Statehood in the Climate Crisis

More than two years after the United Nations General Assembly (UNGA) adopted Resolution 77/276, the International Court of Justice (ICJ) issued its highly anticipated Advisory Opinion on the Obligations of States in Respect of Climate Change on 23 July 2025. The ICJ was unanimous in its findings that states have obligations under international law to protect the climate system and other parts of the environment from human-caused greenhouse gas emissions and uphold the effective enjoyment of human rights in the climate context, with breaches by states of these obligations entailing an internationally wrongful act, triggering state responsibility (para. 457). Additionally, as also noted elsewhere, the opinion supplies the international legal community with material on the relationship between treaty and customary international law, lex specialis, state responsibility, aspects concerning maritime zones, and statehood, among other things.

In this blog post, we zero in on the part of the opinion that concerns statehood. Specifically, we analyze the ICJ’s restatement of the presumption of state continuity, examining both what the Court says and doesn’t say, and what the implications could be. We also consider the individual opinions that discuss statehood and add some brief reflections on the applicability of Article 1 of the Montevideo Convention on the Rights and Duties of States (Montevideo Convention) and on State extinction. Our analysis is preliminary, and certainly much ink will be spilled on the ICJ’s remarks going forward.

The ICJ’s Remarks on Statehood

During the advisory proceedings, which featured a record-setting number of participants, thirty-three states and seven international organisations addressed in one way or another the topic of statehood. Many of these participants articulated, in varied ways, support for the continuity as States under international law of the small island nations that may become uninhabitable or be submerged  due to the impacts of climate change, particularly sea level rise. Even with different States bringing up statehood in this context, it was not at all clear, as suggested elsewhere, whether the ICJ would weigh in on the matter. The request made no mention of statehood, and the ICJ has generally been cautious when it comes to this topic, as evidenced by the 2010 Kosovo Advisory Opinion. Seven direct references to statehood and three key paragraphs put these doubts to rest. The ICJ did comment on the issue of statehood, as did four judges in their individual opinions.

The ICJ’s advisory opinion explicitly mentioned statehood in several places. In paragraph 110, the ICJ recalled that many participants in the proceedings noted concerns over sea level rise, which causes coasts to recede and, thus, may impact the outer boundaries of maritime zones or even threaten the very existence of small island and low-lying coastal states. In paragraph 355, the ICJ referred again to arguments in the proceedings ‘‘that existing baselines, maritime entitlements, maritime delimitations and statehood should be preserved, notwithstanding the physical effects of sea level rise, including coastal recession.”

The ICJ’s view of the presumption of state continuity and most important part of the opinion concerning statehood is set out in paragraph 363. The ICJ started by recalling the participants’ statements that sea level rise “poses a significant threat to the territorial integrity and thus to the very statehood of small island States” and that “in the event of the complete loss of a State’s territory and the displacement of its population, a strong presumption of continued statehood should apply.” It then notably declared that “[i]n the view of the Court, once a State is established, the disappearance of one of its constituent elements would not necessarily entail the loss of its statehood.” Although the opinion does not name them, it is difficult to think that these constituent elements are anything other than those reflected in Article 1 of the Montevideo Convention: population, territory, government, and capacity to enter into international relations.

Individual Opinions

The Advisory Opinion is accompanied by twelve individual opinions from the Court’s judges. Four judges – Vice-President Sebutinde, Judge Aurescu, Judge Bhandari, and Judge Tomka – addressed statehood in their individual opinions. 

Vice-President Sebutinde (para. 8) and Judge Aurescu (paras. 20-21) both argued that the opinion could have been clearer or more resolute in affirming the presumption of state continuity in the context of climate change. According to Judge Aurescu (paras. 21-22), it would have been important to add that the loss of constituent elements of statehood not only does not affect existing statehood, but also does not and cannot affect membership in international organisations, including the United Nations (UN). Judge Aurescu also stated that the ICJ should have included as a legal basis for presumption in the context of climate change the principle of legal stability, security, certainty, and predictability (paras. 4, 23). Finally, it was opined by Judge Aurescu (para. 24) and alluded to by Judge Bhandari (para. 7) that the opinion could or should have acknowledged continued recognition of statehood as a form of restitution under the law of state responsibility for those small island States that may lose their effective statehood. 

The most detailed treatment of statehood is in the declaration of Judge Tomka. Judge Tomka focused particularly on the ambiguity of the opinion’s part on the presumption of state continuity and the lack of a customary legal basis for the ICJ’s possible affirmation of the presumption of state continuity in the context of climate change. 

Did the ICJ Endorse State Continuity in the Context of Climate Change?

There are two ways to read paragraph 363. On the one hand, the ICJ can be seen as merely restating a conventional position that statehood is not a legal status that is easily affected (e.g., here). Alternatively, it can be read as affirming the presumption of state continuity in the context of climate change, in which case the implications are profound: it would involve the ICJ accepting that statehood as a legal status can exist even without the constituent elements of statehood, primarily population and territory. The differences between the two scenarios are significant. 

Starting with the first interpretation, there is nothing particularly  remarkable about the ICJ declaring  that “once a State is established, the disappearance of one of its constituent elements would not necessarily entail the loss of its statehood.” International law is not unfamiliar with situations where States lost compliance with the constituent criteria of statehood, e.g., due to military occupation or government failure (“failed States”), without this affecting their status as States (e.g., here). It is, after all, this practice that has informed and substantiates the presumption of State continuity in international law. According to this interpretation, paragraph 363 of the opinion holds little significance beyond entailing the ICJ’s support or confirmation of this presumption, with no significant implications capable of being drawn from it.

Under the second interpretation of paragraph 363, the ICJ’s restatement of the presumption of State continuity is not just a general remark, but it is considered and framed against the backdrop of climate change (separate opinion of Judge Aurescu, separate opinion of Judge Bhandari, declaration of Judge Tomka, para 2).  There are two main arguments favouring this reading. First, not only is the declaration issued in an advisory opinion on climate change, but it comes after the ICJ recalls the existential threats of sea level rise and participant statements backing the presumption for the States that may be impacted. Second, the ICJ did not say that the presumption applies only when there is a change in the constituent elements of statehood, but also when those elements disappear entirely.  According to Judge Tomka (para. 2), there is no doubt that here the ICJ “has in mind the disappearance of the territory of a State in case it becomes completely submerged as a result of sea-level rise.” 

On the other hand, however, the ICJ was extremely careful and did not, in the sentence in question, include any references to sea level rise or climate change more broadly. It is likely that this was a deliberate decision; were the ICJ as a whole comfortable and legally convinced that this presumption extends to the situation of statehood in relation to climate change, the opinion would have clearly stated this. The individual opinions stating that the opinion could have been firmer in affirming a presumption of State continuity in the context of climate change lend support to what the ICJ intentionally left out (see particularly the separate opinion of Vice-President Sebutinde). Sometimes refraining from saying something can be as powerful – and revealing – as stating it, especially in legal writing.

Further Reflections

If one is ready to accept that the ICJ extended the presumption of continuity to the context of climate change (e.g., here), the question then becomes whether this is supported by state practice, either past or present (see particularly the declaration of Judge Tomka). 

It is not obvious that a presumption of State continuity in relation to climate change, and thus the ICJ’s view, can be based on past State continuity practice. As discussed by Judge Tomka (para. 5) and also some States in other fora (e.g., here), international practice surrounding the presumption of State continuity is in situations distinct from that of climate change (see more on the limited value of past practice in Corneo and Scherer’s analysis in this symposium). It has been linked to temporary situations of loss of constituent elements, e.g., of effective government (Judge Tomka, para. 5) or other situations related to changes in the size of territory and population (e.g., here). Even if a number of States favouring State continuity have referred to this past international practice, climate change may present challenges to statehood that are much more far reaching and lasting (e.g., here). The elements of population and territory may be gone entirely. This would, of course, compromise the elements of government and capacity to enter into international relations. It follows that it is not clear and certain that the presumption of State continuity, as developed through international practice, furnishes a valid legal ground for presumption in relation to climate change.  

True, as also expressed by Judge Tomka (para. 6), in recent years an increasing number of States have advanced the position in both bilateral and multilateral settings that climate change should not affect the existing international legal personality of small island states that may be impacted. But a widespread and consolidated body of State practice is still to grow. Much of the evidence regarding State practice is contained in the reports of the Co-Chairs of the International Law Commission (ILC) Study Group on sea level rise in relation to international law (here, here and here). Importantly, neither of these reports posits that State practice, accompanied by opinio juris, has developed to extend the presumption of state continuity to the context of climate change. It is relevant to note that the opinion does not engage with recent State practice on this matter, nor does the ICJ provide any systematic empirical examination of it. All that is mentioned is the view of “several participants” in the proceedings that sea level rise “poses a significant threat … to the very statehood of small island States” and that “in the event of the complete loss of a State’s territory and the displacement of its population, a strong presumption in favour of continued statehood should apply” (para. 363).

Some States have also linked their support for continuing statehood in the context of climate change with the right of self-determination,  respect for territorial integrity, the State’s fundamental right of survival, permanent sovereignty over natural resources, and so on (e.g., written comments of Kiribati, oral statement of Tonga, oral statement of Tuvalu, and oral statement of El Salvador; see also Judge Tomka, para. 7). While the ICJ did mention territorial integrity, permanent sovereignty over natural resources, and self-determination, this was done in the context of the threats that sea level rise presents to these legal norms (paras. 357 and 363). The opinion did not deal with the legal arguments that connect these legal norms with the presumption of State continuity, if or how they interact with one another, and then what content or scope the norms have. Judge Tomka devoted some attention to these arguments in his separate declaration. For him, the essential difficulty in applying these legal norms to State continuity is that they “are heavily tied to territory” and presuppose the existence of territory or the State as a territorial unit, suggesting that they do not apply to a situation in which territory has been submerged due to rising sea levels (paras. 7-8).

Finally, if one is to accept the interpretation that paragraph 363 implies an acceptance of State continuity in the context of rising sea levels, the ICJ’s restatement of the presumption of State continuity also bears on the applicability of Article 1 of the Montevideo Convention and the contours of State extinction. The full submergence of States due to rising sea levels implies not merely the loss of one of the constituent elements listed in Article 1 but rather all of them.  Without territory, the population is likely to disperse, there is little left to govern, and the capacity to engage in international relations will be severely constrained. Thus, if paragraph 363 is to be understood as endorsing State continuity in the context of climate change, Article 1 of the Montevideo Convention becomes largely irrelevant when it comes to maintaining statehood, and a State would not necessarily be extinguished by the disappearance of all of the basic elements of statehood.

Conclusion

Paragraph 363 of the ICJ’s advisory opinion could have significant implications – or very limited ones – depending on how it is understood. If one were to look for a silver lining, it is that at least the ICJ did not assert that the presumption of state continuity could not apply in the context of climate change, and that is still meaningful in itself. At the same time, the ambiguity in the discussion of statehood and state continuity is unhelpful for the small island nations that are at greatest risk from climate change but have contributed next to nothing to it and the international community more broadly. The ICJ ought to have addressed this crucial matter with greater care, articulating a clearer stance and providing more rigorous legal analysis and relying more substantively on State practice.