The Régime of Islands and Sea-Level Rise

Abstract

Climate change resulting from human activity is causing sea-levels to rise. Rising sea-levels pose an existential threat to small islands. Some have argued that this might result in islands losing their status as ‘islands’ and, at the same time, their maritime areas. The present article disagrees. In order to qualify as an ‘island’, a coastal feature must be ‘a naturally formed area of land, surrounded by water, which is above water at high tide’: Article 121(1) of the United Nations Convention on the Law of the Sea (UNCLOS). A feature that meets these requirements is, according to Article 121(2), entitled to a territorial sea, an exclusive economic zone and a continental shelf. Article 121(3) provides that rocks which cannot sustain human habitation or an economic life of their own have no exclusive economic zone or continental shelf. The words ‘naturally formed area of land’, as well as broader considerations, suggest that the status of a feature is determined on the basis of its natural condition—not changes generated by human activity. Just as construction through human artifice cannot elevate a coastal feature into an island, man-made climate change which causes sea-level rise cannot turn an island into something other than what is described in Article 121(1).

1. Introduction

In 1988 the United Nations (UN) General Assembly stated in Resolution 43/53 that ‘the emerging evidence indicates that continued growth in atmospheric concentrations of “greenhouse” gases could produce global warming with an eventual rise in sea levels’. ¹ The Intergovernmental Panel on Climate Change (IPCC) observed in 2021 that ‘[h]eating of the climate system has caused global mean sea level rise’. ² In 2022 the IPCC warned that sea-level rise could pose ‘an existential threat for some small islands’. ³ In 2023 it observed that ‘[g]lobal mean sea level increased by 0.20m between 1901 and 2018’ and that, since at least 1971, ‘[h]uman influence was very likely the main driver of these increases’. ⁴ The UN Secretary-General has stated that ‘[r]ising seas are a crisis entirely of humanity’s making’. ⁵ Against this background, the International Tribunal for the Law of the Sea observed in its Advisory Opinion on Climate Change that ‘climate change represents an existential threat’ for the populations concerned. ⁶ The International Court of Justice (Court) observed in Obligations of States in respect of Climate Change that:

[t]he consequences of climate change are severe and far reaching; they affect both natural ecosystems and human populations. Rising temperatures are causing the melting of ice sheets and glaciers, leading to sea level rise and threatening coastal communities with unprecedented flooding. ⁷

The régime of islands in international law is set out in Article 121 of the UN Convention on the Law of the Sea (UNCLOS or Convention). ⁸ The provision forms ‘an indivisible régime’ and reflects customary international law. ⁹ It states:

1. i. An island is a naturally formed area of land, surrounded by water, which is above water at high tide.

2. ii. Except as provided for in paragraph 3, the territorial sea, the contiguous zone, the exclusive economic zone and the continental shelf of an island are determined in accordance with the provisions of this Convention applicable to other land territory.

3. iii. Rocks which cannot sustain human habitation or economic life of their own shall have no exclusive economic zone or continental shelf. ¹⁰

The phenomenon of anthropogenic greenhouse gas emissions, along with the sea-level rise that they cause, has brought to the fore the following questions as regards the régime of islands: could a feature that is today a naturally formed area of land, surrounded by water, which is above water at high tide, find in the future that it is, by reason of man-made sea-level rise, no longer an island as it is no longer above water at high tide? ¹¹ If so, it would mean that it had lost its entitlement to an exclusive economic zone and a continental shelf. ¹² Similarly, could a feature that today qualifies as an island tomorrow find itself, again by reason of anthropogenic sea-level rise, deprived of its exclusive economic zone and continental shelf on account of its no longer being able to sustain human habitation or economic life of its own? ¹³ And, finally, what if a feature that used to be an island then finds itself ‘surrounded by and above water at low tide but submerged at high tide’—would it be reduced to the status of a low-tide elevation, and thereby deprived of its territorial sea? ¹⁴ As the Co-Chairs of the Study Group of the International Law Commission (ILC) on Sea-level Rise in relation to International Law (ILC Study Group) observed:

The partial inundation of a fully entitled island owing to sea-level rise could call into question its possible reclassification from the category of a fully entitled island to that of a rock, or even a low-tide elevation, if the capacity to sustain human habitation or economic life of its own is lost. The criterion of sustaining human habitation and economic life of their own can be especially important in the case of islands made [un]inhabitable because of sea-level rise. This can be the result of increased flooding due to elevated tides, infiltration of salt water in freshwater supplies, loss of agricultural land and food production, and other factors making the island uninhabitable for humans or unable to sustain economic activities. ¹⁵

As regards the practice of States in relation to this question, the Co-Chairs of the ILC Study Group concluded that State practice was not clear on the issue but ‘raises questions as to whether a fully entitled island that has lost territory could be deemed to become a rock as defined under paragraph 3’. ¹⁶

Caron observed in 1990 that ‘[a] rising sea level could taint the freshwater reservoir of an island potentially rendering it uninhabitable, submerge enough of it to leave only an uninhabitable rock, or submerge it entirely’. ¹⁷ His general argument, that the law makes climate change worse, was based in part on the assertion that under the system of UNCLOS baselines are ambulatory. ¹⁸ This, in turn, was based on an a contrario reading of Articles 7(2) ¹⁹ and 76(9) UNCLOS. ²⁰ As those two provisions were the only ones that laid down the permanency of baselines or outer limits of maritime zones, he argued that baselines were ambulatory rather than permanent. ²¹ The weakness of this argument is evident already from its a contrario basis. Such a reading of treaty provisions is warranted only ‘when it is appropriate in light of the text of all the provisions concerned, their context and the object and purpose of the treaty’. ²² The present article will seek to argue against this position and show that, in the context of islands and sea-level rise caused by climate change, such a reading of UNCLOS is not appropriate.

The balance of the article focusses, in Section 2, on the broader considerations on which the régime of islands is based, with a view to putting the interpretation of Article 121 in the context of sea-level rise on the right footing. The focus then turns, in Section 3, to the understanding of the régime of Article 121 in its proper context. Finally, Section 4 sets out concluding remarks. The question of statehood, including the potential disappearance of an entire State, owing to the effects of climate change on sea-level rise, falls outside the remit of the article. ²³

2. Fundamental considerations

The Court observed in its Reparations Advisory Opinion that, ‘[t]hroughout its history, the development of international law has been influenced by the requirements of international life’. ²⁴ If, however, the emergence of new requirements gives rise to novel legal questions, the fact that the answers, too, seem novel does not always mean that the law has changed. Judicial reasoning, for instance, is a process that works by way of ‘the disengagement from accidental circumstances of the principles underlying rules of law already established’. ²⁵ Thus Waldock observed in 1979 that, if the Court’s contribution to the modern law of the sea had been considerable and even progressive, the Court had actually done no more than to throw ‘fresh light on the considerations and the principles on which the law was based in a manner to suggest the path for its future development’. ²⁶ A recent example of this type of contribution, which throws fresh light on considerations already inherent in the existing law, was given by the arbitral tribunal in South China Sea Arbitration, which was concerned to reflect, in its construction of Article 121, ‘the sensitivity to the lifestyles of small island peoples that was apparent at the Third UN Conference [on the Law of the Sea]’. ²⁷ This is the approach that the present article seeks to take to the interpretation of the régime of islands in Article 121 in the context of climate change and sea-level rise.

Before turning to an analysis of those considerations, however, it is necessary to make a terminological clarification. The term ‘delimitation’, as in maritime delimitation, means not only bilateral but also unilateral delimitation. ²⁸ It is, of course, true that ‘[b]oundaries cannot be established unilaterally’. ²⁹ But when a coastal State unilaterally declares, on the basis of a maritime feature which it considers to be an island, that the feature in question has a territorial sea, an exclusive economic zone and a continental shelf, that is an act of delimitation. The Court made this apparent in the Anglo–Norwegian Fisheries case, where it observed, in connection with Norway’s unilaterally drawn straight baselines, that ‘the act of delimitation is necessarily a unilateral act, because only the coastal State is competent to undertake it’. ³⁰ The Court added, no less importantly, that although the act of delimitation was necessarily a unilateral act ‘the validity of the delimitation with regard to other States depends upon international law’, ³¹ a fundamental principle since adopted in the context of land boundaries as well. ³² There are, in particular, two considerations to be taken into account in the present context.

2.1. Stability and predictability

The first such consideration is stability and predictability. ³³ It is convenient, first, to focus on the former. The question of changes in the status of a feature under Article 121 must ‘be viewed in a broader context which contemplates also the effect of rocks entitlement on the overall picture of stability and continuity of maritime borders’. ³⁴ It is a principle of international law that ‘a state of things which actually exists and has existed for a long time should be changed as little as possible’. ³⁵ Thus the Court observed in Aegean Sea that, in relation to land boundaries and maritime delimitation, ‘the process is essentially the same, and inevitably involves the same element of stability and permanence’. ³⁶ The general position is that boundaries are permanent unless they are altered by agreement between the States concerned. ³⁷ This is why the Court observed in Jan Mayen that the attribution of maritime areas to the territory of a State is, by its nature, ‘destined to be permanent’. ³⁸

It is provided in the preamble of UNCLOS that the general purpose of the Convention is to ‘contribute to the strengthening of peace, security, co-operation and friendly relations among all nations’. ³⁹ UNCLOS was meant to be a stabilizing factor in inter-State relations concerning questions relating to the oceans: ‘[s]table, predictable and continuous ocean borders become of paramount importance in achieving this fundamental goal’. ⁴⁰ International tribunals have recognized the link between such stability and the peaceful relationship between States. Thus the arbitral tribunal in Bay of Bengal emphasized that ‘maritime delimitations, like land boundaries, must be stable and definitive to ensure a peaceful relationship between the States concerned in the long term’. ⁴¹

As regards predictability, a close cognate of stability, this consideration is an aspect of the rule of law. ⁴² In a discussion of the legal concept of equity, the Court observed in Continental Shelf (Libyan Arab Jamahiriya/Malta) that ‘the justice of which equity is an emanation, is not abstract justice but justice according to the rule of law; which is to say that its application should display consistency and a degree of predictability’. ⁴³ By making this observation, the Court ‘emphasized two of the core requirements of a legal system based on the rule of law: consistency and predictability’. ⁴⁴ In observations concerning the role that law plays in international life, then UN Secretary-General Dag Hammarskjold considered that those core requirements were values to be promoted in international relations generally. ⁴⁵ In a similar vein, the Court stressed in Obligations of States in respect of Climate Change the necessity of achieving ‘the essential consistency of international law, as well as legal security’. ⁴⁶ Although, as is evident from these instances, the considerations of consistency and predictability could well be seen as considerations applicable in every field of international law, they have over time taken on particular importance in the law of the sea. ⁴⁷ In fact the development of the modern law of the sea and, in particular, maritime delimitation has been described as a steady move from unpredictability towards predictability. ⁴⁸

2.2. The island population may not be deprived of its own means of subsistence

The second consideration is that ‘[i]n no case may a people be deprived of its own means of subsistence’, which is codified in Common Article 1 of the International Covenant on Civil and Political Rights and the International Covenant on Economic, Social and Cultural Rights. ⁴⁹ This principle is an aspect of the right to self-determination of peoples, a right for the exercise of which ‘sea level rise is not without consequences’. ⁵⁰

The principle that a people may not be deprived of its own means of subsistence, along with its ‘corresponding duties for all States and the international community’, ⁵¹ has received specific recognition in the context of the law of the sea. In 1927 Norway referred to the ‘means of subsistence’ of its coastal population, ‘whose existence almost everywhere depends on fishery’. ⁵² In the Santiago Declaration on the Maritime Zone, Chile, Ecuador and Peru declared in 1952 that ‘[g]overnments have the obligation to ensure for their peoples the necessary conditions of subsistence, and to provide them with the resources for their economic development.’ ⁵³ The three States Parties emphasized their duty to prevent any exploitation of maritime resources:

beyond the scope of their jurisdiction, which endangers the existence, integrity and conservation of these resources to the detriment of the peoples who, because of their geographical situation, possess irreplaceable means of subsistence and vital economic resources in their seas. ⁵⁴

In 2010 the United Kingdom relied on the principle that ‘in no case may a people be deprived of its own means of subsistence’ in order to argue for what it considered to be the entitlement of the Falklands/Malvinas Islands Government to exploit for the benefit of its population economic resources within its maritime zones. ⁵⁵

In Anglo–Norwegian Fisheries the Court, in apparent agreement with Norway’s State practice relating to the ‘means of subsistence’ of its coastal population, laid emphasis on ‘the vital needs of the population’ of the coastal areas of Norway. ⁵⁶ There is, as a Chamber of the Court observed in Gulf of Maine, inherent in the international law governing maritime delimitation a reluctance to condone results which should ‘be revealed as radically inequitable, that is to say, as likely to entail catastrophic repercussions for the livelihood and economic well-being of the population of the countries concerned’. ⁵⁷ While this consideration will rarely be taken into account as a relevant circumstance in maritime delimitation, it may ‘feed into broader assessments of equitability’. ⁵⁸ The Court relied on this consideration in Jan Mayen, where, in order to ‘ensure equitable access to the capelin fishery resources for the vulnerable fishing communities concerned’, the Court shifted the median line in favour of Denmark. ⁵⁹ This consideration is also reflected in Article 121(3) UNCLOS. One of the purposes of Article 121(3) was ‘that the local population should benefit from the resources of the adjacent sea area and that such resources should be better managed’. ⁶⁰ Indeed Gidel pointed out that, in the context of islands, this consideration is the obverse of the fundamental principle, famously set forth in the Grisbadarna award, that ‘the maritime territory is an essential appurtenance of land territory’: ⁶¹ as he observed, ‘[l]e territoire maritime est sans doute une dépendance nécessaire du territoire terrestre; mais il faut que ce territoire terrestre soit effectivement utilisé ou susceptible de l’être’. ⁶²

3. Understanding Article 121 in its context

The States Parties to UNCLOS recorded in its preamble their desire to settle ‘all issues relating to law of the sea’. They wished to do so ‘conscious that the problems of ocean space are closely interrelated and need to be considered as a whole’. As the Court has observed, the method of negotiation at the Third UN Conference on the Law of the Sea ‘was designed against this background and had the aim of achieving consensus through a series of provisional and interdependent texts on the various questions at issue that resulted in a comprehensive and integrated text forming a package deal’. ⁶³ That package deal was ‘never conceived as a mere consolidation and elaboration of existing law, but always as a vehicle for new law to meet new needs, in a new and greatly expanded international society’. ⁶⁴ The Conference was concerned more with law reform than codification. ⁶⁵

One part of the resulting integrated text that was doubtlessly an admixture of law reform and codification is Article 121, concerning the ‘régime of islands’. As already mentioned, it forms ‘an indivisible régime’ which today reflects customary international law. ⁶⁶ Although UNCLOS, as a whole, was more than a consolidation and elaboration of existing law, parts of it were very similar to provisions in the Geneva Conventions adopted in 1958—the Convention on the Territorial Sea and the Contiguous Zone (CTS); the Convention on the High Seas; the Convention on Fishing and Conservation of the Living Resources of the High Seas; the Convention on the Continental Shelf; and the Optional Protocol of Signature concerning the Compulsory Settlement of Disputes—as well as their precursors. The backdrop of the legislative history is therefore pertinent. For present purposes, it is relevant that, for at least the last 100 years, States have taken the view that whether a feature qualifies as an island is to be determined on the basis of ‘normal’ or ‘natural’ circumstances, such that ‘artificial’ changes are to be disregarded.

3.1. Legislative history

The question of islands arose during the Imperial Conference of 1923, where the constituent entities of the British Empire sought to set out a common policy as regards the territorial sea. Resolution 4 of the Imperial Conference was in the following terms:

The coastline from the low-water mark of which the 3-mile limit of territorial waters should be measured, is that of the mainland and also that of all islands. The word “island” covers all portions of territory permanently above high water in normal circumstances and capable of human habitation. ⁶⁷

The explanatory memorandum provided that it was intended that the words ‘“capable of habitation” should mean capable, without artificial addition, of permanent human habitation’. ⁶⁸

The definition proposed in 1930 at the first properly intergovernmental discussion of the régime of islands—the Hague Codification Conference organized by the League of Nations—was in these terms: ‘[a]n island is an area of land, surrounded by water, which is permanently above high-water mark’. ⁶⁹ The commentary explained that this definition:

does not exclude artificial islands, provided these are true portions of the territory and not merely floating works, anchored buoys, etc. The case of an artificial island erected near to the line of demarcation between the territorial waters of two countries is reserved. ⁷⁰

The United Kingdom’s view, set forth in 1929 in its reply to the points submitted to governments by the Preparatory Committee of the Hague Conference, was that: ‘[a]n island is a piece of territory surrounded by water and in normal circumstances permanently above high water. It does not include a piece of territory not capable of effective occupation and use.’ ⁷¹ In 1934, Gidel, who had represented France at the Hague Conference, defined an island as ‘une élévation naturelle du sol maritime qui, entourée par l’eau, se trouve d’une manière permanente au-dessus de la marée haute et dont les conditions naturelles permettent la résidence stable de groupes humains organisés’. ⁷²

Although the Hague Conference ended in relative failure, ⁷³ no convention having been agreed, the discussions at The Hague would inform the work taken up by the ILC in preparation for the First UN Conference on the Law of the Sea. The first draft of the relevant provision, Article 9, in the first report by the Special Rapporteur, JPA François, was in these terms: ‘[c]haque île comporte une mer territorial qui lui est propre. Une île est une étendue de terre, entourée d’eau, qui se trouve d’une manière permanente au-dessus de la marée haute.’ ⁷⁴

In the ILC discussions, Lauterpacht suggested, in keeping with Gidel’s definition, that the definition of ‘island’ should include the requirement that a feature should be ‘capable of effective occupation and control’. ⁷⁵ This suggestion was not taken up.

The words ‘d’une manière permanente’ from the Special Rapporteur’s first draft were not included in the final text of what became Article 10(1) CTS. ⁷⁶ It is unclear why. Article 10(1) provides that: ‘[a]n island is a naturally formed area of land, surrounded by water, which is above water at high-tide.’ The terms of Article 10(1) CTS are repeated word for word in Article 121(1) UNCLOS. ⁷⁷

3.2. Interpretation of Article 121

The purpose of treaty interpretation is ‘to establish the meaning of the text which the parties must be taken to have intended it to bear in relation to the circumstances with reference to which the question of interpretation has arisen’. ⁷⁸ Interpretation of rules of international law divorced from factual circumstances is not likely to be a productive exercise. As the Court advised in Interpretation of the Agreement of 25 March 1951 between the WHO and Egypt, ‘a rule of international law, whether customary or conventional, does not operate in a vacuum; it operates in relation to facts’. ⁷⁹ Examples of such interrelation between rules of international law and facts are not difficult to find. One is afforded by the South China Sea Arbitration, where the tribunal took account of the fact:

that remote island populations often make use of a number of islands, sometimes spread over significant distances, for sustenance and livelihoods. An interpretation of Article 121(3) that sought to evaluate each feature individually would be in keeping neither with the realities of life on remote islands nor with the sensitivity to the lifestyles of small islands that was apparent at the Third UN Conference. ⁸⁰

This meant that, ‘provided that such islands collectively form part of a network that sustains human habitation in keeping with the traditional lifestyle of the peoples in question, the Tribunal would not equate the role of multiple islands in this manner with external supply’. ⁸¹

In the present context, an important part of the factual circumstances in relation to which Article 121 operates is that the global mean sea level is increasing by reason of human activity, ⁸² sea-level rise having been referred to as being ‘entirely of humanity’s making’. ⁸³

Article 31(1) of the Vienna Convention on the Law of Treaties (VCLT) provides that ‘[a] treaty shall be interpreted in good faith in accordance with the ordinary meaning to be given to the terms of the treaty in their context and in the light of its object and purpose’. ⁸⁴ As the Court has observed, ‘[t]hese elements of interpretation—ordinary meaning, context and object and purpose—are to be considered as a whole’. ⁸⁵ Three points should be made in this connection.

First, the interpretation of Article 121, like any other treaty provision, must ‘be based above all upon the text of the treaty’. ⁸⁶ This injunction, however:

does not mean relying solely, or mainly, on the ordinary meaning of the terms. Such a solution would effectively ignore the references to good faith, the context, and the object and purpose of the treaty. The ordinary meaning of the terms is even itself determined as a function of the context, object and purpose of the treaty. ⁸⁷

Second, as arbitral tribunals have observed, international law ‘does not sanction any absolute and rigid method of interpretation’. ⁸⁸ The provisions of treaty interpretation, as reflected in Articles 31–32 VCLT, ‘must not be misread as introducing either a rigid, or still less a hierarchical, set of rules’. ⁸⁹ In that vein, it has been observed that Article 121(3) must be interpreted ‘en faisant preuve de souplesse et en attribuant un poids particulier au but et à l’objet de cette disposition, qui est celui de traiter équitablement les différents types de formations insulaires’. ⁹⁰

Third, and closely connected with the second point, the Court observed in Continental Shelf (Tunisia/Libyan Arab Jamahiriya) that, ‘when applying positive international law, a court may choose among several possible interpretations of the law the one which appears, in the light of the circumstances of the case, to be closest to the requirements of justice’. ⁹¹ This means that, in the law of the sea, ‘as in all other fields of international law, it is necessary that the law be applied reasonably’. ⁹² As DH Anderson has observed, ‘reasonableness is called for in interpreting the different articles in the Convention which refer to the myriad of natural coastal features of the Earth’s surface’. ⁹³

An ‘island’ is, according to Article 121(1), a naturally formed area of land, surrounded by water, which is above water at high tide. The words ‘a naturally formed area of land’ are vital. An island is not defined only as a maritime feature which is above water at high tide: the focus is, as Gilbert Guillaume has observed, more fundamentally on ‘a naturally formed area of land’. ⁹⁴ The wording is an expression of the fact that inherent in the very régime of islands is a focus on whether the processes in question are natural, or whether they are by contrast anthropogenic. The focus has, throughout the last 100 years, been on the natural state of the feature in question—‘without artificial addition’ in the words of the Imperial Conference; ⁹⁵ ‘in normal circumstances’ in the words of the United Kingdom in 1929; ⁹⁶ and ‘a naturally formed area of land’ in Article 10(1) CTS and Article 121(1) UNCLOS. This is why, according to Article 60(8) UNCLOS, artificial islands ‘do not possess the status of islands’ and, accordingly, generate no maritime zones. It is this natural condition, not ‘des changements générés par l’homme’, that will determine whether a feature qualifies as an island or not. ⁹⁷ As the arbitral tribunal pointed out in South China Sea Arbitration, ‘the inclusion of the term “naturally formed” in the definition of both a low-tide elevation and an island indicates that the status of a feature is to be evaluated on the basis of its natural condition’. ⁹⁸

Such an interpretation accords with the considerations on which the law of the sea is based. ⁹⁹ It is in keeping with the consideration of stability: ‘maritime delimitations, like land boundaries, must be stable and definitive to ensure a peaceful relationship between the States concerned in the long term’. ¹⁰⁰ This led the tribunal in Bay of Bengal to focus on the ‘physical reality at the time of the delimitation’; ‘[i]t need not address the issue of the future instability of the coastline’ that might over time be caused by climate change. ¹⁰¹ As to predictability, it is true that ‘[s]ubmerged baselines go against the whole ethos of UNCLOS, which is that at some point in the tidal cycle baselines and base points must be above water’. ¹⁰² On the other hand, predictability, an aspect of the rule of law, would be gravely compromised if sea-level rise caused by the anthropogenic emissions by some States of greenhouse gases would be allowed to deprive for example small island States, which have contributed only minimally to historical emissions, of their maritime areas. And, as the Court has pointed out, States have given expression to strong concerns in relation to ‘sea level rise and its implications, especially for the stability of maritime zones’. ¹⁰³

As regards the consideration that in no case may the island population be deprived of its means of subsistence, it should be recalled that for many small island States the exclusive economic zone and the continental shelf are the ‘key maritime entitlements and major sources of income’ for their island populations. ¹⁰⁴ To use the words of the Court, ‘the vital needs of the population’ depend on the exploitation of the maritime zones, especially the exclusive economic zone, appurtenant to their islands. ¹⁰⁵ One of the purposes of Article 121(3) was that the local population, rather than populations potentially far removed, should benefit from the resources of the adjacent sea area. ¹⁰⁶ It must be the case that ‘the meaning attributed to the terms of Article 121(3) should serve to reinforce, rather than counter, the purposes that the exclusive economic zone and Article 121(3) were respectively intended to serve’. ¹⁰⁷ As the Co-Chairs of the ILC Study Group have observed, a different reading of Article 121(3) ‘would mean that an island that has become uninhabitable because sea-level rise has, for example, caused seawater infiltration contaminating its freshwater supplies, and not because of loss of territory, might lose its exclusive economic zone and continental shelf entitlements’. ¹⁰⁸ Consequences of this kind could be ‘economically, socially and culturally catastrophic’. ¹⁰⁹ Article 121 must be interpreted such that anthropogenic climate change, and the sea-level rise attendant on it, is not allowed to deprive an island of that status, with the result that it and its population is despoiled of maritime entitlements.

The question of human habitation concerns the potential of such activity. Only an uninhabitable, not simply uninhabited, rock would fall into this category in Article 121(3). ¹¹⁰ There is State practice dating back to the nineteenth century to this effect. ¹¹¹ It has also been confirmed in judicial decisions. The Supreme Court of Norway held in Haraldsson that Abel Island qualified as an island under Article 121(1). As regards the requirement of that provision, the court held, in a judgment delivered by Justice Schei, that:

The facts suggest that it would have been possible to carry out significant hunting for polar bears in the area, if this had not been prohibited for environmental reasons. When it is the prohibition that hinders such hunting, and not lack of resources, I fail to see that the additional requirement in paragraph 3 is met. ¹¹²

The arbitral tribunal in South China Sea Arbitration similarly reasoned that it must:

consider whether there is evidence that human habitation has been prevented or ended by forces that are separate from the intrinsic capacity of the feature. War, pollution, and environmental harm could all lead to the depopulation, for a prolonged period, of a feature that, in its natural state, was capable of sustaining human habitation. ¹¹³

The Co-Chairs of the ILC Study Group have on this basis indicated that the natural condition, as opposed to human intervention, determines whether a feature is habitable or not. Human intervention could include sea-level rise that is caused by man-made climate change, such that change of this kind would not alter the intrinsic capacity of the feature and not therefore affect its status. ¹¹⁴

The correct position is, indeed, that the requirements of Article 121(3) refer to the ability of the feature in question to sustain—in normal circumstances and free from intervention such as anthropogenic environmental harm—human habitation or economic life of its own. Just as construction through human artifice cannot elevate a coastal feature into an island, man-made climate change which causes rising seas cannot turn an island into something other than that which is described in Article 121(1).

It could be argued that there is a qualitative difference between the artifice of man in the form of the coastal State (or a similarly placed State) trying to convert a low-tide elevation into an island, on the one hand, and the effects of climate change on sea-level rise worldwide, on the other. In the first case, the coastal State (or a similarly placed State) is directly involved: in the latter case, it might be argued that no particular State is involved. Given the development of attribution science, however, it is now possible to attribute greenhouse gas emissions and their effects to particular States, such that it is possible to determine which States are directly involved in this context too. The Court has accordingly held that, while climate change is caused by cumulative greenhouse gas emissions, ‘it is scientifically possible to determine each State’s total contribution to global emissions, taking into account both historical and current emissions’. ¹¹⁵

4. Conclusion

The phenomenon of rising sea levels, a crisis of humanity’s own making, ¹¹⁶ is only likely to continue and intensify over the coming decades. One could well ask whether UNCLOS is capable of providing all the answers to the difficult new questions that arise, or whether those answers lie instead in the realm of policy. ¹¹⁷ It is nevertheless the case that ‘when a decision has to be made as to the legal status of a feature such as an island, the sea level in relation to it, whether high or low water, should be determined in accordance with the rules in the Convention and the physical facts as they are known to exist at that time’. ¹¹⁸ The Court observed in Obligations of States in respect of Climate Change that, once the breadth of maritime zones measured from the baselines has been duly established and has received due publicity in accordance with UNCLOS, ‘there is no provision in the Convention requiring States parties to update them’; ¹¹⁹ and ‘the provisions of UNCLOS do not require States parties, in the context of physical changes resulting from climate-change related sea level rise, to update their charts or lists of geographical co-ordinates that show the baselines and outer limit lines of their maritime zones’. ¹²⁰ If a feature that, at one point in time, is naturally an island later becomes submerged or uninhabitable by reason of anthropogenically caused climate-change related sea-level rise, that does not result in the loss of maritime entitlements. The régime of islands in Article 121 UNCLOS is to the effect that it is the natural condition, not conditions caused by human activity, that determines whether a feature is or is not an island. This interpretation of the régime of islands is, in the context of climate change and sea-level rise, in keeping with the fundamental considerations and principles to which the law of the sea, as codified in UNCLOS, gives authoritative expression.