—Lila García. Adjunct Professor, University of Mar del Plata and LIAS Fellow (2025-2026) Leuphana University; Estefanía Giaccone, PhD Candidate, Assistant Professor, Constitutional Law, University of Buenos Aires; and Laura Clérico, Chair Constitutional Law, University of Buenos Aires. Hon. Prof. Human Rights Law, CHREN-FAU University Erlangen Nurnberg
Introduction
On July 3rd 2025, the Inter-American Court of Human Rights (IACtHR) issued a long-awaited advisory opinion: the AO 32/2025 on the “Climate Emergency and Human Rights”. Through the most participative process ever seen, the Court is firmly taking the lead in this “climate era” of judicial pronouncements. Praised by both climate scholars (“a blueprint” in a “defining moment” for rights-climate action, a historical contribution), activists (“a landmark”), migration scholars (“a transformative moment in international legal doctrine that entails a “fundamental reorientation of the human rights law”) and human rights experts (“a milestone in the global fight for climate justice”; “a bold decision that strides towards a victim-centered and multidimensional approach), the IACtHR closed the gap between climate change and human mobility with human rights. In fact, and within the trilogy of advisory opinions (International Court of Justice and International Tribunal for the Law of the Sea) handed down by international judicial institutions, the IACtHR is the only one in which specific questions relating to climate-induced human mobility have been raised.
On the one hand, the court grounds its reasoning in the internal production of the Inter-American System of Human Rights. It draws on AO 18/03 on the rights of undocumented migrant workers; on AO 23/17 on the human right to the environment; and on AO 21/14 on the rights and guarantees of children in the context of migration and/or in need of international protection. It also builds on the Court’s extensive case law on the human rights of migrants—Ricardo Canese v. Paraguay and Moiwana Community v. Suriname (linking climate-related mobility to the right to freedom of movement and residence under Article 22 ACHR); Valle Jaramillo et al. v. Colombia and Massacre of the Village of Los Josefinos v. Guatemala (highlighting the de facto lack of protection faced by displaced persons in highly vulnerable situations)—as well as on precautionary measures and the IACommHR Resolution No. 2/2024 on human mobility induced by climate change.
On the other, what role did the amici curiae play? By involving the most participative process the Inter-American system ever witnessed (with 263 written observations or “amici curiae” submitted by 613 stakeholders and three large hearings), the Court raises some expectations concerning to the engagement with the amici within its argumentation in the advisory opinion. Yet, were these voices heard? How and to what extent? Do amici curiae merely accompany judicial reasoning, or do they actively shape the standards developed by international human rights courts? The IACtHR itself has explicitly acknowledged the epistemic value of written observations. In her concurring opinion in AO-32/25, Judge Verónica Gómez emphasized the relevance of submissions by indigenous and indigenous women’s organizations, highlighting their contribution to understanding climate justice as inseparable from gender justice and community-based and ecosystem-based care. A similar recognition appears in other recent cases, such as Indigenous Peoples Tagaeri and Taromenane v. Ecuador (2024), where Judge Eduardo Ferrer Mac Gregor Poisot’s concurring opinion explicitly noted the impact of amici curiae on the Court’s reasoning. Last but not least, Judge Verónica Gómez also emphasized that the written contributions and public hearings conducted throughout the development of AO 31/25 provide valuable insights into the human right to care, its challenges, and recommended best practices.
Against this backdrop, this post explores how, and to what degree, the IACtHR relied on amici curiae briefs when constructing standards on climate-related human mobility in AO 32/25. It also assesses whether the Court used the amici’s arguments to consolidate, expand, transform, or restrict its jurisprudence, similarly to other previous analysis on domestic courts (Papini, 2025).
Methodological Approach
Our approach is limited to studying the explicit use, represented by citations, of amici curiae, even if the IACtHR might also rely on other amici without acknowledging it. We apply a methodological framework regarding the explicit use of International Human Rights Law by Latin American Courts (Clérico/Cardinaux, 2025; Serrano, 2021). This methodology was transposed to the text of AO 32/25 to understand the explicit use of amici curiae submissions by the IACtHR. More particularly, our focus is on paragraphs 413 to 434, which address the relation between the climate emergency and human (im/hyper) mobility to develop standards about State obligations towards, in the court’s words,“people mobilised in the context of climate change”, but also (voluntary or involuntary) immobilised and even under risk of facing forced mobilisation.
The methodological framework identifies three intensities of explicit judicial use of amici curiae: (i) Mere reference or passing citation, where the judgment simply acknowledges the amicus curiae without more; (ii) Relevant argument, where the amicus curiae submission is used in support of the Court’s reasoning; (iii) Standard of review (control parameter), where the amicus curiae submission contributes decisively to the construction of the standard of review applied by the court (Clérico/Cardinaux, 2025).
We have also been influenced by scholarship that conceptualizes amici curiae as a democratizing and feminist/gender instrument (Sáenz, Jimena, 2020; Bartlett, 1989). Amici curiae submissions enable civil society organizations, social movements, and international bodies to participate as third parties in cases involving situations that differentially affect people living in structural inequalities. From this perspective, amici curiae facilitate the incorporation of voices and social contexts that courts may not have fully identified during the proceedings, with the aim of challenging biases and stereotypes, thereby opening pathways for transformative changes. Our post makes two key contributions. First, it sheds light on how amici curiae participate in the development of standards concerning the human rights of people on the move in times of climate emergency. Second, it advances ongoing debates on how these amici briefs might be strategically used (e.g. by practitioners, to strategic litigation) to define, restrict, or expand the courts’ standards.
Empirical Findings
With respect to climate-induced mobility, we identify three categories of participants who submitted amici curiae and are explicitly referenced in AO 32/25: i) international organizations, including the UNHCR (United Nations High Commissioner for Refugees), IOM (International Organization for Migrations) and the UN Special Rapporteur on the Human Rights of Internally Displaced Persons; ii) the academic community, represented by the contribution of the “European Professors”; and iii) affected populations, specifically the “Comunidad El Bosque”.
Our analysis of paragraphs 414–434 indicates that the IACtHR relied extensively on amici curiae submitted primarily by international organizations. In terms of the frequency of citations, the IOM and the UN Special Rapporteur are referenced most often, followed by UNHCR, whereas submissions from academic actors and affected populations are cited only once each.
In three cases, amici curiae function as relevant arguments by providing contextual information that reinforces State obligations related to climate mobility. First, the UNHCR’s submission is used to demonstrate that climate-related displacement often extends over prolonged periods, supporting the Court’s conclusion regarding States’ reinforced duties of due diligence. This amicus provides context to the Court. (para. 421). Second, the written observations submitted by the “European Professors” support the Court’s reasoning on the scope and importance of shared responsibility and international and regional cooperation (para. 431), highlighting (in footnote 729) that reference was made to the importance of the international community taking a collective approach to migration flows based on a “good neighbor” approach as part of the international obligation to cooperate at the international and regional levels. Third, the submission made by the UN Special Rapporteur on the Human Rights of Internally Displaced Persons is used to reinforce States’ obligations to guarantee respect for the family unit within human mobilization processes (para. 428).
This role is reflected in the following instances. First, the Court relies on written observations submitted by the IOM to establish an admissibility standard for relocation (para. 429). Second, the Court draws extensively on the submission of the UN Special Rapporteur, holding that relocations should occur only in exceptional circumstances, when they are unavoidable and strictly necessary due to the impossibility of maintaining human settlements in areas exposed to danger and to preserve the life, integrity, and health of the affected populations (para. 429).
Third, the Court relies on the IOM’s written submission to build State obligations, such as the duty to establish adequate legal frameworks governing the planned relocation process in accordance with human rights standards, as well as the right to return voluntarily, and the obligation to provide mechanisms enabling affected persons to recover land, housing, property and other possessions (para. 429). That is to say, the written observation is used to determine the States’ obligation of guarantee and its content.
Fourth, the amicus curiae submission of the UN Special Rapporteur invokes the Sendai framework to reinforce cross-border cooperation. It may be inferred that, by incorporating the Sendai Framework as a foundation for active cooperation among States, the Court consolidates its corpus juris (para. 430). In turn, the IOM’s submission outlines good practices to ensure humanitarian protection for displaced persons, offering concrete guidance for States and illustrating regulatory approaches to the practical implementation of rights, through appropriate migration categories (para. 433).
Regarding the participation of communities, only one amicus is mentioned and it corresponds to observations submitted by Guadalupe Cobos Pacheco, Áurea Sánchez Hernández, Yesenia del Socorro Albino Sánchez on behalf of the Community of El Bosque (Tabasco, Mexico); Our Rights to the Future and a Healthy Environment A.C. (“Our Future”); Conexiones Climáticas campaign and Greenpeace Mexico (para. 417). The Court collected this contribution in the consultative process. This brief is relevant insofar as its mention in the judgment shows that the IACtHR engaged with the voices presented at the hearing, highlighting the real consequences of climate-induced displacement.
Concluding Remarks
The analysis suggests that amici curiae in AO 32/25, at least regarding human mobility, are not merely supplementary materials. Rather, they constitute active and substantive contributions, either as relevant arguments or by providing standards of review to the Court’s reasoning, particularly in an area where legal standards remain underdeveloped. However, the voice of experts, particularly from international organizations, dominated over other voices. On the one hand, we may wonder why the IACtHR selected “big players” to support its arguments and develop its main standards. It is plausible that, amid growing attacks on regional human rights courts, the Court chose to align itself and its reasoning with established international human rights bodies to avoid accusations of unilaterally creating new standards. On the other hand, it seems paradoxical that, amidst the most participatory process in advisory opinions in the history of the IACtHR, there were so few explicit references to interventions by communities, human rights NGOs, and others in this part of AO 32/25. Even so, community perspectives related to climate mobility are not entirely absent. Through indirect references, such as the Special Rapporteur’s declaration following his visit to Lajas Blancas in Honduras, the Court recovered lost voices by incorporating local experiences in a mediated form.
More generally, in the emerging field of climate-related human mobility, amici curiae appear to play a heightened role in shaping the content and scope of State obligations. This raises broader questions for future research: Do written observations expand the scope of protected rights? Do they introduce new interpretive frameworks not previously employed by the Court? Can they serve as a basis for delimiting State power in the context of climate emergency and human mobility? In this sense, amici curiae submissions emerge as more than participatory tools; their authors may become key actors in the construction of evolving human rights standards.
Suggested citation: Lila García, Estefanía Giaccone, and Laura Clérico, Developing Standards on Climate-Related Human Mobility With (a Little) Help of Amici Curiae in the Advisory Opinion 32/2025, Int’l J. Const. L. Blog, Mar. __, 2026, at: http://www.iconnectblog.com/developing-standards-on-climate-related-human-mobility-with-a-little-help-of-amici-curiae-in-the-advisory-opinion-32-2025/