Summary of the Judgment of 16 December 2015

INTERNATIONAL COURT OF JUSTICE

2015/3 Summary
2015 December 16

Certain activities carried out by Nicaragua in the Border Area

Construction of a Road in Costa Rica along the San Juan River

Procedural background (paras. 1-52)

The Court begins by recalling that, on 18November2010, the Republic of CostaRica
(hereinafter “Costa Rica”) instituted proceedings against the Republic of Nicaragua (hereinafter

“Nicaragua”) in the case concerning Certain Activities carried out by Nicaragua in the Border Area
(Costa Ricav. Nicaragua) (hereinafter the “Costa
Costa Rica alleged in particular that Nicaragua
and dug a channel thereon; it also reproached Nicaragua with conducting works (notably dredging
of the San Juan River) in violation of its international obligations. The Court further states that, on

the same day, Costa Rica filed a request for provisional measures, as a result of which, by an Order
of 8 March 2011 (hereinafter “the Order of 8 Ma rch 2011”), the Court indicated certain provisional
measures addressed to both Parties.

The Court goes on to recall that, by an

22December2011, Nicaragua instituted proceedi ngs against Costa Rica in a dispute concerning
Construction of a Road in Costa Rica along the
(hereinafter the “Nicaraguav. CostaRica case”).
case related to “violations of Nicaraguan sovere

territory”, contending, in particular, that Cost
works in the border area between the two countries along the San Juan River, in violation of several
international obligations and with grave environmental consequences.

The Court explains that, by two separate Orders dated 17April2013, it joined the

proceedings in the Costa Rica v. Nicaragua and Nicara gua v. Costa Rica cases. It adds that, by an
Order of 22November2013 rendered in the Cost
provisional measures indicated on 8 March 2011 and indicated new provisional measures addressed
to both Parties.

Finally, the Court recalls that public hearings were held in the joined cases from
14 April 2015 to 1 May 2015, where both Parties’ experts were heard. - 2 -

I.J URISDICTION OF THE C OURT PARAS . 54-55)

The Court notes that both CostaRica and Nicaragua invoke, as bases of jurisdiction,
Article XXXI of the Pact of Bogotá and the declar ations by which they recognized the compulsory
jurisdiction of the Court under paragraphs2 and5 of Article36 of the Statute, and that neither
Party has contested the Court’s jurisdiction to ente rtain the other Party’s claims. The Court finds

that it has jurisdiction over both cases.

II. GEOGRAPHICAL AND HISTORICAL CONTEXT AND ORIGIN
OF THE DISPUTES (PARAS . 56-64)

The Court first recalls the geographical context to the two cases. It explains in this regard
that the San Juan River runs approximately 205 km from Lake Nicaragua to the Caribbean Sea. At
a point known as “Delta Colorado” (or “Delta Cost a Rica”), the San Juan River divides into two

branches: the Lower San Juan, which is the nor therly of these two branches and flows into the
Caribbean Sea about 30 km downstream from the de lta; and the Colorado River, the southerly and
larger of the two branches, which runs entirely within Costa Rica, reaching the CaribbeanSea at
Barra de Colorado, about 20 km south-east of the mouth of the Lower San Juan. The area situated

between the ColoradoRiver and the Lower San Ju an is broadly referred to as IslaCalero
(approximately 150sqkm). Within that area, there is a smaller region known to CostaRica as
Isla Portillos and to Nicaragua as Harbor Head (approxi mately 17 sq km); it is located north of the
former Taura River. In the north of Isla Portillos is a lagoon, called Laguna Los Portillos by

CostaRica and Harbor Head Lagoon by Nicaragua. This lagoon is at present separated from the
Caribbean Sea by a sandbar (see attached sketch -map No.1). The area includes two wetlands of
international importance: the Humedal Caribe Noreste (Northeast Caribbean Wetland) and the
Refugio de Vida Silvestre Río San Juan (San Juan River Wildlife Refuge).

The Court then describes the historical context to the present disputes between the Parties. It
observes in this regard that, following hostilities between the two States in 1857, the Governments
of Costa Rica and Nicaragua concluded in 1858 a Treaty of Limits ( hereinafter the “1858 Treaty”),

which fixed the course of the boundary between th e two countries from the Pacific Ocean to the
Caribbean Sea. While establishing Nicaragua’s dominium and imperium over the waters of the
San Juan River, at the same time it affirmed Costa Rica’s right of free navigation on the river for
the purposes of commerce. Following challenges by Nicaragua on various occasions to the validity

of this Treaty, CostaRica and Nicaragua si gned another instrument on 24December1886,
whereby the two States agreed to submit the question of the validity of the 1858 Treaty, as well as
various other points of “doubtful interpretati on”, to the President of the UnitedStates,

Grover Cleveland, for arbitration.

The Court notes that, in the Award handed down by him in1888, PresidentCleveland,
interalia, confirmed the validity of the Treaty, and that, subsequent to that decision, in
1896 Costa Rica and Nicaragua agreed to establis h two national Demarcation Commissions, which

were to include an engineer, who “shall have broa d powers to decide whatever kind of differences
may arise in the course of any operations and his ruling shall be final”. UnitedStates
General Edward Porter Alexander was so appointed. During the demarcation process (which began

in1897 and was concluded in1900), GeneralAlex ander rendered five awards, the first three of
which are of particular relevance to the Costa Rica v. Nicaragua case.

The Court further explains that, starti ng in the 1980s, disagreements arose between

Costa Rica and Nicaragua concerning the precise scope of Costa Rica’s rights of navigation under
the 1858Treaty. This dispute led CostaRica, on 29September2005, to file an Application with
the Court instituting proceedings against Nicara gua. On 13July2009 the Court rendered its
Judgment, interalia, clarifying Costa Rica’s navi gational rights and the extent of Nicaragua’s

power to regulate navigation on the San Juan River. - 3 -

The Court then comes to the origin of the two disputes, indicating that, on 18 October 2010,
Nicaragua started dredging the San Juan River in order to improve its navigability, while also

carrying out works in the northern part of Isla Po rtillos. The Court notes that Costa Rica contends
that Nicaragua had artificially created a channel (both Parties refer to such channels as “caños”) on
Costa Rican territory, in Isla Portillos between the San Juan River and Laguna Los Portillos/Harbor
Head Lagoon, whereas Nicaragua argues that it w as only clearing an existing caño on Nicaraguan

territory. The Court further notes that Nicaragua also sent some military units and other personnel
to that area.

The Court then explains that, in December2010, CostaRica started works for the

construction of Route1856 Juan Rafael Mora Po rras (hereinafter the “road”), which runs in
Costa Rican territory along part of its border with Nicaragua, and has a planned length of 159.7 km,
extending from Los Chiles in the west to a point just beyond “Delta Colorado” in the east.
For108.2km, the road follows the course of the Sa nJuan River (see attached sketch-map No. 2).

Finally, the Court notes that, on 21February2011, Costa Rica adopted an Executive Decree
declaring a state of emergency in the border area, which Costa Rica maintains exempted it from the
obligation to conduct an environmental impact assessment before constructing the road.

III. SSUES IN THE C OSTA R ICA V . NICARAGUA CASE (PARAS . 65-144)

A. Sovereignty over the disputed territory and alleged

breaches thereof (paras. 65-99)

The Court observes that, since it is uncontested that Nicaragua conducted certain activities in
the disputed territory, it is necessary, in orde r to establish whether there was a breach of

CostaRica’s territorial sovereignty, to determine which State has sovereignty over that territory.
The Court recalls that the “disputed territory ” was defined by the Court in its Order of
8 March 2011 on provisional measures as “the northern part of Isla Portillos, that is to say, the area
of wetland of some 3squarekilometres between the right bank of the disputed caño [dredged by

Nicaragua in 2010], the right bank of the San Juan River up to its mouth at the Caribbean Sea and
the Harbor Head Lagoon”. The Court points out that this definition does not specifically refer to
the stretch of coast abutting the Caribbean Sea which lies between the Harbor Head Lagoon (which
lagoon both Parties agree is Nicaraguan) and the m outh of the San Juan River, adding that, since

neither Party has requested the Court to define th e boundary more precisely with regard to this
coast, the Court itself will accordingly refrain from doing so.

In order to settle the question of which of th e two Parties has sovereignty over the disputed

territory, the Court examines the relevant provis ions and passages relied on by the Parties in the
1858 Treaty, the Cleveland Award and the Alexander Awards. The Court considers that these lead
to the conclusion that Article II of the 1858 Tr eaty, which places the boundary on the “right bank
of the . . . river”, must be interpreted in the context of Article VI, which provides that “the Republic

of CostaRica shall... have a perpetual right of free navigation on the... waters [of the river]
between [its] mouth... and a point located three English miles below CastilloViejo”. As
GeneralAlexander observed in demarcating the boundary, the 1858Treaty regards the river, “in
average condition of water”, as an “outlet of commer ce”. In the view of the Court, ArticlesII

and VI, taken together, provide that the right bank of a channel of the river forms the boundary on
the assumption that this channel is a navigable “ outlet of commerce”. Thus, Costa Rica’s rights of
navigation are linked with sovereignty over the righ t bank, which has clearly been attributed to
Costa Rica as far as the mouth of the river.

The Court notes Nicaragua’s argument that, as a result of natural modifications in the
geographical configuration of the disputed territory, the “first channel” to which General Alexander
referred in his first Award is now a channel c onnecting the river, at a point south of the

Harbor Head Lagoon, with the southern tip of that lagoon, and that this is the caño that it dredged - 4 -

in 2010 only to improve its navigability. Costa Ri ca disputes this, contending that the caño is an
artificial one. The Court then proceeds to ex amine the evidentiary materials submitted by the

Parties. It finds that the satellite and aerial imag es relied on by Nicaragua are insufficient to prove
that a natural channel linked the San Juan River with the Harbor Head Lagoon following the same
course as the caño that it dredged. The Court fu rther observes that the affidavits of Nicaraguan
State officials, which were prepared after the institution of proceedings by Costa Rica, provide little

support for Nicaragua’s contention. Regarding the maps submitted by the Parties, the Court finds
that, while these tend on the whole to give support to CostaRica’s positi on, their significance is
limited, given that they are all small-scale maps which are not focused on the details of the disputed
territory. Finally, as regards effectivités, the Cour t, noting that these are in any event of limited

significance, points out that they cannot affect the title to sovereignty resulting from the
1858 Treaty and the Cleveland and Alexander Awards.

The Court further notes that the existence over a significant span of time of a navigable caño

in the location claimed by Nicaragua is put into qu estion by some of the evidence, in particular the
fact that in the bed of the channel there were trees of considerable size and age which had been
cleared by Nicaragua in2010. Furthermore, the fa ct that, as the Parties’ experts agree, the caño
dredged in 2010 no longer connected the river with the lagoon by mid-summer 2011 casts doubt on

the existence over a number of years of a naviga ble channel following the same course before
Nicaragua carried out its dredging activities. This caño could hardly have been the navigable outlet
of commerce referred to above.

The Court therefore concludes that the ri ght bank of the caño which Nicaragua dredged
in 2010 is not part of the boundary between Cost a Rica and Nicaragua, and that the territory under
Costa Rica’s sovereignty extends to the right bank of the Lower San Juan River as far as its mouth
in the Caribbean Sea. Sovereignty over the disputed territory thus belongs to Costa Rica.

The Court recalls that it is not contested that Nicaragua has carried out various activities in
the disputed territory since 2010, including ex cavating three caños and establishing a military
presence in parts of that territory. These activit ies were in breach of CostaRica’s territorial

sovereignty. Nicaragua is responsible for these br eaches and consequently incurs the obligation to
make reparation for the damage caused by its unlawful activities (see below, Section E).

The Court then considers Costa Rica’s submission that, “by occupying and claiming

CostaRican territory”, Nicaragua also committed other breaches of its obligations, including in
particular its obligation “not to use the San Juan River to carry out hostile acts” under Article IX of
the 1858Treaty. The Court, however, takes the view that no evidence of hostilities in the

San Juan River has been provided, and accordingly rejects Costa Rica’s submission on this point.

Costa Rica further asks the Court to find a breach by Nicaragua of “the prohibition of the
threat or use of force under Article 2 (4) of the Charter of the United Nations and Article 22 of the
Charter of the Organization of American States”. The Court observes that the relevant conduct of

Nicaragua has already been addressed in the cont ext of its examination of the violation of
CostaRica’s territorial sovereignty. The Cour t notes, however, that the fact that Nicaragua
considered that its activities were taking place on its own territory does not exclude the possibility

of characterizing them as an unlawful use of force. This raises the issue of their compatibility with
both the United Nations Charter and the Charter of the Organization of American States.
Nonetheless, in the circumstances, given that the unlawful character of these activities has already
been established, the Court is of the view that it need not dwell any further on this submission.

Finally, Costa Rica requests the Court to find that Nicaragua made the territory of Costa Rica
“the object, even temporarily, of military occupation, contrary to Article21 of the Charter of the
Organization of American States”. The Court cons iders that, having already established that the - 5 -

presence of military personnel of Nicaragua in th e disputed territory was unlawful because it
violated CostaRica’s territorial sovereignty, it do es not need to ascertain whether this conduct of

Nicaragua constitutes a military occupation in breach of Article21 of the Charter of the
Organization of American States.

B. Alleged violations of international environmental law (paras. 100-120)

The Court then turns to CostaRica’s allegati ons concerning violations by Nicaragua of its
obligations under international environmental la w in connection with its dredging activities to
improve the navigability of the Lower San Juan River.

1. Procedural obligations (paras. 101-112)

The Court begins by examining Costa Rica’s a llegations regarding Nicaragua’s violation of

procedural obligations.

(a) The alleged breach of the obligation to carry out an environmen tal impact assessment
(paras. 101-105)

The Court starts by addressing Costa Rica’s contention that Nicaragua breached its
obligation to conduct an environmental impact assessment.

After recalling its conclusion in the case c oncerning Pulp Mills on the River Uruguay
(Argentinav. Uruguay), namely that “it may no w be considered a requirement under general
international law to undertake an environmental im pact assessment where ther e is a risk that the
proposed industrial activity may have a significant adverse impact in a transboundary context, in

particular, on a shared resource” (I.C.J. Reports 201 0 (I), p. 83, para. 204), the Court explains that,
even though that statement referred to industr ial activities, the underlying principle applies
generally to proposed activities which may have a significant adverse impact in a transboundary
context. Thus, to fulfil its obligation to exercise due diligence in preventing significant

transboundary environmental harm, a State must , before embarking on an activity having the
potential adversely to affect the environment of another State, ascertain if there is a risk of
significant transboundary harm, which would trigger the requirement to carry out an environmental

impact assessment.

The Court recalls that determination of the content of the environmental impact assessment
should be made in light of the specific circumstan ces of each case. If the environmental impact

assessment confirms that there is a risk of significant transboundary harm, the State planning to
undertake the activity is required, in conformity with its due diligence obligation, to notify and
consult in good faith with the pote ntially affected State, where th at is necessary to determine the
appropriate measures to prevent or mitigate that risk.

The Court notes that, in the present case, th e principal risk cited by CostaRica was the
potential adverse impact of those dredging activ ities on the flow of the ColoradoRiver, which
could also adversely affect Costa Rica’s wetland.

Having examined the evidence in the case file, including the reports submitted and testimony
given by experts called by both Parties, the C ourt finds that the dredging programme planned
in 2006 was not such as to give rise to a risk of significant transboundary harm, either with respect

to the flow of the Colorado River or to CostaRi ca’s wetland. In light of the absence of risk of
significant transboundary harm, Nicaragua was not re quired to carry out an environmental impact
assessment. - 6 -

(b) The alleged breach of an obligation to notify and consult (paras. 106-111)

The Court then turns to Costa Rica’s allegati on that Nicaragua has breached an obligation to
notify and consult with it, both under general in ternational law and pursuant to a number of
instruments, namely the 1858Treaty, the Conve ntion on Wetlands of In ternational Importance
especially as Waterfowl Habitat, signed at Ramsar on 2February1971 (hereinafter the “Ramsar

Convention”), and the Convention for the Conserva tion of Biodiversity and Protection of Priority
Wildlife Areas in Central America.

The Court observes that, contrary to what Nicaragua contends, the fact that the 1858 Treaty

may contain limited obligations concerning notifica tion or consultation in specific situations does
not exclude any other procedural obligations with regard to transboundary harm which may exist in
treaty or customary international law. In any ev ent, the Court finds that, since Nicaragua was not
under an international obligation to carry out an environmental impact assessment in light of the

absence of risk of significant transboundary harm, it was not required to notify, or consult with,
Costa Rica.

As regards the Ramsar Convention, the Court notes that, although Article3, paragraph2,

contains an obligation to notify, that obligation is limited to noti fying the Ramsar Secretariat of
changes or likely changes in th e “ecological character of any wetland” in the territory of the
notifying State. In the present case, the Cour t considers that the evidence before it does not

indicate that Nicaragua’s dredging programme h as brought about any changes in the ecological
character of the wetland, or that it is likely to do so unless it were to be expanded. Thus the Court
finds that no obligation to inform the Ramsar S ecretariat arose for Nicaragua. Regarding Article 5
of that same instrument, the Court observes that, while this provision contains a general obligation

to consult “about implementing obligations aris ing from the Convention”, it does not create an
obligation on Nicaragua to consult with CostaRi ca concerning a particular project that it is
undertaking, in this case the dredging of the Lo wer San Juan River. In light of the above,
Nicaragua was not required under the Ramsar Conve ntion to notify, or consult with, CostaRica

prior to commencing its dredging project.

Finally, as to the Convention for the Conserva tion of Biodiversity and Protection of Priority
Wildlife Areas in Central America, the Court sees no need to take its enquiry further, as neither of

the two provisions invoked by Costa Rica contains a binding obligation to notify or consult.

(c) Conclusion (para. 112)

The Court concludes that it has not been est ablished that Nicaragua breached any procedural
obligations owed to Costa Rica under treaties or the customary international law of the
environment. The Court takes note of Nicaragua’s commitment, made in the course of the oral
proceedings, to carry out a new environmental impact study before any substantial expansion of its

current dredging programme. The Court further not es that Nicaragua stated that such a study
would include an assessment of the risk of transboundary harm, and that it would notify, and
consult with, Costa Rica as part of that process.

2. Substantive obligations concerning transboundary harm (paras. 113-120)

The Court, having already found that Nicaragua is responsible for the harm caused by its

activities in breach of Costa Rica’s territorial s overeignty, proceeds to examine whether Nicaragua
is responsible for any transbounda ry harm allegedly caused by its dredging activities which have
taken place in areas under Nicaragua’s territorial s overeignty, in the Lower San Juan River and on
its left bank. - 7 -

The Court begins by examining the relevant a pplicable law. It considers that it would be
necessary for it to address the qu estion of the relationship between the 1858Treaty as interpreted

by the Cleveland Award and the current rule of customary international law with regard to
transboundary harm only if Costa Rica were to prove that the dredging programme in the
Lower San Juan River had produced harm to Costa Rica’s territory.

However, in the Court’s view Costa Rica has not provided any convincing evidence that
sediments dredged from the river were deposited on its right bank. Nor has it proved that the
dredging programme caused harm to its wetland, or has had a significant effect upon the
Colorado River.

The Court therefore concludes that the ava ilable evidence does not show that Nicaragua
breached its obligations by engaging in dredging activities in the Lower San Juan River.

C. Compliance with provisional measures (paras. 121-129)

The Court recalls that, in its Order on provi sional measures of 8March2011, it indicated
that “[e]ach Party shall refrain from sending to, or maintaining in the disputed territory, including

the caño, any personnel, whether civilian, police or security”, and also required each Party to
“refrain from any action which might aggravate or extend the dispute before the Court or make it
more difficult to resolve”. On the basis of facts that have become uncontested, the Court finds that
Nicaragua breached its obligations under the Orde r of 8 March 2011 by ex cavating two caños and

establishing a military presence in the disputed territo ry. On the other hand, it finds that there has
been no breach of its provisional measures Order of 22 November 2013.

The Court thus concludes that Nicaragua act ed in breach of its obligations under the

2011 Order by excavating the second and third caños and by establishing a military presence in the
disputed territory. The Court observes that this finding is independent of its previous conclusion
(see SectionA) that the same conduct also constitut es a violation of the territorial sovereignty of
Costa Rica.

D. Rights of navigation (paras. 130-136)

The Court recalls that, in its final submissions, Costa Rica also claims that Nicaragua has
breached “Costa Rica’s perpetual rights of free na vigation on the San Juan in accordance with the
1858 Treaty of Limits, the 1888 Cleveland Award and the Court’s Judgment of 13 July 2009”.

Nicaragua contests the admissibility of this su bmission, which it considers not covered by
the Application and as having an object unconnected with that of the “main dispute”. The Court
observes, however, that paragraph 41 (f) of Costa Rica’s Application requests the Court to adjudge
and declare that, “by its conduct, Nicaragua has breached... the obligation not to prohibit the

navigation on the San Juan River by Costa Rican nationals”. Although Costa Rica’s submission
could have been understood as related to the “dredging and canalization activities being carried out
by Nicaragua on the San Juan River”, to which the same paragraph of the Application also referred,
the wording of the submission did not contain any r estriction to that effect. The Court accordingly

considers that Costa Rica’s final submission concerning rights of navigation is admissible.

Costa Rica includes among the alleged breaches of its rights of navigation the enactment by
Nicaragua of an October2009 Decree, concerning na vigation on the SanJuanRiver. The Court

observes that, while it is clear that the decree should be consistent with ArticleVI of the
1858Treaty as interpreted by itself, none of the instances of interference with CostaRica’s rights
of navigation specifically alleged by Costa Rica relates to the application of this Decree. The Court
therefore takes the view that it is not called upon to examine this decree. - 8 -

The Court further notes Costa Rica’s allegati ons regarding five incidents where it claims
breaches of its navigational rights took place. The Court finds that Nicaragua failed to provide a

convincing justification with regard to Article VI of the 1858Treaty for the conduct of its
authorities in two of these incidents, which concer ned navigation by inhabitants of the Costa Rican
bank of the San Juan River. The Court accordingl y considers that the two incidents show that
Nicaragua breached Costa Rica’s rights of navigation on the San Juan River under the 1858 Treaty.

It adds that, given this finding, it is unnecessar y for it to examine the other incidents invoked by
Costa Rica.

E. Reparation (paras. 137-144)

Finally, the Court addresses the issue of reparations . It notes in this regard that, in view of
the conclusions reached by it in SectionsB andD, CostaRica’s requests concerning the repeal of
the 2009Decree on navigation and the cessation of dredging cannot be granted. The Court

considers that its declaration that Nicaragua breach ed the territorial sovereignty of CostaRica by
excavating three caños and establishing a militar y presence in the disputed territory provides
adequate satisfaction for the non-material injury su ffered on this account. The same applies to the

declaration on the breach of the obligations under the Court’s Order of 8March2011 on
provisional measures. Lastly, the finding regarding the breach of Costa Rica’s rights of navigation
in the circumstances described in Section D provides adequate satisfaction for that breach.

As to Costa Rica’s request for “appropriate assurances and guarantees of non-repetition”, the
Court considers that, although Nicaragua faile d to comply with its obligations under the
2011Order, account must also be taken of the f act that Nicaragua subsequently complied with
those set out in the Order of 22November2013. The Court accordingly takes the view that

Nicaragua will have the same attitude with regard to the legal situation resulting from the present
Judgment, in particular in view of the fact that the question of territorial sovereignty over the
disputed territory has now been resolved.

The Court finds that Costa Rica is entitled to receive compensation for the material damage
caused by those breaches of obligations by Nicaragua that have been ascertained by the Court. It
states that the relevant material damage and the amount of compensation may be assessed by the
Court only in separate proceedings. The Court is of the opinion that the Parties should engage in

negotiation in order to reach an agreement on these i ssues. However, if they fail to reach such an
agreement within 12months of the date of the pr esent Judgment, the Court will, at the request of
either Party, determine the amount of compen sation on the basis of further written pleadings
limited to this issue.

Finally, while noting that the breach by Nicaragua of its obligations under the 2011Order
necessitated Costa Rica engaging in new proceedings on provisional measures, the Court finds that,
taking into account the overall circumstances of th e case, an award of costs to CostaRica, as the

latter requested, would not be appropriate.

IV. ISSUES IN THE N ICARAGUA V . COSTA RICA CASE PARAS . 145-228)

The Court recalls at the outset that the Application filed by Nicaragua on 22 December 2011
concerns the alleged breach by CostaRica of bot h procedural and substa ntive obligations in
connection with the construction of the road along the San Juan River.

A. The alleged breach of procedural obligations (paras. 146-173)

The Court begins by considering the alleged breach of procedural obligations. - 9 -

1. The alleged breach of the obligation to ca rry out an environmental impact assessment
(paras. 146-162)

The Court turns first to Nicaragua’s claim that CostaRica breached its obligation under
general international law to assess the environmental impact of the construction of the road before
commencing it, particularly in view of the road’s length and location.

The Court recalls that a State’s obligation to exercise due diligence in preventing significant
transboundary harm requires that State to ascertain whether there is a risk of significant
transboundary harm prior to undertaking an activit y having the potential adversely to affect the

environment of another State. If that is the case, the State concerned must conduct an
environmental impact assessment. The obligation in question rests on the State pursuing the
activity. Accordingly, in the present case, it fe ll on CostaRica, not on Nicaragua, to assess the
existence of a risk of significant transboundary ha rm prior to the construction of the road, on the

basis of an objective evaluation of all the relevant circumstances.

The Court notes that, in the oral proceedings, counsel for Costa Rica stated that a preliminary
assessment of the risk posed by the road project had been undertaken when the decision to build the

road was made. The Court observes that to cond uct a preliminary assessment of the risk posed by
an activity is one of the ways in which a State can ascertain whether the proposed activity carries a
risk of significant transboundary harm. It considers, however, that Costa Rica has not adduced any
evidence that it actually carried out such a preliminary assessment.

The Court points out that, in evaluating whether, as of the end of2010, the construction of
the road posed a risk of significant transboundary harm, it will have regard to the nature and
magnitude of the project and the context in which it was to be carried out. Given that the scale of

the road project was substantial, and given the planned location of the road along the
San Juan River and the geographic conditions of the river basin where the road was to be situated
(and in particular because it would pass thr ough a wetland of international importance in
CostaRican territory and be located in close pr oximity to another protected wetlandsituated in

Nicaraguan territory), the Court finds that the cons truction of the road by Costa Rica carried a risk
of significant transboundary harm. Therefore, the threshold for triggering the obligation to
evaluate the environmental impact of the road project was met.

The Court then turns to the question of whether Costa Rica was exempted from its obligation
to evaluate the environmental impact of the road pr oject because of an emergency. First, the Court
recalls its holding that “it is for each State to determine in its domestic legislation or in the
authorization process for the project, the specific content of the environmental impact assessment

required in each case”, having regard to va rious factors (Pulp Mills on the River Uruguay
(Argentinav. Uruguay), Judgment, I.C.J. Reports 2010(I), p.83, para.205). The Court observes
that this reference to domestic law does not rela te to the question of whether an environmental
impact assessment should be undertaken. Thus, the fact that there may be an emergency exemption

under Costa Rican law does not affect Costa Rica’s obligation under international law to carry out
an environmental impact assessment.

Secondly, independently of the question whether or not an emergency could exempt a State

from its obligation under international law to carry out an environmental impact assessment, or
defer the execution of this obligation until the em ergency has ceased, the Court considers that, in
the circumstances of this case, CostaRica has not shown the existence of an emergency that

justified constructing the road without undertaking an environmental impact assessment.

Given this finding, the Court does not need to decide whether there is an emergency
exemption from the obligation to carry out an en vironmental impact assessment in cases where

there is a risk of significant transboundary harm. - 10 -

It follows that CostaRica was under an ob ligation to conduct an environmental impact
assessment prior to commencement of the construction works.

Turning next to the question of whether Costa Rica complied with its obligation to carry out
an environmental impact assessment, the Court notes that CostaRica produced several studies,
including an Environmental Management Plan for the road in April2012, an Environmental

Diagnostic Assessment in November 2013, and a foll ow-up study thereto in January 2015. These
studies assessed the adverse effects that had already been caused by the construction of the road on
the environment and suggested steps to prevent or reduce them.

The Court recalls that, in its Judgment in the Pulp Mills case, it held that the obligation to
carry out an environmental impact assessment is a continuous one, and that monitoring of the
project’s effects on the environment shall be unde rtaken, where necessary, throughout the life of
the project (I.C.J. Reports2010(I), pp.83-84, pa ra.205). Nevertheless, the obligation to conduct

an environmental impact assessment requires an ex ante evaluation of the risk of significant
transboundary harm, and thus “an environmental impact assessment must be conducted prior to the
implementation of a project” (ibid., p. 83, para. 205). In the present case, Costa Rica was under an
obligation to carry out such an assessment prior to commencing the construction of the road, to

ensure that the design and execution of the pr oject would minimize the risk of significant
transboundary harm. In contrast, Costa Rica’s E nvironmental Diagnostic Assessment and its other
studies were post hoc assessments of the environmental impact of the stretches of the road that had
already been built. These studies did not evaluate the risk of future harm. The Court notes

moreover that the Environmental Diagnostic Assessment was carried out approximately three years
into the road’s construction.

For the foregoing reasons, the Court concludes that CostaRica has not complied with its

obligation under general interna tional law to carry out an envi ronmental impact assessment
concerning the construction of the road.

2. The alleged breach of Article 14 of the Convention on Biological Diversity (paras. 163-164)

In respect of Nicaragua’s submission that Costa Rica was required to carry out an
environmental impact assessment by Article14 of the Convention on Biological Diversity, the
Court considers that the provision at issue does not create an obligation to carry out an

environmental impact assessment before undertakin g an activity that may have significant adverse
effects on biological diversity. Therefore, it h as not been established th at CostaRica breached
Article 14 of the Convention on Biological Diversity by failing to conduct an environmental impact
assessment for its road project.

3. The alleged breach of an obligation to notify and consult (paras. 165-172)

The Court then turns to Nicaragua’s contenti on that CostaRica breached its obligation to

notify, and consult with, Nicaragua in relation to the construction works. Nicaragua founds the
existence of such obligation on three grounds, namely, customary international law, the
1858 Treaty, and the Ramsar Convention.

The Court first of all reiterates its conclusi on that, if the environmental impact assessment
confirms that there is a risk of significant transboundary harm, a State planning an activity that
carries such a risk is required, in order to fulfil its obligation to exercise due diligence in preventing
significant transboundary harm, to notify, and cons ult with, the potentially affected State in good

faith, where that is necessary to determine the appropriate measures to prevent or mitigate that risk.
It notes, however, that the duty to notify and cons ult does not call for examination by the Court in
the present case, since it has established that Cost a Rica has not complied with its obligation under
general international law to perform an environm ental impact assessment prior to the construction

of the road. - 11 -

As regards the 1858 Treaty, the Court reca lls its finding in the 2009Judgment that
Nicaragua’s obligation to notify Costa Rica under the said Treaty arises, amongst other factors, by

virtue of Costa Rica’s rights of navigation on the rive r, which is part of Nicaragua’s territory. In
contrast, the 1858 Treaty does not grant Nicaragua any rights on Costa Rica’s territory, where the
road is located. Therefore, no obligation to no tify Nicaragua with respect to measures undertaken
on CostaRica’s territory arises. The Court concludes that the 1858Treaty did not impose on

Costa Rica an obligation to notify Nicaragua of the construction of the road.

Regarding the Ramsar Convention, the Court is of the view that Nicaragua has not shown
that, by constructing the road, Costa Rica has ch anged or was likely to change the ecological

character of the wetland situated in its territory. Moreover, contrary to Nicaragua’s contention, on
28February2012 CostaRica notified the Ramsar Secr etariat about the stretch of the road that
passes through the Humedal Caribe Noreste. Theref ore, the Court concludes that Nicaragua has
not shown that Costa Rica breached Article 3, para graph 2, of the Ramsar Convention. As regards

Article 5 of the Convention, the Court finds that this provision creates no obligation for Costa Rica
to consult with Nicaragua concerning a particul ar project it is undertaking, in this case the
construction of the road.

In conclusion, the Court finds that Costa Rica failed to comply with its obligation to evaluate
the environmental impact of the construction of the road. Costa Rica remains under an obligation
to prepare an appropriate environmental impact a ssessment for any further works on the road or in
the area adjoining the SanJuan River, should they carry a risk of significant transboundary harm.

Costa Rica accepts that it is under such an obligation. There is no reason to suppose that it will not
take note of the reasoning and conclusions in this Judgment as it conducts any future development
in the area, including further construction works on the road. The Court also notes Nicaragua’s
commitment, made in the course of the oral proceed ings, that it will co-operate with Costa Rica in

assessing the impact of such works on the river. In this connection, the Court considers that, if the
circumstances so require, CostaRica will have to consult in good faith with Nicaragua, which is
sovereign over the San Juan River, to determin e the appropriate measures to prevent significant

transboundary harm or minimize the risk thereof.

B. Alleged breaches of substantive obligations (paras. 174-223)

The Court then turns to the examination of the alleged violations by CostaRica of its

substantive obligations under customary interna tional law and the applicable international
conventions.

1. The alleged breach of the obligation not to cause significant transboundary harm to

Nicaragua (paras. 177-217)

(a) The contribution of sediment from the road to the river (paras. 181-186)

Regarding the contribution of sediment from the ro ad to the river, the Court notes that it is
not contested that sediment eroded from the road is delivered to the river. As regards the total
volume of sediment contributed by the road, the Co urt observes that the evidence before it is based
on modelling and estimates by experts appointed by the Parties. The Court further observes that

there is considerable disagreement amongst the experts on key data such as the areas subject to
erosion and the appropriate erosi on rates, which led them to reach different conclusions as to the
total amount of sediment contributed by the road. Seeing no need to go into a detailed examination
of the scientific and technical validity of the different estimates put forward by the Parties’ experts,

the Court simply notes that the amount of sediment in the river due to the construction of the road
represents at most 2 per cent of the river’s tota l load, according to Costa Rica’s calculations based
on the figures provided by Nicaragua’s experts and uncontested by the latter. - 12 -

(bWhether the road-derived sediment ca used significant harm to Nicaragua
(paras. 187-216)

The Court points out that the core question it must decide is whether the construction of the
road by CostaRica has caused significant harm to Nicaragua. The Court begins its analysis by
considering whether the fact that the total amount of sediment in the river was increased as a result

of the construction of the road, in and of itself, caused significant harm to Nicaragua.

(i)Alleged harm caused by increased sediment concentrations in the river
(paras. 188-196)

In the Court’s view, Nicaragua’s submission that any detrimental impact on the river that is
susceptible of being measured constitutes significan t harm is unfounded. Sediment is naturally
present in the river in large quantities, and Nicaragua has not shown that the river’s sediment levels

are such that additional sediment eroded from the road passes a sort of critical level in terms of its
detrimental effects. Moreover, the Court finds that, contrary to Nicaragua’s submissions, the
present case does not concern a situation wher e sediment contributed by the road exceeds
maximum allowable limits, which have not been de termined for the San Juan River. Thus, the

Court is not convinced by Nicaragua’s argument that the absolute quantity of sediment in the river
due to the construction of the road caused significant harm per se.

The Court therefore proceeds to consider the relative impact of the road-derived sediment on

the current overall sediment load of the San Juan River. On the basis of the evidence before it, and
taking into account the estimates provided by the experts of the amount of sediment in the river due
to the construction of the road and of the total sediment load of the SanJuanRiver, the Court
observes that the road is contributing at most 2 per cent of the river’s total load. It considers that

significant harm cannot be inferred therefrom, part icularly taking into account the high natural
variability in the river’s sediment loads. In any event, in the C ourt’s view, the only measurements
that are before it do not support Nicaragua’s clai m that sediment eroded from the road has had a
significant impact on sediment concentrations in the river.

The Court concludes that Nicaragua has not established that the fact that sediment
concentrations in the river increased as a result of the construction of the road in and of itself
caused significant transboundary harm.

(ii) Alleged harm to the river’s morphology, to navigation and to Nicaragua’s dredging
programme (paras. 197-207)

The Court then examines whether the sedimen t contributed by the road caused any other
significant harm. It begins by considering wh ether the increased sediment has had an adverse
impact on the morphology of the river, navigation and Nicaragua’s dredging programme.

The Court notes that Nicaragua has produced no direct evidence of changes in the
morphology of the Lower San Juan or of a deterioration of its navigability since the construction of
the road began. It further considers that th e expert evidence before it establishes that the
accumulation of sediment is a long-standing natural feature of the Lower SanJuan, and that

sediment delivery along the San Juan is not a linear process. The road-derived sediment is one of a
number of factors that may have an impact on th e aggradation of the Lower San Juan. The Court
therefore considers that the evidence adduced by Nicaragua does not prove that any morphological
changes in the Lower San Juan have been caused by the construction of the road in particular.

As to Nicaragua’s claim that the construction of the road has had a significant adverse
impact on its dredging burden, the Court notes th at Nicaragua has adduced no evidence of an
increase in its dredging activities due to the construction of the road. The Court observes that there

is no evidence that sediment due to the construc tion of the road is more likely to settle on the - 13 -

riverbed than sediment from other sources. Thus, sediment coming from the road would
correspond to at most 2 per cent of the sediment dredged by Nicaragua in the Lower San Juan. The

Court is therefore not convinced that the road-der ived sediment led to a significant increase in the
bed level of the Lower San Juan or in Nicaragua’s dredging burden.

Finally, the Court turns to Nicaragua’s clai m that the sediment deltas along the Costa Rican

bank of the river have caused significant harm to th e river’s morphology and to navigation. In the
Court’s view, the photographic evidence adduced by Nicaragua indicates that there are deltas on
the CostaRican bank of the river to which the cons truction of the road is contributing sediment.
Nonetheless, it considers that Nicaragua has not pr esented sufficient eviden ce to prove that these

deltas, which only occupy the edge of the rive r’s channel on the CostaRican bank, have had a
significant adverse impact on the channel’s morphology or on navigation.

For the foregoing reasons, the Court conclud es that Nicaragua has not shown that sediment

contributed by the road has caused significant harm to the morphology and navigability of the
San Juan River and the Lower San Juan, nor that such sediment significantly increased Nicaragua’s
dredging burden.

(iii) Alleged harm to water quality and the aquatic ecosystem (paras. 208-213)

The Court then considers Nicaragua’s conten tion concerning harm to water quality and the
aquatic ecosystem. It is of the view, however, that the Environmental Diagnostic Assessment and

the expert report relied upon by Nicaragua do not substantiate the claim that the construction of the
road caused significant harm to the river’s ecosystem and water quality.

(iv) Other alleged harm (paras. 214-216)

Lastly, the Court turns to Nicaragua’s argument that the construction of the road has had an
adverse impact on the health of the communitie s along the river, which is dependent upon the
health of the river itself.

It finds, however, that Nicaragua did not subs tantiate its contentions regarding harm to
tourism and health. The Court further observes th at Nicaragua’s arguments concerning the risk of
toxic spills into the river and of further devel opment of the CostaRican bank of the river are

speculative and fail to show any harm. Therefore, these arguments fail.

(c) Conclusion (para. 217)

In light of the above, the Court concludes that Nicaragua has not proved that the construction

of the road caused it significant transboundary harm. Therefore, Nicaragua’s claim that Costa Rica
breached its substantive obligations under custom ary international law concerning transboundary
harm must be dismissed.

2. Alleged breaches of treaty obligations (paras. 218-220)

The Court notes that Nicaragua further argues that CostaRica violated substantive
obligations contained in several universal a nd regional instruments, namely the Ramsar

Convention, the 1990Agreement over the Border Protected Areas between Nicaragua and
CostaRica, the Convention on Biological Diversity, the Convention for the Conservation of
Biodiversity and Protection of Priority Wildlife Areas in Central America, the Central American
Convention for the Protection of the Environment, the Tegucigalpa Protocol to the Charter of the

Organization of Central American States, a nd the Regional Agreement on the Transboundary
Movement of Hazardous Wastes. - 14 -

The Court notes that both Nicaragua and Cost aRica are parties to the instruments invoked
by Nicaragua. Irrespective of the question of the binding character of some of the provisions at

issue, the Court observes that, in relation to these instruments, Nicaragua simply makes assertions
about Costa Rica’s alleged violations and does not explain how the “objectives” of the instruments
or provisions invoked would have been breached, esp ecially in the absence of proof of significant
harm to the environment. The Court therefore considers that Nicaragua failed to show that

Costa Rica infringed the above-mentioned instruments.

3. The obligation to respect Nicaragua’s terri torial integrity and sovereignty over the
San Juan River (paras. 221-223)

As to Nicaragua’s claim that the deltas created by sediment eroded from the road are
“physical invasions, incursions by CostaRica into Nicaragua’s sovereign territory ... through the
agency of sediment” and that th eir presence constitut es “trespass” into Nicar agua’s territory, the

Court considers that, whether or not sediment deltas are created as a consequence of the
construction of the road, Nicaragua’s theory to s upport its claim of a violation of its territorial
integrity via sediment is unconvincing. There is no evidence that CostaRica exercised any
authority on Nicaragua’s territory or carried outany activity therein. Moreover, for the reasons

already expressed above, Nicaragua has not shown th at the construction of the road impaired its
right of navigation on the San Juan River. Ther efore, Nicaragua’s claim concerning the violation
of its territorial integrity and sovereignty must be dismissed.

C. Reparation (paras. 224-228)

With respect to reparation, the Court’s declar ation that Costa Rica violated its obligation to
conduct an environmental impact assessment is the appropriate measure of satisfaction for

Nicaragua.

The Court rejects all of Nicaragua’s other submissions. To conclude, it notes that Costa Rica
has begun mitigation works in order to reduce the adverse effects of the construction of the road on

the environment. It expects that Costa Rica will continue to pursue these efforts in keeping with its
due diligence obligation to monitor the effects of the project on the environment. The Court further
reiterates the value of ongoing co-operation betw een the Parties in the performance of their
respective obligations in connection with the San Juan River.

O PERATIVE PART (PARA . 229)

T HE COURT ,

(1) By fourteen votes to two,

Finds that Costa Rica has sovereignty over th e “disputed territory”, as defined by the Court

in paragraphs 69-70 of the present Judgment;

IN FAVOUR : President Abraham; Vice-President Yusuf; Judges Owada, Tomka, Bennouna,
CançadoTrindade, Greenwood, Xue, Donoghue , Gaja, Sebutinde, Bhandari, Robinson;
Judge ad hoc Dugard;

AGAINST : Judge Gevorgian; Judge ad hoc Guillaume;

U(na)nimously,

Finds that, by excavating three caños and establishing a military presence on Costa Rican
territory, Nicaragua has violated the territorial sovereignty of Costa Rica;

U(na)nimously, - 15 -

Finds that, by excavating two caños in 2013 and establishing a military presence in the
disputed territory, Nicaragua has breached te obligations incumbent upon it under the Order

indicating provisional measures issued by the Court on 8 March 2011;

U(na)nimously,

Finds that, for the reasons given in paragra phs 135-136 of the present Judgment, Nicaragua
has breached Costa Rica’s rights of navigation on the San Juan River pursuant to the 1858 Treaty
of Limits;

(5)

Un(a)nimously,

Finds that Nicaragua has the obligation to compensate Costa Rica for material damages
caused by Nicaragua’s unlawful activities on Costa Rican territory;

U(na)nimously,

Decides that, failing agreement between the Parties on this matter within 12 months from the
date of this Judgment, the question of compensation due to Costa Rica will, at the request of one of

the Parties, be settled by the Court, and reserfor this purpose the subsequent procedure in the
case concerning Certain Activities carried out by Nicaragua in the Border Area (CostaRicav.
Nicaragua);

(c) By twelve votes to four,

Rejects Costa Rica’s request that Nicaragua be ordered to pay costs incurred in the
proceedings;

IN FAVOUR : PresidentAbraham; Vice-PresidentYusuf; JudgesOwada, Bennouna,
CançadTorindade, Xue, Donoghue, Gaja , Bhandari, Robinson, Gevorgian;
Judge ad hoc Guillaume;

AGAINST : Judges Tomka, Greenwood, Sebutinde; Judge ad hoc Dugard;

U(na)nimously,

Finds that Costa Rica has violated its obligatio n under general international law by failing to
carry out an environmental impact assessment concerning the construction of Route 1856;

(7) By thirteen votes to three,

Rejects all other submissions made by the Parties.

IN FAVOUR : President Abraham; Vice-President Yusuf; Judges Owada, Tomka, Bennouna,
CançadoTrindade, Greenwood, Xue, D onoghue, Gaja, Sebutinde, Gevorgian;
Judge ad hoc Guillaume;

AGAINST : Judges Bhandari, Robinson; Judge ad hoc Dugard.

Vice-President USUF appends a declaration to the Judgment of the Court; Judge O WADA
appends a separate opinion to the Judgment of the Court; Judges T OMKA , GREENWOOD ,

SEBUTINDE and JudgeadhocD UGARD append a joint declaration to the Judgment of the Court;
Judge CANÇADO TRINDADE appends a separate opinion to the Judgment of the Court;
Judge DONOGHUE appends a separate opinion to the Judgment of the Court; JudgeB HANDARI - 16 -

appends a separate opinion to theJudgment of the Court; JudgeR OBINSON appends a separate

opinion to the Judgment of the Court; JudgeEVORGIAN appends a declaration to the Judgment of
the Court; JudgeadhocG UILLAUME appends a declaration to the Judgment of the Court;
Judge ad hoc DUGARD appends a separate opinion to the Judgment of the Court.

___________ Annex 1 to Summary 2015/3

Declaration of Vice-President Yusuf

Whilst agreeing with the operative clauses of the Judgment, Judge Yusuf notes that both
Parties claimed that their territorial integrity had been breached by the actions of the other. The

reasoning of the Court, in his view, inadequately addresses these submissions.

The inviolability of borders is a fundamental part of territorial integrity. An intrusion onto
the territory of a State, however small, breaches the territorial inviolability of a State, which is

enshrined in the Charter of the Organization of American States, the Charter of the United Nations,
and in customary international law. Violation of this principle is not necessarily linked to a breach
of the use or threat of force by the intruding party, as is evident from the United Nations
Declaration on Principles of International Law concerning Friendly Relations and Cooperation

among States.

Moreover, in its previous case law, the Court has emphasized the pivotal role that respect for
territorial integrity plays in the international community. By failing to reiterate and emphasize the

importance of this principle, the present Judgment is inconsistent with the Court’s previous case
law.

Separate opinion of Judge Owada

Although Judge Owada voted in favour of the conclusions reached by the Court in the
operative part of the Judgment, in his separate opinion, he wishes to elaborate his view on those
aspects of the reasoning of the Court which he finds have not been developed with sufficient clarity

in the Judgment.

I. THE ISSUE OF SOVEREIGNTY OVER THE DISPUTED TERRITORY

Judge Owada observes that the Court has rightly concluded that the legal instruments
relevant for determining sovereignty over the “disputed territory” should be the 1858 Treaty, the
Cleveland Award of 1888 and the Alexander Award of 1897 (Judgment, paragraph 76). However,

Judge Owada finds that the Judgment has not been sufficiently articulate on the logical sequence
that exists between these legal instruments. In Judge Owada’s view, what is decisive for the
purpose of determining sovereignty over the disputed territory is first and foremost the
interpretation of the relevant legal instruments in light of their assigned roles and purposes in their

contexts.

Judge Owada proceeds by emphasizing that under these circumstances the task for the Court
has not and cannot have been to identify the geographical location of “the first channel met” or to

follow the line described in the first Alexander Award in 1897. Judge Owada takes the position
that the resolution by the Court of the question of territorial sovereignty over the disputed territory
is to be based on the same legal sources and the same legal reasoning that General Alexander
applied in implementing the Cleveland Award of 1888 which provided the authoritative and

binding interpretation and determination of the boundary prescribed by the 1858 Treaty.

Judge Owada notes that General Alexander was trying, in his first Award, faithfully to
follow the prescription of Article II of the 1858 Treaty. As Judge Owada further observes and

discusses in detail, the unequivocal outcome that the Court has reached in the present Judgment on
the question of sovereignty over the disputed territory is confirmed by the application of the
underlying reasoning of the first and third Alexander Awards to the present-day geographical
situation of the disputed area. - 2 -

Judge Owada recalls that the Parties in the present case have provided the Court with a
number of arguments and have produced a range of supporting evidentiary materials, all relating to

the question of whether or not any navigable channels might have traversed or currently traverse
the disputed territory. Judge Owada concurs with the Court’s evaluation of this evidence while
emphasizing his own conclusion that the totality of such evidence amounts in fact to very little that

is material or conclusive for determining the question of territorial sovereignty over the disputed
territory.

II. EGAL CONSEQUENCES OF THE C OURT ’S FINDING RELATING TO SOVEREIGNTY
OVER THE DISPUTED TERRITORY

Judge Owada begins this part of his separate opinion by distinguishing the situation involved

in the present dispute from the situation of a classical territorial dispute that is typically brought
before the International Court of Justice following attempts by the parties to come to a peaceful
settlement. Judge Owada points out that in the present case, as is implied in the language of the
Judgment itself, the territorial dispute has been caused primarily through unilateral action taken in

the form of a physical incursion by one State into the territory of another State that had been
primarily held for many years by the latter State.

In Judge Owada’s view, given this undisputable fact, it would have been appropriate for the

Court to have treated the acts by Nicaragua in question as a straightforward case of the commission
of an internationally wrongful act which could arguably amount to an act constituting an unlawful
use of force under Article 2 (4) of the United Nations Charter. Judge Owada notes that while he

has concurred with the Court’s conclusions on this matter, it would have been more appropriate for
the Court to have gone further by declaring that these internationally wrongful acts by Nicaraguan
authorities constituted an unlawful use of force under Article 2 (4) of the United Nations Charter.

Judge Owada further observes that the Judgment’s reference in this context to the
Cameroon v. Nigeria case seems inappropriate and could be quite misleading. According to
Judge Owada, that case should clearly be distinguished from the present situation, inasmuch as the
Cameroon v. Nigeria case had not been caused by an action of one Party to alter the existing status

quo through unilateral means.

III. THE NATURE OF THE REQUIREMENT TO CONDUCT AN

ENVIRONMENTAL IMPACT ASSESSMENT

Judge Owada begins this part of his separate opinion by observing that in the process of
carrying out the obligation to act in due diligence under international environmental law, the

requirement of conducting an environmental impact assessment becomes a key element for
determining whether certain activities may cause significant transboundary harm. Judge Owada
recalls that in this context both Parties referred approvingly to the dictum from the Court’s

Judgment in the case concerning Pulp Mills on the River Uruguay (Argentina v. Uruguay), where
the Court had referred to the environmental impact assessment as “a practice, which in recent years
has gained so much acceptance among States that it may now be considered a requirement under
general international law” (I.C.J. Reports 2010 (I), p. 83, para. 204).

Judge Owada observes that this dictum of the Court should be placed in contrast with the
finding of the International Tribunal for the Law of the Sea in its 2011 Advisory Opinion on the
Responsibilities and obligations of States with respect to activities in the Area that an

environmental impact assessment as such is a “general obligation under customary international
law” (ITLOS Reports 2011, para. 145). Judge Owada finds that, by comparison, the reasoning of
this Court in its Judgment in the Pulp Mills case appears to take a more nuanced approach to this

requirement. In Judge Owada’s view, the Court in its Judgment in the Pulp Mills case had - 3 -

emphasized the importance of the environmental impact assessment in the context of the process of
carrying out the obligation of due diligence, which is a holistic process. Judge Owada observes

that conducting an environmental impact assessment is one important constituent element of the
process that emanates from the international obligation of States to act in due diligence to avoid or
mitigate significant transboundary harm, rather than a separate and independent obligation standing
on its own under general international law.

In Judge Owada’s view, this balanced approach has been maintained in the present Judgment
and is reflected in the part of the Judgment dealing with the “requirement to carry out an
environmental impact assessment” (Judgment, paragraph 104). Judge Owada recalls that the

Court’s conclusion in the Judgment’s operative part (paragraph 229 (6)) is based on this reasoning.
Finally, Judge Owada emphasizes that the environmental impact assessment, which is essentially of
a technical nature, is one possible means to achieve the ultimate legal objective that is binding upon

States acting in the environmental field  an obligation to act with due diligence in order to
prevent significant transboundary harm in the light of the assessed risks involved.

Joint declaration of Judges Tomka, Greenwood and Sebutinde and Judge ad hoc Dugard

Judges Tomka, Greenwood and Sebutinde and Judge ad hoc Dugard consider that the Court
should have ordered Nicaragua to pay the costs which Costa Rica incurred in obtaining a second
order on provisional measures in 2013. They recall that Article 64 of the Statute of the Court,

together with Article 97 of the Rules of Court, gives the Court the discretion to award costs. They
observe that the costs incurred by Costa Rica were a consequence of serious violations by
Nicaragua of its obligations under the Court’s 2011 Order on provisional measures. They note that
Nicaragua could have taken action that would have rendered hearings in October 2013

unnecessary, but failed to do so. Costa Rica was therefore compelled to incur costs in seeking the
further order on provisional measures. Although Costa Rica will be able to recover compensation
for damage resulting from Nicaragua’s breach of the 2011 Order, it will be unable to recover the

expense of nearly a week of hearings. Judges Tomka, Greenwood and Sebutinde and
Judge ad hoc Dugard consider that it is illogical for a State faced with a breach of provisional
measures to be treated less favourably if it seeks redress before the Court than if it undertakes
unilateral remediation measures. They take the view that, while the power to award costs under

Article 64 has never before been used, the exceptional circumstances of this case warrant the Court
exercising that power and awarding costs to Costa Rica.

Separate opinion of Judge Cançado Trindade

1. In his Separate Opinion, composed of twelve parts, Judge Cançado Trindade observes at
first that, although he aligned with the majority in the present Judgment of the International Court
of Justice (ICJ), of 16.12.2015, in the two joined cases of Certain Activities Carried out by

Nicaragua in the Border Area (Costa Rica versus Nicaragua) and of the Construction of a Road in
Costa Rica along the San Juan River (Nicaragua versus Costa Rica), he finds that there are certain
points ensuing therefrom which, though not dwelt upon at depth by the Court in its reasoning, are
in his view endowed with importance, related as they are to the proper exercise of the international

judicial function. He feels thus obliged to dwell upon them, in the present Separate Opinion,
nourishing the hope that it may be useful for the handling of this matter by the ICJ in future cases.

2. Judge Cançado Trindade begins by singling out (part I) the points he has in mind, namely:
a) the manifestations of the preventive dimension in contemporary international law; b) the
evolution and conformation of the autonomous legal regime of Provisional Measures of Protection;
c) provisional measures and the enlargement of the scope of protection; d) the breach of

Provisional Measures of Protection as an autonomous breach, engaging State responsibility by - 4 -

itself; e) the ICJ’s determination of breaches of obligations under Provisional Measures of
Protection. Next, he presents his reflections, in the form of a plea, for the prompt determination of

breaches of Provisional Measures of Protection.

3. Judge Cançado Trindade then proceeds to examine the following points, namely:

a) supervision of compliance with Provisional Measures of Protection; b) breach of provisional
measures and reparation for damages; c) due diligence, and the interrelatedness between the
principle of prevention and the precautionary principle; d) the path towards the progressive
development of Provisional Measures of Protection. The way is then paved for the presentation, in

an epilogue, of a recapitulation of his conclusions on the aforementioned points.

4. As to the first of the above points, namely, the manifestations of the preventive dimension
in contemporary international law (part II), Judge Cançado Trindade observes that the present two

joined cases of Certain Activities Carried out by Nicaragua in the Border Area and of the
Construction of a Road in Costa Rica along the San Juan River bring to the fore the relevance of
that preventive dimension, as reflected in the present Judgment, in the finding and legal

consequences of breaches of Provisional Measures of Protection (in the Certain Activities case), as
well as in the acknowledgment of the obligation to conduct an environmental impact assessment
(EIA) (in the Construction of a Road case as well). This preventive dimension grows in
importance in the framework of regimes of protection (such as those, e.g., of the human person,

and of the environment). Moreover, it brings us particularly close to general principles of law
(para. 4).

5. Such preventive dimension stands out clearly in the succession of the Court’s Orders of
Provisional Measures of Protection of 08.03.2011, 16.07.2013 and 22.11.2013, and has been
addressed by the contending parties in the course of the proceedings (written and oral phases)
before the Court (also at the merits stage). The Court has duly considered the submissions of the

parties, and has found that the respondent State incurred (in the Certain Activities case) into a
breach of the obligations under its Order of Provisional Measures of Protection of 08.03.2011, by
the excavation of two caños in 2013 and the establishment of a military presence in the disputed
territory (paras. 127 and 129, and resolutory point n. 3 of the dispositif).

6. Judge Cançado Trindade recalls that, already for some time, he has been drawing the
Court’s attention to the autonomous legal regime of Provisional Measures of Protection, in the way

he conceives, and has been conceptualizing, along the years, such autonomous legal regime, in
successive Dissenting and Individual Opinions in this Court (part III). The present Judgment of the
ICJ in the two joined cases of Certain Activities and of the Construction of a Road is yet another
occasion, and a proper one, to dwell further upon it. To start with, that legal regime can be better

appreciated if we consider provisional measures in their historical evolution. May I recall that, in
their origins, in domestic procedural law doctrine of over a century ago, provisional measures were
considered, and evolved, in order to safeguard the effectiveness of the jurisdictional function itself
(para. 7).

7. They thus emerged, in the domestic legal systems, — he proceeds, — in the form of a
precautionary legal action (mesure conservatoire / acción cautelar / ação cautelar), aiming at

guaranteeing, not directly subjective rights per se, but rather the jurisdictional process itself. They
“had not yet freed themselves from a certain juridical formalism, conveying the impression of
taking the legal process as an end in itself, rather than as a means for the realization of justice”
(para. 8). With their transposition into international legal procedure, and the increasing recourse to

them within the framework of domains of protection (e.g., of the human person or of the - 5 -

environment), they came to be increasingly resorted to, in face of the most diverse circumstances
disclosing the probability or imminence of an irreparable damage, to be prevented or avoided. This

had the effect, in his perception, of enlarging the scope of international jurisdiction, and of refining
their conceptualization (para. 9).

8. With their considerable expansion along the last three decades, it became clear to the
contending parties that they were to abstain from any action which might aggravate the dispute
pendente lite, or may have a prejudicial effect on the compliance with the subsequent judgment as
to the merits. Their rationale stood out clearer, turning to the protection of rights, of the equality of

arms (égalité des armes), and not only of the legal process itself. They

“have freed themselves from the juridical formalism of the procedural doctrine of over
a century ago, and have, in my perception, come closer to reaching their plenitude.

They have become endowed with a character, more than precautionary, truly tutelary.
When their basic requisites, — of gravity and urgency, and the needed prevention of
irreparable harm, — are met, they have been ordered, in the light of the needs of
protection, and have thus conformed a true jurisdictional guarantee of a preventive

character” (para. 10).

9. An international tribunal such as the ICJ has the inherent power or faculté to determine the

scope of the provisional measures that it decides to order, and this comes to reinforce the
preventive dimension, proper of those measures (paras. 11, 36 and 62). Such inherent power is
exercised in order to secure the sound administration of justice (la bonne administration de la
justice) (paras. 12 and 63). The autonomous legal regime of provisional measures encompasses, in

Judge Cançado Trindade’s conception (also explained in his own previous Dissenting and Separate
Opinions in the ICJ — paras. 14-16 and 21-23), their juridical nature, the rights and obligations at
issue, their legal effects, and the duty of compliance with them (para. 13).

10. Provisional measures have expanded, and have in practice enlarged the scope of
protection (part IV — paras. 17-18). To Judge Cançado Trindade, it is “not casual” that they came
to be conceived as precautionary measures (mesures provisoires / medidas cautelares), prevention

and precaution underlying them all. And he adds:

“Precaution, in effect, takes prevention further, in face of the uncertainty of
risks, so as to avoid irreparable damages. And here, again, in the domain of

Provisional Measures of Protection, the relationship between international law and
time becomes manifest. The inter-temporal dimension is here ineluctable, overcoming
the constraints of legal positivism. International law endeavours to be anticipatory in
the regulation of social facts, so as to avoid irreparable harm; Provisional Measures of

Protection expand the protection they pursue, as a true international jurisdictional
guarantee of a preventive character” (para. 19).

11. Judge Cançado Trindade then turns to the breach of Provisional Measures of Protection,

which he regards as an autonomous breach, engaging State responsibility by itself (part V), and
additional to the breach which comes, or may come, later to be determined as to the merits of the
case at issue (para. 24). Accordingly, the breach of a provisional measure can, in his

understanding, be promptly determined, with its legal consequences, without any need to wait for
the conclusion of the proceedings as to the merits (para. 25). - 6 -

12. Judge Cançado Trindade then reviews the ICJ case-law on the determination of breaches
of obligations under Provisional Measures of Protection (part VI), when the Court has done so at

the end of the proceedings as to the merits of the corresponding cases, namely, besides the present
Judgment, the previous Judgments of the ICJ as to the merits in the three cases of LaGrand (2001),
of Armed Activities on the Territory of the Congo (2005), and of the Bosnian Genocide (2007). In
the earlier case of the Hostages in Tehran (United States versus Iran, Judgment of 24.05.1980), the

ICJ did not expressly assert that the Order of Provisional Measures of 15.12.1979 had been
breached.

13. It found such breach (of its Order of Provisional Measures of 03.03.1999) in the LaGrand
case (Germany versus United States, Judgment of 27.06.2001), but without drawing any
consequences from the conduct in breach of its provisional measures. Four years later, in its
Judgment of 19.12.2005 in the case concerning Armed Activities on the Territory of the Congo

(D.R. Congo versus Uganda), the ICJ, turning to its Order of Provisional Measures (of 01.07.2000)
adopted half a decade earlier, — concerning breaches of International Human Rights Law and
International Humanitarian Law, — found that the respondent State had not complied with it, and
reiterated its finding in resolutory point n. 7 of the dispositif.

14. Another case of determination by the ICJ of a breach of its Orders of Provisional
Measures of Protection was that of the Application of the Convention against Genocide

(Bosnia and Herzegovina versus Serbia and Montenegro): the Court held so in its Judgment
of 26.02.2007, while the Orders of Provisional Measures had been adopted 14 years earlier,
on 08.04.1993 and 13.09.1993, aiming at ceasing the atrocities that were already being perpetrated.
Two years after the first Order (of 08.04.1993), the U.N. safe-area of Srebrenica collapsed, and the

mass-killings of July 1995 in Srebrenica occurred, in a flagrant breach of the provisional measures
ordered by the ICJ (paras. 30-31).

15. In the meantime, the proceedings in the case before the ICJ prolonged in time: as to
preliminary objections until 1996; as to counter-claims until 1997, and again until 2001; and as to
the merits until 2007. The manifest breaches of the ICJ’s Orders of Provisional Measures of
Protection of 1993 passed for a long time without determination, and without any legal

consequences. It took 14 years for the Court to determine, in its Judgment on the merits (2007), the
breach of its Provisional Measures of Protection in the cas d’espèce. In Judge Cançado Trindade’s
understanding,

“there was no need to wait such a long time to determine the breach of such measures;
on the contrary, they should have been promptly determined by the ICJ, with all its
legal consequences. This tragic case shows that we are still in the infancy of the
development of the legal regime of provisional measures of protection in

contemporary international law. A proper understanding of the autonomous legal
regime of those measures may foster their development at conceptual level” (para. 33).

16. In his following reflections as a plea for the prompt determination of breaches of
Provisional Measures of Protection (part VII), Judge Cançado Trindade ponders at first that, in the
cas d’espèce (Certain Activities case), the breaches of provisional measures have been determined
by the Court within a reasonably short lapse of time, — unlike in the case of Armed Activities on

the Territory of the Congo (half a decade later) and in the Bosnian Genocide case (almost one and a
half decade later). In the cas d’espèce, the damages caused by the breaches of provisional
measures have not been irreparable, — unlike in the LaGrand case, — and “with their
determination by the Court in the present Judgment their effects can be made to cease” (para. 34). - 7 -

17. In effect, in his understanding, “the determination of a breach of a provisional measure of
protection is not — should not be — conditioned by the completion of subsequent proceedings as

to the merits of the case at issue” (para. 35). The legal effects of a breach of a provisional measure
of protection should, in his view, “be promptly determined, with all its legal consequences. In this
way, its anticipatory rationale would be better served”. In his view, “there is no room for raising
here alleged difficulties as to evidence”, as for the ordering of provisional measures of protection,

and the determination of non-compliance with them, “it suffices to rely on prima facie evidence
(commencement de preuve)” (para. 35).

18. Furthermore, the rights that one seeks to protect under provisional measures “are not
necessarily the same as those vindicated on the merits”, as shown in the case of the Temple of
Préah Vihéar. Likewise, “the obligations (of prevention) are new or additional ones, in relation to
those ensuing from the judgment on the merits” (para. 36). The fact that, in its practice, the ICJ has

only indicated provisional measures at the request of a State party, in his view “does not mean that
it cannot order such measures sponte sua, ex officio” (para. 37). The ICJ Statute endows the Court
with the power to do so, if it considers that circumstances so require (Article 41 (1)).

19. And the Rules of Court provide that, irrespective of a request by a party, the Court may
indicate provisional measures that, in its view, “are in whole or in part other than those requested”
(Article 75 (2)). This happened in the case concerning the Land and Maritime Boundary

between Cameroon and Nigeria (Order of 15.03.1996), and the case concerning Armed Activities
on the Territory of the Congo (D.R. Congo versus Uganda, Order of 01.07.2000).
Judge Cançado Trindade adds that

“The Court, thus, is not conditioned by what a party, or the parties, request(s),
nor — in my view — even by the existence of the request itself. Here, in the realm of
Provisional Measures of Protection, once again the constraints of voluntarist legal
positivism are, in my view, overcome. The Court is not limited to what the

contending parties want (in the terms they express their wish), or so request. The
Court is not an arbitral tribunal, it stands above the will of the contending parties.
This is an important point that I have been making on successive occasions within the
ICJ, in its work of international adjudication” (para 39).

20. He next points out that there have, in effect, lately been cases lodged with the Court,
where it has been called upon “to reason beyond the inter-State dimension, not being limited by the

contentions or interests of the litigating States”, as pointed out in his Separate Opinion
(paras. 227-228) in the case of A.S. Diallo (Guinea versus D.R. Congo, Judgment (merits)
of 30.11.2010), and in his Dissenting Opinion in the case of Questions Relating to the Obligation to
Prosecute or Extradite (Belgium versus Senegal, Order (provisional measures) of 28.05.2009), as

well as in his Dissenting Opinion in the case concerning the Application of the International
Convention on the Elimination of All Forms of Racial Discrimination (CERD — Georgia versus
Russian Federation, Judgment (preliminary objections) of 01.04.2011) (paras. 40-41).
Judge Cançado Trindade then warns that the Court

“is not an arbitral tribunal, it stands above the will of the contending parties. It is not
conditioned by requests or professed intentions of the contending parties. It has an
inherent power or faculté to proceed promptly to the determination of a breach of

provisional measures, in the interests of the sound administration of justice. And recta
ratio guides the sound administration of justice (la bonne administration de la justice).
Recta ratio stands above the will. It guides international adjudication and secures its
contribution to the rule of law (prééminence du droit) at international level. - 8 -

The Court is entirely free to order the provisional measures that it considers
necessary, so as to prevent the aggravation of the dispute or the occurrence of

irreparable harm, even if the measures it decides to order are quite different from those
requested by the contending parties” (paras. 42-43).

21. Judge Cançado Trindade then concludes, on this particular issue, that the ICJ may, after
examining the circumstances of the cas d’espèce, proceed to order, sponte sua, provisional
measures of protection. It may do so motu proprio, thus avoiding the aggravation of a situation.
This determination ex officio of the occurrence of a breach of an Order of Provisional Measures of

Protection is keeping in mind the preventive dimension in contemporary international law, thus
avoiding further irreparable harm. In his understanding, “the Court does not have to wait until the
completion of the proceedings as to the merits, especially if such proceedings are unreasonably
prolonged, as, e.g., in the case of the Bosnian Genocide” (para. 44).

22. Judge Cançado Trindade then turns to the issue of the supervision of compliance with
Provisional Measures of Protection (part VIII). The fact that the ICJ has, so far, very seldom

proceeded to the determination of a breach of provisional measures in the subsequent proceedings
as to the merits of the respective cases, in his view does not mean that it cannot do so promptly, by
means of another Order of Provisional Measures. The Court, — he proceeds, — has monitoring
powers as to compliance with provisional measures. If any unforeseeable circumstance may arise,

the ICJ is “endowed with inherent powers or facultés to take the decision that ensures compliance
with the provisional measures it has ordered, and thus the safeguard of the rights at stake”
(para. 45). This enhances the preventive dimension of provisional measures, as well as the rule of
law (prééminence du droit) at international level (para. 46).

23. The following point examined by Judge Cançado Trindade is that of the breach of
provisional measures and reparation for damages (in its distinct forms) (part IX), — a point which

has not passed unperceived in the present Judgment of the ICJ in the two joined cases of Certain
Activities and of the Construction of a Road: the Court has addressed reparations in the two joined
cases, — in particular its declaration (in the Certain Activities case) of a breach of provisional
measures as an “adequate satisfaction” to the applicant, without the need to award costs. (In the

joined case of Construction of a Road, its declaration of breach of the obligation to conduct an
environmental impact assessment has likewise provided adequate satisfaction to the applicant).

24. The grant of this form of reparation (satisfaction) in the two joined cases is necessary and
reassuring. Judge Cançado Trindade adds that, the fact that the ICJ did not establish a breach of
provisional measures nor did it indicate new provisional measures already in its Order
of 16.07.2013 (as it should, for the reasons explained in his Dissenting Opinion appended thereto),

and only did so in its subsequent Order of 22.11.2013, gives weight to its decision not to award
costs. After all, — he proceeds, — “the prolongation of the proceedings (as to provisional
measures) was due to the hesitation of the Court itself. Accordingly, the relevant issue here is,
thus, reparation (rather than costs of hearings) for breach of Provisional Measures of Protection”

(para. 50).

25. In effect, “breach and duty of reparation come together”; as he pointed out in his

Separate Opinion in the A.S. Diallo case (Guinea versus D.R. Congo, reparations, Judgment
of 19.06.2012), “the duty of reparation has deep historical roots, going back to the origins of the
law of nations, and marking presence in the legacy of the ‘founding fathers’ of our discipline”
(para. 51). The duty of reparation, — Judge Cançado Trindade adds, — is “widely acknowledged

as one of general or customary international law”, as “the prompt and indispensable complement of - 9 -

an international wrongful act, so as to cease all the consequences ensuing therefrom, and to secure
respect for the international legal order”. Breach and duty of reparation “form an indissoluble

whole” (para. 51). And he concludes, on this particular issue, that

“The interrelationship between breach and duty of reparation marks presence
also in the realm of the autonomous legal regime of Provisional Measures of

Protection. A breach of a provisional measure promptly generates the duty to provide
reparation for it. It is important, for provisional measures to achieve their plenitude
(within their legal regime), to remain attentive to reparations — in their distinct
forms — for their breach. Reparations (to a greater extent than costs) for the

autonomous breach of Provisional Measures of Protection are a key element for the
consolidation of the autonomous legal regime of Provisional Measures of Protection”
(para. 52).

26. Judge Cançado Trindade then draws attention to due diligence, and the interrelatedness
between the principle of prevention and the precautionary principle (part X). These are elements
which marked presence in the Judgment the ICJ has just adopted, in the two joined cases of Certain

Activities Carried out by Nicaragua in the Border Area and of the Construction of a Road in
Costa Rica along the San Juan River, just as they did in an earlier Latin American case, that of the
Pulp Mills on the River Uruguay (2010), opposing Argentina to Uruguay (paras. 53-54): “while
the principle of prevention assumes that risks can be objectively assessed so as to avoid damage,

the precautionary principle assesses risks in face of uncertainties, taking into account the
vulnerability of human beings and the environment, and the possibility of irreversible harm”
(para. 55).

27. He then ponders that, “[u]nlike the positivist belief in the certainties of scientific
knowledge”, the precautionary principle “is geared to the duty of due diligence, in face of scientific
uncertainties; precaution is thus, nowadays, more than ever, needed”. It is “not surprising that

some environmental law Conventions give expression to both the principle of prevention and the
precautionary principle, acknowledging the link between them, providing the foundation of the
duty to conduct an environmental impact assessment”, — as upheld by the ICJ in the joined case of
the Construction of a Road (para. 56). In the present Judgment, — he continues, — the Court,

addressing the requirement of due diligence in order to prevent significant transboundary
environmental harm. It focused on the undertaking of an environmental impact assessment “in the
wider realm of general international law” (para. 57).

28. Judge Cançado Trindade then endeavours to detect the path towards the progressive
development of provisional measures of protection (part XI), which he regards as the main lesson
to be learned from the adjudication of the cas d’espèce, the joined case of Certain Activities. The

conformation of an autonomous legal regime of Provisional Measures of Protection, with all its
elements and implications, is to be further developed. As he had already warned in his previous
Dissenting Opinion in the ICJ’s Order of 16.07.2013 in the present two joined cases of Certain
Activities and of the Construction of a Road, wherein the Court decided not to indicate new

provisional measures, nor to modify the provisional measures indicated in its previous Order
of 08.03.2011, and he deems it fit here to reiterate:

“My thesis, in sum, is that provisional measures, endowed with a conventional

basis, — such as those of the ICJ (under Article 41 of the Statute), — are also
endowed with autonomy, have a legal regime of their own, and non-compliance with
them generates the responsibility of the State, entails legal consequences, without
prejudice of the examination and resolution of the concrete cases as to the merits. - 10 -

(...) Provisional measures of protection generate obligations (of prevention) for
the States concerned, which are distinct from the obligations which emanate from the

Judgments of the Court as to the merits (and reparations) of the respective cases. This
ensues from their autonomous legal regime, as I conceive it. There is, in my
perception, pressing need nowadays to refine and to develop conceptually this
autonomous legal regime (...).

(...) [T]he matter before the Court calls for a more pro-active posture on its part,
so as not only to settle the controversies filed with it, but also to tell what the Law is
(juris dictio), and thus to contribute effectively to the avoidance or prevention of

irreparable harm in situations of urgency, to the ultimate benefit of all subjects of
international law, — States as well as groups of individuals, and simples particuliers.
After all, the human person (living in harmony in her natural habitat) occupies a
central place in the new jus gentium of our times” (cit. in para. 59).

29. Judge Cançado Trindade adds that the rights protected by Provisional Measures of
Protection are not necessarily the same as those pertaining to the merits of the case at issue; and

the obligations ensuing from Provisional Measures of Protection are distinct from, and additional
to, the ones that may derive later from the Court’s subsequent decision as to the merits (para. 61).
In case of a breach of a provisional measure of protection, “the notion of victim of a harm emerges
also in the framework of such provisional measures; irreparable damages can, by that breach,

occur in the present context of prevention” (para. 61). This being so, the determination of such
breach “does not need to wait for the conclusion of the proceedings as to the merits of the case at
issue, particularly if such proceedings are unduly prolonged” (para. 63).

30. Furthermore, “the determination of their breach is not conditioned by the existence of a
request to this effect by the State concerned”; the Court, — he concludes on the present point, —
“is fully entitled to proceed promptly to the determination of their breach sponte sua, ex officio, in

the interests of the sound administration of justice (la bonne administration de la justice)”
(para. 64). The refinement of the autonomous legal regime of Provisional Measures of Protection
(encompassing reparation in its distinct forms, and eventually costs) “can clarify further this
domain of international law marked by prevention and the duty of due diligence, and can thus

foster the progressive development of those measures in the contemporary law of nations, faithful
to their preventive dimension, to the benefit of all the justiciables” (para. 66). In doing so,
international case-law seems to be preceding legal doctrine (para. 66).

31. In the last part (XII) of his Separate Opinion, in presenting a recapitulation of all his
arguments, Judge Cançado Trindade ponders that Provisional Measures of Protection provide, as
just seen, “a fertile ground for reflection at the juridico-epistemological level. Time and law are

here ineluctably together, as in other domains of international law” (para. 67). Provisional
measures underline the preventive dimension, “growing in clarity, in contemporary international
law”. Provisional measures “have undergone a significant evolution, but there remains a long way
to go for them to reach their plenitude” (para. 67).

Separate opinion of Judge Donoghue

Judge Donoghue considers that States have an obligation under customary international law
to exercise due diligence in preventing significant transboundary environmental harm. This
obligation of due diligence follows from the synthesis of basic principles of the international legal
order, in particular, sovereign equality and territorial sovereignty. The measures that a State of

origin must take to meet this due diligence obligation depend on the particular circumstances, and - 11 -

can include environmental impact assessment, notification of potentially affected States and
consultation with such States. However, Judge Donoghue does not consider that the Court is in a

position to prescribe specific rules of customary international law regarding these three topics. As
to notification and consultation, she also has misgivings about the precise formulation adopted by
the Court.

Separate opinion of Judge Bhandari

In his separate opinion Judge Bhandari recalls that he has voted with the majority in finding

that Costa Rica has violated international law by failing to produce an Environmental Impact
Assessment (EIA) in relation to its comprehensive road project along the San Juan River.
However, he laments the lack of clear guidelines concerning the requirements of an EIA under
international law, and proceeds to recommend certain minimum requirements that, in his view,

must be satisfied when conducting an EIA. He begins his analysis with an overview of modern
trends and various bedrock principles in contemporary international environmental law, including:
the principle of sustainable development; the principle of preventive action; global commons; the
precautionary principle; the polluter pays principle; and the concept of transboundary harm. He

then discusses how the requirement to conduct an EIA arises from these principles. The opinion
further notes that at present the régime of international environmental law relating to the
performance of EIAs is scattered throughout a patchwork of different international instruments, and
ultimately fails to lay down certain minimum procedural and substantive requirements. By

reference to the Espoo Convention and other authorities, Judge Bhandari endeavours to distil
certain basic obligations relating to the conduct of an EIA that, he believes, ought to be
incorporated into the canon of international environmental law. Finally, Judge Bhandari urges
nations to come together to conclude an international treaty governing the minimum requirements

of EIAs. Absent the creation of such a régime, he suggests that nations may wish to follow the
suggestions contained in his opinion as “best practices” to be applied by nation States in
discharging their duty to conduct a transboundary EIA.

Separate opinion of Judge Robinson

Judge Robinson’s separate opinion explains the reasons for which he voted against the

Court’s rejection in paragraph 229 (7) of the Judgment of all other submissions made by the
Parties. Judge Robinson is of the view that the Court should have explicitly determined
Costa Rica’s claim that Nicaragua breached Article 2 (4) of the United Nations Charter, rather than
deciding, as the Judgment states, not to “dwell any further” on this submission “given that the

unlawful character of these activities has already been established”.

Article 2 (4) of the United Nations Charter prohibiting the “threat or use of force against the
territorial integrity or political independence of any state, or in any other manner inconsistent with

the Purposes of the United Nations”, is, in the Court’s own words, “a cornerstone of the
United Nations Charter”. Given the foundational nature of the prohibition in the international legal
order, as well as the role envisaged for the Court in upholding the Purposes of the
United Nations Charter, the Court should play its part in strengthening respect for the prohibition

on the use of force. In Judge Robinson’s view, the Court should develop a practice of making an
express and discrete finding on a claim that the prohibition of the use of force has been breached,
unless it is of the opinion that the claim is patently unmeritorious or frivolous.

Judge Robinson interprets the “injury suffered by Costa Rica” discussed in paragraph 97, as
incorporating any potential injury suffered by Costa Rica as a result of the breach of the use of
force. He is unconvinced that it is possible to ensure that injury is remedied without an
examination of the fact of and circumstances surrounding the potential breach. Judge Robinson is

equally sceptical that, in the context of this case, reparation flowing from Nicaragua’s breach of - 12 -

territorial sovereignty may remedy any injury suffered as a result of breach of the prohibition of the
use of force. The Court did not examine any equivalence between the two norms, which, in

Judge Robinson’s view, serve distinct functions and reflect overlapping but not identical concerns.

The Court’s jurisprudence establishes that a State’s actions must reach a certain threshold
before they qualify as a an unlawful use of force. Assessing whether or not this threshold has been

met requires an analysis of the gravity and the purpose of the allegedly unlawful measures. It is
Judge Robinson’s view that the evidence before the Court in this case shows that Nicaragua did
breach the prohibition on the use of force.

Declaration of Judge Gevorgian

Judge Gevorgian explains in his declaration the reasons why he has voted against
paragraph 1 of the dispositif, which provides that “Costa Rica has sovereignty over the ‘disputed

territory’”. In his view, this finding of the Court  made in response to a claim brought by
Costa Rica only when presenting its final submissions in the Certain Activities case  was not
required in the circumstances of the case.

Judge Gevorgian shares the Court’s refusal to delimit the course of the boundary in the
“disputed territory” defined by the Court in its Orders for provisional measures rendered on
8 March 2011 and 22 November 2013. However, he finds problematic that the Court declares

Costa Rica’s sovereignty over an area whose limits are far from being clear. In Judge Gevorgian’s
opinion, the Court should have avoided such a finding for two main reasons.

First, the Parties did not address the issue of the precise location of the mouth of the river or

of the boundary at the coast, as the majority rightly indicates in paragraph 70 of the Judgment.
Therefore, Judge Gevorgian considers that the Court was not in a position to fully address
Costa Rica’s final submission.

Second, the geography of the disputed area  in which important geomorphological
alterations have occurred in the last century  is highly unstable. Thus, according to
Judge Gevorgian, the Court’s conclusion on sovereignty over the disputed territory may become

the source of future disagreement between the Parties.

Declaration of Judge ad hoc Guillaume

Judge ad hoc Guillaume agrees with a number of the findings reached by the Court. He has,
however, expressed his disagreement on a point in the case concerning Certain Activities carried
out by Nicaragua in the Border Area (Costa Rica v. Nicaragua). He notes that this case originally

related solely to those activities, and that all Costa Rica was seeking was judgment against
Nicaragua for having violated its sovereignty over the northern part of Isla Portillos. It was only at
the close of the oral proceedings that, for the first time, Costa Rica asked the Court to find that it
had sovereignty over the disputed territory. The Court has so decided, while failing to determine in

full the limits of that territory.

Judge ad hoc Guillaume recalls that, according to the Court’s jurisprudence, the
subject-matter of a dispute is defined by the claims submitted in the application, as is provided in

Article 40 of the Statute. Additional claims are admissible only if they fall within the scope of that
subject-matter. The sole exception to that rule is if the new claims were implicit in the application,
or arose directly out of the question which was the subject-matter of the application
(Ahmadou Sadio Diallo (Republic of Guinea v. Democratic Republic of the Congo), Merits,

Judgment, I.C.J. Reports 2010 (II), p. 656, citing Certain Phosphate Lands in Nauru (Nauru v.
Australia), Preliminary Objections, Judgment, I.C.J. Reports 1992, p. 267). - 13 -

Judge ad hoc Guillaume points out that Costa Rica’s new claims have transformed a case
concerning State responsibility into a territorial dispute. He takes the view that this is not possible,

and accordingly concludes that the new claims were out of time and therefore inadmissible. For
this reason, he voted against point 1 of the operative clause.

Judge ad hoc Guillaume has also clarified his thinking on a number of other points. As

regards freedom of navigation on the San Juan River, he observes that Costa Rica cited five
incidents which had allegedly infringed that freedom. Judge ad hoc Guillaume notes that the Court
accepted only two of these as proven. He believes that two incidents over a period of several years,
regrettable though they may be, cannot be regarded as indicative of Nicaragua’s overall conduct.

In the second case, that concerning the Construction of a Road in Costa Rica along the
San Juan River (Nicaragua v. Costa Rica), Judge ad hoc Guillaume notes that this road was not
only constructed without a prior environmental impact assessment, but had caused real

harm to Nicaragua. However, Judge ad hoc Guillaume notes that Nicaragua failed to show that
such harm was “significant”. Since this jurisprudential threshold had not been reached,
Judge ad hoc Guillaume finds that Costa Rica’s responsibility has not been engaged.

Separate opinion of Judge ad hoc Dugard

The obligation to conduct an environmental impact assessment in respect of an activity that

poses a risk of significant transboundary harm featured prominently in both Certain Activities and
Construction of a Road. The Court chose to describe this obligation as one of “general
international law”, but a scrutiny of this term suggests that it is almost synonymous with
“customary international law”. The obligation to conduct an environmental impact assessment is

an obligation independent from the duty of due diligence, which is the standard of conduct required
of a State when carrying out such an assessment. Although it has been suggested that the
environmental impact assessment obligation has no content, an analysis of the Court’s decision
established the presence of certain rules inherent in such an obligation.

The Court, relying on the principles it had expounded in respect of the content of the
environmental impact assessment obligation, rightly found that Costa Rica had breached its
obligation to conduct an environmental impact assessment by failing to conduct such an assessment

when it embarked on the construction of a road along the San Juan River. The circumstances
showed clearly that the road posed a risk of significant harm to Nicaragua’s environment.

The Court’s handling of the complaint of Costa Rica that Nicaragua had failed to conduct an

adequate environmental impact assessment when it planned its programme to improve the
navigability of the San Juan River by dredging was less satisfactory. I therefore dissented on this
issue.

Without examining the factual situation pertaining to Nicaragua’s dredging programme
when it was planned in 2006 and the risk it posed to Costa Rica’s wetland, the Court tersely
declared that the reports submitted to the Court and the testimony of witnesses called by both
Parties led it to conclude that Nicaragua’s dredging programme planned in 2006 was not such as to

give rise to a risk of significant transboundary harm. A close examination of the most relevant
reports and the testimony of witnesses led me to conclude that they did not substantiate the Court’s
factual finding. In my opinion the evidence showed that the dredging of the San Juan posed a risk
to Costa Rica’s wetland protected by the Ramsar Convention. The evidence of one of Nicaragua’s

own witnesses that the fact that an activity that took place in the vicinity of a wetland protected by
the Ramsar Convention was sufficient reason alone to require an environmental impact assessment
was particularly compelling and seems to have been ignored by the Court. A further objection to
the Court’s handling of this issue is that it failed to apply the principles that it had followed in

dealing with Nicaragua’s complaint against Costa Rica’s building of the road. There was a clear - 14 -

contradiction between the reasoning it applied in the two cases. Finally, an analysis of the
provisions of the Ramsar Convention suggested that Nicaragua was obliged to conduct an

environmental impact assessment in this case.

Undoubtedly the road Costa Rica built along the San Juan River posed a greater risk of
environmental harm to the river than did Nicaragua’s dredging programme to Costa Rica’s

wetland. This was, however, no justification for the faulty fact-finding and contradictory reasoning
of the Court.

___________ Sketch-map No. 1:

Geographical context

84°45’W 84°30′W 84°15′W 84°0′W 83°45′W 83°30′W

11° 15’N CARIBBEAN
SEA

NICARAGUA Harbor
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3 Sketch-map No. 2:

Route 1856 Juan Rafael Mora Porras

83°30′W
84°45’W 84°30′W 84°15′W 84°0′W 83°45′W

11° 15’N CARIBBEAN
SEA

NICARAGUA

Lake
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Marker II de Nicaragua IslaPortillos
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