In 2025, two of the world’s most prominent international courts, the International Court of Justice (ICJ) and the Inter-American Court of Human Rights (IACtHR), although on opposite sides of the globe, delivered similar Advisory Opinions regarding the climate crisis.
These two courts, independently, established binding frameworks that require States to take urgent, human rights-focused action to combat the climate emergency.
Although the ICJ and IACtHR approached the issue from different legal systems, their central arguments were the same: climate inaction is no longer only a policy failure, but a violation of international legal obligations. The climate emergency constitutes a threat to global human rights and requires combative action for the benefit of present and future generations.
Both courts’ legal opinions may mark a turning point and set a new legal standard for all States. This focus on human rights could establish the next phase of climate international policy and law. The recognition of the right to a healthy environment could serve as a powerful new legal tool, enforcing environmental quality and climate-related measures as a human right. Additionally, the call for differentiated and proactive protective measures for vulnerable communities might enhance pressure on States to handle certain groups with specialized care, as some individuals are more vulnerable than others. Also, fighting misinformation could be a helpful tool to unite public information and set a precedent for the public to have complete, accurate, and accessible information.
This Expert Column will explore the two courts’ decisions and point out key aspects where they have differentiated strengths and applications regarding the climate emergency.
What Is the Climate Crisis?
Firstly, the climate crisis is the change in the state of the climate that persists for an extended period of time, threatening the very well-being of human existence.
This crisis stems from both natural and anthropogenic (human) factors, the latter being the more prominent cause. Anthropogenic factors include the combustion of fossil fuels, land use changes (deforestation, agriculture, etc.), and industrial processes.
The consequences of the climate crisis pose an urgent threat to natural ecosystems and human populations across the globe. Climate change not only depletes the environment but also adversely affects human life and human health, putting populations at risk of illness, displacement, emotional anguish, and even death. These harsh results impact vulnerable communities and individuals disproportionately, as highlighted by both the ICJ and IACtHR.
The Requests
The universality of these decisions is demonstrated by how they were requested and the questions posed to the courts. ICJ’s opinion, for one, is derived from a broader body of international law, while the IACtHR’s is rooted primarily in a regional human rights framework.
The ICJ’s opinion was requested by the United Nations General Assembly. The ICJ’s analysis of the request comprehensively wove together climate treaties, customary international law, the law of the sea, and human rights law.
On the other hand, the IACtHR’s opinion was a joint request from the republics of Chile and Colombia, grounded in specifying the scope of the regional State’s obligations to respect and guarantee the rights of humans and the environment threatened by the climate emergency.
The Final Opinions
The ICJ recognized the consequences of climate change as severe and an urgent and existential threat. Beyond the human rights focus, the Court founded its decision on a broad scope of public international law sources, finding that climate inaction constitutes a violation of international legal frameworks. This decision was rooted in public international law sources such as the UN Charter, the UN Convention on the Law of the Sea (UNCLOS), and the Vienna Convention for the Protection of the Ozone Layer. Under international human rights law, the ICJ affirmed that States have an obligation to respect and ensure the enjoyment of human rights. To do this, they must ensure to protect the climate system due to the court’s conclusion that the human right to a clean, healthy, and sustainable environment is essential for the enjoyment of other human rights.
Further, the court acknowledged that the duty to prevent significant harm to the environment is an obligation to act with due diligence. States must practice mitigation (using the best available science) as a binding obligation under the climate change treaties. If there is failure to take proper combative action to protect the climate, then it is considered an internationally wrongful act and can result in legal consequences. Such consequences include cessation, guarantees of non-repetition, and full reparation (restitution, compensation, and satisfaction).
The IACtHR’s opinion, on the other hand, was very similar but with specialty applications. The court unanimously declared the current situation a climate emergency, characterized by rapid temperature increase due to human activities. It recognized the autonomous right to a healthy environment and an independent right to a healthy climate, acting as an aspect of the right to a healthy environment. These obligations derive from substantive rights, procedural rights, and the principle of equality/non-discrimination. The states must act with enhanced due diligence and must protect the global climate by mitigating Green House Gas (GHG) emissions. Mitigation targets must be backed by the best available science and include measures to decrease GHG production by looking into fossil fuels, agriculture, and deforestation. States must ensure individuals have access to judicial remedies for human rights violations. Legal consequences must be all-encompassing, including measures to restore ecosystems and enhance resilience.
On Vulnerable Groups
A notable factor that both courts considered is the disproportionate effects the climate crisis has on vulnerable groups. These vulnerable groups include children, the elderly, persons with disabilities, environmental defenders, indigenous/tribal peoples, etc.
The ICJ acknowledged that climate change may “significantly impair” the enjoyment of human rights. It declared that States have obligations to respect and ensure enjoyment by taking necessary measures to protect the climate system.
On the other hand, the IACtHR took a more serious stance by unanimously finding a higher duty to protect and adopt measures specific to the needs of vulnerable groups. This court made these groups central to the opinion, noting that people in multidimensional poverty are often the first and most seriously impacted.
In all, the IACtHR’s opinion was far more detailed and specific when discussing vulnerable groups, establishing a higher duty and differentiative protection measures, while the ICJ’s opinion was much broader.
On Misinformation
Misinformation is a powerful threat to the advancement of environmental protection, often with people weaponizing the topic of climate change in general. Thus, the spread of accessible, accurate information is vital to rebuilding public trust and ensuring human rights protection.
The ICJ had no explicit mention of protecting against misinformation. Their broader mandate did not lead to them specifically addressing this important issue.
The IACtHR, however, established a duty for States to adopt measures to counter disinformation. The Court recognized that the spread of false or misleading information could diminish public trust, decrease effective climate action, and halt the full exercise of human rights. Therefore, States have an obligation to provide active transparency, including the adoption of measures to counter disinformation.
Looking Forward
The climate crisis is posing more and more of a threat to populations across the globe, and especially a risk to their human rights. Enacting legal frameworks could be an effective start to shift States towards accountability and sustainability. These Advisory Opinions from the ICJ and IACtHR join an array of other decisions with similar content, most notably the International Tribunal for the Law of the Sea (ITLOS) and the European Court of Human Rights (ECtHR), which clearly indicate that international obligations on climate change exist as a matter of law. These decisions indicate that States are legally bound to protect the climate system for present and future generations.
In all, these opinions could strengthen the future of climate litigation as they clarify state responsibility, empower the affected, and target some causes of climate change, such as fossil fuels. These opinions will hopefully encourage other bodies to follow similar recommendations in order to work towards a healthier and more just planet.
DISCLAIMER: The views and opinions expressed in this piece are those of the author and do not reflect the views of the O’Neill Institute.
