- September 22, 2025
In July 2025, the Inter-American Court of Human Rights issued its long-awaited Advisory Opinion on Human Rights and the Climate Emergency. The Court’s 234-page Opinion, supported by more than 1,000 footnotes, provides a master class in climate science, policy, and law. For the first time, the Court treated the climate crisis not merely as an issue of environmental protection, but as a foundational challenge for the entire human rights system of the Americas. In addition to declaring the right to a healthy climate, it lays out detailed legal obligations for States and private actors to protect the climate system.
The Court emphasizes the risks of crossing tipping points such as the collapse of the Atlantic Meridional Overturning Circulation and highlights the Montreal Protocol and Kigali Amendment as a successful global governance model of rapid mitigation, particularly in phasing down super climate pollutant hydrofluorocarbons (HFCs). The Court also underscores the imperative of addressing methane to slow the rate of warming in the near term.
The Advisory Opinion on the Climate Emergency stands alongside two other recent opinions—one issued in July 2025 by the International Court of Justice and another in 2024 by the International Tribunal for the Law of the Sea—that converge on a single point: climate change constitutes an urgent existential threat requiring binding, enforceable action by governments and corporations under their control. Collectively, this trifecta of opinions reflects a shared understanding by the world’s most esteemed jurists that climate change presents an existential risk, and judicial engagement is essential to address this risk. Significantly, every international court asked about the responsibilities of governments in the climate emergency has found them to be mandatory, setting clear standards for judges and advocates.
Among the many milestones of the Advisory Opinion on the Climate Emergency, we note three: the central role of climate science in legal reasoning, the mandatory obligation to include climate considerations in environmental impact assessments as an essential accountability mechanism, and the articulation of an enhanced due diligence standard applicable to both States and corporations. Taken together, these elements create a transformative framework that integrates science, governance, and human rights protection in unprecedented ways.
This essay examines the significance of these shifts and the profound jurisprudential turn where science is no longer merely background context but a binding standard of conduct; where due diligence obligations expand to meet the gravity and urgency of the climate emergency, including through environmental and climate impact assessments.
Science as Legal Foundation
A key contribution of the Advisory Opinion on the Climate Emergency is its integration of climate science into the core of legal reasoning. The Court repeatedly cites the findings of the Intergovernmental Panel on Climate Change (IPCC), particularly the dangers of passing the 1.5°C guardrail and the risks of crossing planetary tipping points. These findings are presented as binding benchmarks that shape the scope of States’ obligations under the American Convention on Human Rights.
As the Court explains, “[States] must take all necessary measures to reduce … risks derived … from the degradation of the global climate system.” Because these risks are scientifically measurable, the requirement to follow the “best available science” becomes a legal standard. Climate science thus plays a normative role, defining the content of due diligence, the adequacy of adaptation plans, and the effectiveness of mitigation measures. This approach represents a powerful convergence between law and science. By grounding legal duties in climate science, the Court ensures that the human rights system responds to the crisis at the pace and scale required.
1.5°C and Tipping Points as Human Rights Thresholds
One of the most consequential findings is the Court’s legal anchoring of the 1.5°C limit and climate tipping points as human rights thresholds. The Advisory Opinion holds that the 1.5°C guardrail is not safe for most of the world’s people and should be considered a minimum starting point, not an end goal. The Inter-American Court recognizes that exceeding these thresholds would result in severe harm to all substantive rights, including the right to life, personal integrity, and health, among others.
The Court shifts the debate from what is politically negotiable to what is legally non-negotiable. Preserving the 1.5°C threshold is no longer merely a policy aspiration—it is a legal duty to protect human dignity and prevent existential harm. The same is true for tipping points in ecosystems such as the Amazon rainforest or polar ice systems, where, as the Court recognizes, the continuing increase in the temperature increases the probability of exceeding them. Crossing them would trigger cascading effects that no adaptation measures could fully address.
The Strategic Importance of Short-Lived Climate Pollutants (SLCPs)
One of the most sophisticated elements of the Advisory Opinion is its explicit recognition of short-lived climate pollutants (SLCPs) such as methane, black carbon, and hydrofluorocarbons (HFCs). These pollutants are far more potent than CO₂ in the short term but persist in the atmosphere for a much shorter period. Reducing them delivers rapid climate and health benefits, particularly for vulnerable communities exposed to air pollution.
By recognizing reducing SLCPs as a legal priority, the Court elevates fast mitigation from a technical option to a human rights obligation. It highlights that SLCP reductions is crucial to keep the 1.5°C target within reach and simultaneously improve air quality, food security, and public health. This legal framing resonates with successful multilateral experiences like the Montreal Protocol, recognized as a “benchmark for international cooperation” by the Court, and its Kigali Amendment, which have already proven the feasibility of rapid pollutant phaseouts. By embedding SLCP mitigation in human rights law, the Court gives advocates and policymakers a powerful tool to demand accelerated action.
Enhanced Due Diligence
The Court established an enhanced due diligence standard for States to comply with their duty to prevent climate harm and protect human rights, given the extreme gravity and urgency of climate impacts. In line with the International Tribunal for the Law of the Sea Advisory Opinion, it emphasizes that due diligence is a variable standard, dependent on the level of scientific and technological knowledge available, as well as the risks and urgency of potential damage. Similarly, the International Court of Justice has also characterized due diligence as a variable obligation—one that must adjust to evolving scientific knowledge, state capacity, and the urgency of the risks at stake.
In practical terms, this standard requires comprehensive identification and assessment of risks, coupled with proactive and ambitious preventive measures to avoid the worst climate scenarios. It demands that States use the best available science in the design and implementation of climate actions, while integrating a human rights perspective into policies and measures so as not to create or deepen vulnerabilities. Enhanced due diligence also entails permanent monitoring of adopted measures, democratic participation, transparency, accountability, and strict compliance with procedural rights such as access to information and justice. The Court further stresses the need for effective regulation and supervision of corporate due diligence and calls for enhanced international cooperation in areas such as technology transfer, financing, and capacity building.
The Obligation to Conduct Climate Impact Assessments
The Court makes clear that enhanced due diligence requires States to carry out a thorough, science-based assessment of any activity that could significantly harm the climate system before granting approval. This means that projects must be evaluated against the best available scientific knowledge, as well as the mitigation strategies and targets the State has already defined. Because many climate impacts are irreversible once they occur, the Court emphasizes the need for a precautionary approach: the strongest possible safeguards must be adopted to avoid long-term damage to the climate system. The Court elevates climate impact assessments into a binding obligation and central tool for ensuring that State decisions align with human rights and climate protection.
The Advisory Opinion explicitly places environmental and climate impact assessments at the heart of States’ obligations to prevent human rights violations in the context of the climate emergency. Traditionally, environmental impact assessments (EIAs) functioned as procedural safeguards to identify and mitigate environmental harm before projects move forward. In its Advisory Opinion, the Court expands and sharpens this tool by explicitly requiring EIAs to include a climate impact assessment whenever a project poses a risk of generating significant greenhouse gas emissions.
This obligation applies in particular to sectors responsible for emitting super climate pollutants, that is, methane, black carbon and HFCs. These are short-lived climate pollutants with disproportionate impacts on near-term warming, meaning that, under the Court’s due diligence standard, any sector or project that emits at least one of these super pollutants must undergo a climate impact assessment.
While the Court recognizes that States retain discretion to determine which projects and activities must undergo climate impact assessments, it makes clear that this discretion is tightly bounded by the obligation to rely on the best available science. In other words, States cannot arbitrarily exempt high-emitting sectors from scrutiny: science dictates the scope of the duty.
The Court reinforces this point by going further in paragraph 353, where it explicitly identifies a baseline list of sectors “exploration, extraction, transportation and processing of fossil fuels, cement manufacture, agro-industrial activities, and other inputs used in those activities” that must, at a minimum, be supervised, monitored, and subjected to climate impact assessments. By combining the scientific standard with this explicit enumeration, the Court significantly narrows State discretion and establishes a mandatory framework in which activities most responsible for greenhouse gasses, including SLCPs emissions, cannot escape rigorous climate evaluation.
In other words, States cannot treat climate change as an incidental side effect of environmental harm; they must directly measure and evaluate how proposed projects contribute to the degradation of the global climate system. This makes climate considerations a mandatory, differentiated component of project approval processes and positions EIAs as a frontline mechanism for climate accountability.
From paragraphs 353 to 363, the Court insists on both the procedural rigor and substantive depth of EIAs. EIAs must be carried out by technically qualified and independent entities, cover cumulative and long-term impacts, and incorporate the participation of affected communities, including Indigenous Peoples. They must include clear contingency plans, mitigation measures, and transparent decision-making—ensuring that climate assessments are not box-ticking exercises but real determinants of whether a project proceeds. Importantly, the Court warns against practices such as greenwashing, requiring that States set binding regulations to ensure credibility and accountability. By tying this obligation to the enhanced due diligence standard, the Court underscores that these assessments are not optional good practices but enforceable legal duties.
Failure to conduct or properly regulate climate impact assessments would constitute a breach of States’ human rights obligations under the American Convention.
In practical terms, this requirement strengthens accountability mechanisms at the project level. Infrastructure, energy, and industrial projects will now face a higher threshold of scrutiny, ensuring that their climate impacts are assessed transparently and mitigated effectively. In summary, the Court’s opinion strengthens emerging global standards on enhanced climate due diligence through robust EIAs.
Conclusion
The Advisory Opinion on Human Rights and the Climate Emergency marks a turning point in the jurisprudence of the Inter-American Court of Human Rights. It acknowledges the climate emergency as an existential threat to human rights and provides a framework for States to respond with urgency, ambition, and accountability.
The Opinion transforms climate science into a legal compass. It operationalizes the right to science, elevates the 1.5°C threshold and tipping points into human rights standards, recognizes the centrality of fast action on SLCPs, and expands due diligence obligations to match the gravity of the crisis through upgraded mechanisms such as climate impact assessments. For judges, policymakers, and advocates across the Americas, this is a new jurisprudential roadmap—one that binds law to science and science to human rights.
As the highest authoritative interpretation of binding human rights obligations in the Americas, the Advisory Opinion is legally binding on States under the doctrine of conventionality control. This doctrine, developed by the Inter-American Court, requires all domestic authorities—judicial, legislative, and executive—to act in conformity with the Court’s pronouncements. Where a national law conflicts with the American Convention on Human Rights, judges must set aside the conflicting provision and apply the Convention as interpreted by the Court.
The challenge now is to translate this Advisory Opinion into domestic law, regulatory frameworks, and other concrete actions. Civil society, Indigenous peoples, and communities on the frontlines of the climate emergency will play a decisive role in doing this to hold their governments and corporations accountable.
SIMPOSIO OC 32
LISTADO DE ARTÍCULOS