Dr Peter Lawrence is an Adjunct Senior Researcher at the University of Tasmania (UTAS) Law School, Coauthor of Representing Future Generations: Climate Change and the Global Legal Order with Michael Reder (Cambridge University Press, 2026)

The 23 July 2025 International Court of Justice (ICJ) advisory opinion on climate change has many strengths but is fairly thin in terms of clarifying the obligations of states in relation to future generations. This is surprising given that the UN General Assembly resolution specifying the mandate for the Court explicitly requested that it examine states’ obligations 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’. In addition the mandate required the Court to examine the ‘legal consequences under these obligations for States’ with respect to ‘[p]eoples and individuals of the present and future generations affected by the adverse effects of climate change’.

The Court’s largely sidestepping of this part of the mandate is curious given that future generations featured in many of the submissions it received (see for example the submissions of the EU paras 173-184; Vanuatu paras 479-483 and IUCN para 352).  Moreover, the issue of obligations to future generations was addressed in detail in recent decisions of the European Court on Human Rights (ECtHR) (see below), and the July 10, 2025 Inter-American Court of Human Rights (IACtHR) advisory opinion on the climate emergency. In this context, ICJ Vice President Sebutintende’s criticism of the Court for not addressing this part of the mandate is justifiable  ((Separate Opinion), Vice President Sebutinde, 23 July 2025, paras. 3-7). This brief note critically explores how the ICJ approached this issue.

The Advisory Opinion

The question of states’ obligations towards future generations is interconnected with some key principles of international environmental law. How did the Court deal with these principles? The Court concluded that ‘sustainable development… equity, intergenerational equity and the precautionary approach or principle are applicable as guiding principles for the interpretation and application of the most directly relevant rules’ (para. 161). Intergenerational equity was considered to be a ‘manifestation of equity’ (para. 157) and previous ICJ statements that ‘equity’ was a direct emanation of the idea of justice and a general principle directly applicable as law were endorsed (para.152).  In particular, intergenerational equity was seen as an expression of the idea that ‘present generations are trustees of humanity tasked with preserving dignified living conditions and transmitting them to future generations,’ (para 156). In this context the Court quoted with approval a statement by the Intergovernmental Panel on Climate Change (IPCC) which emphasised the increasing impacts of global warming over time meant that climate change increasingly threatened ecosystems, biodiversity and the livelihoods, health and well-being of current and future generations (para 156). The Court further endorsed its statement in the 1996 Legality of Nuclear Weapons Case, (para 29) that the ‘environment is not an abstraction but represents the living space, the quality of life and the very health of human beings, including generations unborn’.

The Court also pointed to the references to intergenerational equity in the Preamble of the Paris Agreement and in article 3 of the United Nations Framework Convention on Climate Change (para. 155) and went on to state that it considered intergenerational equity to constitute ‘a guide for the interpretation of the applicable rules’ (para. 157). Accordingly, ‘considerations of intergenerational equity must play a role infra legem, without displacing or exceeding the limits of the applicable law’ (para 157). 

Finally, the Court specified that ‘[d]ue regard to the interests of future generations and the long-term implications of conduct are equitable considerations that need to be taken into account where States contemplate, decide on or implement policies and measures in fulfilment of their obligations under the relevant treaties and customary international law’ (para 157).

Analysis

It is clear that in approaching its mandate the Court avoided considering whether states owe obligations towards future generations. Only Vice-President Sebutinde tackled this issue, concluding that states ‘owe the identified obligations to protect the climate system from the adverse effects of GHG emissions and from significant environmental harm not only to present generations but also to future generations’ (para. 7). The Vice-President seems to suggest that the preventative principle – according to which states must avoid causing significant harm to the environment of other states or of areas outside national jurisdiction – includes an obligation to prevent significant harm to future generations. However, the basis of such an extension,  which could have been justified on the basis of intergenerational equity (see Peter Lawrence), is not spelt out.

In addition to avoiding consideration of whether states owe obligations to future generations, a weakness of the Court’s procedural approach to intergenerational equity is that this approach could be seen as requiring a mere ‘box ticking’ exercise. The concern here is that states could meet the procedural requirement by giving lip service to intergenerational equity – by stating that they had considered the interests of future generations, while failing to put in place the necessary policies to ensure that the interests of future generations are appropriately protected (cf Carolin Foster and Bella Belcher).

The Advisory Opinion of the IACtHR is instructive in this regard. Unlike the ICJ, that Court held that the obligation on states to maintain a human rights-based strategy to achieve mitigation targets entailed avoiding imposing ‘disproportionate burdens on future generations’. According to the IACtHR, it flowed from this that states must ‘take immediate and intermediate measures while carbon neutrality is being achieved’ (para 334). The IACtHR, in this respect built on the decision of the European Court of Human Rights in Klimaseniorinnen Verein v. Switzerland  (9 April, 2024).

The ICJ also missed an opportunity to specify the inter-temporal dimension of human rights. As expressed in the submission of the Government of Vanuatu: ‘The rights protected across general international law and in the human rights treaties are “living”, in the sense that they must be interpreted with regard to the future’ (para. 481). Following this logic, Vanuatu argued that, in the context of human rights obligations, states must ‘respect’ and ‘ensure’ the rights of future generations and ‘take into account the best interests of future generations of children when making decisions that will affect them’ (para. 483).  

Similarly, the ICJ was reticent to acknowledge the intertemporal dimension of the right to a healthy environment. The IACtHR in its Advisory Opinion stated that: ‘the purpose of the obligations derived from the right to a healthy climate is to protect the global climate system for the benefit of humanity as a whole, and both present and future generations are part of this’. Furthermore, the IACtHR declared that the ‘ethical and legislative grounds’ for international human rights law’s recognition that everyone is the possessor of nondelegable rights ‘transcends the people who inhabit the planet in the present, extending also to humanity as a moral and legal community that endures over time’ (para. 311).

In contrast, the ICJ recognised the right to a ‘clean, healthy and sustainable environment’ (para. 393) but failed to specify how this principle related to future generations. The IACtHR went much further than the ICJ, stating that there was ‘an emerging trend towards recognising future generations as rights holders’ (para. 307, referring to the Maastricht Principles on the Human Rights of Future Generations). Although the IACtHR left unclear whether claims on behalf of future generations could be brought to this court (Aoife Nolan).

It is possible that the ICJ shied away from the future generations aspect of its mandate owing to concerns that this may have been perceived as favouring the interests of developed countries over developing countries (see Stephen Humphries cf Wewerinke-Singh, Garg and Agarwalla; Peter Lawrence). However, the IACtHR’s advisory opinion demonstrates that international tribunals can begin to build a jurisprudence that requires states to balance both the interests of current and future generations (Aoife Nolan). The IACtHR stated that the responsibility for climate actions and impacts ‘should avoid imposing disproportionate burdens on both future and present generations’(para. 310).

Critics might argue that courts do not have the expertise to undertake this balancing of interests, and that this role is one for parliaments and the executive and not the courts. The ECtHR, in its decision in Klimaseniorinnen Verein v. Switzerland, pre-empted this concern by pointing out that within democratic decision-making processes, particularly vulnerable groups, such as young people below voting age, and future generations are at a procedural disadvantage in that, while they face increasingly severe climate impacts, they have ‘no possibility of participating in relevant current decision-making processes’ (para. 420). The existence of this procedural disadvantage was used by the ECtHR to loosen the relevant standing requirements. A similar approach could have been adopted by the ICJ to its rules of procedure to allow amicus briefs by organisations on behalf of future generations (see Peter Lawrence and Michael Reder). If this had occurred, perhaps more judges of the Court would have been able to fully answer the questions related to future generations posed in the mandate.

Finally, given the emphasis on the destructive impact of climate change on Pacific Island peoples including their culture, it was disappointing that the ICJ did not recognise the application of the principle of intergenerational equity as entailing an obligation to preserve indigenous cultural heritage and transmit it to future generations. This is in stark contrast to the IACtHR Advisory Opinion (see para. 306) which built on its earlier jurisprudence recognising the interconnection between intergenerational equity and the imperative of preserving cultural heritage and transmitting it to future generations (para 306).

Conclusion

This short note has argued that the ICJ advisory opinion on climate change should have gone further in addressing the interests of future generations in the climate change context. Defenders of the court’s approach may argue that by delineating states obligations to take action on climate change now, the ICJ has implicitly addressed the interests of future generations because strong mitigation actions now benefits future generations. While this is true at one level, it results in a truncated version of international legal obligations, partially blind to the ever-worsening impacts of climate change on the earth and future generations. Given this reality, international legal obligations need to be fully responsive to both the intragenerational and intergenerational requirements of justice. This means, for example, as explained above, that state actions required to implement the relevant international legal obligations need to be responsive to the ongoing need for short-term, intermediate as well as longer-term targets in order to avoid unjust burden shifting.

Moving forward, it is important to note that future international jurisprudence on this issue may, nevertheless, build on some elements in the ICJ advisory opinion – including the idea of states acting as trustees with a duty to ensure a liveable climate for future generations. Jochen Rauber has observed that the ‘due regard to future generations’ requirement was not limited to the climate context and that it is part of a broader positive development involving the Court moving towards a future-oriented vision of international law. Future jurisprudence can also draw on the recent decisions of the IACtHR and the ECtHR.

The ICJ’s narrow interpretation of its mandate as far as states’ obligations to future generations is concerned meant that certain possibilities were off the table. Unlike the IACtHR, the ICJ missed an opportunity to elaborate on the close linkages between intergenerational equity and protection of the global ecological system. In addition, the Court failed to address how the human rights of future generations could be procedurally protected in terms of standing in court proceedings.  It will be interesting to see if the request for an advisory opinion on human rights obligations of African states in addressing the climate crisis made to the African Court on Human and People’s Rights, which is scheduled to be released over the coming months, follows the approach of the ICJ or the bolder approach of the IACtHR. In the Petition to the African Court, future generations are listed as a vulnerable group, perhaps giving hope that that Court will give full consideration to the interests of this group in its decision.