A number of maritime delimitation disputes, the resolution of which has been referred to international courts or tribunals, include overlapping outer continental shelf claims without relevant recommendations from the Commission on the Limits of the Continental Shelf (CLCS) in support of the claimed entitlements. The case law of courts and tribunals regarding the exercise of jurisdiction over such disputes has developed and appears now somewhat crystallized in a common understanding. Yet numerous uncertainties remain, which have arisen from the non-homogeneous approaches that underlie the decisions of courts and tribunals to exercise jurisdiction in the absence of recommendations from the CLCS. While courts and tribunals share the view that delimitation necessarily requires a prior determination of entitlement, differences appear in defining the threshold for ascertaining such a determination. In any event, treating submissions to delimit such claimed overlaps as admissible in the absence of recommendations from the CLCS may entail significant risks. Where a plea is considered admissible, a court or tribunal will not have unfettered discretion as to whether to exercise jurisdiction. This may result in unfortunate situations as it cannot be assumed that the CLCS will accept coastal states’ proposed outer limits of the continental shelf.

This article addresses the dispute between Greece and Turkey concerning the reach of their sovereign rights and jurisdiction in the Eastern Mediterranean, which is essentially about delimitation of the continental shelf and exclusive economic zone (EEZ). Turkey has delineated its continental shelf in the region to extend directly to the outer limits of the territorial waters of the Greek islands, specifically Crete, Rhodes, and Kastellorizo. Greece sees this as an attempt to deprive the islands of their maritime zones. The present article discusses what the two states might expect if they would request the International Court of Justice (ICJ) to determine the course of their maritime boundaries. The outcome of such a process would be difficult to foresee because international case law regarding the effect of islands on the delimitation of the continental shelf and EEZ is rather diffuse. Nevertheless, this article will explore what an equitable solution could look like. In particular, the small island of Kastellorizo, Greece’s most remote outpost in the Eastern Mediterranean, which lies just off the Turkish coast, requires special consideration. The present article discusses different options for dealing with this island in a future delimitation.

Do states take court decisions into account when formulating policies? If so, how do they process new judicial input and make policies in response to them? While self-interest and incentives are the usual elements involved in a rational choice explanation of policymaking, behavioralist scholarship casts doubt on whether decisionmakers are able to identify and pursue their interests in a rational manner. We draw on rational and behavioral approaches to formulate different expectations about the process of policymaking and updating in the context of maritime delimitation. We focus on how states formulate policies about the appropriate method of maritime delimitation given relevant decisions of the International Court of Justice. Using a dataset of continental shelf delimitation policies, we find evidence that at least some states change policies in line with court decisions. However, we are unable to distinguish between mechanisms consistent with rational choice and those suggested by behavioralism. We discuss why behavioralist explanations of policymaking processes are difficult to test in a large-N setting. Moreover, we discuss why additional evidence from interviews also proves insufficient, notably due to actors’ tendency to rationalize state policies. We end by suggesting how these problems can be addressed in future research.

Geographical phenomena impacting the shape of coastlines may have implications for the stability of maritime boundaries delimited by agreement or judicial process. Sea level rise resulting from human-caused climate change has recently arisen as an additional phenomenon compelling the re-assessment of the stability of maritime boundaries over time. In a recent article published in this Journal, Dr. Snjólaug Árnadóttir has argued that a solution to the challenges of coastline change could be for maritime boundaries to fluctuate following the fluctuation of the baselines on which their course depends. By way of reply to Dr. Árnadóttir’s suggestion, this article argues that fluctuating boundaries have no legal basis either in the United Nations Convention on the Law of the Sea or in judicial decisions. Moreover, the delimitation process in three stages, commonly applied by international courts and tribunals since the Black Sea judgment, appears to be ill-suited for establishing fluctuating boundaries. There seems to be other solutions to the problem of coastline change, which this article also briefly explores.

Environmental changes, such as sea level rise and coastal erosion, have an increasing impact on coastlines worldwide. Unilaterally declared maritime limits are generally determined by reference to coastlines and they are only binding insofar as they conform to the applicable law. Bilateral maritime boundaries are not equally affected by changing coastal geography because, once established, they are binding on parties to the arrangement under the pacta sunt servanda and res judicata principles. Maritime delimitation generally produces geographically stable boundaries. In principle, these remain fixed notwithstanding changes to the coastal geography that generates maritime entitlements or the ecosystems central to national interests. Indeed, stability and predictability are among the objectives of maritime delimitation. However, legal stability can be achieved without geographic stability and the requirement of predictability may be unattainable in a new world of environmental uncertainty. After all, baselines and derived outer limits fluctuate to reflect changing coastal geography and the same is true of bilateral boundaries, unless and until otherwise agreed. States have concluded boundary agreements that refer to fluctuating concepts, such as the equidistance line, instead of fixed co-ordinates. Furthermore, the International Court of Justice has left a segment of a maritime boundary to fluctuate until otherwise agreed and a Chamber of the Court has addressed the possibility of establishing a boundary by reference to a fluid oceano-biological boundary in the marine environment. This suggests that maritime boundaries can fluctuate if established by reference to sufficiently clear and relevant limits in the natural environment.

Owing to soaring energy needs and improved drilling technology, offshore hydrocarbon activities have been on the rise in recent years. A delimited maritime boundary is an essential precondition for the establishment of a safe and stable environment which will facilitate investment and development. Nevertheless, the conclusion of delimitation agreements can be a difficult task due to competing interests and long-standing enmities among neighbouring countries. Significant maritime areas remain undelimited. In order to avoid the problems of both unilateral activities and a complete ‘moratorium’ in undelimited areas, Articles 74(3) and 83(3) of the 1982 United Nations Convention on the Law of the Sea impose two obligations of conduct: pending delimitation agreement, States are under duty to ‘make every effort to enter into provisional arrangements of a practical nature’, while, at the same time, the interested parties should refrain from acts that might ‘jeopardize or hamper the reaching of the final agreement’. Bearing this in mind, it is argued that unilateral drilling and, under certain circumstances, unilateral seismic surveys in undelimited maritime areas should not be allowed and such conduct might trigger State responsibility. However, given that complete inactivity in such areas was not the intention of the drafters of the Convention, it is argued that several activities may be permitted as long as they are performed in good faith and do not put any final agreement at risk.