binding on the parties either through treaty law or customary

NORTH SEA international law.

CONTINENTAL SHELF
CASES (SUMMARY)
International Court of Justice Contentious Case: The North
Sea Continental Shelf Cases (Germany/Denmark;
Germany/Netherlands).

Year of Decision: 1969.

Note: This post discusses only  aspects of the case related to

treaty and customary international law.

Overview: The jurisprudence of the North Sea Continental Shelf

Cases sets out the dual requirement for the formation
of customary international law: (1) State practice (the objective
element) and (2) opinio juris (the subjective element). In these
cases, the Court explained the criteria necessary to establish
State practice – widespread and representative participation.
North Sea Continental Shelf Cases  (commons.wikimedia.org)
It highlighted that the practices of those States whose interests
were specially affected by the custom were especially relevant in
the formation of customary law. It also held that uniform Questions before the Court (as relevant to this post):
and consistent practice was necessary to
demonstrate opinio juris – opinio juris is the belief that Is Germany under a legal obligation to accept the equidistance-
State practice amounts to a legal obligation. The North Sea special circumstances principle, contained in Article 6 of the
Continental Self Cases also dispelled the myth that duration of Geneva Convention on the Continental Shelf of 1958, either as a
the practice (i.e. the number of years) was an essential factor in customary international law rule or on the basis of the Geneva
forming customary international law.  Convention?

The case involved the delimitation of the continental shelf areas The Court’s Decision:
in the North Sea between Germany and Denmark and Germany
and Netherlands beyond the partial boundaries previously The use of the equidistance method had not crystallised into
agreed upon by these States. The parties requested the Court to customary law and the method was not obligatory for the
decide the principles and rules of international law that are delimitation of the areas in the North Sea related to the present
applicable to the above delimitation because the parties proceedings.
disagreed on the applicable principles or rules of delimitation.
Netherlands and Denmark relied on the principle of Relevant Findings of the Court:
equidistance (the method of determining the boundaries in such
a way that every point in the boundary is equidistant from the
1. Nature of the treaty obligation: Is the 1958 Geneva
nearest points of the baselines from which the breath of the
Convention, and in particular Article 6, binding on Germany?
territorial sea of each State is measured). Germany sought to get
a decision in favour of the notion that the delimitation of the
relevant continental shelf was governed by the principle that 1. Article 6 of the Geneva Convention  stated that unless the
each coastal state is entitled to a just and equitable share parties had already agreed on a method for delimitation or unless
(hereinafter called just and equitable principle/method). special circumstances exist, the equidistance method would
Contrary to Denmark and Netherlands, Germany argued that apply. Germany had signed, but not ratified, the Geneva
the principle of equidistance was neither a mandatory rule in Convention, while Netherlands and Denmark were parties to the
delimitation of the continental shelf nor a rule of customary Convention. The latter two States argued that while Germany is
international law that was binding on Germany. The Court was not a party to the Convention (not having ratified it), she
not asked to delimit because the parties had already agreed to was still bound by Article 6 of the Convention because:
delimit the continental shelf as between their countries, by
agreement, after the determination of the Court on the “…(1)  by conduct, by public statements and proclamations, and
applicable principles. in other ways, the Republic has unilaterally assumed the
obligations of the Convention; or has manifested its acceptance
Facts of the Case: of the conventional regime; or has recognized it as being
generally applicable to the delimitation of continental shelf
areas…
Netherlands and Denmark had drawn partial boundary lines
based on the equidistance principle (A-B and C-D). An
agreement on further prolongation of the boundary proved (2) the Federal Republic had held itself out as so assuming,
difficult because Denmark and Netherlands wanted this accepting or recognizing, in such a manner as to cause other
prolongation to take place based on the equidistance principle States, and in particular Denmark and the Netherlands, to rely
(B-E and D-E) where as Germany was of the view that, together, on the attitude thus taken up” (the latter is called the  principle
these two boundaries would produce an inequitable result for of estoppel).
her. Germany stated that due to its concave coastline, such a line
would result in her loosing out on her share of the continental 2. The Court rejected the first argument. It said that only a ‘very
shelf based on proportionality to the length of its North Sea definite very consistent course of conduct on the part of a State
coastline. The Court had to decide the principles and rules of would allow the Court to presume that the State had somehow
international law applicable to this delimitation. In doing so, the become bound by a treaty (by a means other than in the formal
Court had to decide if the principles espoused by the parties were manner: i.e. ratification) when the State was ‘at all times fully
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able and entitled to…’ accept the treaty commitments in a formal limits, be admitted; whereas this cannot be so in the case of
manner. The Court held that Germany had not unilaterally general or customary law rules and obligations which, by their
assumed obligations under the Convention. The court also took very nature, must have equal force for all members of the
notice of the fact that even if Germany ratified the treaty, she had international community, and cannot therefore be the subject of
the option of entering into a reservation on Article 6, following any right of unilateral exclusion exercisable at will by any one
which that particular article would no longer be applicable to of them in its own favor…. The normal inference would
Germany (in other words, even if one were to assume that therefore be that any articles that do not figure among those
Germany had intended to become a party to the Convention, it excluded from the faculty of reservation under Article 12, were
does not presuppose that it would have also undertaken those not regarded as declaratory of previously existing or emergent
obligations contained in Article 6). rules of law …” (see para 65 for a counter argument and the
Court’s careful differentiation)
3. Note: The Vienna Convention on the Law of Treaties of 1969
(VCLT), which came into force in 1980, discusses in more (b) Did the provisions in Article 6 on the equidistance principle
detail treaty obligations of third States (those States who are not attain the customary law status after the Convention came into
parties to the treaty). It clearly stipulates that obligations arise for force?
third States from a provision of a treaty only if (1) the actual
parties to the treaty intended the provision to create obligations 9. The Court then examined whether the rule contained in Article
for third States; and (2) third State expressly accept 6 had become customary international law after the Convention
those obligations in writing (Article 35 of the VCLT). The entered into force – either due the Convention itself (i.e., if
VCLT was not in force when the Court deliberated on this case. enough States had ratified the Convention in a manner so as to
However, as  seen above, the Court’s position is consistent the fulfil the criteria specified below), or because of subsequent
VCLT. (See the relevant provisions of the Vienna Convention on State practice (i.e. even if an adequate number of States had not
the Law of Treaties). ratified the Convention, one could find sufficient State practice
to meet the criteria below). The Court held that Article 6 of the
4. The Court held that the existence of a situation of Convention had not attained a customary law status. (Compare
estoppel would have allowed Article 6 to become binding on the 1958 Geneva Convention with the four Geneva Conventions
Germany – but held that Germany’s action did not support an on 1949 relating to international humanitarian law in terms of the
argument for estoppel. The Court also held that the mere fact that latter’s authority as a pronouncement of customary international
Germany may not have specifically objected to the equidistance law).
principle as contained in Article 6, is not sufficient to state that
the principle is now binding upon it. 10. For a customary rule to emerge the Court held that it
needed: (1) very widespread and representative participation in
5. In conclusion, the Court held that Germany had not acted in the Convention, including States whose interests were specially
any manner so as to incur obligations contained in Article 6 of affected (in this case, they were coastal States) (i.e. generality);
the Geneva Convention. The equidistance–special circumstances and (2) virtually uniform practice (i.e. consistent and uniform
rule was not binding on Germany by way of treaty law. usage) undertaken in a manner that demonstrates (3) a general
recognition of the rule of law or legal obligation (i.e. opinio
2. Nature of the customary international law obligation: Is juries). In the North Sea Continental Shelf cases the court held
Germany bound by the provisions of Article 6 of the Geneva that the passage of a considerable period of time was
Convention in so far as they reflect customary international law? unnecessary (i.e. duration) for the formation of a customary law.

6. Netherlands and Denmark argued that Article 6 also reflected Widespread and representative participation
‘the accepted rule of general international law on the subject of
continental shelf delimitation’ and that it existed independently 11. The Court held that the first criteria was not met. The number
of the Convention. Therefore, they argued, Germany is bound by of ratifications and accessions to the Convention (39 States)
the subject matter of Article 6 by way of customary international were not adequately representative or widespread.
law.
Duration
7. To decide if the equidistance principle bound Germany by
way of customary international law, the Court examined (1) the 12. The Court held that the duration taken for a customary law
status of the principle contained in Article 6 as it stood when the rule to emerge is not as important as widespread and
Convention was being drawn up; and (2) its status after the representative participation, uniform usage, and the existence of
Convention came into force. an opinio juris. It held that:

(a) What was the customary law status of Article 6 at the time of “Although the passage of only a short period of time (in this
drafting the Convention? case, 3 – 5 years) is not necessarily, or of itself, a bar to the
formation of a new rule of customary international law on the
8. The Court held that the principle of equidistance, as contained basis of what was originally a purely conventional rule, an
in Article 6 did not form a part of existing or emerging indispensable requirement would be that within the period in
customary international law at the time of drafting the question, short though it might be, State practice, including that
Convention. The Court supported this finding based on (1) the of States whose interests are specially affected, should have been
hesitation expressed by the drafters of the Convention, the both extensive and virtually uniform in the sense of the provision
International Law Commission, on the inclusion of Article 6 into invoked and should moreover have occurred in such a way as to
the Convention and (2) the fact that  reservations to Article 6 was show a general recognition that a rule of law or legal obligation
permissible under the Convention. The Court held: is involved.”

“… Article 6 is one of those in respect of which, under the Opinio juris

reservations article of the Convention (Article 12) reservations
may be made by any State on signing, ratifying or acceding, – 13. Opinio juris is reflected in acts of States (Nicaragua Case) or
for speaking generally, it is a characteristic of purely in omissions (Lotus case), in so far as those acts or omissions
conventional rules and obligations that, in regard to them, some were done following a belief that the said State is obligated by
faculty of making unilateral reservations may, within certain

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law to act or refrain from acting in a particular way. (For more
on opinio juris click here).

14. The Court examined 15 cases where States had delimited

their boundaries using the equidistance method, after the
Convention came into force (paras. 75 -77). The Court
concluded that even if there were some State practice in favour
of the equidistance principle, the Court could not deduct the
necessary opinio juris from this State practice. The North Sea
Continental Shelf Cases confirmed that both State practice (the
objective element) and opinio juris (the subjective element) are
essential pre-requisites for the formation of a customary law
rule. This is consistent with Article 38 (1) (b) of the Statute of
the ICJ. The Court explained the concept of opinio jurisand the
difference between customs (i.e. habits) and customary law:

“Not only must the acts concerned amount to a settled practice,

but they must also be such, or be carried out in such a way, as to
be evidence of a belief that this practice is
rendered obligatory by the existence of a rule of law requiring
it. The need for such a belief, i.e, the existence of a subjective
element, is implicit in the very notion of the opinio juris sive
necessitatis. The States concerned must therefore feel that they
are conforming to what amounts to a legal obligation. The
frequency, or even habitual character of the acts is not in itself
enough. There are many international acts, e.g., in the field of
ceremonial and protocol, which are performed almost
invariably, but which are motivated only by considerations of
courtesy, convenience or tradition, and not by any sense of legal
duty.” (Para 77).

15.  The Court concluded that the equidistance principle was not
binding on Germany by way of treaty or customary international
law. In the case of the latter, the principle had not attained a
customary international law status at the time of the entry into
force of the Geneva Convention or thereafter. As such, the Court
held that the use of the equidistance method is not obligatory for
the delimitation of the areas concerned in the present
proceedings.

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