Reading the thought-provoking article by Lukas Herich and Katharina Thiehoff on the effects of sea-level rise on statehood reminded me of my earlier research on the concept of Metaverse States. It quickly became evident that, in the short span of two years, significant new developments had emerged on this issue, particularly concerning Tuvalu, in addition to the advisory opinion discussed in the aforementioned article. In this three-part series, I first examine the precarious statehood of low-lying island nations threatened by climate change and Tuvalu’s efforts to confront this challenge. Second, I explore the potential solutions available to states facing territorial disappearance. Finally, I consider whether relocation into cyberspace could offer a viable path to preserving statehood.

1. Disappearing States?

As a result of climate change, sea levels are rising rapidly. Global average sea levels have risen by 21-24 centimeters since the 1880s. In 2023, they reached a new record high, exceeding the level from ten years earlier by 101.4 millimeters. The rate of increase is also accelerating: while sea levels rose by an average of 1.4 millimeters per year for most of the twentieth century, between 2006 and 2015 they increased by 3.6 millimeters annually. By 2100, climate change could affect all continents, potentially destroying the homes of up to 250 million people. In the most extreme scenario, rising sea levels could threaten the existence of internationally recognized states.

Four countries – Kiribati, the Marshall Islands, and Tuvalu in the Pacific Ocean, as well as the Maldives in the Indian Ocean – are particularly vulnerable, as their entire territory lies on atolls (coral reefs rising from the rims of extinct volcanoes), with a maximum elevation of 3-5 meters and an average elevation of 1-2 meters. Their combined population is currently approximately 600,000. However, it is not only microstates and Pacific islands that may become victims of sea level rise. Numerous coastal cities are threatened by flooding with increasing frequency compared to previous periods, with certain areas becoming uninhabitable, particularly in China, India, Bangladesh, and the United States.

It is therefore evident that the issue of shifting state borders as a result of sea-level rise (and, in the long term, the disappearance of small island states themselves) cannot yet be regarded as an acute problem today; however, sooner or later, it will undoubtedly become relevant to speak of a modification in the framework of statehood.

2. On the Definition of the State

There is no universally accepted definition of the concept of a state. Scholarly works most often refer to the 1933 Montevideo Convention on the Rights and Duties of States, which was negotiated under the auspices of the Organization of American States. It has 19 participant states, which, except for the United States, are Latin American countries. On customary law grounds, however, the provisions of this document are applied worldwide. According to the Convention’s four criteria, a state must have (1) a permanent population, (2) a defined territory, (3) a government, and (4) the capacity to enter into relations with other states.

Relating these criteria to the situation of sinking small island states, it is conceivable that all four will be challenged. No  one will want to stay in a state whose territory is sinking, or remain a citizen when the government of that state permanently loses control. Therefore, international law will have to respond to the questioning of all four criteria. However, in what follows, by narrowing the scope of the issue, I will deal exclusively with the underlying cause of the problem – that is, the question of territorial loss as related to the second Montevideo criterion.

3. Montevideo Criterion No. 2.: Territory

Based on the Montevideo definition of statehood, the general assumption therefore remains that the relationship between territory and sovereignty is absolute: a state cannot exist without a territory, meaning that the essence of statehood lies in exercising sovereignty over a given territory.

The territory of a state is not necessarily fixed in a permanent manner. It may be small, fragmented, surrounded by bodies of water, or enclosed as an enclave. It is also possible, in a definitional sense, that another state claims parts or all of the territory of a given state, since numerous areas with disputed legal status exist even today. However, the territory must be habitable.

According to the United Nations Convention on the Law of the Sea, islands that “cannot sustain human habitation or economic life of their own” are considered “rocks”. From the perspective of statehood, however, even a single inhabited island is sufficient (if the state formerly consisted of several islands, all but one of which have submerged). The territorial criterion is also met if the land is protected by coastal defense structures, such as seawalls, or if its geographical characteristics are variable – when the area is above water, then submerged, and later emerges again at low tide. According to UNCLOS, however, artificial islands and seabed-based platforms do not meet the requirement of territory, except when they serve to extend an already existing land area over which the state ‘extends’ its sovereignty (for example, a floating island or a seabed-based platform). Under the current rules, therefore, the concept of territory does not include the ‘solution’ proposed by China to Tuvalu, namely the construction of artificial islands in exchange for Tuvalu’s recognition of mainland China rather than Taiwan.

4. The Findings of the Advisory Opinion on Statehood

The advisory opinion issued by the International Court of Justice on July 23, 2025, titled Obligations of States on Respect of Climate Change, does not define the concept of a state; it employs the term in the sense customarily accepted under international law. Based on paragraph 363 – which cites the examples of territory and population to illustrate that the loss of such criteria does not terminate statehood – it may be inferred that this advisory opinion, too, relies on the conceptual framework of the Montevideo Convention.

The advisory opinion clearly takes the position that statehood does not necessarily cease to exist even if one of its constitutive elements is no longer present: “363. Several participants argued that sea level rise also poses a significant threat to the territorial integrity and thus to the very statehood of small island States. In their view, 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. In 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.”

However, any further elaboration of the topic is nowhere to be found in this otherwise quite lengthy document. Judge Aurescu, in his declaration , offers what I consider a highly logical and well-founded clarification. The judge explains that the advisory opinion refers only to the disappearance of one constitutive element of statehood, even though the submergence of a state’s territory also affects a second element: the population. He therefore argues that the text of the advisory opinion referring to ‘one constituent element’ should not be interpreted strictly or restrictively. Furthermore, he considers it a missed opportunity that the advisory opinion did not explicitly declare that a state forced to migrate as a result of losing both criteria of statehood (territory and population) would retain its membership in international organizations such as the United Nations. He also notes that the articles of the UN Charter concerning the exclusion of states are not applicable in such cases.

Judge Tomka, in his declaration, draws attention to the fact that the wording of the advisory opinion is unfortunate, as the phrase ‘would not necessarily’ conveys uncertainty and thus constitutes ‘a quasi-endorsement of the deconstruction of the conditions of statehood as such.’ He also points out that the Montevideo criteria do not relate to the continued existence of states but only apply at the time of their creation. He firmly maintains that no analogy can be made with other situations in which statehood became uncertain due to governments in exile or foreign occupation, since in those cases the state’s territory was occupied, creating a different legal context from one in which the territory itself ceases to exist as land. He further notes that no customary law has yet developed that would allow one to assert that most states would continue to recognize statehood even after the disappearance of its fundamental criteria.

5. Tuvaluan fforts so far

Tuvalu, a Pacific island nation, seeks to preserve itself as the first digitalized country after climate change and rising sea levels have posed an existential threat to its roughly 12,000 inhabitants. In 2021, Simon Kofe, Tuvalu’s Minister for Justice, Communications and Foreign Affairs, addressed COP26, the UN climate change conference, standing knee-deep in seawater and saying, ‘We are sinking.’ A year later, at the COP27 climate summit, he announced the ‘Future Now’ initiative, which aims to recreate the nation in the metaverse. The goal of this digitalization effort is not only to preserve Tuvalu’s geographical features but also to safeguard its culture, language, traditions, history, and community values in digital form. In 2024, Tuvalu scanned Funafuti Atoll – home to its capital – using high-resolution 3D LiDAR technology, along with eight other major reef islands and atolls, and more than one hundred small, uninhabited islets. The project’s resulting ‘digital twin’ collects real-time data on rainfall, temperature, fishing activities, and coastal changes. Thus, the digitalization project carries a dual message: on the one hand, it represents a practical solution for the ‘digital preservation’ of cultural assets; on the other, it serves as an appeal to the international community to take action to halt climate change.

Thanks to the announcement of the metaverse state and Tuvalu’s other diplomatic efforts, 25 countries have already recognized the continued existence of the nation’s statehood for the future. They have already signed joint communiques with 12 states, in which they acknowledged “Tuvalu’s permanent sovereignty”. Following this, the 18 member states of the Pacific Island Forum collectively pronounced in the 2023 Declaration on the Continuity of Statehood and the Protection of Persons in the Face of Climate Change-Related Sea-Level Rise that „their statehood and sovereignty will continue, and the rights and duties inherent thereto will be maintained, notwithstanding the impact of climate change-related sea-level rise.” According to Tuvalu’s official digital nation website: this takes “the current total of countries who have legally recognized Tuvalu’s digital sovereignty to 25”.

Among the countries recognizing Tuvalu’s future statehood, Australia stands out, having concluded a separate agreement with Tuvalu, creating the world’s first bilateral climate mobility treaty. The Falepili Union was signed on November 9, 2023, and entered into force on August 28, 2024. It is based on Tuvaluan ‘falepili’ values, namely good neighborliness, care, and mutual respect. Australian Prime Minister Anthony Albanese described it as “the most significant agreement between Australia and a Pacific island nation ever.” The agreement – alongside several other commitments less relevant to our discussion – enables the mobility of 280 Tuvaluan citizens annually through a so-called “special human mobility pathway.” They can “live, study and work in Australia” and “access Australian education, health, and key income and family support on arrival.” At the same time, the agreement recognizes Tuvalu’s sovereignty and statehood for the future, despite the effects of climate change. Australia declares that “the statehood and sovereignty of Tuvalu will continue, and the rights and duties inherent thereto will be maintained, notwithstanding the impact of climate change-related sea-level rise.” Additionally, Australia pledges assistance to the country in combating climate change and in security matters.

From Tuvalu’s perspective, the purpose of the treaty is clearly the protection of its small population of barely 10,000 people, along with their identity and culture, and the safeguarding of their continued statehood. The question arises, however, as to why this agreement is advantageous for Australia. The reason lies in Tuvalu’s commitment that it „shall mutually agree with Australia any partnership, arrangement or engagement with any other State or entity on security and defence-related matters. Such matters include but are not limited to defence, policing, border protection, cyber security and critical infrastructure, including ports, telecommunications and energy infrastructure.” Thus, Tuvalu has undertaken not to conclude any defense pact with other countries without Australia’s consent. The Pacific island nation is one of the 12 countries maintaining diplomatic relations with Taiwan (instead of mainland China), at a time when China is seeking to expand its influence in the region. Australia, therefore, has found an ally in Tuvalu to counterbalance this trend.

Gellért Magony JD is a PhD student in law at the Doctoral School of Law and Political Sciences of the Pázmány Péter Catholic University in Budapest (Hungary). He is a graduate of the University of Szeged (Hungary) with a degree in law, where he worked for many years with the Institute of Public Law in different research projects as a student fellow. His main research interests are constitutional law and media law