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Spring 2023: Comparative and Global Perspectives

Nonstate Actors in International Environmental Law

Jesse Colin Medlong, Amanda McCaffrey, and Alberto J Corona


  • Explores the developments and challenges presented in international environmental law.
  • Discusses the “state-centricity” of international environmental law.
  • Investigates the role of nonstate actors in virtually every stage of multilateral IEL developments.
Nonstate Actors in International Environmental Law

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Traditionally, states are the sole subjects of international law—the entities regulated by and empowered to define it; all others are merely its objects, bearing its effects without agency to shape it. Today, however, nonstate actors have come to enjoy numerous, significant, and proliferating roles in the development of international law. Industry groups, unions, and civil society organizations, for instance, possess experience and expertise that can contribute to crafting, monitoring, and implementing complex policy frameworks. This trend is nowhere more salient than in international environmental law (IEL). The rise of mere “objects” into the constellation of players on a stage that was built by and for states is among the most consequential developments in international law during the past century. And the world of states has bet that modern IEL can solve some of our most pressing problems. The question, then, is whether and how nonstate actors affect the odds.

Policy makers parse oceans of scientific and economic data to develop global processes for addressing systemic environmental problems that don’t respect borders. Nonstate actors channel public sentiment, information, finance, and expertise into these processes and their mechanisms. And they represent the interests of key constituents and affected populations to inform multilateral approaches to global challenges like climate change, biodiversity loss, and plastic waste, with all the opportunities and pitfalls such approaches entail. For global enterprises, engagement in these processes is a two-way street: Industry buy-in is now seen as important to the success of multilateral environmental agreements, and engagement allows companies to understand and help shape global policy, making engagement a competitive imperative.

Below we explore the evolving role of these nonstate actors in the development of IEL over the last several decades, and we explain where some think it may lead. To that end, we begin with a review of key concepts, and then narrow our focus to the kinds of roles these private actors play in IEL settings, highlighting some prominent examples.

International Environmental Law

IEL comprises the web of international agreements, rules, and norms reflecting states’ (i.e., countries’) interest in the use of shared resources, sustainable development, and environmental conservation. International rules governing the use of shared resources have a centuries-old pedigree. Agreements with such rules were usually small affairs with no more than a handful of signatories. Agreements and norms concerning environmental protection and sustainable development are a more recent phenomenon. This modern genre of IEL has proliferated since the latter half of the 20th century, when developments in scientific research made clear that environmental challenges have global causes and effects requiring coordinated intergovernmental solutions. Such protections may be the central purpose of a far-reaching multilateral agreement or may be relegated to ancillary provisions of bilateral investment treaties or regional trade pacts.

Like other types of public international law, the sources of IEL include formal treaties, which bind parties to express terms; customary international law, which consists of norms so widespread that nearly all states deem them binding even in the absence of a formal instrument; and decisions of international tribunals, which may be binding on the parties to a dispute and may clarify others’ obligations under customary international law or treaties. Nonbinding norms, general principles of law, and the writings of eminent experts also contribute to IEL.

One example of how the primary sources of international law can interact is the evolution of IEL norms around environmental impact assessments (EIAs). A fundamental norm in customary IEL is that each state is responsible for ensuring that activities within its jurisdiction do not cause environmental harm in the territories of other states. See, e.g., Stockholm Declaration on the Human Environment, Principle 21 (1972). Honoring this obligation, of course, requires states to regulate private activities within their borders. In the late 20th century, a related norm developed around a state’s duty to notify another state of adverse effects likely to result from activity within the source state’s territory. This emergent rule, first reflected in a handful of treaties, came to be so widely accepted and observed that it too attained the status of customary international law binding on all states.

A multilateral environmental agreement . . . binds only those states that have agreed to be bound. But it may affect nonparty states or private actors by limiting parties’ rights to engage in certain trade or commercial activities.

The rule took on a new dimension in European countries’ negotiation of the Convention on Environmental Impact Assessment in a Transboundary Context, also known as the Espoo Convention. The Espoo Convention requires each party to conduct an EIA before undertaking any activity likely to cause a significant adverse transboundary effect in the territory of another party. The Espoo Convention was developed under the auspices of the Economic Commission for Europe; it now has 45 parties (but remains essentially a European regional agreement) and entered into force in 1997.

A little over a decade later, in Pulp Mills on the River Uruguay—a case originating from a treaty dispute between Argentina and Uruguay—the International Court of Justice (ICJ) held that customary international law requires a state to conduct an EIA before it implements an industrial project likely to cause significant transboundary harm. Pulp Mills on the River Uruguay (Arg. v. Uru.), Judgment, 2010 I.C.J. 14, ¶¶ 204–205 (Apr. 20). The ICJ’s judgment in the Pulp Mills case binds only Argentina and Uruguay and is not enforceable against some other state that commences a project without an EIA. But because customary international law emerges from state practice and a sense of legal obligation, and because ICJ holdings indicate how the court will rule in similar cases in the future, the judgment in Pulp Mills—and the numerous EIA-related treaty provisions it cites—will accrete to customary IEL on this issue.

Affairs of States

To say that states are the “subjects of international law” is to say that the behavior of states is what international law seeks to regulate. In the most formal sense, international law binds only states, and it must be implemented by and among states—hence international law’s state-centricity.

States have thus far ratified more than 1,300 multilateral environmental agreements, more than 2,200 bilateral environmental agreements, and more than 250 other international environmental agreements (including agreements between governments and private parties). See Ronald B. Mitchell, International Environmental Agreements Database Project, Univ. of Or. (2022). Many—although not all—of these agreements remain in force today.

A multilateral environmental agreement—which may be styled as an agreement, convention, treaty, or protocol, and may consist of multiple related written instruments—binds only those states that have agreed to be bound. But it may affect nonparty states or private actors by limiting, for instance, parties’ rights to engage in certain trade or commercial activities. Multilateral environmental agreements may include only a few parties or have widespread regional or global membership. The venue for negotiations under an existing treaty is generally the conference of its parties, or COP. Thus, the UN Framework Convention on Climate Change (UNFCCC) is implemented through annual meetings of the COP, where the parties negotiate supporting commitments and instruments, some of which may be treaties themselves, like the Kyoto Protocol and the Paris Agreement.

A new treaty may be negotiated under the auspices of an international organization or committee according to agreed rules of procedure. If negotiations produce a final text, participants will adopt the agreement, and authorized state representatives will sign it, expressing that state’s intent to be bound by its terms. A signatory is not legally bound by a treaty, however, until it ratifies or accedes to it—processes governed by the state’s domestic law and the provisions of the treaty itself. In monist states, certain treaties attain the status of domestic law upon ratification, with no need for additional implementing legislation. In many circumstances, however, parties to a treaty may need to adopt or amend domestic laws or regulations or reorganize government institutions to effectively implement the agreement.

The state’s role as the primary author—and editor—of IEL is rooted in twin foundational principles of international law: States are sovereign, and states must honor their agreements. Sovereignty is the principle that a state’s authority over what happens within its borders is limited only by its voluntary agreements and customary law. This principle has been the bedrock of the international legal order for nearly four centuries.

While some read the proliferation of various kinds of treaties as an erosion of state sovereignty signaling greater and more intricate restrictions on what states can do, a core tenet of modern international law is that states’ agreeing to be bound is an exercise of sovereignty, not an abrogation of it. Thus, the Permanent Court of International Justice (the precursor to the ICJ) held “the right of entering into international engagements is an attribute of State sovereignty.” S.S. Wimbledon (U.K. v. Japan), 1923 P.C.I.J. (ser. A) No. 1 (Aug. 17). States serve their own interests through collaboration with other states and private actors. Input from private parties, in turn, informs and refines states’ understanding of their interests, particularly with respect to IEL.

Nonstate Actors—Changing the Subjects?

But states do not operate in a vacuum. IEL may impose indirect obligations on private parties if, for instance, a treaty’s implementation requires the restriction of certain private activities, such as the emissions restrictions in the 1973 International Convention for the Prevention of Pollution from Ships, the 1979 Convention on Long-Range Transboundary Air Pollution, and the 1998 Protocol on Heavy Metals. Treaties may also require certain undertakings that states rely on individuals or even companies to carry out, such as the preliminary work on industrial projects referenced in the Pulp Mills case.

Nonstate stakeholders also facilitate democratic engagement in IEL processes, in line with the long-standing principle that IEL should be guided by public participation. Such participation lends legitimacy to international initiatives and encourages public buy-in. These stakeholders often possess unique insights that can be critical to a well-intended program’s success. Recognition of these practical advantages has, over the past several decades, made private actors—most notably multinational business entities and NGOs—increasingly active in developing, implementing, and enforcing IEL rules and norms.

These efforts culminated in the formal inclusion of nine “Major Groups” in Agenda 21—a plan of action produced at the 1992 UN Conference on Environment and Development to address human impacts on the environment. Meaningful, active involvement of these nine Major Groups is a key goal of all UN sustainable development initiatives. The Major Groups reflect the key categories of stakeholders that engage in, and are affected by, IEL processes: (1) NGOs, (2) business and industry, (3) the scientific and technological community, (4) Indigenous Peoples and their communities, (5) local authorities, (6) workers and trade unions, (7) farmers, (8) women, and (9) children and youth. Many of these constituencies overlap—women, for instance, are an important constituency of the other eight groups. All are represented by organizations that participate at many levels of IEL. A few prominent examples, discussed below, show how these stakeholder groups have attained significant stature in IEL processes. Today, these nonstate actors contribute at virtually every stage of efforts to develop multilateral IEL, from influencing national positions and public sentiment, to administering quasi-regulatory standards for implementation.

NGOs have been particularly active in multilateral forums. For instance, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), one of the earliest multilateral treaties focused on conservation and sustainable use, arose from a process initiated by the International Union for Conservation of Nature (IUCN), an organization whose members are both governments and NGOs. IUCN adopted a resolution in 1963 calling for a treaty to protect endangered species, kicking off negotiations among 80 states, leading eventually to adoption of the final CITES text in 1973. CITES now has 184 states parties, making it one of the world’s most widely ratified IEL treaties. NGOs continue to play a prominent role in its administration and progress today.

The scientific and technological community supplies empirical data by which decision-makers understand problems, and it applies its findings in practical ways that clarify the range of possible solutions. How scientists frame and explain policy challenges has catalyzed a great deal of IEL discourse. This community also enjoys a fairly direct line to state policy makers, both through government employment of experts and through institutions like the Intergovernmental Panel on Climate Change (IPCC).

The role of business and industry has also increased as companies participate not just in implementing programs like international carbon markets, but also in shaping the policies that will affect their own activities and interests. Take COP21 in 2015, the UNFCCC conference that produced the Paris Agreement. COP21 was among the most important events in the history of modern IEL. Thousands of private actors participated on the sidelines, including “[o]ne third of the 2,000 biggest global companies [that] committed to climate action with a market value equivalent to the combined [gross domestic product] of China, Germany, and Japan.” Press Release, UN Climate, Massive Mobilization by Non-State Stakeholders Summarized at COP21 (Dec. 9, 2015). Many large, influential enterprises have come to see COPs as unmissable opportunities to influence policy, gather intelligence, make connections, and showcase their own achievements.

Raising the Stakeholders

But what are the practical implications of this sort of engagement? Is participation by NGOs and businesses anything more than public relations or greenwashing? Decidedly so. The roles nonstate stakeholders can play in the elaboration of IEL are as varied as the stakeholders themselves.

Is participation by NGOs and businesses anything more than public relations or greenwashing?

Specialized NGOs and industry organizations have become fixtures of multilateral negotiations. These organizations may advocate from the sidelines to get or keep certain issues on the negotiating agenda. Charlotte Streck, Filling in for Governments? The Role of the Private Actors in the International Climate Regime, 17 J. for European Env’t & Plan. L. 5, 11 (2020). This holds both states and private-sector actors accountable by pressuring relevant government officials and representatives to take affirmative steps to develop climate policy and enforce it where necessary. See id. at 24–27.

NGOs also contribute their expertise in multilateral work concerning specialized subject matters—at least, that is, if states have agreed for them to serve in such roles. For instance, the Climate Technology Centre and Network (CTCN) of the UNFCCC “promotes the accelerated transfer of environmentally sound technologies for low carbon and climate resilient development at the request of developing countries.” Climate Technology Centre and Network, UN Climate Tech. Centre & Network (2022). The CTCN, which is the implementation arm of the UNFCCC’s technology mechanism, is accountable to the parties (states) via an Advisory Board (AB). As conceived, the CTCN AB consisted of various representatives of states and other UNFCCC bodies, but also one representative from each of three NGO constituencies—namely environmentalists, business and industry interests, and researchers. Work of Adaptation Comm., Decision 11/CP.18, Report of the Conference of the Parties to the UNFCCC, FCCC/CP/2012/8/Add.2 (2012). As of COP26 in Glasgow, that number increased from three NGO representatives to six, with seats now also reserved for youth, Indigenous peoples, and women and gender NGO constituencies. (In the interest of disclosure, two of the authors worked in support of one of the national delegations in helping to achieve this reform of the CTCN AB.)

The rise of sustainability initiatives and ESG reporting in the private sector have also created new opportunities for nonstate actors to engage in norm creation.

The CTCN also illustrates another way the private sector is engaged in multilateral IEL. Specifically, it “provides technology solutions, capacity building and advice on policy, legal, and regulatory frameworks tailored to the needs of individual countries by harnessing the expertise of a global network of technology companies and institutions.” Climate Technology Centre and Network, supra (emphasis added). This is only one example of how nonstate actors help to implement IEL initiatives. Such actors can also be found financing and developing technological innovations, studying and analyzing the effects and effectiveness of climate policy, and issuing findings that hold governments accountable to their IEL commitments and obligations.

Indeed, nonstate stakeholder engagement is now considered the norm. Many treaty bodies provide specific avenues for NGOs to participate. For instance, private actors participate in UN Environment Programme (UNEP) processes by providing scientific and technical expertise to assist UNEP’s monitoring and reporting functions that form the basis of policy making, participating in UNEA policy dialogues, and implementing and assessing policies and programs. Again, multilateral climate action provides a key illustration. Under the UNFCCC, whose membership includes all UN member states, parties must encourage the widest possible cooperation in the effort to address the climate crisis, including from NGOs; seek support and information from nongovernmental bodies; and admit competent organizations to be represented at climate COPs as observers. UN Framework Convention on Climate Change, arts. 4(1)(i), 7(2)(l), 7(6), opened for signature June 4, 1992, 1771 U.N.T.S. 107. Further, the UNFCCC Subsidiary Body for Scientific and Technological Advice (SBSTA) maintains direct communication with the scientific community represented by the IPCC, and it considers presentations from other observer stakeholders. The Kyoto Protocol further elaborated the role of private parties in UNFCCC processes, including by enabling their participation in international carbon markets; and the Paris Agreement calls for enhanced private sector participation in implementing national emissions targets.

The rise of sustainability initiatives and ESG reporting in the private sector have also created new opportunities for nonstate actors to engage in norm creation. NGOs and industry groups have taken the lead in setting soft law standards that support IEL frameworks and goals. These include general environmental social and governance (ESG) standards, such as those of the Sustainability Accounting Standards Board and the Global Reporting Initiative, but also others focused specifically on issues like climate risks, water conservation, deforestation, and biodiversity loss. Companies turn to these standards for clarity on ESG issues deemed material to investors and other stakeholders. Although these “soft norms” are not truly IEL, policymakers at the national, regional, and multilateral levels look to their execution for clues about how best to regulate corporate sustainability and ESG.

NGOs are also helping companies achieve their climate targets and other sustainability goals by filling hybrid roles within IEL frameworks. For instance, NGOs develop and manage various projects to produce high-quality carbon offsets to help companies meet their net-zero goals. See Nature Conservancy, Carbon Offsets, Illustrated (May 17, 2021). Similarly, NGOs are doing the work of validating and verifying projects that produce these offsets, including for projects under the Kyoto Protocol, under the UN’s REDD+ program, and soon under the Paris Agreement. This network of continuous interactions and exchanges of information connecting NGOs, the private sector, and IEL processes is thickening the IEL “ecosystem” and blurring the lines between the “subjects” and “objects” of IEL.

Turning the Page

Nonstate actors have gained considerable influence and become more important partners to states across most (if not all) areas of international law since the late 20th century. This has been particularly true in the case of IEL, where NGOs, multinational corporations, industry lobbies, and independent standards setters have become enmeshed in solving some of the world’s most pressing ecological challenges. This shift has spawned new niches of emergent norms and law, such as the intersection of environmental law and human rights law.

These changes in the international legal landscape have led some commentators to argue that the role of states in international legal affairs—even the integrity of state sovereignty itself—is diminishing. From this perspective, the rise of multilateral institutions and the steady increase of influence from civil society and multinational businesses presage a post-state international order. Others argue that private actors’ participation in processes historically dominated by states remains essentially peripheral, leaving the state-centricity of IEL largely undisturbed. Indeed, proponents of that view see such participation not as a symptom of the state’s recession from preeminence but instead as a feature of an order fully in sovereignty’s orbit.

We take no side in this debate (although we confess skepticism of deterministic claims either way). What is clear, however, is that the trend toward nonstate actors’ engaging in the processes of developing and refining IEL is, at least for the moment, not only continuing but growing. And with the importance of the private sector and civil society to achieving Sustainable Development Goal (SDG) 17 (“partnerships for the goals”), states have baked that expectation into the most consequential multilateral agendas of the modern era—at least until 2030, when the SDGs are intended to be achieved. Thus, although we can never predict whether a trend will continue, all indications are that states themselves are expecting more, not less, of a role for nonstate actors in a widening world of international environmental law.