An Analysis of the Sources of International Responsibility of States in the Face of Climate Change: a Customary Rule in the Making?

Un análisis sobre las fuentes de la responsabilidad internacional de los estados ante el cambio climático: ¿una norma consuetudinaria en formación?

Gustavo de la Orden Bosch[1]

Universidad de Deusto

gustavodelaorden@deusto.es 0000-0002-8779-5904

I. Introduction

In 2023, a number of requests for advisory opinions have been submitted to various international tribunals to clarify the international responsibility of states to prevent and mitigate the damage caused by climate change. This paper focuses on one such request: the one submitted by the United Nations General Assembly to the International Court of Justice (ICJ) on 29 March 2023. The latter is analysed as one of the manifestations of the international community’s growing concern about climate change.

The interest of this paper is to explore what contributions the Hague Tribunal could make to the development of international climate change law. The analysis seeks to develop some lines that the Court could draw in its jurisprudence. This objective is linked to the need to transcend the status quo of the prevailing discourse in international law, which is laden with programmatic language that condemns it to indefinite repetition. Given the lack of specific jurisprudence on climate change in the ICJ, the analysis of the advisory opinion request focuses on the sources of international law that the Court could apply or develop in this area. In particular, the study focuses on the analysis of international custom, its elements and the difficulties in identifying them in the field of climate change.

In view of the different meanings of the term «climate change», this paper adopts the concept set out in Article 1.2 of the United Nations Framework Convention on Climate Change (UNFCCC), which defines it as follows: «a change in climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods».

II. A brief overview of progress towards international responsibility of states to address climate change

Since the 1980s, the international community has been seeking political and legal instruments to mitigate the effects of climate change. The problem is undeniably global in nature and requires joint action. The first attempts began almost simultaneously with the scientific evidence that climate change was already a clear reality, and were mostly channelled through the United Nations system via intergovernmental mechanisms[2]. Since then, international law has become an enabling environment for achieving the goals of mitigation and adaptation to the environmental crisis (Giles Carnero, 2021). Such goals are of common interest to the international community.

However, the first responses were mainly soft law, unable to establish precise rules and concrete obligations, despite a growing global concern[3]. At the beginning of the 21st century, recent developments increasingly point to the construction of binding legal norms by States, which are beginning to assume that international responsibility in this area must be collective and requires precise rules[4]. This is demonstrated at least by the gradual –if sometimes interrupted[5]-, transition of legal instruments from soft to hard law. Although these advances are doubtful and mostly ineffective in practice, it is possible to identify the beginnings of a certain consensus on the imperative nature of international law in the face of global warming and the climate emergency.

For their part, national and international courts have been key actors in the development of international environmental law and the recognition of the right to a healthy environment as an independent and justiciable human right. Both the International Court of Justice and some national courts, as will be analysed below, have issued rulings of great impact in this area, mainly in the context of resolving disputes between states. Similarly, regional human rights courts have issued judgments that have broadened the understanding and philosophy of human rights in the natural environment. In the latter respect, the Inter-American Court has been particularly active, for example, in protecting the rights of indigenous peoples and their relationship with the habitat[6]. Likewise, in its Advisory Opinion 23/17 on human Rights and the environment[7], the Inter-American Court ruled that human rights cannot respond exclusively to the interests of individuals, but must be adapted to the protection of the natural environment in which life develops.

In 2023, a new strand has arisen on the international judicial scene, with a particular focus on international law in the face of climate change. International tribunals have been called upon to use their contentious and advisory jurisdiction to address the obligations of States to prevent, mitigate and remedy the damage caused by climate change. Various bodies have been asked or consulted to pronounce on aspects that have hitherto depended on the will of the state and the greater or lesser environmental awareness of governments in power. The ICJ, the Inter-American Court of Human Rights (IACHR) and the International Tribunal for the Law of the Sea (ITLOS) have received a series of requests for advisory opinions on this issue[8]. Although the opinions were requested by representatives of States, civil society has played a decisive role in their implementation through the promotion of their respective approaches by non-governmental organisations. For example, the request to the ICJ was promoted by the World’s Youth for Climate Justice (WYCJ), and the request to the Inter-American Court of Human Rights was promoted by the Centre for Justice and International Law (CEJIL).

Indeed, the consequences of the climate emergency are of particular interest in the field of international human rights law (IHRL). Since the beginning of the codification process in the twentieth century, IHRL has been marked by the simultaneous expansion of political liberalism. Even earlier, the earliest antecedents of codification, in the context of the French Revolution, were driven by liberal political currents. In both cases, political liberalism was accompanied by economic liberalism. Similarly, since the end of the Cold War in the late 1980s, the economic justification for globalisation has to some extent been characterised by an alleged link with the exercise of the most basic individual freedoms. However, in the current conditions of climate emergency, unbridled economic growth may ultimately be contradictory and incompatible with respect for human rights, particularly those affected by violations of the right to a healthy environment. Since the second decade of the 21st century, extreme right-wing or related political parties that advocate positions that deny the existence of climate change have been gaining strength in a number of countries[9]. Such parties advocate the strengthening of neo-liberal economic processes, deregulated or with minimal state intervention, which can exacerbate the climate emergency. In a break with the traditional combination of political and economic liberalism, the new parties push for authoritarian political regimes that promote neoliberal, deregulated policies.

Against this background, in the specific field of the protection of human rights, the question arises as to the role of international law in determining the responsibilities stemming from the environmental crisis. Although there are a number of concerns about the effectiveness of IHRL in addressing climate change (Mayer, 2021, 412)[10], this issue has been raised before the Inter-American Court of Human Rights following a request for an advisory opinion by the States of Chile and Colombia. To answer this question, the Court has important precedents in the field of international environmental law. In particular, the aforementioned Advisory Opinion 23/17 represents a fundamental decision in clarifying the relationship between human rights and the environment. In it, the Court recognised the right to a healthy environment as an autonomous and justiciable human right[11], and stated that «environmental degradation and the adverse effects of climate change impair the effective enjoyment of human rights» [12]. The same criterion has been used by the Inter-American Court in some cases concerning the protection of environmental defenders[13]. Likewise, within the Inter-American system, the Inter-American Commission has developed some specific criteria for the human rights obligations of the States of the region in the face of the climate emergency[14].

In fact, the issue has not only been channelled through the advisory channel of the international courts, but also through other functions carried out by various international bodies. Thus, previously, within the Inter-American system, the Inter-American Commission on Human Rights (IACHR) and the Office of the Special Rapporteur on Economic, Social, Cultural and Environmental Rights (REDESCA) published the Resolution 3/21 «Climate Emergency: Scope of Inter-American Human Rights Obligations»[15]. For its part, the European Court of Human Rights (ECHR) is hearing a number of contentious cases against states for damages that could be linked to their inaction in the face of global warming[16]. Similarly, the Committee on the Rights of the Child issued a General Comment in the specific context of climate change, stating that «States must protect children not only from present environmental harm, but also ensure their well-being and development, taking into account future risks and harms»[17]. With regard to the latter, as McMenamin (2023, 219) outlines, the ICJ could enrich its analysis by considering the general comments and views in individual communications issued by the Human Rights Committee and other treaty bodies.

The activation of the advisory competence of the different international bodies, as well as the general observations and contentious cases in progress, demonstrate the growing concern of the international community on this issue. They also show that international law is being called upon to play a leading role in clarifying the obligations of States. The simultaneous handling of these different processes runs the risk of accentuating the fragmentation of a system that is still evolving and in search of certainties. However, these processes can also be seen as complementary tools (Jiménez Pineda, 2023, 6). In particular, the simultaneous development of the various consultative processes can be enriched by a dialogue between international bodies in their respective fields of competence.

III. Requests for advisory opinions pending before international tribunals

This paper focuses its analysis on the request for an advisory opinion submitted to the ICJ. However, there are two other requests for opinions pending before the Inter-American Court and the ITLOS, respectively. The activation of the advisory function of various international tribunals is a sign of the concern of states to clarify their responsibilities arising from the global impacts of the climate emergency.

The request to the ICJ was submitted by a resolution of the UN General Assembly, adopted by consensus of the 193 Member States[18]. The initiative was registered at the 77th session of the General Assembly by a group of 18 States, led by the Republic of Vanuatu, an island State in the South Pacific whose existence is threatened by the foreseeable rise in sea levels. Through this application, the Assembly asks the Court, firstly, what obligations States have under international law to ensure the protection of the climate system and other elements of the environment from anthropogenic emissions of greenhouse gases for the benefit of States and present and future generations. Secondly, the request asks what legal consequences flow from these obligations for States which, by their acts and omissions, have caused significant damage to the climate system and other elements of the environment, with respect to: (1) States, including, in particular, small island developing States, which, because of their geographical circumstances and level of development, are adversely affected or particularly affected by, or particularly vulnerable to, the adverse effects of climate change; and (2) Peoples and individuals of present and future generations affected by the adverse effects of climate change.

Many other States are currently in similar geographical and environmental situations to those of the Republic of Vanuatu (Aznar Gómez, 2023). Such is the case of Chile, which, together with Colombia, submitted a request for an advisory opinion to the Inter-American Court. In this request, the two Latin American States ask the Inter-American Court to «clarify the scope of State obligations, in their individual and collective dimension, to respond to the climate emergency in the framework of international human rights law»[19] .

In addition, in December 2022, a group of island States, led by Antigua and Barbuda and Tuvalu, submitted a request for an advisory opinion to the ITLOS[20] . On this occasion, the Tribunal is requested to rule on the obligations of States, on the one hand, to prevent, reduce and control pollution of the marine environment in relation to the effects arising or likely to arise from climate change, including ocean warming and sea level rise, and ocean acidification, caused by anthropogenic emissions of greenhouse gases into the atmosphere; and, on the other hand, to protect and preserve the marine environment in relation to such effects of climate change.

IV. Possible questions about sources before the international court of justice: signs of a custom in the making?

The ICJ has not yet had the opportunity to make a specific pronouncement on the responsibilities of States in the face of climate change. The request for an advisory opinion opens a new door for the development of international law, for the identification of legal obligations in this area and, in particular, for the determination of the sources of international law from which they may emanate. Although climate change is a new issue in the jurisprudence of the Hague Tribunal, some of its judgments resolve conflicts between States related to international environmental law and closely linked to the harmful effects of human activities on the environment (Fitzmaurice, 2014; Bodansky, 2023).

Given the questions that the General Assembly has put to the Court, it is interesting to ask what sources of law the Court will consult in its search for legal answers to the question. According to the wording of Article 38 of the ICJ Statute, most of the sources mentioned do not regulate climate change or the damage it may cause. Specifically, there is only one binding convention (the aforementioned UNFCCC and its protocols), while the rest of the written instruments are contained in declarations and resolutions without direct binding effect. At the same time, the International Court could draw on the jurisprudence of other national and international judicial bodies. Although jurisprudence is not a rich source for identifying precise and concrete rules, the Court already has at its disposal the jurisprudence of the Inter-American Court, Resolution 3/2021 of the Inter-American Commission or General Comment 26 of the Committee on the Rights of the Child (cited above), which opens up the possibility of dialogue between the different international bodies.

Given the lack of clarity regarding the other two sources of law, i.e. international custom and general principles of law, the next question is what their respective usefulness might be. These two sources are probably the most difficult to grasp because of their higher level of abstraction and the lack of explicit legal acts indicating their origin. However, the jurisprudence of the International Court of Justice since its inception has been particularly rigorous and abundant in resolving cases submitted to its jurisdiction through the application of both sources of law.

The established jurisprudence of the Court emphasises international custom as the product of the two elements set out in Article 38 of the Statute[21]. The Court has repeatedly pointed out that international custom as a source of law requires the integration of the objective and subjective elements. The objective element is the result of practice, which is embodied in the acts and omissions of States in a continuous manner over time, without there being specific and homogeneous periods for each situation. Each practice requires a particular exercise of interpretation, which depends to a large extent on the reality in which the State acts. On the other hand, the subjective element or opinio iuris is defined by Article 38 of the Statute itself as the conviction that the practice constitutes an obligation. Because of its subjective nature, this second element is in most cases more difficult to explain, mainly because it seeks to unravel the subjective conviction of abstract entities such as States. However, the jurisprudence of the Court has clearly indicated that the subjectivity of States is inferred from the intentionality of their acts and manifestations.

In the exercise of applying the general theory of international custom to the specific field of climate change, it is necessary to analyse the emergence of each element separately. Firstly, the identification of a custom in this area would not require its maintenance over a long period of time, since it is a relatively recent phenomenon. The first alarms about climate change in the 1980s provide a timeline. Since then, the concern of states to prevent, mitigate and repair the damage caused by climate change has materialised at the international level through intergovernmental summits and the adoption of programmatic instruments. Beyond these formal agreements, it is not possible to point to actions or omissions that have taken place at a real level, at least in a widespread and shared way. The identification of the objective element becomes difficult in the absence of common and sustained actions or omissions over time.

In contrast to the objective element, the subjective element - or awareness - of an imperative to act is beginning to take shape in the international community. A germ of opinio iuris could be represented by the unanimous adoption of the General Assembly resolution to submit the request for an advisory opinion to the ICJ. This circumstance is reinforced by the submission of the other two requests to the Inter-American Court and ITLOS. In addition, the various summits held in the context of the Paris Agreement show a common awareness among states, regardless of their position in the Global North or the Global South. A significant event in this regard was the decision by the then US President Donald Trump to withdraw his country’s ratification of the Paris Agreement (Zhang et al., 2017; Fajardo del Castillo, 2018). Criticism of this decision showed that it was not seen simply as a sovereign state expressing its position on an international agreement, but as a violation of the obligations that all states have in this area, especially those that contribute most to environmental degradation.

However, the logical relationship between the two elements of international custom is a matter of debate in doctrine (Evans, 2014, 98). The debate centres on the chronological order of practice and opinio juris: if the two elements do not occur simultaneously, does practice precede the awareness of binding force, or is practice the evidence or material confirmation of an earlier awareness? The latter would be consistent with what is happening in the area of climate change: the international community is showing signs of an emerging awareness of the need to act on climate change. The question that remains open, therefore, is whether it is possible to speak of an emerging international custom regarding the obligations of states to prevent, mitigate and reduce the effects of climate change. According to the elements of Article 38 of the ICJ Statute, subjective awareness would be separate and awaiting a practice that does not yet exist or has not yet been consolidated.

On the other hand, under the first hypothesis of the precedent character of the material element, the Court would have to find the existence of a constant, repeated, uniform practice which is subsequently accepted by the States concerned as the exercise of an obligation. The objective element would precede the subjective element. From this point of view, it is problematic at this stage to identify the formation of an international custom - even if it is still in the process of formation - with regard to the obligations of States, since it is not possible to establish the existence of a practice that meets the material requirements indicated. This could be an obstacle for the Court in analysing the application of this source of law to the advisory opinion. The preclusion of any court from creating law would prevent the Court from confirming the existence of a custom, even if only in its genesis, in the absence of the objective element.

In view of the difficulties of the latter argument, the question arises whether the possible opinio iuris without material practice is in fact the manifestation of a principle on climate change. In such a case, liability could derive from the general principle of responsibility for internationally wrongful acts and the principle of due diligence, following the rules of the Draft Articles on the Responsibility of States for internationally wrongful acts. In particular, Principle 7 of the 1992 Rio Declaration, which affirms the duty to «cooperate in a spirit of global solidarity to conserve, protect and restore the health and integrity of the Earth’s ecosystem»[22], is useful from the perspective of common but differentiated responsibilities according to each State’s respective contribution to environmental degradation.

Similarly, the obligation could derive from the principle of strict liability of States for the effects of conduct under their jurisdiction, based on the «do no harm» rule and the principle of good neighbourliness between States, as enshrined in Principle 2 of the 1992 Rio Declaration[23]. However, the precise limits and elements of this rule are under discussion (Mayer, 2016, 90). Moreover, the difficulties in applying the principles of responsibility - both generally for wrongful international acts and more specifically in environmental matters - have to do with the complexity of the behaviours that provoke and exacerbate the climate emergency, the attribution of the behaviour to the State, and the lack of a legal basis that delineates precise international obligations in this matter.

V. Conclusions

Global warming is an urgent appeal to the international community in the face of a global phenomenon whose effects transcend the strict limits of territorial sovereignty and affect all people, regardless of their nationality or location in the Global North or South. The international community’s responses to climate change have evolved in different ways over the past decades. For its part, international law has been a tool that has led to important agreements between states on the issue. To date, however, the legal norms in force have mainly been of a soft law nature. The latter can still be observed in those norms contained in international treaties or protocols that are binding, but their wording is ambiguous when it comes to determining the corresponding responsibilities, as they generally resort to formulas that are left to the discretion of the State. The requests for advisory opinions submitted in 2023 to various international tribunals demonstrate the above-mentioned urgency of the search for clearer and more precise criteria in the field of public international responsibility.

International jurisprudence has not yet developed significantly in this area. This may be due to uncertainty on the part of States themselves, as well as on the part of other members of the international community –including international organisations and individuals, non-governmental organisations and multinational corporations–. The extent of their respective responsibilities is unclear. Against this background, a number of cases have recently been brought before international and regional courts whose decisions are still pending (and some have been dismissed, as in the case of the ECtHR, for lack of proof of the specific and concrete scope of the alleged violations in relation to the plaintiffs as victims). In other words, the momentum is also beginning to build at the international judicial level. The main doubt is whether the forthcoming judgments will provide a fertile ground on which to set up clear and legally binding norms; or, on the contrary, whether courts will opt for positions deferential to state sovereignty on an issue of an undoubtedly global character.

In light of the soft-law nature of existing international law, the requests for advisory opinions submitted to the ICJ, the IACHR and the IMRT (as well as the contentious individual cases pending before the ECtHR) provide an opportunity to identify and clarify the obligations of states in the face of current and potential climate damage, and to identify what might be effective mechanisms of accountability. In order to avoid legal fragmentation, an inherent problem of the decentralised structure of international law, the overlapping timeframe of the different cases could serve to promote dialogue between the different international bodies.

In particular, the ICJ has the opportunity to promote the sources of international law on climate change. First, the Court will be able to interpret and shed light on treaty obligations already in force. But there may also be a particular opportunity for the Court to develop its jurisprudence on other sources of international law, such as custom or general principles. One of the main questions is whether the development of international conventions, together with recent acts of the international community in the judicial (as well as in the political) sphere, constitutes a possible international custom in the making. More specifically, the question arises as to whether we are facing an emerging opinio juris. The problem inherent in this hypothesis, however, is the lack of an objective element. Thus, the question remains as to what practices states will develop on the basis of the obvious concerns that are already evident and firmly established on the international scene. Moreover, the hypothesis of a customary norm in statu nascendi raises the question of whether it is possible for opinio juris to anticipate practice. As a further alternative hypothesis, the next question is whether, in the absence of custom, it is possible to argue for the emergence of a new climate change principle derived from the more general principles of state liability for damage and, in particular, the duty to cooperate in preserving, protecting and restoring the ecosystem.

References

AZNAR GÓMEZ, M.J. (2023), El Estado sin territorio: La desaparición del territorio debido al cambio climático. Revista Electrónica de Estudios Internacionales, 26, 1-23.

BODANSKY, D. (2023). The role and limits of the International Court of Justice in International Environmental Law. In C. Espósito, K. Parlett (eds.), The Cambridge Companion to the International Court of Justice (pp. 389-410). Cambridge University Press.

EVANS, M.D. (2014). International Law. Oxford University Press.

FAJARDO DEL CASTILLO, T. (2019). Avances y retrocesos en la negociación del Pacto Mundial por el Medio Ambiente. Actualidad Jurídica Ambiental, 95, 8-52.

FAJARDO DEL CASTILLO, T. (2018). El acuerdo de París sobre el cambio climático: sus aportaciones al desarrollo progresivo del Derecho internacional y las consecuencias de la retirada de los Estados Unidos. Revista Española de Derecho Internacional, 70, 1, 23-51.

FITZMAURICE, M. (2014). The International Court of Justice and International Environmental Law. In C.J. Tams, J. Sloan, James (eds.), The Development of International Law by the International Court of Justice (pp. 353-374). Oxford Academic.

GILES CARNERO, R. (2021). El régimen jurídico internacional en materia de cambio climático. Dinámica de avances y limitaciones. Thomson Reuters Aranzadi.

JIMÉNEZ PINEDA, E. (2023). Hacia una Opinión Consultiva sobre cambio climático: a propósito de la solicitud de dictamen de la Comisión de pequeños Estados insulares al Tribunal Internacional del Derecho del Mar. Revista Electrónica de Estudios Internacionales, 45, 1-23.

KANG, S., HAVERCROFT, J., EISLER, J., WIENER, A., SHAW, J. (2023). Climate change and the challenge to liberalism. Global Constitutionalism, 12, 1, 1-10.

MAYER, B. (2021). Climate change mitigation as an obligation under human rights treaties? American Journal of International Law, 115, 3, 409-451.

MAYER, B. (2016). The relevance of the no-harm principle to climate change law and politics. Asia Pacific Journal of Environmental Law, 19, 79-104.

MCMENAMIN, R. (2023). Advisory Opinion on obligations of States in respect of climate change: Potential contribution of Human Rights Bodies. Climate Law, 13, 3-4, 213-223.

VON BASSEWITZ, N. (2013). International climate change policy: Where do we stand?. In O.C. Ruppel, C. Roschmann, K. Ruppel-Schlichting (eds.), Climate Change: International Law and Global Governance, (pp. 101-169). Nomos.

ZHANG, Y., CHAO, Q., ZHENG, Q., HUANG, L. (2017). The withdrawal of the U.S. from the Paris Agreement and its impact on global climate change governance. Advances in Climate Change Research, 8, 213-219.

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