The International Court of Justice’s long-awaited Advisory Opinion on Obligations of States in respect of Climate Change (Climate Change Advisory Opinion) has received a lot of attention in recent weeks. Much of the discussion of the Advisory Opinion has focused on the substantive obligations it confirmed states to have under the international law governing climate change (see, for example, here, here, and here), but another important element of the Advisory Opinion that has largely escaped attention so far is the Court’s use of equity and how it related this to its previous case law. This is an issue that is not only relevant to substantive international environmental law, but to the Court’s exercise of its function as a forum for the settlement of international disputes as well, particularly in questions of state responsibility and reparations for breaches of international obligations.
International environmental law and policy is replete with references to equity. This is evidenced by the various instruments containing the term that the Court made reference to, and was asked to take into account by General Assembly Resolution 77/276 that contained the request for the Advisory Opinion. For example, the Cancún Agreements of 2010 stated that urgent action should be taken by parties to achieve a reduction in greenhouse gas emissions in order to keep the rise in temperature below 2°C above pre-industrial levels ‘consistent with science and on the basis of equity’ (para 4). It also stated that a periodical review of this goal ‘should be guided by the principles of equity, and common but differentiated responsibilities and respective capabilities’ (para 139). Similarly, the Paris Agreement of 2015 aimed to ‘strengthen the global response to the threat of climate change’ (article 2(1)) and stated that the Agreement ‘will be implemented to reflect equity and the principle of common but differentiated responsibilities and respective capabilities, in the light of different national circumstances’ (article 2(2), also see the preamble).
While these instruments treat equity and the principle of common but differentiated responsibilities as separate, the Court in its Advisory Opinion seems to have merged the two. It stated that the principle of common but differentiated responsibilities and respective capabilities is ‘a manifestation of the principle of equity’ which ‘guides the interpretation of obligations under international environmental law beyond its express articulation in different treaties’ (para 151) – an approach that was criticised by Vice-President Sebutinde in her separate opinion for ‘downplaying’ the importance of the principle (paras 9, 11). Similarly, the Court called intergenerational equity ‘a manifestation of equity in the general sense’ (para 157). The Court stressed that it did not see these principles as constituting obligations in themselves, but that it was simply treating them as a guiding factor in its application of applicable law (paras 161, 178).
Equity in the Court’s Earlier Case Law
In its discussion on equity in the Climate Change Advisory Opinion, the Court referred to its case law in other fields of law (para 152) such as maritime delimitation and reparations.
In the Tunisia/Libya judgment, for example, equity was applied as a general principle of law and was called ‘a direct emanation of the idea of justice’ (para 71). Here, the principle served as a guideline in the determination of a maritime boundary between Tunisia and Libya. The Court interpreted equity as allowing it to choose an interpretation of law which it considers to be ‘the closest to the requirements of justice’ (Tunisia/Libya para 71, Climate Change Advisory Opinion para 152). The Advisory Opinion also stated that ‘the legal obligation to co-operate requires States, in the context of sea level rise, to work together with a view to achieving equitable solutions, taking into account the rights of affected States and those of their populations’ (para 365). This resonates with maritime delimitation case law focusing heavily on the goal of achieving an equitable result in light of the particular geographical circumstances of a case (see for example the North Sea Continental Shelf cases para 92 and Tunisia/Libya para 72, showing an approach that was later also recognised in articles 74 and 83 of the United Nations Convention on the Law of the Sea). However, this approach lacks clarity which makes it difficult to translate into the context of climate change. On what basis will a court decide what interpretation comes ‘the closest to the requirements of justice’ and what exactly an equitable solution is? In the maritime delimitation case law, these questions were strongly related to geographical circumstances of the area to be delimited. In the context of climate change, it seems to be the principle of common but differentiated responsibilities and respective capabilities that the Court kept in mind. But grouping these considerations under the header of equity provides very little indication of its actual practical effect.
The Court in the Climate Change Advisory Opinion also discussed the concept of ‘equitable considerations’. First, it discussed this concept in the realm of policymaking, where the Court identified ‘equitable considerations that need to be taken into account where States contemplate, decide on and implement policies and measures in fulfilment of their obligations under the relevant treaties and customary international law’ in the form of ‘[d]ue regard for the interests of future generations and the long-term implications of conduct’ (para 157). This line of reasoning again links equity to intergenerational equity and the principle of common but differentiated responsibilities and respective capabilities.
Second, the Court envisaged a role for ‘equitable considerations’ in contentious cases concerning reparations for harm caused by failure of states to meet their obligations under the law governing climate change. While it clearly stated that it would not engage in any extensive examination of the issue of reparations as that had to be done on a case-by-case basis should any action be brought against a state for failing to meet its obligations (paras 449–455), it did discuss some of its previous case law on reparations that it deemed relevant which have introduced the notion of ‘equitable considerations’ in these types of cases.
In paragraph 454, the Court reiterated the approach it took in the Armed Activities reparations judgment where it stated that it may ‘on an exceptional basis, award compensation in the form of a global sum, within the range of possibilities indicated by the evidence and taking account of equitable considerations’ (paras 106, 166, 181, 193, 206, 225, 258 and 365; see similarly Diallo (Compensation) paras 24, 33 and 36 where compensation was also decided on the basis of equitable considerations). The Court’s approach in Armed Activities was criticised by Diane Desierto in the context of grave human rights violations. Her overall criticism of lack of explanation by the Court could be applied to the context of climate change reparations as well. For instance, it is unclear what exactly the ‘equitable considerations’ the Court notes in Climate Change consist of and how they could assist the Court in its determination of an appropriate remedy in case of a failure of states to meet their obligations under the law relating to climate change. There are certainly similar challenges in determining reparations in the context of grave human rights violations and climate harm – rooted mainly in the difficulties of attribution, quantification and causation (discussed in the context of climate change in paras 421–438 of the Advisory Opinion). However, if or when a contentious case in respect of climate harm is brought and the Court will have to grapple with how equitable considerations apply to reparations in the context of climate change, a more thorough explanation of what equitable considerations are and what their exact role in the determination of reparations is would be expected.
Conclusion
An often-encountered problem with equity was summed up well by the Court when it stated that ‘[m]any participants referred to equity, displaying different understandings of this concept’ (para 152). Equity in international law has often been used in a very open-ended way, as evidenced by the Court’s statement in 1969 that ‘there is no legal limit to the considerations which States may take into account for the purpose of making sure that they apply equitable procedures’ (North Sea Continental Shelf cases para 93). Equity has, in the case law of the Court, always been closely linked to either geographical circumstances (in the context of maritime delimitation) or difficulties in obtaining evidence or attributing responsibility (in the context of reparations). In the Climate Change Advisory Opinion, the Court tied equity to the ideas of common but differentiated responsibilities and respective capabilities and intergenerational equity as ‘manifestations’ of equity. However, how these manifestations of equity would, in practice, guide the Court in determining responsibility and reparations for failure of states to live up to their obligations under the international law governing climate change remains to be seen.
