Introduction
The forthcoming Advisory Opinion of the International Court of Justice (ICJ) on climate change, expected on 23 July 2025, marks a pivotal moment in the evolution of international environmental law[1]. Against a backdrop of escalating climate disruptions and persistent deficiencies in the legal accountability of principal greenhouse gas emitters, this Opinion promises to redefine state responsibilities within the global climate governance framework[2].The implications of this jurisprudential development extend beyond doctrinal exposition, potentially reshaping multilateral climate cooperation across diverse institutional architectures.
Legal Framework and Core Questions
The ICJ’s deliberations focus on two interrelated issues central to contemporary climate law[3]. First, the Court examines the precise nature and scope of state obligations under international law—spanning human rights instruments, the UN Charter, maritime law, and environmental treaties—to mitigate climate change and facilitate adaptation measures for present and future generations[4].This inquiry engages principles of intergenerational justice increasingly recognised in international fora. Second, the Court considers the legal consequences when states fail to fulfil these duties, particularly where such omissions disproportionately affect vulnerable populations[5]. This question confronts the reality that those least responsible for historical emissions often suffer the greatest climate impacts[6]. The Court’s treatment of reparations as binding legal obligations or discretionary political measures remains a critical unresolved issue[7].
Parallel to the ICJ, the International Tribunal for the Law of the Sea (ITLOS) has issued an Advisory Opinion elucidating state duties concerning the protection of marine ecosystems from climate change impacts[8]. This development complements the ICJ’s broader assessment of environmental law obligations, underscoring the interconnection between maritime law and climate governance[9].
Historical Emissions and State Responsibility
Among the most contentious facets of this case is the treatment of historical greenhouse gas emissions within international law[10]. Many developed states have historically contended that their past emissions should not influence contemporary legal responsibilities, effectively insulating them from accountability for their disproportionate climate contribution[11]. The ICJ’s Opinion appears poised to challenge this stance fundamentally, signalling a potential jurisprudential shift.
By potentially recognising loss and damage responses as legally binding duties rather than voluntary acts, the ICJ’s Opinion could compel a comprehensive reassessment of state climate obligations grounded in cumulative emissions[12]. Such a development might set influential precedents for broader international environmental jurisprudence[13].
Emerging Jurisprudential Context
This Advisory Opinion must be viewed within the expanding body of international environmental jurisprudence integrating climate concerns with existing legal frameworks[14]. Specialised tribunals increasingly link environmental degradation with fundamental rights and state duties. For example, the Inter-American Court of Human Rights has connected environmental harm to violations of the rights to life and health[15],while the African Court on Human and Peoples’ Rights is expected to contribute regional perspectives to this evolving legal landscape[16].
Together with the ITLOS Opinion[17], these developments suggest a converging international legal consensus reinforcing stronger climate accountability frameworks. The ICJ Opinion may serve as a unifying jurisprudential element catalysing further legal innovation.
Key Legal Themes
The ICJ’s examination addresses six principal legal themes with significant ramifications:
- Scope of International Obligations
A principal question is whether state duties extend beyond explicit commitments under the United Nations Framework Convention on Climate Change (UNFCCC) and the Paris Agreement[18]. Major emitting countries often assert that their obligations are confined to these climate-specific instruments. However, this narrow interpretation neglects ancillary obligations under human rights law, maritime law, and foundational principles such as due diligence and the prevention of transboundary harm[19]. The Court’s clarification may establish a more holistic legal foundation for climate accountability, integrating a broad spectrum of international duties[20].
- Remedies and Reparations
Determining legal consequences for states’ inadequate climate action is among the most politically sensitive matters[21]. Reparations in this context extend beyond financial compensation to include institutional reform, technology transfer, and restorative justice[22].A strong ruling here could close a significant accountability gap and afford affected states and communities meaningful avenues for redress[23].
- Human Rights and Future Generations
The framing of climate change as a human rights issue has gained significant traction[24]. Courts such as the European Court of Human Rights have acknowledged links between environmental harm and violations of fundamental rights including life and health[25]. If the ICJ affirms rights to a healthy environment and protections for future generations, it could cement human rights as a foundational principle in climate governance, enabling new rights-based litigation[26].
- Prevention and Precaution
The Court is likely to reaffirm prevention and precautionary principles requiring proactive state action to avoid environmental harm[27]. Embedded in customary international law and environmental treaties, these principles mandate regulation of potentially harmful activities within state jurisdictions[28]. Their application to climate mitigation and emerging technologies will be critical to defining the scope of state responsibility and avoiding further harm[29].
- Equity and Differentiated Responsibilities
The principle of common but differentiated responsibilities (CBDR) is central to international climate law, recognising varied historical responsibilities and capacities among states[30].^The ICJ’s Opinion offers an opportunity to clarify CBDR’s precise legal meaning, facilitating more equitable implementation of climate obligations that address inequalities between developed and developing nations.
- Corporate Accountability
An emerging issue concerns states’ duties to regulate private sector actors, particularly fossil fuel corporations—the primary source of greenhouse gas emissions. The ICJ’s approach, drawing on due diligence, human rights obligations, and intergenerational equity, may set important precedents for corporate accountability, potentially challenging corporate immunity and accelerating transitions away from fossil fuels[31].
Implications Beyond Doctrine
The Advisory Opinion’s significance extends beyond doctrinal refinement to practical impact in climate governance[32]. Clearer legal standards could influence state compliance assessments in domestic and international arenas[33], reinvigorate multilateral climate negotiations such as COP30 in Belém[34],and strengthen claims for enhanced climate finance, especially loss and damage mechanisms[35]. The Opinion may also support normative initiatives addressing fossil fuel non-proliferation and global environmental regulation more broadly. The legal clarity and moral authority it confers could be instrumental in overcoming political barriers to effective climate action[36].
Conclusion
The ICJ’s Advisory Opinion represents a potentially transformative milestone in international environmental law, situating accountability, reparations, and human rights at the core of climate governance[37]. It reflects an international legal order increasingly shaped by Global South leadership and youth activism advocating urgent climate action[38]. The Opinion’s legal clarity and normative force could shift climate justice from aspirational rhetoric to enforceable obligation, imposing binding duties on states and indirectly on corporations[39].The ultimate measure of its impact will be its capacity to catalyse meaningful behavioural change amid the escalating climate crisis[40].
*Dual-qualified (England & Wales and India) commercial litigator and international arbitration practitioner specialising in international commercial arbitration and investor-state dispute settlement. Currently practising as a barrister at The Barrister Group in London and as an advocate in New Delhi. She is an alumna of Queen Mary University of London and a member of The Honourable Society of Gray’s Inn. Email: divya.kesar@tbgbarri
*Barrister in England and Wales
[1] International Court of Justice, Advisory Opinion on Climate Change (23 July 2025) https://www.icj-cij.org/sites/default/files/case-related/187/187-20250707-pre-01-00-en.pdf accessed 22 July 2025.
[2] See generally Doelle and Seck, ‘Loss and Damage from Climate Change: From Concept to Remedy?’ (2020) 50 Environmental Law 669.
[3] ICJ (n 1).
[4] UN Charter (1945); Universal Declaration of Human Rights (1948); United Nations Framework Convention on Climate Change (adopted 9 May 1992, entered into force 21 March 1994) 1771 UNTS 107; Paris Agreement (adopted 12 December 2015, entered into force 4 November 2016) UNTS No 54113.
[5] M Doelle and S Seck (n 2).
[6] Ibid.
[7] P Dupuy and J Vinuales, International Environmental Law (2nd edn, CUP 2018) 389–412.
[8] International Tribunal for the Law of the Sea, Advisory Opinion on Climate Change and Marine Environment (21 May 2024) https://www.itlos.org/fileadmin/itlos/documents/cases/31/Advisory_Opinion/C31_Adv_Op_21.05.2024_corr.pdf accessed 22 July 2025.
[9] Ibid.
[10] M Doelle and S Seck (n 2).
[11] Ibid.
[12] ICJ (n 1).
[13] See generally ILC, ‘Draft Principles on the Allocation of Loss in the Case of Transboundary Harm Arising Out of Hazardous Activities’ (2006) UN Doc A/61/10.
[14] Jacqueline Peel and Hari M Osofsky, ‘Climate Change Litigation’ (2020) 16 Annual Review of Law and Social Science 21–38, available at SSRN:https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3711276 accessed 22 July 2025.
[15] See, eg, López Ostra v Spain (1995) 20 EHRR 277; Urgenda Foundation v State of the Netherlands [2018] ECLI:NL:HR:2019:2006.
[16] African Court on Human and Peoples’ Rights, cases pending.
[17] ITLOS (n 9).
[18] UNFCCC (n 4); Paris Agreement (n 4).
[19] Trail Smelter Arbitration (US v Canada) (1938 and 1941) 3 RIAA 1905; Corfu Channel (UK v Albania) (Merits) [1949] ICJ Rep 4.
[20] Nuclear Tests (Australia v France; New Zealand v France) [1974] ICJ Rep 253, 457
[21] Doelle and Seck (n 2).
[22] Dupuy and Vinuales (n 8).
[23] Doelle and Seck (n 2).
[24] Ibid.
[25] ILC (n 14).
[26] Urgenda Foundation (n 16).
[27] López Ostra v Spain (n 16); Öneryildiz v Turkey (2005) 41 EHRR 20.
[28] UN Human Rights Council, ‘Human Rights and Climate Change’ Resolution A/HRC/RES/50/9 (2022).
[29] Rio Declaration on Environment and Development (adopted 14 June 1992) UN Doc A/CONF.151/26/Rev.1, Principle 15.
[30] Pulp Mills on the River Uruguay (Argentina v Uruguay) [2010] ICJ Rep 14, para 101.
[31] Doelle and Seck (n 2).
[32] United Nations Framework Convention on Climate Change, COP30 Outcomes (2025).
[33] Ibid.
[34] Ibid.
[35] Ibid.
[36] Doelle and Seck (n 2).
[37] ICJ (n 1).
[38] UNFCCC (n 4).
[39] Peel and Lin (n 34).
[40] Ibid.