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Analysis & trends
The ICJ’s advisory opinion on state obligations in respect of climate change – What it means for Africa? (part 2)
This article is a more detailed piece following the earlier article published in November 2024 by Saadia Bhatty and Jack Bownes (available here), prior to the publication of the ICJ Advisory Opinion.
INTRODUCTION
On 23 July 2025, the International Court of Justice (the “ICJ” or “Court”) published its much-anticipated advisory opinion on the obligations of States in respect of climate change (the “Advisory Opinion”).
Following three rounds of written submissions (including responses to questions raised by the Court) and oral hearings in 2024, the Court delivered its much awaited Advisory Opinion at a sitting at the Peace Palace in The Hague.
Partner Saadia Bhatty and Associate Jack Bownes, who were part of a team of legal counsel who represented the African Union in the proceedings, provide an overview of the ICJ’s conclusions in its Advisory Opinion (1), highlighting in particular what it means for Africa (2) and for corporate entities, especially those operating in the fossil fuel industry (3), and conclude by emphasising the severe criticism by several judges of the Court by way of separate opinions and declarations (4).
1. Overview of the ICJ’s advisory opinion
The ICJ’s Advisory Opinion addressed the two following questions submitted to it by the General Assembly of the United Nations in its Resolution 77/276 adopted on 29 March 2023:
(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? ; and
(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?[1]
This section will highlight the key findings of the Court, noting in particular: the crucial role played by science in the proceedings (i); the rejection of the lex specialis argument, emphasising the importance of the principle of systemic integrity (ii); the confirmation of the intersection between international human rights law and environmental law (iii); the application of the CBDR-RC principle as part of customary international law (iv); and the discussion of the legal consequences that may arise under ARSIWA (v).
(i) The Crucial Role played by Science
Importantly, yet unsurprisingly, the Court gave particular weight to science in its Advisory Opinion. On 26 November 2024, in the week prior to the oral hearings at the Peace Palace, authors of the Intergovernmental Panel on Climate Change (the “IPCC”) reports met with members of the ICJ to present their findings.[2] Referring to these reports in its Advisory Opinion, the ICJ heralded the significant role science has played in determining the severity of the climate emergency. [3] The Court took into account the “severe and far-reaching” consequences of climate change on “both natural ecosystems and human populations”,[4] and observed that the IPCC reports were widely considered by participants as constituting the “best available science on the causes, nature and consequences of climate change”.[5]
A similar emphasis on science was put by the International Tribunal for the Law of the Sea and the Inter-American Court of Human Rights – the two other international tribunals which have issued opinions on obligations of States arising out of climate change – when they referred to the IPCC reports as “representative, methodologically rigorous” and “the best available source of scientific guidance on climate change”.[6]
The ICJ’s pro-science stance aligns with the position advocated by the African Union, African States and other “particularly vulnerable” States, who all stressed that the Court’s Advisory Opinion should be informed by leading climate science, and many of whom submitted expert testimony with their written submissions.[7]
The importance given to science will undoubtedly continue to be significant in future climate-change related litigations and arbitrations, in the determination of both liability and damages related to environmental claims.
(ii) Applicable law not restricted by Lex Specialis – Principle of Systematic Integration
Before answering the questions asked by the United Nations General Assembly, the Court clarified their scope and meaning. Notably, the Court agreed with a large number of participants (including the African Union) that it should consider the obligations of States under “the entire corpus of international law”[8] which includes, but is not limited to, international climate law treaties currently in force such as the United Nations Framework Convention on Climate Change (“UNFCCC”), the Kyoto Protocol, the Paris Agreement, and other environmental treaties. The Court also referred to obligations under the Law of the Sea and international human rights law, as well as customary international law relating to climate change.[9] It therefore rejected the argument made by a minority of participants that the obligations of States should be read only through the applicable lex specialis, that is, specific climate-change law treaties.[10]
The Court concluded that these different sources of international law “inform each other” and must be considered together, in application of the “principle of systemic integration”, as argued by a majority of States.[11] The Court rejected, however, the argument that the “polluter pays” principle should be part of the applicable law.[12]
(iii) Confirmation of the Intersection between International Human Rights law and the Protection of the Environment
Importantly, the Court highlighted how State obligations to take measures to protect the environment are fundamental to international human rights law, finding that States cannot ensure the full protection of human rights without safeguarding the climate system. [13] Consequently, States are obliged to take measures to protect the environment in order to ensure the enjoyment of human rights under international human rights law. This conclusion from the Advisory Opinion is in line with what many domestic and regional, including constitutional, courts have considered in recent matters.[14]
The Court’s clarification on the intersection between international human rights law and environmental law is significant not least because it may give additional incentives to claimants to bring environmental damages claims against States before human rights courts.
(iv) Application of the Common but Differentiated Responsibilities and Respective Capabilities (CBDR-RC) principle as part of Customary International Law
The Court also confirmed that in addition to the customary international law “duty to cooperate” and “duty to prevent significant harm to the environment by acting with due diligence”, States also have an obligation to prevent activities that cause significant harm to the climate system in accordance with their “common but differentiated responsibilities and respective capabilities” (“CBDR-RC”),[15] a principle which acknowledges the historic responsibilities of certain States in respect of climate change as well as their respective capabilities to adopt preventative and mitigating measures.[16]
The Court found that the principle does not create new obligations for States. Rather, it “guides the interpretation of obligations under international environmental law beyond its express articulation in different treaties” and is “relevant to […] the determination of rules of customary law relating to the environment”. [17] Consequently, the “burdens of the obligations in respect of climate change” under international law should be “distributed equitably” amongst States by reference to their respective historic contributions to the climate emergency and current capabilities.[18]
Guided by IPCC reports dating back as far as 1990, the Court observed that “the most developed States […] have contributed significantly to the overall amount of GHG emissions […] and have resources and the technical capacity to implement wide-ranging emission reduction”. The Court noted that, comparatively, the “least developed States have contributed only minimally to historical emissions and have only a limited capacity to transform their economies”.[19]
As a result, States that have contributed more to climate change and possess greater capabilities of combatting climate change have, inter alia, a duty to adopt more ambitious nationally determined contributions (“NDCs”) in accordance with the Paris Agreement,[20] and an obligation to cooperate through technology and financial transfers to States more vulnerable to the adverse effects of climate change.[21]
The Court’s application of the principle to the current climate emergency is significant for States particularly vulnerable to climate change, including small island States and African States who all emphasized the importance of applying the CBDR-RC principle to achieve climate justice through an equitable distribution of State obligations.[22] It is no less significant that the Court confirmed the CBDR-CR principle to be part of customary international law, in line with the submissions from the most vulnerable States, including those in Africa.[23]
(v) Legal consequences under ARSIWA
Turning to the second question on legal consequences (question (b)), the Court first confirmed that a breach by a State of its international law obligations in respect of climate change would constitute an internationally wrongful act.[24] Dismissing the submissions by a number of participants that legal consequences should be limited to a lex specialis created by the climate treaty framework,[25] the Court found that, in theory, a breach of said obligations could engage States’ responsibility under the Draft articles on Responsibility of States for Internationally Wrongful Acts (“ARSIWA”).[26]
The legal consequences resulting from a State’s breach of international climate law obligations could therefore include cessation and guarantees of non-repetition of the wrongful act or omission (Article 30, ARSIWA); full reparation to injured States in the form of restitution (Article 35, ARSIWA), compensation (Article 36, ARSIWA) or satisfaction (Article 37, ARSIWA).[27]
In practical terms, States that have suffered the most from the adverse effects of climate change may be able to seek compensation from the States that have contributed the most to climate change and caused the most harm to the environment. For this to be possible, the conditions for establishing State responsibility must be satisfied and a “sufficiently direct and certain causal nexus” would have to be shown “between the wrongful act and injury”.[28] On this last point, the Court cautioned that determining the particular harm caused by a State’s specific wrongful actions or omissions would be difficult, albeit not impossible.[29]
2. Africa’s contribution and the significance of the advisory opinion for the continent
The significance of these proceedings to Africa’s fight against climate change cannot be understated. Not only was it significant from the number of submissions from African participants,[30] but also considering the several African legal instruments that informed the Court’s Advisory Opinion.
The Court expressly referred to the United Nations Convention to Combat Desertification in Those Countries Experiencing Serious Drought and/or Desertification, Particularly in Africa (the “Desertification Convention”) at several instances, underlining the important scientific contribution of this instrument to understanding the role that desertification and land degradation prevention can play in the efforts to combat climate change.[31] In addition to the Desertification Convention, the Court referred to provisions of the UNFCCC that establish an obligation for State signatories to “develop and elaborate appropriate and integrated plans…for the protection and rehabilitation of areas, particularly in Africa, affected by drought and desertification”.[32]
These instruments highlight Africa’s particular exposure to the adverse effects of climate change. The Advisory Opinion recognises this, and the fact that Africa, and other developing regions, are suffering the most from climate change despite having contributed the least to GHG emissions.[33] The Court’s advocation of the principle of CBDR-RC is therefore a salient development for Africa and one that promises to encourage States with greater capabilities to increase their assistance and support to African States, whilst also providing greater contributions through their own efforts.
The Court’s Advisory Opinion was also informed by the position taken by Africa’s human rights institutions – the African Court and the African Commission on Human and Peoples’ Rights – on the interrelationship between protection of the environment and the protection of human rights.[34] Crucially, the Court considered the recognition in numerous regional human rights instruments of the right to a clean, healthy and sustainable environment. In particular, it referred to Article 24 of the African Charter on Human and Peoples’ Rights, which provides that “[a]ll peoples shall have the right to a general satisfactory environment favourable to their development”.[35]
Further, the conclusions drawn by the Court in respect of legal consequences, particularly compensation, and the duty of States to cooperate on financial and technology transfers to injured or vulnerable States aligns with the position of the African Union and other African States on these issues.[36]
The Court found that, when a State breaches its international climate law obligations and restitution is impossible, “responsible States have an obligation to compensate” as such remedial action “has the function of addressing the losses incurred as a result of the internationally wrongful act […] by the injured State or its nationals”.[37]
Acknowledging that “the Paris Agreement establishes obligations for developed States to provide financial resources to developing States”, the Court considered that such level of assistance could be evaluated “on the basis of […] the capacity of developed States and the needs of developing States”.[38]
The result is that African States that find themselves on the front line of the fight against climate change could seek compensation and request financial assistance from developed States.
3. Consequences of the advisory opinion ON corporate entities
The ICJ’s findings will also have a significant indirect impact on corporate entities.
The Court made clear that States will be required to “put in place a national system, including legislation, administrative procedures and an enforcement mechanism necessary to regulate the activities” of corporate entities while also “exercising adequate vigilance” to ensure compliance with international law obligations as determined by the Court. [39] Consequently, corporate entities will be subjected to stricter regulations and will be required to align their practices with State climate policy.
The Court considered that, whilst environmental impact assessments for both domestic and transboundary operations are not a requirement under general international law, they are a means to satisfy the “more general rule requiring the assessment of risks to the environment”.[40]
The Court did not however provide further examples of how States could heighten regulations for corporate entities in order to ensure compliance with international climate law obligations. In addition to requiring environmental impact assessments, States might look to increase taxes, prohibit certain harmful practices, or increase corporate due diligence. One possible solution is reformed international investment treaty practice that incorporates an increase in investor obligations concerning environmental protection, climate change and corporate social responsibility generally. The African Union is adopting this approach at a continental level in the Protocol to the Agreement establishing the African Continental Free Trade Area on Investment (the “AfCFTA Investment Protocol”). [41] Many States are also entering into bilateral investment treaties (“BIT”) with similar investor obligations concerning the protection of the environment.[42]
The ICJ’s most progressive finding concerns fossil fuels.
Significantly, the Court emphasised that “fossil fuel production, fossil fuel consumption, the granting of fossil fuel exploration licenses or the provision of fossil fuel subsidies…may constitute an internationally wrongful act which is attributable to that State”.[43] Ultimately, States that continue to deliver exploration and exploitation licenses for fossil fuels could be found liable of an internationally wrongful act, and their liability may be invoked by another State or a private entity. Taken further, a State’s failure to reduce fossil fuel production, consumption or subsidies could result in legal consequences under its international obligations. However, the Court did not expand on this finding. Notably, it did not clarify this point in the context of CBDR-CR specifically, so questions may remain as to whether developed and lesser-developed States are exposed to this liability in equal measure.
The consequences of this finding could be transformative for fossil fuel investors and therefore corporate entities around the world, as States accelerate their efforts to transition towards green energy and curtail investment in the fossil fuel sector. It could also put States in a pernicious dilemma, in what is known as a “Catch-22” type-situation: if governments continue to grant licences to oil, gas and mining companies, they may be held liable by another State for the damages it suffers from the adverse effects of climate change. On the other hand, States that accelerate their phasing out of fossil fuels might also expose themselves to actions brought by investors under investment treaties or contracts, many of which are outdated and incompatible with international climate law. Some European Union Member States, such as Germany, Slovenia and the Netherlands, have already been on the receiving end of such claims brought under the Energy Charter Treaty.[44]
As such, should State action of this kind be inconsistent with commitments made to fossil fuel investors under contracts, treaties or other investment agreements, we will likely see an increase in investor-State disputes, before domestic and/or international tribunals.
4. Severe critiqUES OF THE ADVISORY OPINION FROM SEVERAL judges OF the court
It should be noted that out of the total number of 15 judges sitting at the ICJ: 11 judges, including the 3 African judges, expressed the view that the Court did not go far enough on several of the issues raised by the questions, by way of separate opinions and declarations published with the Advisory Opinion.
By way of example, Vice-President Sebutinde (Uganda) suggested that the Court “presented a narrow view of the answer to question (b)” by “downplaying the importance of the principle of common but differentiated responsibilities and respective capabilities” by simply equating it to the principle of equity and failing to articulate the precise components of the principle of CBDR in the context of climate change obligations.[45] Judge Xue (China) similarly underlined the ambiguity of the Court’s reference to a “spectrum of States” as a parameter for CBDR-RC in her own separate opinion,[46] whilst Judge Yusuf (Somalia) emphasized that the Court should have engaged more concretely with the principle of CBDR-RC in his separate opinion.[47]
Vice-President Sebutinde also suggested that the Court should have affirmed that reparation measures should be dependent on national circumstances of the affected State and “include some of the innovative remedial measures proposed by several developing States” (such as monetary compensation and reforestation) who are suffering from the adverse effects of climate change whilst “heavily or chronically indebted to developed or industrialised States”.[48]
This view was shared by a number of other judges in their separate opinions; including that of Judge Yusuf who criticised the Court for adopting an “excessively formalistic” approach that fails to address the real-world implications for injured States and scientific realities underlying the questions posed by the UN General Assembly.[49] In his very critical view, the Advisory Opinion failed to analyse the legal avenues available to injured States, and highlighted the inadequacy of relying solely on the regime of State responsibility for internationally wrongful acts.[50] Judges Bhandari (India) and Aurescu (Romania) similarly critiqued the ICJ’s “general and abstract” and “cautious and minimalistic” approach to legal consequences.[51]
On the interplay between international human rights and environmental law, Judge Tladi (South Africa) praised the Court for its recognition, albeit “in a way that might be unclear”, of the right to a clean and healthy environment as a human right under international law.[52] Conversely, Judge Aurescu contended that the Court should have recognised this right as having achieved the status of a customary international law in the dispositive part of its opinion.[53]
The judges also shared opinions on the role the Advisory Opinion could, or should, have in the context of the climate emergency. Judge Yusuf concluded that the Advisory Opinion “failed to rise to the occasion and to provide the international community with the legal tools necessary for combating climate change in an equitable manner for all States”,[54] whilst Judges Tladi, Bhandari and Cleveland (United States of America) underscored the Court’s limited role in addressing the climate crisis and called on concerted international action in order to achieve meaningful progress;[55] Judge Tladi reflected that, whilst “it seems that those who are in a position of authority value war over the plight of humanity and the future of the planet”, he maintains hope that “those in positions of power will realize, before it is too late, that money cannot be eaten” and that “future generations will make better choices”.[56]
Conclusion
The ICJ’s Advisory Opinion follows a string of landmark opinions from similar international tribunals. On 21 May 2024, the International Tribunal for the Law of the Sea (“ITLOS”) published an advisory opinion on States’ obligations to protect and preserve the world’s oceans from climate change impacts. A little more than a year after, on 3 July 2025, the Inter-American Court of Human Rights issued an advisory opinion on the obligations of States in responding to the climate emergency, whilst the African Court on Human and Peoples’ Rights recently received a request for an opinion on State obligations in the context of climate change earlier this year. Together, these advisory opinions are shaping the international climate law framework.
Although not binding, the ICJ’s Advisory Opinion is another significant development in international climate justice. As an informed, authoritative determination of what the legally binding international rules are on climate change, it should bring some level of certainty to questions of State obligations and motivate States to enhance their climate policies. However, as communicated by the Judges of the Court in their numerous separate opinions, there remain reservations that the ICJ took too conservative a stance on important elements of international climate law, such as legal consequences and CBDR-RC especially with respect to the most vulnerable States, including African States.
Consequently, it remains to be seen if and to what extent, in practice, a breach of international climate law obligations will have concrete legal consequences for a State. However, whether injured States or populations seeking compensation from polluting States, or actions brought by fossil fuel investors or other corporate entities against States, we will likely see an increase in climate disputes before domestic and international fora in the months and years to come.
