Right before the holiday weekend, the InterAmerican Court of Human Rights (IACtHR), the Americas' highest human rights court, released a landmark advisory opinion (AO) establishing the human right to a healthy climate.

This powerful statement of law and principle is part of a growing wave of international legal action on climate change, following last year's AO from the International Tribunal for the Law of the Sea and ahead of a highly anticipated opinion by the International Court of Justice. A similar petition is currently under consideration by the African Court on Human and People's Rights.

The Inter-American Court of Human Rights undertook an unprecedented effort to hear and understand the human rights dimensions of the climate emergency in preparation for its forthcoming Advisory Opinion on state obligations. The Court held three public hearings over seven days in Bridgetown, Barbados, and in Brasília and Manaus, Brazil, where 185 delegations offering testimony including States, international organizations, academic institutions, civil society groups, Indigenous peoples, Afro-descendants and rural communities, and youth.

I was lucky to be part of that powerful process, presenting before the Court on behalf of a coalition of scientists and lawyers, where we emphasized the critical role of corporate accountability in addressing climate change. Being in the room was a reminder of what's at stake and how urgently the law must rise to meet this moment. That's why I'm excited to walk through why this advisory opinion matters, share key take aways, and explore what it means for climate litigation and international negotiations moving forward.

Advisory opinions interpret international law

Unlike a trial or ruling in a specific case, AOs provide a court's interpretation of binding international law in response to a question from an agency or government. In this instance, the governments of Chile and Colombia requested this AO in early 2023.

As I wrote in a blog ahead of our oral intervention to the court, past opinions from these international bodies have helped to shape debate and international law around key issues like the human right to the environment (IACtHR Advisory Opinion 2018) and the use of nuclear weapons in armed conflict (ICJ Advisory Opinion 1996). The latter opinion contributed to the development of the Treaty on the Prohibition of Nuclear Weapons. While the outcome of these climate focused advisory opinions will unfold over the next several years, they have the potential to similarly shape international law and policy.

5 key ways this opinion advances climate justice and accountability

This opinion provides important legal context and reasoning for the protection of a range of climate-related rights and outlines key obligations for governments. These range from protecting environmental defenders and prioritizing intergenerational equity to mitigating against further climate disruption and adapting to the known hazards that climate change presents.

While I could write an entire blog series unpacking all 200+ pages of the opinion, the 5 most important aspects of the decision for advancing justice and accountability are:

1. Establishes the right to a healthy climate-The opinion concluded that the human right to a healthy climate is an extension of the established human right to a healthy environment. It recognized both individual dimensions, such as threats to life and health, and collective ones, including impacts on future generations and on ecosystems. This legal recognition reinforces decades of scientific consensus that climate change threatens basic human rights.
   
2. States must regulate high-emitting companies-The Court clearly stated that certain sectors and industries, namely the fossil fuel industry and agribusinesses have played an outsized role in driving climate change, and as a result, must work toward reporting and reducing their GHG emissions. The opinion included the key fact that 71% of greenhouse gas emissions between 1988 and 2017 could be traced to just 90 companies, the Carbon Majors. Along these same lines, the Court specified that certain business have greater responsibilities due to their cumulative, historical contributions. The opinion nods to the polluter pays principle and names "contributions to just transition plans and strategies, investment in education, adaptation measures, or addressing loss and damage, among others" as examples of obligations that high polluting companies could undertake. The obligations outlined in the opinion may strengthen current and future litigation seeking accountability for both states and corporate actors.
   
3. States must act to prevent disinformation-The Court acknowledged the role of disinformation, the deliberate spreading of false or misleading information, in obstructing climate action. It emphasized that states have an obligation to provide the public with reliable, science-based information that is free from conflicts of interest. This includes preventing greenwashing and ensuring that climate-related data and communications are evidence-based. This strikes at the heart of a long-standing strategy used by fossil fuel companies to delay climate action, obscure their own involvement in driving climate change, and mislead consumers about the climate impacts of their products.
   
4. Communities have the right to science and best available knowledge-The court explicitly stated that communities and individuals have a right to science, meaning a right to accurate, transparent and complete information about drivers, impacts, and solutions to the climate crisis. The opinion took an expansive perspective on the right to science and broadened its scope to 'best available knowledge' - which goes beyond just western science and includes traditional knowledge and Indigenous knowledge, which can offer key insights particularly for groups that are the most vulnerable to climate change. The Court cited the IPCC as an authoritative source and emphasized the role of knowledge in empowering communities to act.
   
5. States must protect environmental defenders-Latin America and the Caribbean are particularly dangerous places for defenders of human rights and the environment. In 2023, murders of environmental defenders in Latin America represented 85% of such killings globally. This stark reality is the backdrop for States' 'special duty of protection' obligation as described in the Court's opinion -one that guarantees the human rights of environmental protectors and prohibits states from creating obstacles or limitations on their activities.
   

What does this mean for climate litigation?

This opinion follows a series of legal wins for corporate accountability and climate justice, moving us deeper into an era of climate accountability.

From the perspective of governments, last year's advisory opinion from the International Tribunal for the Law of the Sea defined greenhouse gas emissions as marine pollutants and concluded that states have an obligation to prevent, reduce and control that pollution. In the corporate accountability sphere, a court in Hamburg, Germany recently affirmed that major polluters, like RWE, one of Germany's largest electricity producers, can be held liable for their contributions of heat trapping gases to the atmosphere and the climate impacts that follow from that pollution.

This opinion goes beyond previous rulings by establishing the human right to a healthy climate, an important legal development that could support future efforts to hold both governments and corporations accountable.

The official English translation will be released on Friday July 11^th. Until then, the Spanish summary and full text of the opinion are available here.

On the heels of this decision, the International Court of Justice announced that it will release its climate-focused advisory opinion in roughly two weeks on July 23^rd. Together, these opinions could reshape the climate litigation landscape internationally and highlight the importance of justice and equity in addressing the climate crisis.

This is just the beginning of unpacking what this opinion means. What's clear already, though, is that this opinion raises the bar. It gives advocates, communities, and courts powerful new tools and language to push for accountability and protect human rights in the face of climate breakdown. As this legal reasoning makes its way into litigation, legislation, and international negotiations, it has the potential to reshape how the law responds to the climate crisis and to move us closer to a future grounded in justice, equity, and responsibility.

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UCS Lead Scientist L. Delta Merner contributed to this blog