Climate Change and the Responsibility of States for Private Actors: Insights from Advisory Proceedings
By Lizbeth Espinosa Macías*
Introduction
The advisory proceedings currently before the International Court of Justice (ICJ) and the Inter-American Court of Human Rights (IACtHR), along with the recently delivered advisory opinion by the International Tribunal for the Law of the Sea (ITLOS), represent a historic moment in the development of international climate law. These tribunals have been called upon to clarify the scope of States’ obligations in the context of climate change.
This post explores the positions of both the international and regional tribunals involved in the advisory proceedings, as well as those of participating States, regarding the extent to which States may be held responsible for the conduct of corporations. Towards the end, special attention will be given to the Latin American context and the role of the IACtHR in advancing this critical area of law.
Background
According to The Carbon Majors Database, over 50% of fossil fuel and cement CO2 emissions since the start of the Industrial Revolution in 1751 can be traced to just 78 corporate and State producing entities. Moreover, from 2016 to 2022— seven years after the Paris Agreement— 58% of investor-owned and state-owned companies tracked by Carbon Majors increased emissions compared with the same period before the Paris Agreement. Many of those companies have been consistently forwarded unsupportive positions on climate-related policies.
These numbers highlight the importance of holding corporate actors accountable for their significant contribution to climate change. While private law tools— such as contractual obligations, shareholder duties, and corporate governance mechanisms— can influence corporate behavior, they are insufficient when implemented in isolation. Without a robust regulatory framework that enforces sustainable practice as legal duties, such tools lack the necessary reach and consistency to drive systemic change.
This underscores the critical role of States in shaping and enforcing policies that effectively regulate corporate conduct. Under this context, questions arise about the extent to which States themselves are responsible under international law for enabling or failing to prevent harmful activities from private actors.
State responsibility
In international law, State responsibility refers to the accountability of States when they breach their international legal obligations. The Articles on the Responsibility of States for Internationally Wrongful Acts (ARSIWA), adopted by the International Law Commission in 2001, provide the foundational framework for determining when such responsibility arises. Under Articles 1 and 2 of ARSIWA, international responsibility arises when a State breaches an international obligation through conduct—either an act or omission—that is legally attributable to it.
As a general rule, the conduct of private persons or entities is not attributable to the State under international law (see more in commentary 1 of article 8 of ARSIWA). Nevertheless, there are several exceptions where a direct connection between the private actor and the State justifies attribution— such as when private actors exercise elements of governmental authority (see more in article 5 of ARSIWA), act under the instructions or control of the State (see more in article 8 of ARSIWA), or when the State acknowledges and adopts their conduct as their own (see more in article 11 of ARSIWA).
Still, beyond those specific scenarios, even when the harmful conduct per se is not directly attributable to the State, responsibility may arise from the State’s own failure to take necessary measures to prevent it (see more in commentary 4 of Chapter II of ARSIWA).
The ongoing advisory proceedings, along with the advisory opinion already delivered by ITLOS, provide valuable insight into how international judicial bodies— and the States participating in these processes— assess this dimension of responsibility in the specific context of climate change.
ITLOS
In its Advisory Opinion rendered on 21 May 2024, ITLOS reaffirmed that a State cannot be held internationally responsible for pollution caused by private actors solely on the basis that such pollution occurred. However, it emphasized that States are bound by an obligation of due diligence— an obligation that becomes particularly relevant when environmentally harmful activities are carried out by private entities (see para. 236 of the Advisory Opinion).
According to the Tribunal, the obligation of due diligence requires States to set a national legal framework— including legislation, administrative procedures and enforcement mechanisms— capable of regulating the activities that may cause environmental harm. This obligation also entails exercising adequate vigilance to ensure that the system operates efficiently and serves its intended objective (see para. 235).
Moreover, the Tribunal clarified that such obligation of due diligence is an obligation of conduct, not result— requiring States to take necessary preventive measures but not to guarantee the absence of harm (see para. 233). [It is important to clarify that this refers specifically to the obligations of States— not to those of corporations, whose responsibilities to mitigate climate change follow different legal standards].
Importantly, the Tribunal addressed that the standard of due diligence varies depending on the particular circumstances. These factors include scientific and technological advancements, applicable international standards, the severity of potential harm, and the urgency of the situation. As those factors evolve, the standard of due diligence may also adapt. The Tribunal further emphasized that higher-risk activities demand a correspondingly stricter standard of due diligence (see para. 239).
In this regard, it is crucial to note that the Tribunal recognized the precautionary approach as “an integral part of the general obligation of due diligence” (see para. 242). This comprises that the absence of conclusive scientific evidence does not absolve States from their obligation to take necessary preventive measures against environmental harm. Such conclusion is especially significant in current debates over the scope of the precautionary approach, as illustrated by the recent appeal of Milieudefensie et al v Royal Dutch Shell (see WYCJ’s blog for more).
ICJ
While the ICJ has not yet delivered its Advisory Opinion, it has previously addressed the duties of States in relation to corporate activities. In the Pulp Mills judgement, the Court held that the obligation of due diligence involves not only adopting appropriate rules and measures, but also ensuring their effective enforcement. This includes exercising administrative control and maintaining a level of vigilance over both public and private operators— monitoring the activities they carry out (see more in para. 197).
In line with this decision and the ITLOS Advisory Opinion, several States participating in the ICJ advisory proceedings reinforced the idea that due diligence is a core obligation of States in addressing climate change— particularly when it comes to regulating private actors. Some even pushed the conversation further.
For instance, Antigua and Barbuda emphasized that under the duty to prevent harm, States engaged in fossil fuel production must consider the full scope of emissions generated throughout the entire value chain, regardless of where the fuels are ultimately burned (see para. 12-18 of Responses of Antigua and Barbuda to questions posed by Judges Cleveland, Tladi, Aurescu and Charlesworth).
Tonga acknowledged that due diligence also applies when environmental harm threatens the right to life from sources not directly attributable to the State (see para. 247 of Tonga’s written statement).
Colombia proposed that the standard of due diligence should be the primary lens through which the customary international obligation of environmental protection must be assessed. They further argued that the obligation of due diligence requires the identification and evaluation of the significant risk of an activity at the earliest possible stage in a decision-making process and, moreover, emphasized the use of the precautionary principle as a tool for ambitious climate action. Their submissions also linked due diligence with the principles of good faith, precaution, and intergenerational equity (see para. 3.15; 3.21-3.26 of Colombia’s written comments).
Similarly, the Democratic Republic of Congo and Tuvalu stressed that State responsibility extends to violations of international obligations arising out of GHG emissions generated by non-State actors. They argued that it is not enough for a State to claim that harm was caused by private entities in order to escape or lessen its responsibility (see para. 180-190 of the Democratic Republic of Congo’s written comments). Tuvalu further recalled the ICJ’s judgment in Armed Activities on the Territory of the Congo, where the Court had already determined that a State could be held responsible for failing to exercise their duty of vigilance in preventing harm caused by private actors (see para. 115-117 of Tuvalu’s written statement).
Conversely, some States adopted more limited positions. The United Kingdom, for instance, made no reference to due diligence, precaution, or State obligations relating to corporate activities. Switzerland acknowledged due diligence as part of the general duty of prevention, but offered no further development beyond what the ICJ had already recognized in Pulp Mills. Saudi Arabia went even further, asserting that climate treaties do not aim to establish liability and that acts by private entities do not trigger State responsibility unless directly controlled by the State (see page 75 of Saudi Arabia’s written comments).
These diverging submissions illustrate the significance of the ICJ’s forthcoming Advisory Opinion, which may serve to clarify how States must act to control the climate-related impacts of corporate conduct.
IACtHR**
The Inter-American System already holds an important precedent. In Community of La Oroya v. Peru, the IACtHR recognized that States have a duty to regulate, supervise, and monitor hazardous activities that represent significant risks to the life and personal integrity of individuals under their jurisdiction. While the Court clarified that States are not automatically responsible for all human rights violations committed by private actors, it emphasized that international responsibility may arise when States fail to prevent foreseeable risks they are aware of, and where they have reasonable means to act (see para. 156).
Moreover, the Court underscored that, in line with the principle of prevention, States must take all necessary measures to avoid significant environmental damage, including regulating and overseeing activities that may be harmful. This duty, grounded in a due diligence standard, extends to private entities whose actions could present environmental risks (see para. 157).
Under these arguments, the Court held Peru internationally responsible for environmental harm caused by a private company, establishing a clear precedent: States may incur international responsibility when they fail to regulate or control private actors whose activities result in human rights violations related to environmental degradation (see para. 176).
The 2023 judgment crystallizes the IACtHR’s earlier reasoning in the Advisory Opinion OC-23/17, where the Court affirmed that environmental protection is essential to the enjoyment of rights such as life, health, and access to water. In that opinion, the Court had already recognized that States must take preventive measures against environmental harm caused by third parties— including corporations (see para. 108-111).
In fact, the Inter-American Court has been especially proactive among international tribunals in shaping jurisprudence on corporate accountability in human rights matters. In Kaliña and Lokono Peoples v. Suriname (2015), Lemoth Morris et al. v. Honduras (2021), and Vera Rojas et al. v. Chile (2021), the Court explicitly referred to the United Nations Guiding Principles on Business and Human Rights as a relevant interpretive tool to analyze the acts of corporations in each particular case and evaluate consequent State responsibility— despite their non-binding nature (see more in the article "The UN Guiding Principles on Business and Human Rights in the Jurisprudence of the Inter-American Court of Human Rights.").
This early and progressive development within the Inter-American system is not coincidental. It reflects the particular context of Latin America—a region historically marked by extractive industries, foreign investment, and the exploitation of cheap labor (see more in the following publications regarding child labor, extractive industries and their impact in Latin America). As a consequence, the IACtHR’s jurisprudence acknowledges that the protection of human rights cannot rest solely on State action. Rather, it requires the active participation and accountability of corporations, whose activities hold environmental and social outcomes. This understanding was echoed in several submissions of the advisory proceeding.
For instance, Mexico reaffirmed that States must regulate and sanction private entities whose activities may cause environmental harm, specially when such harm affects children and teenagers, who are entitled to special protection (see more in para. 143 of Mexico’s written observations). Furthermore, Mexico emphasized the obligation of due diligence, not only in protecting the environment, but also in safeguarding environmental defenders, acknowledging the role of private actors in endangering their lives—an issue of particular relevance in Latin America and directly addressed by the Escazú Agreement (see more in para. 273-279).
Similarly, Costa Rica recognized that national courts have a responsibility to assign liability and require compensation from those accelerating climate change, including corporations. It stressed the importance of having judicial processes that allow judges to apply relevant environmental liability laws to companies (see more in page 7 of Costa Rica’s submission). Vanuatu echoed this, affirming States’ duty to ensure corporate accountability—civil, criminal, or administrative—alongside full environmental restoration as part of comprehensive reparations (see more in para. 100 of Vanuatu’s written opinion).
Chile also highlighted the importance of involving businesses in strategies to address climate-related human rights impacts, referencing their responsibilities under the UN Guiding Principles on Business and Human Rights (see more in pages 20, 34-35 of Chile’s written observations).
What comes next for climate accountability?
While advisory opinions do not carry binding force strictu sensu, they play a crucial role in clarifying legal standards, harmonizing interpretations, and nurturing both domestic and international jurisprudence, as they represent authoritative interpretations of existing binding law.
The Advisory Opinion delivered by ITLOS in May 2024 exemplifies this function. The Advisory Opinion has already served as a reference point in the advisory proceedings before the ICJ, cited by several States as indicative of emerging consensus on due diligence obligations.
For younger generations, these developments carry particular weight, as they shape the legal frameworks that will define the future of climate justice. Advisory opinions equip litigants, judges, and advocates with arguments rooted in international law—serving as tools to push for stronger accountability in domestic contexts. For instance, in the ongoing appeal of Milieudefensie et al. v. Royal Dutch Shell, an international tribunal’s opinion on the scope of the precautionary approach could provide valuable guidance on the judicial measures the State must adopt to effectively regulate corporate actors and comply with its international legal obligations.
Lastly, the role of the Inter-American Court of Human Rights is especially relevant in these proceedings. There is a high bar for its upcoming Advisory Opinion, expected on July 3rd. It will be particularly insightful to see whether the IACtHR addresses how States’ due diligence obligations may extend to protecting environmental defenders from damage caused by private actors.
Such recognition would determine that State responsibility includes the duty to prevent, regulate, and sanction corporate conduct that endangers those who advocate for environmental protection. Such a strong and progressive interpretation would not only advance corporate accountability, but also reaffirm the Inter-American System’s leadership in shaping climate and human rights law in Latin America and beyond.
*Lizbeth Espinosa Macías is a law student in her final year at Universidad Panamericana, Campus Aguascalientes (Mexico). She is particularly interested in the intersection between international law, human rights, and corporate accountability. Lizbeth currently works in the environmental law practice of a firm specializing in advising corporations on regulatory compliance and sustainability-related legal matters.
**This blog post was written and approved before the IACtHR advisory opinion 32/25 on the climate emergency and human rights was issued.
DISCLAIMER: The views expressed in the symposium’s blog posts are those of the author and do not represent the views of WYCJ. Furthermore, university chapters were prepared, edited, and approved by the respective universities; WYCJ cannot guarantee the level of scientific and legal inquiry, nor the content of blog posts.