Glacier-loss and arctic ice melt does not just affect those northern countries most proximate to the ice caps. Rather, due to the impact of ice melt on sea-level rise, it may be small island nations that face the most profound consequences as a result of climate change.
This consequence of climate change threatens not only the livelihoods and security of coastal communities, but for small island states, poses an existential question: whether rising seas will sink them, and their statehood.
The effects of the rapid warming of the Arctic and the consequential devastating ice melt will be felt across the world in the form of sea-level rise [SLR]. According to Yaisen, Fayek, and Sharawi (2023), the melting of the ice caps adds significant amounts of water to the oceans, increasing global sea levels. They note that a key consequence of SLR will be felt by low-lying coastal communities and small island nations that face the threat of displacement and loss of land and resources. [1]
These consequences will be devastating to individuals and communities worldwide, and should not be overlooked. However, the unique vulnerability faced by small island nations lies not in incremental land loss, but in the prospect of total territorial submergence, giving rise to an unprecedented question in international law. Can the statehood of sinking island states survive?
Small Island Developing States (SIDS) are particularly vulnerable to total territory loss due to a range of factors. The small, coastal geographies inherently render the entire populations at risk of displacement due to floodings, erosion, and other consequences of sea level rise. Furthermore, it is often harder for SIDS to afford and implement mitigation strategies available to larger and more wealthy states, as they typically do not have the same economic or technological capacity. The combination of these factors means that SIDS are far more likely to suffer loss of their total landmass than other coastal states.
Statehood: The Classical Theory
Under international law, statehood is classically determined on the basis of the fulfilment of a set of criteria, found under Article 1 of the Montevideo Convention on the Rights and Duties of States (1933). The Convention, generally accepted as a codification of customary international law, lists the criteria for statehood requiring: (a) a permanent population; (b) a defined territory; (c) a government; (d) the capacity to enter into relations with other states.
Importantly, the territorial requirement at 1(b) does not impose a minimum size that is ‘sufficient’ to determine statehood – as demonstrated by the existence of microstates. Furthermore, there is no requirement for the boundaries be undisputed nor fixed, [2] thus there is no inherent problem caused by inconsistencies in land borders in island nations or coastal regions experiencing gradual land loss.
More to the point, however, when it comes to losing statehood, the criteria are not so clear.
There is no precedent nor legal consensus as to whether the loss of the entire landmass of a state would lead to the extinction of the existence of the state itself. Could entire loss of land actually mean that the state ceases to exist? This is the question that threatens the sovereignty of small island states in the face of sea level rise, as they face sinking into the ocean – and out of existence.
How Statehood May Respond To Sinking
The Advisory Opinion on Obligations of States in Respect of Climate Change, delivered by the ICJ in 2025, stated that “once a State is established, the disappearance of one of its constituent elements would not necessarily entail the loss of its statehood”, but did not clarify whether the “strong presumption” of the continued existence of statehood.
This was analysed by Judge Tomka, in his declaration, as ‘no doubt’ referring to ‘the disappearance of the territory of a State in case it becomes completely submerged as a result of sea-level rise’, but goes on to criticise the Court’s ‘precocious leap of legal reasoning’, which he suggests does not reflect a spoken consensus among states.
In Judge Tomka’s view, the classical notion of statehood is ‘virtually inseparable from a land and a people’ – thus, he conflates those criteria which establish statehood as those which determine its maintenance.
Crucially, it seems that Judge Tomka’s primary criticism is that there is not yet the opinio juris present to establish the continued existence of states despite a substantial or total loss of territory. In his declaration, Judge Tomka summarises the crucial arguments in favour of finding a continued existence of statehood as follows:
Vulnerable and other like-minded States believe the mechanisms of international law must be marshalled, and if necessary repurposed, to respond to a looming injustice — the deleterious effects of sea-level rise — which are to be disproportionately borne by those least responsible for its causes. Some States have argued for a legal requirement of continued recognition. Others have invoked various interrelated principles and rights, among others the right to defend a State’s territorial integrity and the right of self-determination, along with equitable or climate–justice policy considerations. The latter represent a plea for creativity, a reimagining of categories in response to a novel and existential challenge.
Ultimately, Tomka suggests that this is something that the international community must consider seriously. It is necessary that the effects of territory loss are considered properly, as statehood is “among the most fundamental questions for international law”.
The effect of legal uncertainty in this area is fundamentally about the peoples belonging to the states at risk. Loss of statehood could lead to populations of stateless individuals unable to access the rights and protections provided by citizenship, the loss of political representation, and a diminished capacity to protect their cultural identity, history, and language. To add the loss of national identity to communities already displaced from their homelands and livelihoods is to further compound the injustice they face as states uniquely vulnerable to climate change. If this were to occur, it would raise profound questions as to the adequacy of existing international legal frameworks.
What’s Next for Small Island Statehood?
In the short-term, mitigation and adaptation efforts remain essential. International cooperation is critical to support coastal protection, climate-resilient infrastructure, and the safeguarding of sovereignty, cultural identity, and legal personality. Furthermore, initiatives that work to protect the rights of individuals, communities and populations as they are displaced are crucial in safeguarding human rights and the victims of climate disasters.
However, these short-term solutions are insufficient without addressing the root cause of sea-level rise. Slowing arctic ice melt and limiting global warming is vital to preserving the continued existence of these vulnerable states, and protecting their peoples. The international legal community must not only consider the impact of sea-level rise on the sovereignty of small island states, but how this can be prevented as far as possible.
Ultimately, international law must adapt to a future in which the physical foundations of statehood are no longer secure – and how it can respond to ensure that sea level rise does not result in the erosion of statehood, rights, and the international protection of vulnerable peoples and communities.
[1] Yaisien, Y., Fayek, Y. and Sharawi, H., 2023. Climate change and its profound effects on marine climate. Fusion of Multidisciplinary Research, An International Journal, 4(2), pp.432-444.
[2] Deutsche Continental Gas-Gesellschaft v Polish State (1929) 5 AD 11: ‘In order to say that a State exists and can be recognised as such… it is enough that… [its] territory has a sufficient consistency, even though its boundaries have not yet been accurately delimited.’
