consent to jurisdiction (Western Sahara, para.33). That is to say, the Tribunal should consider whether rendering an opinion may affect the interests of a third State other than those requesting the opinion. Arguably, an advisory opinion on climate change and oceans would be exempt from this possibility since the object of the request entails a public interest. Nonetheless, even where there could exist disagreement on points of law among States (South West Africa, para. 38), this won’t be considered a compelling reason due to the public interest character of the request. 
  • Utility of the advisory opinion. Another feature to assess is the utility of the requested opinion. The legal question should follow logic so the answer delivered by the ITLOS, represents and assistance for the requesting entity and the entire legal system in performing its obligations (SRFC Advisory Opinion, para 77). Therefore, an advisory opinion on climate change and oceans will be convenient for the requesting entities and the international community. 

Requesting an advisory opinion on the legal consequences of climate change on oceans is viable under the advisory jurisdiction of the ITLOS as a plenary. Furthermore, due to the public interest nature of the request, there is a possibility that the Tribunal will abstain from exercising this judicial function due to compelling reasons.

Legal consequences of the opinion

The advisory function of international courts and tribunals is a legal service rendered to assist in the compliance of international obligations by setting the principles and the specific content of those obligations (IACtHR advisory opinion on the environment and human rights, paras. 23-24). An advisory function is a valuable tool in situations where the law seems unclear to tackle a common concern such as a climate emergency or pandemics.  

Regardless of its non-binding nature, advisory opinions entail authoritative statements of law with legal effects (ITLOS, Maritime Delimitation in the Indian Ocean, paras. 202-205). Thereby, an advisory opinion on the legal consequences of climate change in the law of the sea will contribute to providing guidelines to the requesting entities and the international community on their obligations to tackle the impacts of climate change in the oceans. That is to say, the ITLOS will have the opportunity to interpret the UNCLOS and adapt it to new challenges.


First. The peculiarities surrounding the advisory jurisdiction of the ITLOS may turn it into a public interest litigation device aimed at rendering legal advice in the light of common concern. Affected and interested States could rely on this tool, in the context of a climate emergency, by concluding an ad-hoc jurisdictional agreement to request an advisory opinion from the ITLOS. Yet, the Tribunal should be cautious and -if necessary- make use of its discretionary power to protect its legitimacy as a judicial organ.

Second. An advisory opinion on climate change and oceans is not the panacea and will not solve the problems derived from climate change. Nevertheless, the findings of the advisory opinion will enhance the interpretation and application of UNCLOS in the light of climate change;

Third. The findings of the opinion will contribute to present and future efforts aimed to tackle climate change. For example:

  • UNFCCC. The advisory opinion could provide relevant considerations that may assist in the current discussions and negotiations to tackle climate change in the oceans. It could build a systemic bridge between the climate change legal framework and the law of the sea; 
  • ILC. As mentioned, the works of the ILC include the topic of Sea-level rise in relation to international law. An advisory opinion from the ITLOS will entail an important contribution for discussing the issue. 
  • Domestic regulation. The advisory opinion could assist States in designing public policies and laws of adaptation and mitigation of the effects of climate change in the oceans. Particularly, those States already tackling those effects;
  • Climate change litigation. The opinion could provide authoritative statements to prepare a further contentious case at the international or domestic level. Moreover, it may be relevant for those legal systems in which the human right to a healthy environment is present, either at a conventional or constitutional level.
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Courts & Tribunals, Environmental Law, Featured, Law of the Sea, Organizations, Public International Law
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