1. Introduction
Leiden Journal of International Law recently published my article ‘Fluctuating Boundaries in a Changing Marine Environmen’ Footnote 1 and Dr. Massimo Lando wrote an intriguing reply. Footnote 2 These articles discuss the legal basis for fluctuating maritime boundaries and the feasibility of operating fluctuating boundaries where coastal geography is unstable. It seems that the most contentious point relates to the presence of a provisional boundary that neither state can cross in the absence of an agreement establishing a territorial sea boundary. Dr. Lando acknowledges that unilateral maritime limits generally fluctuate. He also highlights an important difference between unilateral limits and bilateral boundaries: the latter are fixed to a geographic location at the time of delimitation. This is generally true but the lack of agreed boundaries can lead to fluctuating provisional boundaries. Footnote 3 Dr. Lando rightly notes that the judicial precedence discussed in my earlier article are shaped by arguments presented by disputing parties and he explains the practical difficulties involved in delimiting and operating fluctuating maritime boundaries. Dr. Lando goes on to suggest that alternative solutions may be more suitable to meet the challenges posed by coastal instability and this is a welcome addition to the conversation. Indeed, fluctuating boundaries may be impractical and the prospect of fluctuating boundaries may act as a driver for states to adopt novel solutions. However, fluctuating boundaries are a viable option in some instances, as demonstrated by the ICJ’s initiative to establish a mobile boundary-segment in 2018. Footnote 4
Provisional boundaries differ from delimited boundaries established by agreements or judicial decisions insofar as they are not established at a particular date and cannot, therefore, be tied to the coastal geography of any specific time. These boundaries more resemble unilateral limits that continuously follow the applicable law because neither acquire the independent legal force that agreed boundaries possess. It is important for this discussion to distinguish between boundaries that fluctuate because they are not subject to an agreement or judicial decision and those that fluctuate despite having been established through such means. The former fluctuate for the same reason as unilateral limits; they have not been permanently established and must continuously satisfy the requirements of international law. The latter fluctuate because states, courts or tribunals have established fluctuating boundaries.
Dr. Lando submits that neither UNCLOS nor judicial decisions provide any legal basis for delimiting fluctuating maritime boundaries. He also maintains that such boundaries are complicated to delimit and manage. This rejoinder will build on my previous article and further demonstrate that UNCLOS does indeed provide a legal basis for fluctuating territorial sea boundaries. It goes on to address legal precedents for the establishment of fluctuating boundaries and, finally, discusses alternative solutions due to the complexity involved with fluctuating maritime boundaries.
2. UNCLOS as a legal basis for fluctuating boundaries
Dr. Lando challenges the assumption that UNCLOS provides a legal basis for provisional boundaries. Footnote 5 This is a core issue that essentially involves two questions. First, are maritime entitlements dependent on positive action by the coastal states or are they automatically generated? Second, does international law provide default rules for the delimitation of inherent maritime entitlements capable of generating provisional boundaries? These questions will be considered in the following sections.
2.1 Inherent maritime entitlements
Coastal states are obligated to define the limits to their maritime zones and to delimit boundaries where entitlements overlap. If a state makes no claim to an exclusive economic zone, no such limits or boundaries are required. However, the entitlement to a territorial sea and continental shelf is inherent or mandatory and failure to establish baselines and maritime limits does not dissolve such entitlements. Footnote 6 They exist without any action by the coastal state, and so do all necessary limits, even in areas of overlapping entitlements. A lack of established baselines leads to the conclusion that states operate normal baselines (identified by reference to the low-water line) Footnote 7 and the outer limits to maritime zones can be determined by reference to baselines and geomorphological criteria in the case of the outer continental shelf. Footnote 8 Similarly, provisional boundaries to the territorial sea can be ascertained by reference to the median line. Footnote 9 All of these limits are subject to change until they are permanently established on the basis of bilateral delimitation or recommendations of the Commission on the Limits of the Continental Shelf (CLCS). Footnote 10
The entitlement to a continental shelf exists ipso facto and ab initio. It can extend beyond 200 nm from baselines in accordance with the natural prolongation of the continental margin and is not dependent on recommendations of the CLCS or any other procedural requirements. Footnote 11 UNCLOS Article 77(3) explicitly provides that ‘[t]he rights of the coastal State over the continental shelf do not depend on occupation, effective or notional, or on any express proclamation’. No such statement is made in regard to the territorial sea but possession of a territorial sea seems to be compulsory Footnote 12 and implicit, without any proclamation to that end. Footnote 13
Failure to satisfy procedural obligations does not eradicate inherent maritime entitlements. UNCLOS certainly entails procedural requirements relating to the establishment of maritime limits and boundaries. However, these do not seem to form a prerequisite to the exercise of coastal state jurisdiction over the continental shelf or territorial sea. Churchill has explained that difficulties in acquiring recommendations from the CLCS and establishing final and binding limits to the continental shelf beyond 200 nm should not prevent states from exercising the ‘full range of [their] continental shelf rights’. Footnote 14 The CLCS is a technical body and its purpose is to ensure that states follow the criteria set forth in UNCLOS. It essentially determines whether the submissions of coastal states regarding their outer continental shelves are ‘technically correct’. Footnote 15 The legal entitlement to a continental shelf is distinct from the obligation to establish outer continental shelf limits based on CLCS recommendations Footnote 16 and the entitlement exists even before the CLCS confirms the legitimacy of the coastal states’ assessment. Consequently, states can proceed to exercise their continental shelf rights in areas within and beyond 200 nm from baselines if they believe the area in question falls within their continental shelf as determined by UNCLOS. However, in doing so, states risk encroaching on the international seabed area or the continental shelf of another state. Footnote 17 Therefore, it is important that states have strong arguments supporting their claim to a continental shelf before exercising such rights.
The same rationale applies to areas of un-delimited continental shelf and territorial sea entitlements. If states can exercise their entitlements to a continental shelf beyond 200 nm despite the lack of CLCS recommendations, they should also be entitled to exercise their rights to a continental shelf and territorial sea in un-delimited areas because the procedural obligation to delimit boundaries is distinct from the legal entitlement to maritime zones. In fact, the 2007 Guyana v. Suriname arbitral award indicates that the absence of a permanent boundary should not unnecessarily restrict the rights of states to exploit inherent entitlements. Here, the tribunal found that Suriname’s eviction of an oil rig and ship licensed by Guyana constituted a violation of UNCLOS, the UN Charter, and general international law. Footnote 18 Furthermore, the tribunal concluded that the parties had breached their obligations to enter into provisional arrangements under UNCLOS Articles 74(3) and 83(3). Footnote 19 Even so, the right to conduct unilateral seismic testing in the disputed area remained Footnote 20 and the tribunal did not consider those acts to be inconsistent with the parties’ obligations ‘not to jeopardise or hamper the reaching of a final agreement’. Footnote 21 This indicates that states can exercise their rights to explore and exploit the continental shelf in un-delimited areas as long as those actions do not cause permanent physical changes to the marine environment. Footnote 22 Therefore, states can exercise certain continental shelf rights (such as seismic testing) in disputed areas pending boundary agreements. Footnote 23 The same may be true of areas subject to overlapping territorial sea claims since those entitlements also exist independently of outer limits or bilateral boundaries and the entitlements should not be unduly restricted by protracted disputes and lack of provisional arrangements.
Anderson has alluded to the fact that states may be entitled to exercise their maritime entitlements in un-delimited areas, explaining that ‘the establishment of a boundary brings legal certainty permitting economic activity to start in previously “grey” areas’. Footnote 24 Indeed, boundaries bring legal certainty and stability but states can have legitimate claims to un-delimited areas and exercise their rights according to such claims. They may even be required to fulfil certain duties accompanying the possession of a territorial sea (such as the publicizing of dangers to navigation) despite the failure to proclaim a territorial sea or delimit boundaries. Footnote 25 The exercise of territorial sea rights and obligations arguably entails reliance upon a provisional boundary.
Exclusive maritime entitlements necessarily call for geographical limits. According to Churchill, the relevant criteria for determining whether a state should exercise its rights and obligations in an un-delimited area might be that of ‘significant uncertainty’. Footnote 26 The International Tribunal for the Law of the Sea (ITLOS) explained that it ‘would have been hesitant’ to assume that Bangladesh and Myanmar had continental shelf entitlements beyond 200 nm in the Bay of Bengal case if it had ‘concluded that there was significant uncertainty as to the existence of a continental margin in the area in question’. Footnote 27 Since ITLOS found it had competence to delimit these entitlements due to a lack of ‘significant uncertainty’ concerning the presence of entitlements in the area, one might assume that coastal states could exercise sovereign rights in that area in the absence of ‘significant uncertainty’ as to the presence of outer continental shelf entitlements. Footnote 28 This same test could be applied to territorial sea entitlements in areas subject to overlapping claims. The obligation to achieve an equitable solution based on international law arguably subjects continental shelf delimitations to significant uncertainties. In contrast, the clarity of UNCLOS Article 15 reduces the uncertainty involved in determining the extent of territorial sea entitlements in un-delimited areas.
2.2 Default rule for delimiting overlapping territorial sea entitlements
If coastal states establish no baselines, or baselines that do not meet relevant UNCLOS requirements, recourse is had to normal baselines to determine the extent of their maritime entitlements. Footnote 29 Similarly, recourse is had to the median line to identify territorial sea boundaries ‘failing agreement between [states] to the contrary’. UNCLOS Article 15 reads as follows:
Where the coasts of two States are opposite or adjacent to each other, neither of the two States is entitled, failing agreement between them to the contrary, to extend its territorial sea beyond the median line every point of which is equidistant from the nearest points on the baselines from which the breadth of the territorial seas of each of the two States is measured. The above provision does not apply, however, where it is necessary by reason of historic title or other special circumstances to delimit the territorial seas of the two States in a way which is at variance therewith. Footnote 30
This Article establishes a default rule for territorial sea delimitation and explains how states with overlapping entitlements must act, unless they agree otherwise. Footnote 31 The lack of agreement to the contrary should lead to the assumption that overlapping territorial sea entitlements are divided by a median line (also referred to as an equidistance line). However, special circumstances and historic title can justify a departure from that line. Here, two readings are possible. This could mean that there is no default territorial sea boundary in cases of historic title or special circumstances or, alternatively, that the default territorial sea boundary is determined with due consideration for special circumstances. The latter reading would codify the equidistance/special circumstances rule of delimitation and be consistent with the travaux préparatoires. According to an early draft version of Article 6 of the Convention on the Continental Shelf Footnote 32 (before territorial sea delimitation was discussed) the default boundary should be ‘determined by application of the principle of equidistance’. This meant that states could depart from the median or equidistance line by reference to special circumstances. Footnote 33 Dr. Lando argues that UNCLOS Article 15 does not establish a default boundary because the median line was only intended to form the ‘basis for delimitation’ Footnote 34 and that ‘the complexity of a case due to special circumstances could result in the effective permanence of a provisional median-line boundary’. Footnote 35 However, the latter reading of UNCLOS Article 15 results in a provisional boundary that is not necessarily a strict median line. This is consistent with the drafting history, which suggests that a departure from a strict median line should not be contingent on an agreement. Footnote 36 Consequently, UNCLOS Article 15 makes the median line a basis for delimitation, and a well-grounded claim to an area beyond the median line can be justified by reference to special circumstances.
UNCLOS Article 15 designates an applicable method for territorial sea delimitation. Other UNCLOS articles designate no default delimitation methods, and that creates comparatively more uncertainty when identifying entitlements in un-delimited areas beyond the territorial sea. Dr. Lando agrees that the situation is different for exclusive economic zone and continental shelf boundaries compared to territorial sea boundaries because UNCLOS Article 15 explicitly refers to the median line. Footnote 37 The lack of any reference to a particular delimitation method in UNCLOS Article 83 makes it difficult to identify a provisional continental shelf boundary, even if the entitlement to a continental shelf is inherent. Instead, UNCLOS Article 83(3) envisions that un-delimited entitlements are subject to provisional arrangements.
UNCLOS Articles 74(3) and 83(3) urge states to establish provisional arrangements pending delimitation agreements. UNCLOS Article 15 has no comparable provision and Dr. Lando assumes that the lack of an explicit reference to provisional arrangements in Article 15 means that no such arrangements are anticipated for the territorial sea. Footnote 38 However, this negative inference from UNCLOS Articles 74(3) and 83(3) is unwarranted. The obligation to seek to agree on provisional arrangements pending delimitation agreements is unnecessary in UNCLOS Article 15 which, unlike Articles 74 and 83, provides a default rule for the delimitation of territorial sea boundaries and refers to agreements as a secondary obligation. Article 15 deals with issues of sovereignty and consequently calls for more certainty than Articles 74 and 83. Footnote 39 In fact, the first draft of what later became Articles 74 and 83 provided that coastal states could not extend their exclusive economic zones or continental shelves beyond the median or equidistance line Footnote 40 but this was replaced with the obligation to adopt provisional arrangements because the drafters wanted to avoid references to the equidistance method. Footnote 41 According to this, the obligation to adopt provisional arrangements under Articles 74(3) and 83(3) represents a softer approach to that taken in UNCLOS Article 15, which is to establish a default provisional arrangement by application of law.
Some states do rely on provisional boundaries. A significant number of potential maritime boundaries have yet to be delimited Footnote 42 and those are arguably subject to provisional boundaries. These can be plotted strictly on the basis of relevant coasts or adjusted by reference to special circumstances but adjusted median lines call for special justification. UNCLOS Article 15 provides the clearest legal basis for provisional boundaries but it seems that some states rely on provisional boundaries even beyond the territorial sea. For example, Italy has declared that, pending agreements, the extent of its entitlement to an ecological protection zone is determined by reference to provisional median lines. Footnote 43 Furthermore, the United States maintain that in the absence of an agreed boundary in the Beaufort Sea, it can rely on an equidistance boundary. Footnote 44 In fact, the United States seem to have delimited overlapping exclusive economic zone entitlements in the Pacific and with Haiti by de facto equidistance boundaries. Footnote 45
3. Judicial precedents for fluctuating boundaries
This section deals with legal precedents for the establishment of fluctuating maritime boundaries. There seems to be no disagreement that states can agree to establish fluctuating maritime boundaries Footnote 46 but Dr. Lando doubts that courts and tribunals have legal authority to establish such boundaries.
In his reply, Dr. Lando explains that ‘[n]othing prevents states from agreeing to establish fluctuating boundaries by treaty’. Footnote 47 Moreover, Purcell, a notable proponent for stable maritime limits, has acknowledged that while the location of a maritime boundary is generally fixed, an ‘ambulatory maritime boundary may still be established by the terms of a boundary agreement or award’. Footnote 48 According to Purcell, ‘the law does not prohibit the establishment of an ambulatory maritime boundary but it does indicate that a fluid character should not be presumed’. Footnote 49 Purcell submits that it is necessary to analyse the specific circumstances of each case to determine whether a boundary is fixed or fluctuating. Footnote 50 The ‘objective’ or ‘declared’ intent of the parties or decision-maker may be relevant for this determination. Footnote 51 Anderson also addresses the possibility of vague expressions in maritime boundary treaties leading to fluctuating boundaries. He notes that a treaty provision indicating that a maritime boundary is ‘the median line’ might result in an ambulatory boundary, ‘for example if baselines changed over the years as a result of natural forces or human intervention in reclaiming land from the sea’. Footnote 52
Dr. Lando assumes ‘international tribunals can delimit fluctuating boundaries, provided that states have agreed to request them to do so’. Footnote 53 However, he rejects the suggestion that two cases, Nicaragua v. Honduras and Costa Rica v. Nicaragua, establish judicial precedents for the establishment of fluctuating boundaries. Indeed, as explained in Dr. Lando’s reply and my original article, the former decision does not establish a fluctuating boundary but leaves a segment of the territorial sea un-delimited. Footnote 54 Dr. Lando doubts the Court intended the un-delimited segment to be ambulatory Footnote 55 but regardless of the Court’s intentions, the application of UNCLOS Article 15 establishes a limit that fluctuates until otherwise agreed. This decision is not a precedent for the establishment of fluctuating boundaries. However, it confirms that courts and tribunals may be unable to delimit boundaries where coastal geography is highly unstable and that can leave states with fluctuating boundary-segments.
The ICJ’s decision in the Costa Rica v. Nicaragua case did establish a fluctuating boundary-segment. Footnote 56 Moreover, both states confirmed in oral submissions that they would be satisfied with a mobile segment. Footnote 57 Dr. Lando submits that this decision is no ‘authority for the delimitation of fluctuating boundaries, but for the narrower proposition that the Court may establish such boundaries when the parties agree to it’. Footnote 58 He suggests that, had it not been for the parties’ consent, the Court might have started the boundary at a fixed point at sea, like it did in Nicaragua v. Honduras. Footnote 59 However, this is speculative and the Court might also, conceivably, have come to the same conclusion as it did without the parties declared willingness to operate a fluctuating boundary-segment. At any rate, the Court clearly found the mobile segment preferable to a fixed boundary (due to coastal instability and erosion) in an area extending 2 nm from the coast. Footnote 60
4. Alternative solutions
Dr. Lando explains the complexities involved with judicial delimitation of fluctuating boundaries. He also discusses, more broadly, how difficult it is to take changing coastal geography into account when delimiting maritime boundaries. This may, according to Dr. Lando, require consideration for future changes to relevant coasts, entailing determination of the relevant timespan, and difficult evidentiary questions. Footnote 61 However, coastal instability can be seen as part of the existing circumstances and can consequently affect the choice of basepoints or delimitation methods, or the weight given to individual coastal features. Footnote 62 This does not necessarily call for an evaluation of future changes, and evidentiary difficulties can be overcome. Footnote 63 Still, as noted by Dr. Lando, it may entail a return to case-specific approaches centred on equitable principles and due regard for all relevant circumstances. Footnote 64 Thus, Dr. Lando may be right in concluding that states are in the best position to address the challenges associated with changing coastal geography; that the boundaries themselves may be the root of the problem; and that the ‘most realistic solution to take stock of the impact of sea level rise on maritime boundaries seems to be joint development of maritime areas’. Footnote 65
Dr. Lando mentions a number of solutions states can adopt on a case-by-case basis, or generally, instead of maritime boundary delimitation. He suggests that these alternative solutions might entail the abolition of maritime boundaries or certain types of maritime zones. Footnote 66 However, solutions that render boundaries or maritime zones obsolete may not sit well with states that have long been preoccupied with territorial acquisition and defined boundaries. Joint development is a more traditional approach which can be useful for managing maritime areas affected by coastal instability and climate change. Footnote 67
Joint development broadly relates to the co-operative exploration or exploitation of particular resources in areas subject to overlapping maritime claims. Footnote 68 Johnston and Valencia have identified three categories of diplomatic solutions to maritime boundary disputes: ‘Agreement to Designate Area in Dispute’, ‘Agreement on Some Limited Degree of Cooperation in Designated Area’, and ‘Arrangement for Integrated Joint Ocean Management’. Footnote 69 Co-operative arrangements may involve joint management, environmental protection measures, or decisions not to exploit resources. States have often negotiated the establishment of joint development zones and the adoption of such arrangements has also been proposed as part of formal dispute settlement. For example, the Conciliation Commission delimiting the continental shelf between Iceland and Jan Mayen urged the parties to agree on a co-operative arrangement for the production of hydrocarbon. Footnote 70 The Conciliation Commission considered recommending co-operation in relation to other activities and explained that such co-operation could involve, for example, training in the petroleum sector and ongoing access to petroleum at reasonable prices.
Co-operative arrangements can replace or supplement traditional maritime boundaries. Footnote 71 It is common practice for states to establish joint development as provisional arrangements under UNCLOS Article 74(3) or 83(3). Footnote 72 Agreements establishing joint development generally demarcate geographic areas and define the applicable resources, rules, and jurisdictions, and they usually specify that the ‘arrangements shall be without prejudice to the final delimitation’, as per UNCLOS Articles 74(3) and 83(3). Footnote 73 However, co-operative arrangements can become permanent even if a boundary is settled. One example is the three-year agreement from 1989 between Denmark, Iceland, and Norway concerning the management of capelin stocks. Footnote 74 This agreement was extended several times, even though after relevant boundaries were agreed, which means that it is no longer a provisional arrangement in the sense of UNCLOS Article 74(3). Footnote 75
The substantive content of agreements concerning co-operative arrangements can vary significantly. For example, states have established joint fisheries zones and adopted ‘clauses concerning future discoveries of transboundary resources’. There are examples of ‘joint regime areas’ or ‘joint development areas’ and ‘joint commissions’ or ‘joint authorities’ to manage the areas and resources within. Footnote 76 States can establish marine protected areas or joint zones for the purposes of managing shared resources. They can also agree not to exploit resources in areas subject to overlapping claims or to co-operate in the protection of particular ecosystems, such as mangrove swamps or salt marshes.
5. Conclusion
This article focused on the legal basis for fluctuating maritime boundaries. It considered whether states have inherent entitlements to a territorial sea and whether UNCLOS Article 15 entails a default rule for the delimitation of overlapping territorial sea entitlements. The article went on to discuss judicial precedents demonstrating the ICJ’s willingness to establish fluctuating boundary-segments. Finally, it explained and exemplified that other solutions might be more feasible in the face of geographic instability. The article concludes that UNCLOS Article 15 does establish a fluctuating provisional boundary and that courts and tribunals do have a legal basis for establishing no boundaries in segments affected by coastal instability, leaving those segments to fluctuate until otherwise agreed. Furthermore, it seems that courts and tribunals can establish fluctuating maritime boundaries but are hesitant to do so without the permission of the parties. Therefore, much depends on the claims brought by disputing parties and their stance on fluctuating boundaries.
States are obligated to establish maritime limits and boundaries in accordance with UNCLOS but what if they fail to meet these obligations? One cannot assume that states possess all maritime zones without express claims to that end. However, there exists an inherent right to the continental shelf and an obligation to have a territorial sea. Therefore, states may be considered to possess those particular maritime zones and to operate accompanying limits and boundaries without any proclamations to that end. If states fail to establish baselines, they are considered to operate normal baselines which may be identified by reference to the low-water line. Similarly, if states fail to delimit a territorial sea boundary, they may be considered to operate an equidistance boundary as described in UNCLOS Article 15. States may also be entitled to exercise their entitlements to a continental shelf in un-delimited areas but the identification of a provisional continental shelf boundary is more complex because, unlike UNCLOS Article 15, Article 83 designates no default method of delimitation and instead urges states to enter into provisional arrangements.
Normal baselines and derived outer limits, including the provisional boundary to the territorial sea, follow the low-water line along relevant coasts and change accordingly. They are consequently subject to significant changes as a result of sea level rise. A large portion of the world’s potential boundaries have yet to be delimited and this article concludes that overlapping territorial sea entitlements in such areas are subject to provisional fluctuating boundaries. States can stabilize otherwise fluctuating maritime boundaries through agreements fixing their location. However, it has already proven difficult to fix stable boundaries by reference to highly unstable coasts, which has led to the delimitation of fluctuating boundary-segments. Such difficulties are bound to increase with the growing impacts of climate change. Indeed, fluctuating maritime entitlements seem inevitable because international law currently offers no way of permanently fixing unilateral maritime limits. Fluctuating boundaries are a natural consequence of fluctuating limits but there is an understandable resistance to this instability, partly due to the complexities involved with delimiting and managing fluctuating boundaries. States can avoid fluctuating maritime boundaries by adopting alternative solutions where geographically stable boundaries are unattainable. Such solutions should be encouraged as they can be beneficial to the marine environment. However, they involve a significant departure from the traditional division of maritime zones into territorial units and they can make maritime boundaries obsolete.
Funding statement
This research is funded by the Icelandic Research Fund (grant number 169369).
