Climate change has a temporal structure that fits awkwardly with adjudication. Emissions released now produce their gravest effects decades later, and those who will bear them have no vote and no voice in the proceedings in which reduction targets are set. Gardiner (2011) called this the intergenerational storm: each generation has an incentive to take the benefits of emitting and pass the costs forward. The scientific assessments leave little doubt about the direction of travel, with every increment of warming bringing more severe and in some cases irreversible harm (IPCC, 2023).

Litigants have responded by asking courts to hold states to account on behalf of the young and the unborn. Surveys of the field record a steady rise in cases against governments and a marked turn towards arguments founded on constitutional and human rights (Peel and Osofsky, 2018; Savaresi and Setzer, 2022; Setzer and Higham, 2023). Within that turn, intergenerational equity has moved from rhetorical background to an operative part of the reasoning in several apex courts.

This review traces that movement. It asks which legal techniques courts have used to give the interests of later generations weight against the preferences of present majorities, how the academic literature has received those techniques, and what remains unsettled. The focus is on claims against states; litigation against corporations raises different questions of causation and attribution and is left aside.

The article is a narrative review of the published literature and of the decisions on which that literature concentrates. Sources were chosen for their influence on the debate, not through a systematic search, and the account is weighted towards jurisdictions whose judgments are available in English or have been closely analysed in English-language journals. That is a real limitation. Reviews of climate litigation scholarship have noted its concentration on a small number of high-profile cases from the Global North and the relative neglect of routine disputes and of courts elsewhere (Setzer and Vanhala, 2019).

The modern legal concept owes most to Weiss (1989), who described each generation as both trustee and beneficiary of the planet and derived three duties from that position: to conserve the diversity of the resource base so that later generations keep their options, to pass on the environment in no worse condition than it was received, and to preserve access to the common legacy. She presented these as principles of international law in the making (Weiss, 1990). Philosophers had prepared the ground. Rawls (1971) included a just savings principle in his account of justice between generations, while Parfit (1984) raised the difficulty that policies affecting the distant future also determine who will exist, so that no identifiable future person is made worse off by them.

Treaty law adopted the vocabulary without giving it hard edges. The Stockholm and Rio Declarations refer to present and future generations. Article 3 of the United Nations Framework Convention on Climate Change directs the parties to protect the climate system for the benefit of present and future generations of humankind on the basis of equity (United Nations, 1992), and the preamble to the Paris Agreement lists intergenerational equity among the matters parties should respect when acting on climate change (United Nations, 2015). The International Court of Justice referred to generations unborn in its 1996 advisory opinion on nuclear weapons and again in Gabcikovo-Nagymaros in 1997. The standard treatise nonetheless treats the principle as one that informs interpretation and does not by itself generate enforceable obligations (Bodansky et al., 2017). Litigation has been the means of testing whether it can do more. Figure 1 places the main decisions in sequence.

Courts have reached the future by different paths, and the differences matter for how far each doctrine can travel between legal systems. Table 1 summarises the five routes discussed below.

Four objections appear across the judgments and the commentary. The first is procedural. Standing rules built around individualised present injury sit uneasily with harm that is diffuse and deferred, and Juliana shows that a claim can fail on redressability even where the facts are accepted. The second is institutional: setting emission pathways involves distributive choices that many judges consider the business of legislatures. The courts that have granted relief have usually answered by ordering the state to meet a floor derived from its own commitments or from scientific consensus and leaving the means open (Peel and Osofsky, 2015).

The third objection is philosophical. If Parfit's non-identity problem holds, a rights claim made for specific future persons is hard to sustain, since different policies produce different people. Lawrence (2014) argues that the difficulty can be met by framing duties towards future generations as a class whose basic interests are foreseeable whoever its members turn out to be. The doctrines that have prevailed in court take a practical way around the problem by anchoring the claim in children and young adults who exist now and will live through the relevant decades.

The fourth objection comes from within progressive scholarship. Humphreys (2022) contends that talk of future generations displaces attention from those already suffering climate harm, most of them in poorer countries, and offers wealthy states a way of expressing concern without redistribution. Wewerinke-Singh et al. (2023) reply that intergenerational and intragenerational justice are complements, and that many of the communities at issue themselves frame their claims in terms of ancestors and descendants. The exchange has made clear that the concept carries political risks as well as legal promise.

Three areas call for further work. Remedies are the first. Declaratory relief and orders to revise targets are now familiar, but there is little analysis of how courts supervise compliance over the long periods involved or of what follows when a state misses a judicially confirmed target. The second is the position of claimants beyond the forum state. Neubauer admitted complainants from Bangladesh and Nepal without granting them the same protection, the European Court declared Duarte Agostinho inadmissible against all but the home state on jurisdictional grounds, and the Committee on the Rights of the Child in Sacchi v Argentina accepted a broader view of jurisdiction before rejecting the communication for failure to exhaust domestic remedies. Intergenerational equity that stops at the border is an incomplete idea.

The third area is the effect of the advisory opinions delivered by international courts. The International Court of Justice, in its 2025 opinion on the obligations of states in respect of climate change, treated intergenerational equity as a consideration relevant to the interpretation of those obligations, and the Inter-American Court of Human Rights has addressed the climate emergency in an advisory opinion of its own. How far domestic courts will draw on these pronouncements, and whether they will harden a principle that treaty practice left soft, is a question for the next phase of research. Comparative work on legislative and institutional alternatives, such as commissioners for future generations, would also help to show what litigation can and cannot be expected to deliver.

Intergenerational equity has become justiciable by being made concrete. The decisions that have changed state policy did not rest on a general right of the unborn. They rested on the finite quantity of emissions compatible with agreed temperature limits and on the recognition that what one cohort uses is unavailable to the next. Seen in that light the German doctrine of intertemporal freedom and the Strasbourg language of burden-sharing are versions of one insight, and the public trust expresses it in the idiom of property. The literature is right to press on the limits of the idea, especially its territorial confinement and its uneasy relation to present inequality. Within those limits it has given courts a principled reason to insist that climate targets be set early, specified in advance and backed by law.

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