Sea-Level Rise Reaches The Hague

The advisory opinion rendered by the Worldwide Courtroom of Justice (ICJ) on 23 July 2025 marks a pivotal second within the articulation of States’ obligations regarding local weather change. Whereas primarily based on broader guidelines and rules of worldwide regulation, the opinion foregrounded the United Nations Conference on the Legislation of the Sea (UNCLOS) as a key authorized framework related to defining States’ local weather obligations. Because the ICJ itself said, UNCLOS ‘kinds a part of essentially the most instantly related relevant regulation’ (para. 124). Thus, removed from peripheral, the regulation of the ocean emerged as a major web site for deciphering and implementing States’ local weather obligations below worldwide regulation.

This publish examines essentially the most salient options of the ICJ’s evaluation of the regulation of the ocean within the context of local weather change, particularly (i) the style during which the ICJ dialogued with the Worldwide Tribunal on the Legislation of the Sea (ITLOS), which issued its personal advisory opinion on local weather change final yr, (ii) the findings of that opinion that have been confirmed by the ICJ; (iii) the ICJ’s discovering on the soundness of States’ maritime baselines, and (iv) the ICJ’s findings on the presumption of continued statehood within the context of sea stage rise.

A Two-Method Avenue from Hamburg to The Hague

The ICJ’s opinion is proof of a rising judicial dialogue between the ICJ and ITLOS, which strengthens a studying of UNCLOS as a supply of States’ obligations within the context of local weather change. Such an alignment of views offers States with authorized certainty and readability relating to the sources and extent of their worldwide obligations.

The dialogue between each courts was already starkly seen in ITLOS’s 2021 judgment on preliminary objections within the Maldives v Mauritius maritime boundary dispute. Right here, ITLOS instantly engaged with the ICJ’s Chagos opinion to affirm Mauritius’ sovereignty over the Chagos archipelago. Remarkably, ITLOS emphasised the function of ICJ advisory opinions as a supply of clarification and growth of the present regulation. As such, though they’re formally non-binding, ITLOS acknowledged that the ICJ’s advisory opinions carry authorized weight equal to judgments, because the principal judicial organ of the United Nations with competence in issues of worldwide regulation (paras. 203 and 246).

Equally, the ICJ drew upon ITLOS’s 2022 advisory opinion on local weather change in a number of key passages of its personal opinion on local weather change, noting that it might “ascribe nice weight to the interpretation adopted by the Tribunal” (para. 338). Thus, the ICJ didn’t take a look at the ITLOS opinion as peripheral commentary; relatively, it built-in the reasoning of ITLOS into its personal evaluation, thereby affirming ITLOS’s interpretive authority.

This rising pattern of mutual borrowing strengthens coherence throughout judicial our bodies and reinforces the function of worldwide courts in clarifying States’ obligations in relation to local weather change. It additionally paves the way in which for additional authorized motion grounded in UNCLOS by small island states and different susceptible actors.

Confirming the Findings of ITLOS

The ICJ largely confirmed the important thing findings of ITLOS in its 2022 advisory opinion. In essence, it confirmed that greenhouse gasoline emissions fall inside the definition of “air pollution of the marine surroundings” below Article 1(1)(4) of UNCLOS, thereby activating the appliance of Half XII of the Conference (para. 340). The ICJ discovered that Article 194 of UNCLOS establishes an obligation to take all mandatory measures to stop, cut back, and management marine air pollution (para. 346). It additional affirmed that that is an obligation of conduct, relatively than end result, characterised by a stringent due diligence normal (paras. 347 and 349). The ICJ additionally reiterated that this obligation contains duties to cooperate and to hold out environmental impression assessments (paras. 350–353). Lastly, it emphasised that in implementing each UNCLOS and local weather change-related treaties, States should interpret and apply their obligations in a mutually supportive method, taking into consideration the necessities below each authorized regimes (para. 354).

Thou Shalt Not Transfer! Sea Stage Rise Impression on Baselines and Maritime Areas’ Outer Limits

The ICJ took the chance in its advisory opinion to make clear some authorized implications of sea stage rise. Being adopted in 1982, previous to scientific research on local weather change, UNCLOS is premised on the idea of a secure world imply sea stage. Unsurprisingly, no provision of UNCLOS incorporates any reference to sea stage rise. The issue is that, below UNCLOS, maritime baselines are established alongside a State’s coastlines and function a place to begin for drawing the outer limits of its territorial sea, unique financial zone, continental shelf, and eventual archipelagic waters. If the shoreline recedes because of sea stage rise, the query arises whether or not these baselines and outer limits must also recede. A parallel query is whether or not sure geographic formations, reminiscent of islands, rocks, and low-tide elevations, have to be re-qualified because of sea stage rise.

UNCLOS is evident in setting the situations for establishing states’ maritime baselines and the outer limits of their maritime jurisdiction and implies their landward adjustment, together with definitions for islands, rocks, and low-tide elevations. These situations and definitions could also be clear, however they don’t seem to be aligned with the pursuits of coastal States. Consequently, a brand new rule has been rising in recent times, primarily based on State observe (e.g., the declarations issued between 2021 and 2024), the works of the Worldwide Legislation Affiliation (ILA) Committee on Worldwide Legislation and Sea Stage Rise, and the report of the Worldwide Legislation Fee (ILC) Examine Group on Sea-Stage Rise. The ILC report, printed earlier this yr, famous a transparent change in State observe (paras. 32, 36) and underscored that States are below “no obligation to replace baselines, geographical coordinates or the outer limits of maritime zones to account for adjustments because of local weather change-related sea-level rise” (para. 28). It  steered adopting an interpretation of UNCLOS “that enables for the preservation of baselines, the outer limits of maritime zones and related entitlements however adjustments to the shoreline because of local weather change-related sea-level rise” (para. 27).

On this context, the ICJ’s opinion remarked that a number of States and teams of States argued through the proceedings in favor of the soundness of baselines and outer limits (para. 355; see, e.g., the written feedback of the Pacific Islands Discussion board Secretariat, the written assertion of the Bahamas, and the written assertion of Australia). The ICJ additionally took notice of the works of the ILA Committee and the ILC Examine Group and the present State observe. All of this led it to conclude that States don’t bear an obligation below UNCLOS “to replace their charts or lists of geographical co-ordinates that present the baselines and outer restrict strains of their maritime zones as soon as they’ve been duly established in conformity with the Conference” (para. 361). This means the soundness of baselines and maritime areas’ outer limits. And but, considerably surprisingly, the ICJ did not say that explicitly. 

Nonetheless, the ICJ’s opinion paves the way in which for ITLOS or one other courtroom (together with the ICJ itself) to carve out the rule on the soundness of baselines and outer limits extra explicitly sooner or later.

Thou Shalt Not Disappear! A Presumption of Continued Statehood of Small Island States

The identical State observe and works of the ILA Committee and the ILC Examine Group additionally level to an rising presumption of continued statehood, regardless of the whole lack of a State’s territory because of sea stage rise. Such a rule is particularly vital for small island States, which don’t contribute to world warming, however are uniquely affected by sea stage rise. For these States, the ICJ’s recognition gives a measure of authorized stability and dignity, reinforcing the concept sovereignty shouldn’t be completely contingent on geography. It affirms that the authorized identification of a State can persist regardless of excessive environmental degradation, some extent with profound implications for entry to treaty rights, maritime entitlements, and participation in worldwide establishments.

Nevertheless, the tone and wording within the works of the ILA Committee and the ILC Examine Group, in addition to these used within the ICJ’s advisory opinion, counsel this presumption shouldn’t be but totally developed. In truth, while the ICJ said that, “as soon as a State is established, the disappearance of considered one of its constituent components wouldn’t essentially entail the lack of its statehood” (para. 363, emphasis added, with a particular spotlight of the verb mode and the adverb used), it might solely discover an obligation of cooperation to take “acceptable measures to handle the antagonistic results of [sea level rise]” (para. 364). This latter obligation, furthermore, was offered as being results-oriented, since States should “achiev[e] equitable options, taking into consideration the rights of affected States and people of their populations” (para. 365). Implied within the phrases of the ICJ is a really broad margin of discretion for States when implementing the duty. This lack of elaboration was expressly regretted within the declaration of Decide Tomka and the separate opinion of Decide Aurescu, who argued for extra detailed steering on the standards and mechanisms by way of which statehood continuity may be assessed.

Nonetheless, the ICJ’s warning shouldn’t be with out justification. While the foundations on the soundness of baselines and maritime areas’ outer limits are binary (i.e., baselines and outer limits both transfer or don’t transfer), the obligations correlative to the presumption of continued statehood essentially contain tough trade-offs and a balancing of competing pursuits that belong to the political sphere. Nonetheless, the ICJ nonetheless highlighted that cooperation “shouldn’t be a matter of alternative for States however a authorized obligation” (para. 364) and rendered an opinion that can be utilized in future pronouncements from ITLOS or the ICJ to make clear and develop these obligations correlative to the presumption of continued statehood.

Concluding Remarks

The advisory opinion clearly demonstrates that the ICJ stays – or strives to stay – a significant and authoritative actor within the evolving regulation of the ocean panorama. By partaking deeply with UNCLOS and associated maritime points, the ICJ bolstered its central function in clarifying states’ rights and obligations within the face of local weather change, signaling that the regulation of the ocean continues to be a significant enviornment for worldwide authorized growth.

Extra importantly, the ICJ’s advisory opinion reinforces the concept worldwide regulation shouldn’t be merely a passive object of examine, however an energetic, participatory technique of claim-making geared toward shaping new guidelines and stabilizing expectations. Worldwide regulation is rarely totally settled; the regulation of the ocean, particularly, exemplifies a authorized regime that should evolve in response to altering situations. By clarifying present norms and recognizing the event of rising ones, the ICJ has made the regulation of the ocean extra attuned to rules of equity and higher outfitted to handle the challenges posed by sea stage rise.