Daniela Fisichella¹

5 de maio de 2026

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Este escrito compõe a Série Especial do Boletim Lua Nova, em conjunto com pesquisadores e pesquisadoras vinculados à rede internacional Justice in the XXI Century: A Perspective from Latin America (JUSTLA). O projeto, coordenado pela Universidade de Catania (Itália) e financiado pela União Europeia no âmbito da ação HORIZON–Marie Skłodowska-Curie Staff Exchanges, reúne 148 integrantes de 18 instituições da América Latina e da União Europeia.

Os escritos são um convite a atravessar diferentes territórios do conhecimento para (re)pensar a justiça no século XXI. Ao longo da série, o JUSTLA promove um diálogo entre pesquisas desenvolvidas em diferentes contextos e abordagens, de modo que o leitor e a leitora poderão acompanhar um movimento no qual ideias, contextos e práticas se entrelaçam para reinventar, no presente, o sentido da justiça. Os textos do Especial podem ser conferidos aqui.

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Events of the 21^st century international community seem to widen the gap between the way international relations are carried out under politics and the framework they are called upon to respect under international law. A virtuous development of international legal order steers into a moral direction. Currently, the more international relations spread worldwide, the more international law is patently infringed. Multiple violations of international law need clear  statements on the rule of law and the International Court of Justice does so by its Advisory  Opinion of 23 July 2025 on “Obligations of States in Respect of Climate Change”: the Court  resorts to an advisory opinion to strongly remark leading principles of international law and  to issue assessments consolidating new trends or, as here, to discourage states from disregarding environmental commitments already set up. By answering the United Nations General Assembly’s request through Resolution 77/276, adopted on 29 March 2023, the Court chose a comprehensive legal approach. The General Assembly’s resolution mirrors Vanuatu’s concern on climate change, sided with Pacific Island Students Fighting Climate Change, a youth-led organisation composed of students from the Pacific Island countries. In accordance with Art. 96 of UN Charter, General Assembly asks the Court the following question: 

“Having particular regard to the Charter of the United Nations, the International Covenant  on Civil and Political Rights, the International Covenant on Economic, Social and Cultural  Rights, the United Nations Framework Convention on Climate Change, the Paris Agreement,  the United Nations Convention on the Law of the Sea, the duty of due diligence, the rights recognized in the Universal Declaration of Human Rights, the principle of prevention of  significant harm to the environment and the duty to protect and preserve the marine  environment, (a) What are the obligations of States under international law to ensure the protection of the  climate system and other parts of the environment from anthropogenic emissions of  greenhouse gases for States and for present and future generations? (b) What are the legal consequences under these obligations for States where they, by their  acts and omissions, have caused significant harm to the climate system and other parts of the  environment, with respect to: (i) States, including, in particular, small island developing States, which due to their  geographical circumstances and level of development, are injured or specially affected by or  are particularly vulnerable to the adverse effects of climate change? (ii) Peoples and individuals of the present and future generations affected by the adverse  effects of climate change?” (Advisory Opinion, 8-9). 

By consequence, the Court focuses its legal analysis mainly on greenhouse gas emissions  (GHG’s) and their impact on the environment and climate change in any Earth space, composed of land, water and air. If climate change is recognized by the Court as “an unprecedented  challenge of civilizational proportions”², its perspective on humankind well-being strongly  includes future generations. The Court’s approach aligns fully with the UN General Assembly’s Agenda 2030 on Sustainable Development Goals, A /RES/70/1 of 21 October 2015, thus openly connecting environmental protection to the overall balance among living things, not only humans. The Court “considers that the principle of sustainable development  guides the interpretation of certain treaties and the determination of rules of customary international law, including the duty to prevent significant harm to the environment and the  duty to co-operate for the protection of the environment.”³.

The Court’s Advisory Opinion presents a very detailed analysis of any available legal rule adopted so far on environmental matters, including non-binding sources and international meetings such as the annual Conference of Parties (COPs) institutionalised by United Nations Framework Convention on Climate Change (UNFCCC), adopted in 1992 at the end of the  huge conference held at Rio de Janeiro, Brazil, from 3 to 14 June. Though COPs’ decisions are not binding, they can be considered as reflecting state practice and an evidence of states’ opinio iuris, but “Whether a particular COP decision has such legal significance can only be  determined in concreto.”⁴.

As already done for international law fundamental principles, the General Assembly request lets the Court define an extensive recap of international rules affecting environmental protection and thus having an impact on climate change. It’s noteworthy that environmental  management falls under the human rights legal system and every human being is entitled to claim a right to a clean, healthy and sustainable environment (UNGA Res. 76/300, 28 July 2022). The relationship between human rights and climate change is broadly remarked by two recently adopted UN Human Rights Council resolutions: A/HRC/RES/56/8, 10 July 2024 and  A/HRC/RES/59/25, 8 July 2025. 

Under the Court’s reasoning, crucial treaties adopted on environmental issues from early  nineties onwards constitute all together the legal framework at stake on climate change: 1992  UNFCCC, the first large treaty on climate change; Kyoto Protocol, added to UNFCCC in 1997 and committing the most developed countries and economies in transition to limit GHGs emissions according to agreed individual targets. These targets became Nationally  Determined Contributions (NDCs) in the Paris Agreement at COP21 of 2015, joined by 195 States Parties, including the European Union. Since the Stockholm Declaration adopted at the UN Conference on the Human Environment in 1972, proclaiming 26 principles to be applied to  ensure environmental health, the international legal framework seems to be consistent and  homogenous. According to Principle 1 of Stockholm Declaration: “Man has the fundamental  right to freedom, equality and adequate conditions of life, in an environment of a quality that  permits a life of dignity and well-being, and he bears a solemn responsibility to protect and  improve the environment for present and future generations. In this respect, policies  promoting or perpetuating apartheid, racial segregation, discrimination, colonial and other  forms of oppression and foreign domination stand condemned and must be eliminated.”. 

The  Court emphasizes how a negative impact on environmental balance brings about detrimental  effects to life as such, threatening food security, water availability and access to it,  and livelihoods. Sustainability of development gets worse whenever the environment is hit by intense  extreme events, like flooding, droughts, heatwaves, hurricanes and other disturbances that disrupt natural habitats. Even basic goals of UN Agenda 2030, as eradicating extreme poverty (Goal 1) and ending hunger (Goal 2) are more at risk for environmental degradation, since access to food and both drinking and clean water become harder, agricultural activities slow down and an increasing number of people is at risk of life and multiple diseases.  

To evaluate states conduct regarding GHGs emissions dropping, the Court says that “The  United Nations Framework Convention on Climate Change and the Paris 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.”⁵.The Court  remarks the moral content of legal obligations recalled in the AdvisoryOpinion as, for  international subjects, morality is a stronger value in the international legal order than in the  domestic ones. The Court’s reasoning gathers several elements to raise states’ attention on  climate change: the best available science on the causes, nature and effects of it, awareness  on adverse consequences of climate change upon the climate system by UN, including UNEP,  and UN specialized agencies, such as IMO, WHO, WMO. The climate system changes in time under the influence of its own internal dynamics and because of external forcings such  as volcanic eruptions, solar variations, orbital forcing, and anthropogenic forcings such as  the changing composition of the atmosphere and land-use change.” (IPCC, 2023, AR6  Synthesis Report, Annex, Glossary, 122, emphasis added), overlapping but extending Art. 1, par. 3 of UNFCCC: ““Climate system” means the totality of the atmosphere, hydrosphere, biosphere and geosphere and their interactions.”, while “Climate Change” means a change of 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.” (UNFCCC, Art. 1, par.2). Under IPCC definitions, climate change is “A change in the state of the climate that can be identified (e.g., by using statistical tests) by changes in the mean and/or the variability of its properties and that persists for an extended period, typically decades or longer. Climate change may be due to natural internal processes or external forcings such as modulations of the solar cycles, volcanic eruptions and persistent anthropogenic changes in the composition of the atmosphere or in land use.” (IPCC, 2023, AR6 Synthesis Report, Annex, Glossary, 122). IPCC defines GHGs emissions as “Gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of radiation emitted  by the Earth’s surface, by the atmosphere itself, and by clouds …” (IPCC, 2023, AR6  Synthesis Report, Annex, Glossary, 124).

Increasing or only moderating reducing GHGs emissions leads to escalating global warming. Hence, adaptation and mitigation mechanisms and measures must be adopted by any state. By combining IPCC multiple assessments on these topics with scientific outputs on climate change, and aware that it  threatens human well-being and planetary health, the Court launches a strong call for action by a strict interpretation of environmental issues under relevant treaties and customary law. By aligning with the UN approach to global commons, the Court stresses the importance of effectively engaging every single state in addressing climate change, taking in due account national circumstances and making a distinction between the burden of responsibility for the most developed countries and economies in transition and that of developing countries. The  Court acknowledges that the latter claim for a derogation to GHGs emissions limits, as they need to enhance their own industrial production to lift domestic development rate. The Court qualifies the climate system as a global common, governed by erga omnes international legal rules: “Climate change is a common concern. Co-operation is not a matter of choice for States but a pressing need and a legal obligation.”⁶.The Court’s call to action revolves around a duty to co-operate, because the more the environment is vulnerable to growing risks, the less each state’s action is effective, obstructing wider cooperation efforts. To define state responsibility, the Court resorts to some meaningful principles of international law: due diligence, the principle of  common but differentiated and respective capabilities (CBDR-RC), launched in its basic assumption by 1992 Rio Declaration on Environment and Development and reiterated in its  advanced version by UNFCCC (sixth preambular paragraph), state obligations of conduct  and of result. 

Under customary international law, later transposed into conventional rules and  interpreted according to the context, due diligence principle gives rise to the duty to prevent significant harm to the environment, which is a prerequisite to promote co-operation. The Court confirms that the no harm principle applies to “global environmental concerns”⁷.  As the climate system is generally exposed to risks, all states must take consistent actions to prevent environmental harm. Therefore, even though some states can be held accountable for specific damages, preventing harm requires an effort which includes the entire international community:  “All States contribute to that risk, albeit to significantly differing degrees, and all States are affected by the cumulative effects of GHG emissions, depending on their respective situations. Climate  change therefore poses a quintessentially universal risk to all States.”⁸. In the Court’s interpretation, due diligence implies both choosing options for suitable measures and vigilance in the whole process of implementation. About the duty to co-operate, it is  enshrined in many environmental treaties as well as in soft law, such as the 1972 Stockholm Declaration, Principle 24 and the 1992 Rio Declaration, Principle 7.  

The due diligence principle matches also CBDR-RC, because it is addressed to all states, but to a different degree. CBDR-RC is ruled by climate change treaties: UNFCCC, Art. 3, par. 1;  Kyoto Protocol, Art. 10; Paris Agreement, Art. 2, par. 2, and Art. 4, par. 3. In the Court’s  reasoning, this principle is “a manifestation of the principle of equity”⁹, because equity  redresses imbalance among countries’ effective conditions. Like sustainability, equity among generations implies that the current generation’s activities must be planned and implemented according to a framework inspired by the precautionary principle, combined with no harm principle and aimed to prevent degradation of the environment  for future generations. The Court observes that all treaties on climate change pursue the final aim of cutting GHGs emissions and there isn’t a rule conflict among UNFCCC, the Kyoto  Protocol and Paris Agreement. Trying to recap multiple arguments embedded in the General Assembly’s request, the most difficult aspect is to link states’ obligations, of both conduct and result, to the international responsibility regime. If climate action is a specific purpose in UN  Agenda 2030, ruled by Goal 13, a good tool to monitor achievements and to propose further advancement is the COP annual meeting, organized from 1995 onwards. 

Adaptation and mitigation are  the keywords to tackle climate change. Adaptation means anticipating the adverse effects of climate change and taking appropriate action to prevent or minimise the damage they can cause, while mitigation aims to slow down GHGs emissions. Scientific research is helpful to support both. Law must regulate the conduct of public and private operators within the states’ jurisdiction or control and be accompanied by effective enforcement and monitoring  mechanisms to ensure their implementation.”¹⁰. Climate change’s status – the Court says – is  an issue of common concern, reflecting its scientific complexity¹¹ and co-operation should be focused on knowledge-sharing initiatives, notably to prevent adaptation and mitigation measures to pose a risk of significant transboundary harm. By recalling the principle of  common but differentiated responsibility, the Court declares that this principle must be evaluated under each state’s capabilities dimension. A legal approach considering both due diligence and precautionary principles, along with the polluter pays principle, must be enacted to make a state producing pollution responsible for paying for harm to the natural environment, a well-established principle in the Organisation for Economic Cooperation and  Development (OECD) and European Union. 

Trying to reach a conclusion, it is hard to provide for a legal framework on state responsibility for environmental harm and to assess its relationship with the enjoyment of human rights, as states’ obligations are strictly interlinked in this matter. Having clarified that violations of environmental law bring to human rights infringement and reporting several examples of it, the Court turns to state responsibility for acts and omissions, stating that it’s not its task to establish individual responsibility of a state or group of  states for environmental harm and that “such responsibility can only be  established on a case-by-case basis.”¹². States think differently about what activities constitute an  international wrongful act on climate change commitments, as they prefer not to feel compelled by environmental rules. The Court clearly declares that if a state didn’t comply  with due diligence principle, by an effective evaluation of its conduct in practice, it’s responsible for an internationally wrongful act, if certain conditions apply, provided that  the actions or omissions are attributable to the state under rules of international law. The Court is aware of  difficulties in determining every state’s contribution to climate change by its own activities  and pinpointing every international wrongful act. Nonetheless, as stated in some past cases not affecting climate change “(T)he rules on State responsibility are capable of addressing situations where damage is caused by multiple States engaging in wrongful  conduct, and that the responsibility of a single State for damage may be invoked without  invoking the responsibility of all States that may be responsible.”¹³. The Court reiterates that states’ concurring activities leading to a damage does not exempt a state from its obligation to  make reparations, but causation can not be presumed and is a necessary element to provide for  reparations¹⁴. 

The common concern qualification of climate change extends the responsibility regime, from the existence of a common interest belonging to the international community as such. It allows  states, parties to a treaty relevant on climate change, but other than the state directly injured, to claim responsibility of the state held responsible for violating obligations on climate change  mitigation. Nonetheless, these states are not entitled to claim reparation. Whenever the damage involves human rights law, also injured individuals may seek a reparation. 

By this Advisory Opinion, the International Court of Justice firmly conceptualizes climate  justice, though avoiding the wording. Morality asserted by international law through the International Court of Justice, one of the most prominent voices for international legality, is an uncomfortable perspective for states. This Advisory Opinion spotlights the concept of climate justice, to be achieved by implementing lots of obligations, not all of them related to  environmental protection and climate change. Like social justice, climate justice is fully entrenched into international law, because of the intertwining affecting various international  legal rules.  

References 
INTERNATIONAL COURT OF JUSTICE. Obligations of States in Respect of Climate  Change. Advisory Opinion 23 July 2025. Available at: https://icj-web.leman.un icc.cloud/sites/default/files/case-related/187/187-20250723-adv-01-00-en.pdf. 
ROY, Suhana. The ICJ’s Climate Opinion: Towards a Jurisprudence of  Planetary Responsibility. International Law Blog, September 23, 2025. Available at:  https://internationallaw.blog/2025/09/23/the-icjs-climate-opinion-towards-a-jurisprudence of-planetary-responsibility/. 
SCOVAZZI, Tullio. Il Parere Consultivo della Corte Internazionale di Giustizia sul Cambiamento Climatico, RGAonline, n. 68, October 2025, p. 1-4. Available at:  https://rgaonline.it/wp-content/uploads/2025/09/Scovazzi_Ottobre25.pdf. 
TIGRE, Maria Antonia; BÖNNEMANN, Maxime; DE SPIEGELEIR, Antoine (eds). The  ICJ’s Advisory Opinion on Climate Change. Berlin: Verfassungsbooks, 2025. DOI: 10.17176/20251210-183825-0 
UNITED NATIONS GENERAL ASSEMBLY. Human Rights and Climate Change.  A/HRC/RES/59/25, 16 July 2025. Available at: https://docs.un.org/en/A/HRC/RES/59/25. 
UNITED NATIONS GENERAL ASSEMBLY. Human Rights and Climate Change. A/HRC/RES/56/8, 16 July 2024. Available at: https://docs.un.org/en/A/hrc/RES/56/8.
UNITED NATIONS GENERAL ASSEMBLY. Protection of global climate for present and  future generations of humankind. A/RES/80/138, 18 December 2025. Available at:  https://docs.un.org/en/A/RES/80/138. 
UNITED NATIONS GENERAL ASSEMBLY. The human right to a clean, healthy and  sustainable environment. A/RES/76/300, 1 August 2022. Available at:  https://digitallibrary.un.org/record/3983329?v=pdf. 

Fonte imagética: Feminist solutions for sustainable peace and environmental justice”. Disponível em: https://www.wilpf.org/our-work/ecological-justice/.

*Este texto não reflete necessariamente as opiniões do Boletim Lua Nova ou do CEDEC. Gosta do nosso trabalho? Apoie o Boletim Lua Nova!

1. University of Catania, Italy, Department of Political and Social Sciences. Lecturer in  International and EU law. Email: daniela.fisichella@unict.it ↩︎
2. Advisory Opinion, 6. ↩︎
3. Ibidem, par. 147, 52. ↩︎
4.  Ibidem, par. 288, 89. ↩︎
5. Ibidem, 7, emphasis added. ↩︎
6. Ibidem, par. 308, 95. ↩︎
7.  Ibidem, par. 134, 49. ↩︎
8. Ibidem, par. 137, 50, italics text. ↩︎
9. Ibidem, par. 151, 51. ↩︎
10.  Ibidem, par. 282, 88. ↩︎
11. Ibidem, par. 285, 88. ↩︎
12.  Ibidem, par. 406, 116, emphasis added. ↩︎
13. Ibidem, par. 430, 123. ↩︎
14. Ibidem, par. 435, 124. ↩︎